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Y G O BIOL O GY L O E G D N A g . Domín A , e t n e S. Clem A. B. Ruiz

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Building

Blocks

SECONDARY EDUCATION

Biology and Geology S. C l e m e n t e , A . D o m ín g u e z , A . B . R u iz

USE THIS CODE TO: access the

RESOURCE BANK available at www.anayaeducacion.es Follow the steps that appear in the section «About the Resource Bank».

this is

your book

ch unit

f ea The opening pages o

Reading We read about the contributions of women in the development of the sciences, and discover some of the difficulties they had to overcome.

We speak about the different issues that will be learnt about throughout the unit.

Speaking quality most important curiosity is the a young age For Ada Yonath, 2 says that from a scientist. She her. necessary to be ng she saw around to explain everythi she was curious a scientist to Discuss with a partner: nt qualities for importa most a) What are the

The Organisation of the human BODY

have? ? any of these qualities other b) Do you have those needed in different from c) Are these qualities subject areas? and encouraged qualities be inspired would you change d) How can these education? What within scientific within science classes?

s by nature

Ada Yonath. Curiou

I And believe me, , you must be curious. years old, I tried To be a scientist was five curious! When I arm! have always been nt and broke my of our apartme to find out the height m, Israel born in Jerusale Yonath and I was so I had to work My name is Ada money, much never had I babysat, in 1939. My family private classes, to study: I gave me a lot to be able hard, but it gave ry lab... It was I cleaned the chemist in secret, so I can’t to learn and research the opportunity . I complain. er was amazing as a research le: impossib Starting my career seemed that in something they was interested like and how ribosomes looked DNA discovering what for decoding the es are responsible proteins. But worked. Ribosom build to them and using know. instructions in cells structure? We didn’t their was what exactly crystals involves creating technique that that I specialise in a The problem was them using x-rays. We and observing extremely easily. we made broke the ribosome crystals one day, we found ng crystals until, that we spent years destroyi strong enough ribosome crystals a way to make e in detail. structur their ry, could observe Prize in Chemist me the 2009 Nobel won y much discover matter This While prizes don’t be used among other awards. discovery can proud that my to me, I’m really and develop new ribosomes of bacteria s. to attack the against infection winning the fight antibiotics to keep so work about having to Ada complain 1 a) Why won’t was younger? hard when she es do? b) What do Ribosom ribosome crystals difficult to observe c) Why was it using x-rays?

The audios of each unit’s content are available at www.anayaeducacion.es

Speaking

I think the most important quality of a scientist is to be patient.

We could encourage patience by doing morea experiments that last longer amount of time.

Writing An interview ture y of how to manufac Yonath’s discover other inventions 3 Similar to Ada there are many

e crystals, stronger ribosom nding of the human improve our understa and write that have helped n or technique medical inventio (s). body. Choose any with their inventor an imaginary interview Include: to solve they were trying it took ➜ What problem n and how long ed their inventio ➜ How they develop them to discover ➜ What it allowed the process How they felt about

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LANG

Writing We write a variety of different styles and types of text about a subject matter in the unit. By practising different styles of writing, we will improve the writing skills we need to do well in our studies. Focus on English Do you think Biology and Geology and English have anything in common? Discover how language, biology and geology are linked so you can learn them together.

CONTENT DEVELOPMENT 2.3 The cytoplasm The cytoplasm is the part of the cell between the plasma membrane and the nuclear membrane.

The cytoplasm is formed from a thick, aqueous liquid called cytosol. Cytosol contains different substances and cell organelles. Cytosol is composed of 70-80 % water and 30-20 % other substances that are dissolved or suspended* within it. These substances include proteins, carbohydrates, lipids, nucleic acids, mineral salts and ions. It is where many of the cell’s vital chemical reactions take place.

2.4 Cell organelles

F ocus on English The phrase to be suspended in something is a technical phrase meaning that something floats within liquid or air without moving. A similar meaning for to suspend is something that is attached to a high place so that it hangs down. Alternatively to suspend can also be used to mean to stop someone from going to school or work for a short time, especially if they have broken the rules.

5.3 The internal environment One characteristic of multicellular organisms, like human beings, is that most of their cells are not in direct contact with the external environment. This means that they cannot exchange substances (gases, nutrients, waste, etc.) with it, as unicellular organisms do. To solve this problem, they have developed an internal environment.

The internal environment is the fluid that bathes all the organism’s cells. It is connected to the external environment by the blood. Cells take the nutrients and oxygen they need from the internal environment, and discharge the waste they produce into it.

Cell organelles are structures that are immersed in the cytoplasm and perform specific functions, like organs.

Non-membranous organelles

Homeostasis is all the physiological processes that keep the internal environment stable. The organism achieves this balance thanks to its different organs and systems. This process of regulation prevents changes in the internal environment that would be fatal for cells.

ORGANISM

Blood

Ribosomes are small particles that synthesise proteins. They can either be attached to the endoplasmic reticulum or scattered around the cytoplasm.

the

The What If What would happen to our bodies if the internal environment didn’t exist? Learn how to apply this thinker’s key at anayaeducacion.es.

Technology

REATE The human body and its systems often offer inspiration to robotics designers. Use one of the systems of the human body as inspiration to design a plan for a sensor system.

CO2

Oxygen (O2)

Carbon dioxide (CO2)

Working with pictures

Waste Urine and sweat

Look at the diagram showing how the internal environment works. Based on this diagram, write a description of how food, oxygen, carbon dioxide and waste are exchanged between the internal environment and the external environment.

The icons included with some activities indicate the keys to the project.

cells

Waste The cytoskeleton is a network of fibres that holds the organelles in place and gives the cell its shape. It also plays a part in cell movements (it forms cilia and flagella).

for

b) It provides thermal insulation.

Tissue cells

Internal environment

Look at the photo of the cell. What cell structure is coloured green? Describe what you can see in the photo.

a) It acts as a vehicle substance exchange.

Food

Nutrients

Working with pictures

does the internal environment perform?

c) It protects surrounds.

External environment

Centrioles are two fibre-based cylinders that direct the movement of the cytoskeleton and the chromosomes during cell division.

Understand, think, search... 1 Which of the following functions

Homeostasis

There are two types of organelles: non-membranous organelles and membranous organelles.

Working with pictures Develop your abilities to observe and interpret pictures.

Create

Unit 1

2 THE HUMAN CELL

Understand, think, search...

In this section we create a crosscurricular project that joins Biology and Geology with other subjects. Have you ever thought that Biology and Geology could be joined with visual arts to improve your creative skills? Visual aids to support your understanding of the contents.

Activities that expand on the contents and inspire curiosity about scientific investigation.

KEY

PROJECT

SDG

SDG Commitment Discover the Sustainable Development Goals and be an active part of our commitment to make a more equal and liveable world.

Developing thinking Work on strategies for thinking: reflect on the content you are learning, generate ideas, organise them, debate them, explain them…

Cooperative learning Get involved in your learning and participate in the group’s learning; you will find that cooperating improves performance and harmony in the class.

Emotional education Get to know yourself; identify the situations that bring up complicated emotions and manage them with constructive, self-affirming experiences.

Research Project This book contains three research projects.

glossary We learn the relevant terms within the unit with a clear definition.

They are divided into steps that you will find at the end of each unit.

Unit 1

Unit 6

ect

research proj

Glossary

INVESTIGATING The HUMAN SENSES Remember: in this science project you are studying the sense organs. Analyse and interpret your experimental data, draw conclusions from your research and report the results to your classmates.

recaP

s Reporting the result of scientific experiments is important for scientific and technological progress.

information needed to understand your science project. Don’t forget to include the project objectives in the introduction.

• Title • Authors • Abstract (sometimes in multiple

Analysing experimental data

Organise your results in tables to present them more clearly and make them easier to understand. Draw conclusions from your research:

14%

➜ Put together some statistics about eye dominance in the people 41% 42%

➜ State your working hypotheses and support them with the necessary information. Show the results of your experiments in tables, graphs and so on.

languages) • Introduction • Materials and methods • Results • Discussion of the results • Conclusions • Bibliography

Analysing experimental data and reporting conclusions

studied. You could calculate the percentage of people whose dominant eye is the left eye, whose dominant eye is the right eye, and in whom neither eye is dominant. Pie charts are very useful for representing percentages clearly. Based on your results, conclude whether or not eye dominance is related to a person’s age and/or sex.

whether they support your hypotheses.

➜ You could use the article you have written to present your research project to your classmates. You could do this in the form of a discussion: read the articles that the class has written on each sense and then discuss the results overall.

M Micrometre or micron Unit of length equal to one millionth of a metre.

Centrioles Non-membranous cell organelles made up of protein fibres that direct the cytoskeleton during cell division.

with the sense of smell, and whether they are perceived when the tongue is completely dry. hypotheses.

Nucleoplasm Part of the cell nucleus made up of a watery liquid containing the genetic material.

O Organ Group of different tissues performing a specific function.

P Plasma membrane Layer that surrounds the cell, protects it and regulates substance exchange with the surrounding environment. It is made up of lipids, carbohydrates and proteins. Polymers Biomolecules formed of long chains of monomers. Proteins Complex biomolecules that form part of cell structures and have various functions like regulating and executing most cell processes.

Proteins

R Ribosomes Non-membranous cell organelles responsible for synthesising proteins.

S System Group of organs performing a shared function.

Nucleic acids

Homeostasis All the processes that keep the composition and properties of an organism’s internal environment stable.

Chromatin Network of all the DNA fibres and proteins found in the cell nucleus.

➜ Check whether the conclusions of your research support your

N Nucleic acids Large biomolecules that contain genetic information, which they transmit to offspring, and that control cell functions. DNA and RNA are nucleic acids.

Golgi apparatus Membranous organelle consisting of a network of flattened sacs that modify the substances synthesised in the ER in order to transport and secrete them.

Cell organelles Small structures in a cell that are specialised to perform different functions.

sound frequencies they can detect. You could draw a bar chart to represent these results.

➜ Based on your results, argue whether tastes are also perceived

Monomers Simple or small molecules that form the basic unit of other, larger molecules known as polymers.

Genetic material A fibrous substance called DNA that controls cell function.

Cell nucleus Cell structure surrounded by a membrane and containing the genetic material.

Nucleolus Part of the cell nucleus where ribosomes are made.

Mitochondrion Cell organelle surrounded by a double membrane whose function is to obtain energy for the cell through cellular respiration.

172

Lipids

Lysosomes Membranous cell organelles responsible for digesting particles.

Eukaryotic cell A type of cell in which the genetic material is contained in a nucleus surrounded by a membrane, and which consists of many different organelles.

Carbohydrates

➜ Present the conclusions of the research and state

➜ Link the age of those studied to their hearing ability and the Blind person Right eye Left eye No dominant eye

Carbohydrates Biomolecules whose main function is to provide energy to cells.

experiment. Your description must be detailed enough that other people could repeat the research in the same conditions.

Lipids Biomolecules that perform various functions like energy storage (triglycerides) and heat insulation. Some lipids form part of the plasma membrane of cells (phospholipids and cholesterol).

➜ Explain the methods you have used in each

Levels of organisation The levels of complexity into which living matter is organised.

Cytoskeleton Network of fibres that gives the cell its shape and enables it to move.

Biomolecules Molecules found exclusively in living beings and containing a high level of carbon.

➜ Start with a brief introduction containing the

Cytoplasm Thick aqueous liquid (cytosol) that fills the inside of the cell and contains the cell organelles.

➜ Write a report in the format of a scientific article in which you explain and share the results of your research. This is one of the most common ways for scientists to report their discoveries, as there are many international specialised scientific journals.

Internal environment Fluid that surrounds all the cells and is connected to the external environment by the blood.

Chromosomes Compact structures made of chromatin fibres that are visible under a microscope when the cell is about to divide.

Atoms The smallest particles into which matter can be divided while retaining its chemical properties.

Reporting the results

Parts of a scientific article

STEP 3

T Tissue Group of similar, coordinated cells that are specialised to perform the same function.

173

REVIEW AND PRACTISE Applying your knowledge to choose Remember o. your portfoli

this resources from

Unit 1

Applying your knowledge

Organising your ideas

Interpreting pictures

3 Copy this drawing and label the cell structures that

Visual aids of the content

Chain of sequences. In your notebook, copy and complete the following chain of sequences about the levels of organisation in living matter. Find out how to use this graphic organiser at anayaeducacion.es.

The systems are The organs are The tissues are

? ? ?

correspond to the letters. What is the function of each structure?

They are joined by chemical bonds.

G ?

such as such as such as

Molecular level Molecules are ? such as ? Biomolecules are ?

? ? ?

They group together to perform the three vital functions.

D E

4 Look at the following pictures of tissues and cells and answer the questions: A

Cellular level Cells are ? Human cells are ? such as ?

b) The plasma membrane is formed of a double layer of proteins. c) Medium-sized substances cross the cell membrane freely and without any help. d) Small substances enter the cell by endocytosis.

a) What type of microscope has been used to take these pictures of red blood cells? b) If the diameter of a red blood cell is approximately 5 μm, how much magnification does each microscope provide?

c) The nucleolus and nucleoplasm?

9 List the names of the cell organelles in a table.

and molecular levels of organisation? Include definitions of bioelement and biomolecule.

• Give a definition of cell. What higher levels are cells organised into?

• What is the cell membrane composed of? What are its functions?

• List the parts of a cell nucleus and explain their

Add another column to describe the shape of each organelle, accompanied by a drawing, and another column for its function.

functions.

a) What types of tissues and cells are shown? b) Link each cell to the tissue it forms part of. c) What is the function of each type of tissue? d) What characteristics of each cell type make them suitable for the function they perform in the human body?

5 What cell structure can you see in the following image? What is it composed of? What level of organisation of living matter does it correspond to?

10 Copy the following sentences and say which tissue they refer to: a) Its matrix is liquid and is called plasma.

the non-membranous organelles. What is the difference between them? What is the main function of each one?

Sustainable Development Goals 14 Sustainable Development Goal 3 aims to ensure

d) It has a protective function in that it lines cavities.

g) Its cells are elongated and it is responsible for body movement.

• Name the different types of human tissue. What

h) Its matrix is solid and contains calcium salts.

are the main characteristics of each type?

11 Why is cell differentiation important? Provide two

• Name the different systems in the human body

examples.

and the function they are involved in. anayaeducacion.es Go to the Science Workshops ‘Observing mucosa cells’ and ‘Studying how transport occurs through the membrane’ in your resource bank.

Many of the body’s cells have names related to the organ they belong to. Search for a picture of each of the following cells and indicate which organ they belong to: hepatocyte, osteocyte, myocyte, chondrocyte.

c) Its matrix is solid and elastic. We find it between the vertebrae and in the ear.

f) Its cells transmit nerve impulses.

• Explain what cell differentiation is.

b) It forms glands, which secrete substances.

e) It contains low levels of intercellular substance and its cells store fat.

• Write a list of the membranous organelles and

Trust in your skills and knowledge, develop creativity, adapt to changing situations and have a proactive and responsible attitude.

a) The cell membrane isolates the cytoplasm from the outside.

b) Chromatin and chromosomes? C

• What is the difference between the atomic

Enterprising culture

Invented in the 16th century, the microscope is a key tool for studying cells. As more and more powerful microscopes were developed, scientists were able to make discoveries about cellular structure. The ‘power’ of a microscope is its resolution; that is, the smallest distance by which two points can be seperated and still seen as separate points. Optical microscopes use visible light, which passes through the sample and provides an image that is magnified by a set of lenses. Their resolution is 0.2 μm. Electron microscopes don’t use light, but rather a beam of electrons. These either pass through the sample or bounce off it and are then captured by a screen, where the image appears. Their resolution is 5 μm.

about the cell membrane:

a) The nucleus and the nucleolus?

below:

12 Read the following text and answer the questions:

8 What is the difference between:

2 Write your own unit summary based on the outline

Questions about the essential parts of the unit so that you can write your own summary.

Moving forward

the following correspond to: calcium; kidney; nucleus; group made up of the mouth, oesophagus, stomach, intestine, pancreas, etc.; spermatozoa; protein.

e) The plasma membrane is not present in all cells. B

They group together to form organelles such as ?

Summarising

6 State what level of organisation in the human body

7 Copy and correct the following incorrect sentences

Atomic level Atoms are ? such as ? Bioelements are ? Organism level The human body is

Pictures to practice analysing images.

unit for

TISE

review and PRAC

anayaeducacion.es Go to ‘Key concepts’ and ‘Learn by playing’ in your resource bank.

healthy lives and promote well-being for all. The UN has set numerous targets for this goal. a) In groups, find out about the targets of Goal 3 at anayaeducacion.es. Choose the target that most interests your group, and research it. b)

Prepare a presentation to give to your class about the importance of your group’s chosen target and what could be done to achieve it.

c) Discuss and draw conclusions about the importance of education and research in achieving this goal. 45

SDG. Reflect and suggest actions that could help achieve the goal mentioned in each unit.

Academic and professional

ICT

orientation

Evaluation

Linguistic Plan

Learn how to obtain information, select it and apply it; to plan, manage and work on projects; and to collaborate online in an ethical and safe manner.

Evaluate your personal skills, discover and awaken your calling, train yourself to make decisions and learn to choose between different options.

Discover different strategies to analyse what you have learnt and how you learnt it; train yourself to take responsibility or overcome difficulties.

Use your communication skills in the different types of text that you will see. Language is always present, communicate!

The resource bank is LIKE THIS www.anayaeducacion.es A space with resources, techniques and activities, designed to strengthen your knowledge. Access the resource bank by registering at anayaeducacion.es. You just need to have an email, the code indicated on the first page of this book and the permission of a parent or a legal guardian. More about the keys

Resources related to

THE keys of the project SDG

SDG Commitment, with microvideos that will help you know what are the targets for reaching the Sustainable Development Goals worked on in this project.

Linguistic Plan, with infographics that will give you models to work with the four linguistic skills using different types of texts (descriptive, narrative, explanatory, etc.).

Developing thinking, where explanations are included on how to apply the different strategies for thinking proposed in the project.

Cooperative learning, which includes the description of the cooperative learning techniques proposed in the project. Emotional education, with resources to support you with overcoming worries in different situations in your learning process (beginning of the school year, taking a test, etc.).

ICT, by using data sheets that will reinforce your healthy, correct and safe use of information and communication technologies.

Academic and professional orientation, with information on different professions linked to the subject content.

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Evaluation, which includes resources for your portfolio, as well as rubrics and targets that will facilitate your self-evaluation.

NOTEWORTHY

resources in the material Language Bank Scientific readings Sicence workshop Key concepts Learn by playing Videos

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Resources classified

by unit

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All the resources are classified so that you can easily locate the ones related with each section of your unit.

Course Contents

THE SCIENTIFIC METHOD 1. The scientific method ........................................................ 2. Research in the laboratory ............................................... 3. Research in a natural environment ............................... 4. Finding information ............................................................ Review and practise ............................................................... Glossary .......................................................................................

SYSTEMS OF THE NUTRITION FUNCTION

1. The digestive system .......................................................... 2. Digestion ................................................................................. 3. The respiratory system ...................................................... 4. The circulatory system ...................................................... 5. Blood flow ............................................................................... 6. The lymphatic system ........................................................ 7. The excretory system.......................................................... 8. Health and the nutrition function .................................. Research project STEP Investigating healthy habits for the heart ....................... Review and practise ............................................................... Glossary .......................................................................................

ORGANISATION OF THE HUMAN BEING

Page 24

1. Levels of organisation ........................................................ 26 2. The human cell ...................................................................... 28 3. Cell differentiation ............................................................... 32 4. Human tissues ....................................................................... 33 5. Organs and systems ........................................................... 36 Research project STEP Investigating healthy habits for the heart ....................... 38 Review and practise ............................................................... 40 Glossary ....................................................................................... 42

THE INTERACTION FUNCTION

1. Interaction in humans ...................................................... 2. Perception: the senses .................................................... 3. The sense organs and health ........................................ 4. Nervous coordination ...................................................... 5. The health of the nervous system ............................... 6. Endocrine coordination .................................................. 7. The health of the endocrine system ........................... 8. Drugs and drug addiction .............................................. 9. Executing responses: the locomotor system .......... 10. Health and the execution response ............................ Research project STEP Investigating the human senses ......................................... Review and practise ............................................................. Glossary .......................................................................................

NUTRITION AND FOOD

1. Nutrition and humans ........................................................ 2. Nutrients ................................................................................. 3. Energy input .......................................................................... 4. Food .......................................................................................... 5. Dietary recommendations ................................................ 6. Food and sustainability ..................................................... 7. Diet and health ..................................................................... Research project STEP Investigating healthy habits for the heart ....................... Review and practise ............................................................... Glossary .............................................................................................

SYSTEMS OF THE REPRODUCTION FUNCTION

1. Human reproduction ........................................................ 2. The reproductive systems .............................................. 3. The human gametes ......................................................... 4. The ovarian and uterine cycle ...................................... 5. Fertilisation, pregnancy and birth ............................... 6. Health and reproductive planning .............................. Research project STEP Investigating the human senses ......................................... Review and practise .............................................................. Glossary .......................................................................................

HEALTHY LIFESTYLE

1. Health and illness ................................................................ 2. Types of illnesses ................................................................ 3. Transmission of infectious illnesses ............................. 4. The immune system ........................................................... 5. Preventing and curing illnesses ..................................... 6. Transplants and donation ................................................ 7. First aid ...................................................................................

Research project STEP Investigating human senses ................................................. Review and practise ............................................................... Glossary .......................................................................................

LANDFORM MODELLING

1. Landform modelling .......................................................... 2. Exogenous geological processes ................................. 3. Water currents and torrents as modelling agents ........................................................... 4. Rivers as modelling agents ............................................. 5. Groundwater as a modelling agent ............................. 6. Glaciers as a modelling agent ........................................ 7. Wind as a modelling agent ............................................. 8. The sea as a modelling agent ........................................ 9. Living things model the Earth’s relief ......................... STEPs 2 Research project Studying soil erosion ..............................................................

Review and practise .............................................................. Glossary .......................................................................................

DYNAMIC EARTH

1. The Earth’s surface and its dynamics ......................... 2. The Earth’s internal energy and endogenous processes ............................................ 3. Magmatism and volcanoes ............................................. 4. Tectonic forces ..................................................................... 5. Geological risks ................................................................... Research project STEP 1 Studying soil erosion .............................................................. Review and practise .............................................................. Glossary .......................................................................................

Organisation of the human being Ada Yonath. Curious by nature To be a scientist, you must be curious. And believe me, I have always been curious! When I was five years old, I tried to find out the height of our apartment and broke my arm! My name is Ada Yonath and I was born in Jerusalem, Israel in 1939. My family never had much money, so I had to work a lot to be able to study: I gave private classes, I babysat, I cleaned the chemistry lab... It was hard, but it gave me the opportunity to learn and research in secret, so I can’t complain. Starting my career as a researcher was amazing. I was interested in something that seemed impossible: discovering what ribosomes looked like and how they worked. Ribosomes are responsible for decoding the DNA instructions in cells and using them to build proteins. But what exactly was their structure? We didn’t know. I specialise in a technique that involves creating crystals and observing them using X-rays. The problem was that the ribosome crystals we made broke extremely easily. We spent years destroying crystals until, one day, we found a way to make ribosome crystals strong enough that we could observe their structure in detail. This discovery won me the 2008 Nobel Prize in Chemistry, among other awards. While prizes don’t matter much to me, I’m really proud that my discovery can be used to attack the ribosomes of bacteria and develop new antibiotics to keep winning the fight against infections.

1 a) Why won’t Ada complain about having to work so hard when she was younger? b) What do Ribosomes do? c) Why was it difficult to observe ribosome crystals using x-rays?

Speaking

For Ada Yonath, curiosity is the most important quality for being a scientist. She says that from a young age she was curious to explain everything she saw around her. Discuss with a partner a) What qualities do you consider to be most important for a scientist? b) Do you have any of these qualities? c) Are these qualities different from other subjects? d) How can these qualities be inspired and encouraged within scientific education? What would you change within science classes?

I think the most important quality of a scientist is to be patient.

We could encourage patience by doing more experiments that last a longer amount of time.

Writing An interview

3 Similar to Ada Yonath’s discovery of how to manufacture stronger ribosome crystals, there are many other inventions that have helped improve our understanding of the human body. Choose any medical invention or technique and write an interview with their inventor(s). Include: ➜ What problem they were trying to solve ➜ How they developed their invention and how long it took ➜ What it allowed them to discover ➜ How they felt about the process

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1 LEVELS OF ORGANISATION Biomolecules make up living beings Carbohydrates Carbohydrates are the cell’s main source of energy. They form part of some cell structures and are used to build other biomolecules. They can be complex, like cellulose, which forms the walls of plant cells, or simple, like glucose.

Lipids Lipids are very chemically diverse. Some, like phospholipids and cholesterol, form part of cell membranes. Others, like triglycerides, provide and store energy for cells.

Like other living beings, human beings are made up of cells that group together to form more complex structures, such as tissues and organs.

Levels of organisation are the different degrees of complexity into which living matter is structured. The elements in each level join together to form other more complex levels. Each new level has new characteristics and properties, which go beyond the sum of the elements in the previous level.

1.1 Atomic level Atoms are the smallest units of matter that have the properties of a chemical element. Hydrogen (H), oxygen (O) and calcium (Ca) are all atoms. Atoms that form part of living matter are called bioelements.

1.2 Molecular level Proteins Proteins form part of cell structures and regulate and carry out most cell processes. For example, the haemoglobin in red blood cells transports oxygen in the blood, and membrane proteins regulate substance exchange in and out of cells.

Nucleic acids Nucleic acids contain genetic information, which they transmit to offspring, and control cell functions. DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are nucleic acids.

Molecules are groups of atoms held together by chemical bonds. Water (H2O), oxygen (O2) and calcium carbonate (CaCO3) are all molecules. Molecules that make up living beings are called biomolecules and contain a high level of carbon. Biomolecules group together to carry out a function within a cell. They form organelles such as ribosomes and mitochondria. Biomolecules are often polymers, chains formed when molecules of the same type, called monomers, bond together. Carbohydrates or sugars, lipids, proteins and nucleic acids (like deoxyribonucleic acid or DNA) are polymers. Other substances like water and mineral salts have a simple chemical structure. They are found in both living and non-living matter.

Understand, think, search... 1 Give definitions of bioelement, biomolecule and chemical bond.

2 What is a polymer? Give some examples of biomolecules that are polymers.

3 Which of the following compounds are only found in living matter? Phospholipids Glucose Iron Sodium chloride

Potassium

Water

DNA Cellulose

anayaeducacion.es Go to ‘The composition of living matter’ in your resource bank.

Unit 1

1.3 Cellular level Cells are the structural and functional units of all living beings. That is, they are the smallest part capable of carrying out the three vital functions. All human cells are eukaryotic* animal cells, although they are specialised into more than 200 different types. Some examples are neurons, red blood cells, adipocytes, ova and sperm.

The word ocu s on Eng lish karyotic comes from a Greek Word meaning kernel or nucleus. The prefix eu- means true, while the prefix pro- means before. What do the words prokaryotic or eukaryotic mean? Which cell is more primitive?

Working with pictures

1.4 Organism level Tissues are groups of similar cells that specialise in the same function, and are sometimes found along with other substances. Some examples are nervous tissue, muscle tissue and epithelial tissue. Tissues group together to form organs, such as the heart, lungs and kidneys, which carry out specific functions. In turn, organs group together in systems to perform a coordinated function. Some examples are the respiratory system, excretory system and the nervous system. Finally, the human body is made up of the combination of organs and systems, which coordinate to carry out the three vital functions.

What level of organisation in the human body do the following parts or groupings belong to? a) Ovum b) Heart c) Group made up of the mouth, oesophagus, stomach, intestine, pancreas, etc. d) Protein e) Nucleus f) Carbon

Atoms bond to form

Carbohydrates

Biomolecules and other substances Lipids

which group together to form

Cells which group together to form

like Tissues

Proteins

which group together to form Nucleic acids

Organs

Water

Mineral salts

which group together to form

Systems

2 THE HUMAN CELL Structure of a eukaryotic animal cell

The human being is a multicellular organism. It is made up of cells which have very different shapes and sizes. Generally, human cells have three basic parts: the plasma membrane (or cell membrane), the nucleus and the cytoplasm.

Plasma membrane

Cytoplasm

2.1 The plasma membrane The cell membrane is a thin layer that surrounds the cell, protects it and regulates exchanges of substances with the surrounding environment.

Nucleus

The cell membrane is made up of lipids. These form a layer, embedded with proteins, around the cell. The functions of the membrane are to:

➜ Protect the cell and separate its contents from the outside environment.

➜ Detect changes in the environment and allow the cell to respond to these changes in an appropriate way.

➜ Regulate the exchange of substances with the environment. The transfer of substances across the cell membrane takes place in different ways and depends on the size of the substance. For example, small substances such as oxygen can cross the membrane on their own, medium-sized substances cross the membrane with the help of proteins, and large substances cannot cross the cell membrane. Instead, large substances reach the inner part of the cell by endocytosis. In this process the cell wall folds inwards to bring the substance into the cell.

Cell organelles

Cell membrane Carbohydrates

Understand, think, search... 1 Give a definition of cell.

rio

te Ex

2 What are the functions of the plasma membrane? 3

Proteins i

r te

Lipids

Although animal cells are usually shown as being round, the cells in our bodies have a variety of different shapes. Look for pictures of different types of cell in the human body and draw them in your notebook. Label the three structures they have in common: – the plasma membrane – the nucleus – the cytoplasm.

anayaeducacion.es Go to ‘Transport through the membrane’ in your resource bank.

Unit 1

2.2 The nucleus

The nucleus

The nucleus is a large spherical structure. It contains the genetic material (DNA) which organises the cell’s activity. The nucleus is made up of the following parts:

Nuclear membrane Nucleolus

Chromatin

➜ The nuclear membrane. It contains nuclear pores which allow substances to be exchanged between the nucleus and the cytoplasm.

➜ The nucleoplasm. It is made up of a thick, aqueous

Nuclear pores

liquid which contains the genetic material or DNA.

➜ The chromatin, which is the network of all the DNA fibres and proteins. When the cell divides the chromatin fibres roll up and become compacted, forming structures called chromosomes which are visible under a microscope.

➜ The nucleolus is a spherical structure inside the

Chromosomes (condensed chromatin)

nucleus where the component parts of ribosomes (a type of cell organelle) are made.

Understand, think, search... 4

anayaeducacion.es Not all cells are the same, and nor do they have the same cellular organisation. Remind yourself of the types of cellular organisation in living beings by going to ‘Prokaryotic and eukaryotic cells’ in your resource bank. What type of organisation do the following cells have? a) A protozoan

d) An insect

b) A fungus

e) A bacterium

c) An alga

f) A pine tree

c) The cell in the picture is round, so we can calculate its volume like we would for a sphere. What is its volume? What is the volume of its nucleus?

5 Draw a cell nucleus in your notebook, then label its parts and write what their functions are.

6 What two structural states can a nucleus be in? 7 As you already know, cells have a microscopic size. To measure them we use a unit called the micrometre or micron (μm). 1 = 0.001 mm = 0.000 001 m a) Use the bar scale to calculate the diameter of the cell in micrometres. b) Find the nucleus in this cell. What is its diameter?

anayaeducacion.es Go to ‘The size of a cell’ in your resource bank.

5 μm

2 THE HUMAN CELL

2.3 The cytoplasm The cytoplasm is the part of the cell between the plasma membrane and the nuclear membrane.

2.4 Cell organelles There are two types of organelles: non-membranous organelles and membranous organelles.

F ocu s on Eng lish The phrase to be suspended in something is a technical phrase meaning that something floats within liquid or air without moving. A similar meaning for to suspend is something that is attached to a high place so that it hangs down. Alternatively to suspend can also be used to mean someone who is stopped from going to school or work for a short time, especially if they have broken the rules.

Cell organelles are structures that are immersed in the cytoplasm and perform specific functions, like organs.

Non-membranous organelles

Centrioles are two fibre-based cylinders that direct the movement of the cytoskeleton and the chromosomes during cell division.

Working with pictures Look at the photo of the cell. What cell structure is coloured green? Describe what you can see in the photo.

Ribosomes are small particles that synthesise proteins. They can either be attached to the endoplasmic reticulum or scattered around the cytoplasm.

The cytoskeleton is a network of fibres that holds the organelles in place and gives the cell its shape. It also plays a part in cell movements (it forms cilia and flagella).

Unit 1

Membranous organelles Mitochondria are oval structures with a double membrane and numerous folds in their internal membrane. They obtain energy for the cell through cellular respiration.

Vesicles are small structures that transport or store substances.

The endoplasmic reticulum (ER) is a network of tubules and sacs that synthesise substances. The rough ER (RER), which has ribosomes attached to its walls, is involved in protein synthesis. The smooth ER (SER), which does not have ribosomes, is involved in the synthesis of lipids.

The Golgi apparatus is a network of flattened sacs that modify the substances that are synthesised in the ER and transport them outside the cell via vesicles.

Lysosomes are vesicles that contain digestive enzymes. They digest the particles captured by the cell.

Understand, think, search... 8

The parts add up. Each of the structures in a cell performs a specific function, and together they allow the cell to work optimally. Draw a table describing the following for each cell organelle: What is its function? What would happen if it didn’t exist? What is its relation to the other parts? To find out how to apply this skill, go to anayaeducacion.es.

9 Look closely at the micrographs on the right and answer the following questions:

0.5 μm

a) Do they show separate cells or the inside of a cell? Explain your answer. b) Use the bar scale (the red line) to calculate the size of organelle A. c) Draw a picture in your notebook showing what you think this organelle would look like in 3D. Calculate its volume.

anayaeducacion.es Go to ‘Observing cells’ in your resource bank.

3 CELL DIFFERENTIATION

Cell differentiation Differentiation is a combination of changes to the shape and structure of the cell which allow it to specialise in a specific function. All the cells in a multicellular organism, such as the human being, are created from one single cell called a zygote, which divides to form an embryo. At first all the cells in an embryo are the same, but later they take on* different shapes and specific functions. That is, they become specialised. This process is called cell differentiation. Therefore, although all human cells share basic characteristics (for example, they have the same genetic material), they don’t all have the same shape or have the same function.

F ocu s on Eng lish Take on is a phrasal verb which, in this text, has been used to mean to have a particular quality or appearance. However, to take something on can also mean to agree to do a new project or extra work. On the other hand, to take somebody on, could mean to employ someone. It can also mean to start a fight or compete with someone, especially if they are more powerful or stronger than you.

After differentiation has taken place in a multicellular organism, cells that look similar and that carry out the same function group together to form tissues. For example, neurons are star-shaped and have an extension filled with cytoplasm which allows the neuron to receive stimuli and to transmit electrical impulses. Neurons form nervous tissue.

Cell differentiation Stem cell

Understand, think, search... 1 In your own words, what is cell differentiation?

2 Are the following statements about cell differentiation true or false?

Glial cells

a) Cells in the human body differentiate because they have different genetic material. b) All the cells that make up the human body have the same genetic material.

Muscle fibers

Red blood cells Neurons

Unit 1

HUMAN TISSUES Understand, think, search... 1 Give a definition of tissue. 2 What tissue forms part of the sweat glands?

3 Look at the photo. What type of epithelial tissue can you see?

A tissue is a group of cells with a similar shape and structure and which specialise in carrying out the same function. Human tissues are classified into four basic types: epithelial, connective, muscle and nervous.

4.1 Epithelial tissue Epithelial tissue (or epithelium) is made up of one or more layers of cells that are very close to each other. Epithelial tissue lines the organs and acts as a protective barrier. There are two types of epithelial tissue:

➜ Covering and lining epithelium. This type of epithelial tissue serves a protective function, lining both the external and the internal surfaces of organs. For example, it lines internal cavities that communicate with the outside environment.

➜ Glandular epithelium. This type of epithelial tissue is formed of cells specialised to produce substances and secrete them onto the epithelial surface. These cells can be scattered around or grouped together as glands, like the sebaceous glands, for example.

Types of epithelial tissue Simple epithelia

Cuboidal cells

Squamous cells Stratified epithelia

Columnar cells Glandular epithelium Secreted substances

4 HUMAN TISSUES

4.2 Connective tissue Connective tissue consists of cells surrounded by fibres and an intercellular substance called the ‘matrix’.

Types of connective tissue Reticular connective tissue Fibres

Cells surrounded by lots of fibres Adipose tissue

Connective tissue supports and connects organs and other tissues in the body. There are various types:

➜ Reticular connective tissue. This tissue has an extensive gel-like matrix containing abundant fibres. It fills the space between organs, keeping them in place, and forms tendons.

➜ Adipose tissue. This tissue has a matrix containing low levels of intercellular substance. Its cells store fat as an energy reserve and for thermal insulation. It is found under the skin. Fat cells or adipocytes with low levels of intercellular substance

➜ Cartilaginous tissue. Cartilage has a solid and elastic matrix. It covers the joints to prevent wear. An example is ear cartilage.

➜ Osseous (bone) tissue. The matrix of this tissue is

Cartilaginous tissue

solid and hard, owing to the presence of calcium salts. It forms bones. Solid and elastic matrix

➜ Blood. Blood has a liquid matrix called plasma, which has blood cells suspended in it (red blood cells, white blood cells and platelets).

Chondrocytes Osseous tissue (Bone)

Understand, think, search... 4 What type of connective tissue can you see in each of the following pictures?

Bone cells or osteocytes surrounded by a solid matrix

Blood

Blood plasma White blood cells Red blood cells Platelets

Unit 1

4.3 Muscle tissue

Types of muscle tissue Skeletal striated muscle tissue

Muscle tissue is made up of elongated cells that group together to form muscle fibres and that are able to contract and relax. It is the tissue responsible for body movement. There are three types of muscle tissue:

➜ Skeletal striated muscle tissue. This tissue forms the

Multinucleated muscle fibre.

muscles of the locomotor system and can be moved voluntarily. The cells that make it up have several nuclei.

Cardiac striated muscle tissue

➜ Cardiac striated muscle tissue. This tissue forms the walls of the heart. It is similar to skeletal striated muscle tissue, but its cells only have one nucleus and it contracts involuntarily.

➜ Smooth muscle tissue. This tissue is found in the walls of various organs, like the stomach and the bladder. It contracts involuntarily. The cells that make it up only have one nucleus.

Muscle fibres that are similar to striated muscle, but with only one nucleus. Smooth muscle tissue

4.4 Nervous tissue Nervous tissue is the main component of all the structures in the nervous system. It consists of neurons, which are star-shaped cells that specialise in collecting and transmitting information, and glial cells, which are responsible for neuron nutrition, defence and support.

Muscle cells with only one nucleus.

Nervous tissue Neuron

Understand, think, search... 5

The mirror. Go to anayaeducacion.es to find out how to apply this thinker’s key, and draw a table comparing the different types of muscle tissue.

6 Compare the tissue shown below to the diagrams on these pages. What type of tissue is it? Why?

Glial cells anayaeducacion.es Go to ‘A dichotomous key for identifying tissues’ in your resource bank.

5 ORGANS AND SYSTEMS

As we have just seen, cells of the same kind are organised into tissues. In turn, different tissues are organised into more complex structures called organs, which form coordinated systems.

5.1 Organs Understand, think, search... 1

Puzzles. Form groups in your class and share out the topics to be researched. Each group will research a specific organ (brain, heart, stomach, small intestine, etc.) with a focus on the following: a) What is its function? b) What tissues is it made of? c) What type of cells make up these tissues?

The organs of the human body are made up of several tissues that work together to perform a specific function. For example, the heart pumps blood, the kidneys clean blood, and the lungs exchange gases.

5.2 Systems Systems are groups of organs that work together to perform a shared activity. When the different systems work as a whole, the organism is able to perform the three vital functions (nutrition, interaction and reproduction).

Systems and the vital functions

For nutrition For interaction Digestive

For reproduction

Respiratory Nervous

Skeletal Female

Circulatory Muscular

Excretory

Male

Lymphatic Endocrine

anayaeducacion.es Go to ‘Organs and systems of the human body’ in your resource bank.

Unit 1

Understand, think, search... 1 Which of the following functions does the internal environment perform? a) It acts as a vehicle substance exchange.

b) It provides thermal insulation. c) It protects surrounds.

Homeostasis Homeostasis is all the physiological processes that keep the internal environment stable. The organism achieves this balance thanks to its different organs and systems. This process of regulation prevents changes in the internal environment that would be fatal for cells. External environment

ORGANISM Nutrients

Blood

Nutrients

the

cells

The What If What would happen to our bodies if the internal environment didn’t exist? Learn how to apply this thinker’s key at anayaeducacion.es.

C RE AT E Human

Food

for

Technology

systems and robotic systems. The human body and its systems often offer inspiration to robotics designers. Use one of the systems of the human body as inspiration to design a sensor system.

O2 CO2

Oxygen (O2)

Tissue cells Carbon dioxide (CO2) Internal environment

Working with pictures

Waste

Waste Urine and sweat

ject

research pro

Investigating healthy habits for the heart Cardiovascular diseases, like arteriosclerosis, heart attack and stroke, are the leading cause of death in Spain and in other developed countries (see graph).

project introduction Leading causes of death worldwide Cardiovascular diseases

32.3 %

Cancer

16.3 %

Respiratory diseases

6.5 %

Diabetes

5.8 %

Acute respiratory infections

4.4 %

Dementia

4.4 %

Neonatal death

3.2 %

Diarrhoeal diseases

3 %

Road accidents

2.5 %

Liver diseases

2.3 %

Knowing the annual figures for deaths and their causes is a good way to assess how effective a country’s health system is. These figures help health authorities to take targeted public health measures. For example, if mortality due to heart disease and diabetes shoots up in the space of a few years, health authorities will often launch programmes aimed at encouraging healthy habits to prevent these diseases. It has been proven that the rise in cardiovascular diseases is directly linked to certain habits and lifestyles. Factors that increase the risk of developing a cardiovascular disease include obesity, smoking, a sedentary lifestyle, high levels of cholesterol in the blood, high blood pressure and diabetes.

Main cardiovascular risk factors Genetic predisposition Age

Alcoholism

Smoking

Diabetes

Obesity

High blood pressure

Some medications

Poor eating habits

A sedentary lifestyle

project objective

In this research project, you will be studying cardiovascular risk factors in people of different ages and sexes and with different lifestyles. One of the key objectives is to find out whether adopting certain healthy habits prevents cardiovascular diseases. With the information you have collected, you will prepare a presentation to report the results of your research and the conclusions you have drawn.

project steps

This project consists of three stages or steps:

➜ Step 1 (in this unit). Organising your work and searching for the information you need to start your research.

➜ Step 2 (in unit 2). Formulating a hypothesis, carrying out the research and obtaining experimental data.

➜ Step 3 (in unit 3). Analysing the results and drawing conclusions. Finally, you will prepare a presentation that you can use to report and explain your results in class. 38

Unit 1

STEP 1

Organising your work and searching for information Organising your work Your teacher will split the class into groups of 3 or 4. In your groups, discuss the project you are going to carry out and the methods you could use. Divide up the work among the members of your team. Share your ideas with the other groups. Discuss the number of people you are going to include in the study, the age range, what lifestyles you will look at, and so on. It is important to select a study sample that is representative of as many situations as possible. This will make your conclusions from the study more realistic.

Finding and analysing information When searching for and selecting information for your project, make sure you use reliable sources. Consult sources in different formats (articles, infographics, graphs, etc.). Analyse information about cardiovascular risk factors, their incidence in the population and their effect on the physiological state of the circulatory system. To help you search for information, you could write a list of questions like the ones below:

ing a cardiovascular ow does age influence the risk of develop ✓H

disease? And gender? ssure increase the risk hy do excess weight and high blood pre ✓W of developing a cardiovascular disease? the cardiovascular ow does smoking affect the health of ✓H system? diet help prevent cardiovascular ced lan ba a and se rci exe l sica phy r ula reg do ow ✓H diseases? risk factors at the same se the of one n tha e mor e hav to ous ger dan so hy is it ✓W time? 39

m this resources fro r to choose be em m Re lio. your portfo

unit for

TISE

AC review and PR

Organising your ideas

Interpreting pictures

3 Copy this drawing and label the cell structures that

The systems are The organs are The tissues are

? ? ?

1 2

Atomic level Atoms are ? such as ? Bioelements are ? Organism level The human body is

correspond to the numbers. What is the function of each structure?

They are joined by chemical bonds.

5 ?

such as such as such as

Molecular level Molecules are ? such as ? Biomolecules are ?

? ? ?

They group together to perform the three vital functions.

Cellular level Cells are ? Human cells are ? such as ?

4 8

4 Look at the following pictures of tissues and cells and answer the questions: A

They group together to form organelles such as ?

Summarising 2 Write your own unit summary based on the outline below:

• What is the difference between the atomic and molecular levels of organisation? Include definitions of bioelement and biomolecule.

• Give a definition of cell. What higher levels are cells organised into?

• What is the cell membrane composed of? What are its functions?

• List the parts of a cell nucleus and explain their functions.

5 What cell structure can you see in the following image? What is it composed of? What level of organisation of living matter does it correspond to?

• Write a list of the membranous organelles and the non-membranous organelles. What is the difference between them? What is the main function of each one?

• Explain what cell differentiation is. • Name the different types of human tissue. What are the main characteristics of each type?

• Name the different systems in the human body and the function they are involved in. 40

anayaeducacion.es Go to ‘Science workshop: Observing mucosa cells’ and ‘Studying how transport occurs through the membrane’ in your resource bank.

Unit 1

Applying your knowledge 6 State what level of organisation in the human body the following correspond to: calcium; kidney; nucleus; group made up of the mouth, oesophagus, stomach, intestine, pancreas, etc.; sperm; protein.

Moving forward 12 Read the following text and answer the questions: Invented in the 16th century, the microscope is a key tool for studying cells. As more and more powerful microscopes were developed, scientists were able to make discoveries about cellular structure. The ‘power’ of a microscope is its resolution; that is, the smallest distance by which two points can be seperated and still seen as separate points. Optical microscopes use visible light, which passes through the sample and provides an image that is magnified by a set of lenses. Their resolution is 0.2 µm. Electron microscopes don’t use light, but rather a beam of electrons. These either pass through the sample or bounce off it and are then captured by a screen, where the image appears. Their resolution is 5 µm.

7 Copy and correct the following incorrect sentences about the cell membrane: a) The cell membrane isolates the cytoplasm from the outside. b) The plasma membrane is formed of a double layer of proteins. c) Medium-sized substances cross the cell membrane freely and without any help. d) Small substances enter the cell by endocytosis. e) The plasma membrane is not present in all cells.

a) What type of microscope has been used to take these pictures of red blood cells?

8 What is the difference between: a) The nucleus and the nucleolus? b) Chromatin and chromosomes?

b) If the diameter of a red blood cell is approximately 5 µm, how much magnification does each microscope provide?

c) The nucleolus and nucleoplasm?

9 List the names of the cell organelles in a table. Add another column to describe the shape of each organelle, accompanied by a drawing, and another column for its function.

10 Copy the following sentences and say which tissue they refer to:

a) Its matrix is liquid and is called plasma. b) It forms glands, which secrete substances. c) Its matrix is solid and elastic. We find it between the vertebrae and in the ear. d) It has a protective function in that it lines cavities. e) It contains low levels of intercellular substance and its cells store fat. f) Its cells transmit nerve impulses. g) Its cells are elongated and it is responsible for body movement. h) Its matrix is solid and contains calcium salts.

11 Why is cell differentiation important? Provide two examples. anayaeducacion.es Go to ‘Key concepts’ and ‘Learn by playing’ in your resource bank.

Many of the body’s cells have names related to the organ they belong to. Search for a picture of each of the following cells and indicate which organ they belong to: a) hepatocyte, b) osteocyte, c) myocyte, d) chondrocyte.

Sustainable Development Goals 14 Sustainable Development Goal 3 aims to ensure healthy lives and promote well-being for all. The UN has set numerous targets for this goal. a) In groups, find out about the targets of Goal 3 at anayaeducacion.es. Choose the target that most interests your group, and research it. b)

Prepare a presentation to give to your class about the importance of your group’s chosen target and what could be done to achieve it.

c) Discuss and draw conclusions about the importance of education and research in achieving this goal. 41

Glossary

A Atoms The smallest particles into which matter can be divided while retaining its chemical properties.

B Biomolecules Molecules found exclusively in living beings and containing a high level of carbon.

Chromosomes Compact structures made of chromatin fibres that are visible under a microscope when the cell is about to divide. Cytoplasm Thick aqueous liquid (cytosol) that fills the inside of the cell and contains the cell organelles. Cytoskeleton Network of fibres that gives the cell its shape and enables it to move.

C Carbohydrates Biomolecules whose main function is to provide energy to cells.

Carbohydrates

Endoplasmic reticulum (ER) Cell organelle consisting of a network of tubules and sacs extending out from the cell membrane. There are two types: the rough ER (RER), which has ribosomes attached to it and is involved in protein synthesis; and the smooth ER (SER), which does not have ribosomes attached to it and is involved in the synthesis of lipids. Eukaryotic cell A type of cell in which the genetic material is contained in a nucleus surrounded by a membrane, and which consists of many different organelles.

Cell Structural and functional unit of a living being. That is, a cell is a unit capable of carrying out the three vital functions. Cell differentiation Process by which cells take on a shape and structure that allows them to become specialised for a particular function. Cell nucleus Cell structure surrounded by a membrane and containing the genetic material. Cell organelles Small structures in a cell that are specialised to perform different functions. Centrioles Non-membranous cell organelles made up of protein fibres that direct the cytoskeleton during cell division. Chromatin Network of all the DNA fibres and proteins found in the cell nucleus.

G Genetic material A fibrous substance called DNA that controls cell function. Golgi apparatus Membranous organelle consisting of a network of flattened sacs that modify the substances synthesised in the ER in order to transport and secrete them.

H Homeostasis All the processes that keep the composition and properties of an organism’s internal environment stable.

Unit 1

I Internal environment Fluid that surrounds all the cells and is connected to the external environment by the blood.

L Levels of organisation The levels of complexity into which living matter is organised. Lipids Biomolecules that perform various functions like energy storage (triglycerides) and heat insulation. Some lipids form part of the plasma membrane of cells (phospholipids and cholesterol). Lipids

Lysosomes Membranous cell organelles responsible for digesting particles.

M Micrometre or micron Unit of length equal to one millionth of a metre.

Nucleolus Part of the cell nucleus where ribosomes are made. Nucleoplasm Part of the cell nucleus made up of a watery liquid containing the genetic material.

O Organ Group of different tissues performing a specific function.

Mitochondrion Cell organelle surrounded by a double membrane whose function is to obtain energy for the cell through cellular respiration. Monomers Simple or small molecules that form the basic unit of other, larger molecules known as polymers.

N Nucleic acids Large biomolecules that contain genetic information, which they transmit to offspring, and that control cell functions. DNA and RNA are nucleic acids.

Proteins

R Ribosomes Non-membranous cell organelles responsible for synthesising proteins.

S System Group of organs performing a shared function.

Nucleic acids

T Tissue Group of similar, coordinated cells that are specialised to perform the same function.

Building Blocks is an educational project of Anaya Educación for Secondary Education with the participation of: S. Clemente, A. Domínguez, A. B. Ruiz, Danny Latimer, Hannah Peat, Karen Piper, Denise Suárez, Begoña Fuente Larrazabal, Sara Gascón Martin. The following people have also contributed to this book:

Editorial team:

Hannah Peat and Departamento de Ciencias Naturales (Almudena Alcón, Esther Fernández, Mª Isabel García, Marco Sánchez, Mercedes Sacristán and Jorge Torres).

Design, technical drawings and maps: Patricia G. Serrano, Juan Carlos Quignón, Miguel A. Castillejo, Miguel A. Díaz-Rullo and Miriam Arribas.

Illustrations: Sara Mateos, Celia López Bacete, Santi Martín, Alicia Posada, Mª Carmen Fuente, David Menéndez and Carlos Moreno.

Layout:

Mª Nieves Merino and Oscar Latorre.

Corrections: Departamento de correcciones de Anaya Educación. Translation: Montero Language Services. Proofreading: Rachel Bland (Bakun S. L.) Graphic edition: Olga Sayans. Photographs: Age Fotostock (AndreyPopov, ARCO / Muehlmann, K., Auscape / UIG, BILDAGENTUR-ONLINE/ MCPHOTO-SCHULZ, BRITISH ANTARCTIC SURVEY, DENNIS KUNKEL MICROSCOPY-SPL, E R Degginger, GERD GUENTHER, J M Barres, JANNICKE WIIK-NIELSEN, Jens Meyer, Jerónimo Alba, Lucas Vallecillos, Michael Abbey, Nasa via ZUMA Wire, ROGELIO MORENO, Science Photo Library, Spike Walker, STEVE GSCHMEISSNER, Wim van Egmond), Agencia EFE (EFE/lafototeca.com) Alamy/Cordon Press (Anne-Marie Palmer, blickwinkel, cbimages, Greenshoots Communications, jeremy sutton-hibbert, Nino Marcutti, Valentyn Volkov, YAY Media AS), Archivo Anaya (Alcón, A. and Santos, V.E.; Candel, C.; Canto, M.; Cosano, P.; Cruz, M.; CSIC/IFI/Barcenilla, J.; Hernández Moya, B.; Lezama, D.; Martín, J. A.; Martínez, C.; Moreno, C.; Muñoz, M.; Ortega, A.; Padura, S.; Peñuela Py, E.; Pozo, M.; Quintas, D.; Ramón Ortega, P.-Fototeca España; Rico, J.J.; Rivera Jove, V.; Ruiz, J.B.; Sanz, C.; Steel, M.; Sánchez, J.; Valls, R.; Velasco, P-Fototeca España; Zuazo, A.H.), Dreamstime (Ekinaa, Fokinol, Sarah 2), GettyImages (Hero Images, Jason Edwards), GSFC Ozone Processing Team, iStock/Gettyimages, Mediateca DGT, NASA/ESA/The Hubble Heritage Team (STScI/AURA), NASA/JPL-Caltech/R. Hurt (SSC/Caltech), NASA/JPL-Caltech/University of Arizona, NASA/NASA Ozone Watch/Katy Mersmann, Nature Picture Library/CordonPress (Andy Rouse, Anup Shah, Chris & Monique Fallows, David Shale, Linda Pitkin, Richard Robinson, Tony Wu, Yukihiro Fukuda), 123rf and collaborators.

Special thanks to Ana Codeseda for writing the scientists’ biographies. Other thanks: to Almudena Monge for permission to use the field notebook illustation.

Academic and Professional Orientation: created in conjunction with Fundación Bertelsmann. Coordinator: Juan José Juárez Calvo. Expert collaborators: Sara Lozano Santiago, Belén Pérez Castro and Pilar Vázquez Hernández.

Commitment to Sustainable Development Goals Our publications contain carefully selected content, illustrations and language to comply with non-discrimination on the grounds of gender, culture or opinion. Grupo Anaya considers social and environmental responsibility to be one of its fundamental values. For this reason, we are committed to: · continually improving our contents and materials related to the environment. · reducing our carbon emissions. · using natural resources responsibly. · making sure that our activity has no negative consequences for endangered forests. These commitments, among others, mean that 100% of the paper used in our books has the PEFC label. Important information: The activities proposed in this book should be completed in a separate notebook or on sheets of paper, not in the book itself. The links to webpages which appear in this book have been checked before printing. The publisher cannot be liable for any changes or modifications which occur after the date of publication. © GRUPO ANAYA, S.A., 2021 - C/ Juan Ignacio Luca de Tena, 15 - 28027 Madrid. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of the publishers.