2 minute read
Quiz
• Genes can mutate to form similar proteins to the original protein, a totally different functional protein, or a totally non-functional protein. • A gene that codes for a non-functional protein is called a pseudogene.
1. Which nucleotide on DNA usually hydrogen bonds with the adenine nucleotide?
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a. Thymine b. Guanosine c. Cytosine d. Uracil Answer: a. It is usually the thymine molecule that bonds with the adenine nucleotide in a hydrogen bond to create an adenine-thymine bond.
2. About how many tons of carbon atoms are made up from human DNA in the world? a. One ton b. Two tons c. Three tons d. Four tons Answer: d. About four tons of carbon atoms in the world come from human DNA alone.
3. About what percentage of human DNA strands are not encoded for any protein? a. Fifty percent b. Seventy percent c. Eighty percent d. Ninety-eight percent Answer: d. About 98 percent of all DNA in the world is not actually encoded into any type of protein. The rest have no known purpose or are used in regulation.
4. What type of protein is found in the nucleus of DNA in eukaryotes that isn’t found in the cytoplasm of prokaryotes? a. RNA polymerase b. Histone proteins c. DNA polymerase d. Transcriptase proteins Answer: b. Histone proteins are found in the nucleus of eukaryotes in order to condense the DNA and to decide which DNA segments get transcribed. These types of proteins are unnecessary in prokaryotes.
5. What type of bonding connects the two strands of DNA together in human DNA and, in fact, all DNA strands? a. Van der Waals forces b. Ionic bonding c. Hydrogen bonding d. Covalent bonding Answer: c. It is hydrogen bonding that connects the strands of DNA by loosely connecting two attracting nucleotides to one another that are located on different strands of DNA.
6. Which human DNA chromosome is the longest? a. Chromosome 1 b. Chromosome 6 c. Chromosome 20 d. The X chromosome Answer: a. Chromosome 1 is the longest DNA chromosome, having 220 million pairs of nucleotides making up the total length of the chromosome.
7. Which is the most common conformation of DNA found in normal cell? a. A-DNA b. B-DNA c. C-DNA d. Z-DNA Answer: b. B-DNA is the type of DNA found mainly in cells under normal physiological conditions.
8. Which enzyme replicates the extreme 3’ end of a DNA strand? a. DNA replicase b. DNA polymerase c. Telomerase d. 3’ DNA polymerase Answer: c. Telomerase is the only enzyme capable of replicating the extreme 3’ end of a DNA strand, called the telomere or cap on the end of the DNA strand at the 3’ end.
9. How many strands of DNA are found in the D-loop of the telomere at the extreme end of the chromosome? a. One strand b. Two strands c. Three strands d. Four strands
Answer: c. There are three strands that are made from the D-loop of the telomere on the extreme end of each chromosome.
10. About how many essential genes do humans and higher organisms have? a. One hundred b. Two thousand c. Ten thousand d. Fifty thousand Answer: b. There are only about 2000 essential human genes in the human genome, which represents only about ten percent of the human genome.
