Download Baird Chem in Your life Chapter 09

Baird Chem in Your life Chapter 09
1. The subunits of DNA and RNA are called ______.
a. nucleotides
b. nucleic acid
c. deoxyribose
d. ribose
a: The definition of nucleotides is on page 325.
2. How many nitrogen bases can occur in each DNA and RNA chain?
a. four
b. two
c. six
d. eight
a: On page 327 it is shown as ACGT.
3. Which molecular structures of the nitrogen bases are classified as purines?
a. guanine and adenine
b. guanine and uracil
c. guanine and cytosine
d. guanine and thymine
a: This is shown on page 329.
4. What atoms are part of the ring in cytosine, thymine, and uracil?
a. 4-carbon atoms and 2-nitrogen atoms.
b. 6-carbon atoms
c. 3-carbon atoms and 3-nitrogen atoms
d. 2-carbon atoms and 4-nitrogen atoms
a: This is shown on page 327.
5. What type of chemical do the terms “deoxyribo” and “ribo” refer to?
a. sugars
b. amines
c. amides
d. purines
b: They are forms of sugar molecules.
6. What bases are aligned when replication takes place?
a. A with T
b. A with C
c. T with C
d. T with G
a: This is explained on page 331.
7. How many three-letter combinations consist of the letters of the four nitrogen bases A, C, G, and T?
a. 64
b. 16
c. 32
d. 12
a: Calculating possibilities of four bases A,C,G and T (4 × 4 × 4) gives 64 combinations.
8. How many pairs of chromosomes do humans possess?
a. 23
b. 69
c. 46
d. 92
b: Each human cell has 46 chromosomes divided by two, which gives 23 pairs.
9. What is the process called that is responsible for messenger RNA to be complementary to the DNA
sequence?
a. transcription
b. transfer
c. replication
d. translation
a: This is explained on page 333.
10. Which of the following RNA is responsible for building proteins in molecules?
a. tRNA
b. mRNA
c. rRNA
d. cRNA
a: tRNA is transfer ribosomes.
11. What is the nitrogen base sequence C and U that would be complimentary bases on part of a DNA
molecule?
a. GGTAGCCCT
b. GTGAGCCCT
c. GAGTGCCCT
d. GGTAGTCCC
a: The G can be replaced by C, and A can be replaced by U. This is illustrated on page 334.
12. On an mRNA molecule, what number is required of a sequence of consecutive nitrogen bases called a
“codon”?
a. 3
b. 2
c. 4
d. 6
a: “Codons” are defined as a sequence of three nitrogen bases.
13. What complex protein molecules build polypeptides?
a. ribosomes
b. codons
c. nucleotides
d. nucleic acids
a: This is explained on page 341.
14. What type of structure, chemically speaking, are proteins similar to?
a. polyamides
b. amides
c. polyamines
d. nucleic acids
a: This is explained on page 343.
15. What is the minimum number of amino acid molecules required to be classified as a polypeptide?
a. three
b. two
c. one
d. four
c: This is explained on page 342.