CH.5

Question 1

if a DNA sample were composed of 10% thymine, what would be the % of guanine?

Answer 1

40%

Question 2

which of the following description best fits the class of molecules known as nucleotides

Answer 2

a nitrogenous base, a phosphate group, and a pentose sugar

Question 3

which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA

Answer 3

5’-A-T-G-C-3’ with 5’-G-C-A-T-3’

Question 4

enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. what would happen to DNA molecules treated with these enzymes?

Answer 4

the phosphate linkages between deoxyribose sugars would be broken

Question 5

which of the following are nitrogenous bases of the purine type?

Answer 5

guanine and adenine

Question 6

a new organism is discovered in the forests of Costa Rica. Scientist there determine that the polypeptide sequence of hemoglobin from the new organism has 72 aa differences from humans, 65 differences from a gibbon, 49 differences from a rat, and 5 differences from a frog. This data suggest that the new organism

Answer 6

is more closely related to a frog than to humans

Question 7

of the following function, the major purpose of RNA is to

Answer 7

function in the synthesis of protein

Question 8

if a DNA sample were composed of 10% thymine, what would be the percentage of guanine?

Answer 8

40%

Question 9

which of the following best describes the flow of info in eukaryotic cells?

Answer 9

• DNA —> RNA—> proteins

Question 10

if one strand of a DNA molecule has the sequence of bases 5’ATTGCA3’, the other complementary strand would have the sequence

Answer 10

3’TAACGT5’

Question 11

what is the structural feature that allows DNA to replicate?

Answer 11

complementary pairing of the nitrogenous bases

Question 12

a double stranded dna molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of

Answer 12

120 thymine and 120 adenine molecules

Question 13

which of the following statements about the 5’ end of a polynucleotide strand of dna is correct

Answer 13

the 5’ end has a phosphate group attached to the number 5 carbon of ribose

Question 14

In the double helix structure of nucleic acids, cytosine hydrogen bonds to

Answer 14

guanine

Question 15

which of the following statements best summarizes the structural differences between dna and rna

Answer 15

dna nucleotides contain a different sugar than RNA nucleotides

Question 16

which of the following store and transmit hereditary info

Answer 16

nucleic acids

Question 17

the difference between the sugar in dna and the sugar in rna is that the sugar in dna

Answer 17

contains one less O atom

Question 18

which of the following are nitrogenous bases of the pyrimidine type?

Answer 18

cytosine and uracil

Question 19

which of the following is an example of hydrolysis

Answer 19

the reaction of a fat, forming glycerol and fatty acids with the utilization of water

Question 20

DNAase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. what would 1st happen to DNA molecules treated with DNAase?

Answer 20

the phosphodiester bonds between deoxyribose sugars would be broken.