Chapter 4

Question 1

List the components of a nucleotide.

Answer 1

phosphate group, 5 carbon sugar, and nitrogenous base

Question 2

Which carbon is the phosphate bonded to on sugar?

Answer 2

5’

Question 3

Which carbon is the base bonded to on sugar?

Answer 3

1’

Question 4

What is the difference between DNA and RNA?

Answer 4

DNA: deoxyribose, H bonded to 2’ Carbon
RNA: ribose, OH bonded to 2’ Carbon

Question 5

Which bases are pyrimidines?

Answer 5

C, U, T

Question 6

Which bases are purines?

Answer 6

A, G

Question 7

Are purines or pyrimidines larger?

Answer 7

purines (have a two ring structure)

Question 8

Polymerization occurs through what kind of rxn?

Answer 8

condensation

Question 9

What is the sequence of a nucleic acid chain?

Answer 9

5’ phosphate to 3’ OH

Question 10

Why is ATP a good source of cellular energy?

Answer 10

Because of the phosphate groups; ATP contains 3 phosphates that link through phosphodiester linkages. Since they are negatively charged, they repel each other

Question 11

Energy is released when phosphates are…

Answer 11

hydrolyzed

Question 12

How are DNA structures set up?

Answer 12

5’ to 3’ antiparallel helices

Question 13

The pairing of purines and pyrimidines allows ____ bonding?

Answer 13

Hydrogen

Question 14

Adenine forms ____ H bonds with thymine

Answer 14

2

Question 15

Guanine forms ____ H bonds with cytosine

Answer 15

3

Question 16

Would DNA strands with more C-G pairs than A-T pairs have a higher or lower melting temp and why?

Answer 16

Higher because there are more hydrogen bonds in C-G

Question 17

What are Chargaff’s two rules?

Answer 17

1. the # of purines = the # of pyrimidines
2. the DNA molecule has an = number of A/T and C/G

Question 18

Primary structure of DNA

Answer 18

basic nucleotide sequence

Question 19

Secondary structure of DNA

Answer 19

double helix

Question 20

Tertiary structure of DNA

Answer 20

compacted double helix for better storage (supercoiling)

Question 21

Primary function of DNA…

Answer 21

storage

Question 22

3 other things about DNA…

Answer 22

1. stable
2. unreactive
3. serves as template for its own synthesis

Question 23

Primary structure of RNA

Answer 23

same as DNA EXCEPT uracil replaces thymine

Question 24

Secondary structure of RNA

Answer 24

multiple hairpains instead of helixes