Exam 4: Week 7 Class 2 (excluding Experiments)

Question 1

What are the levels of DNA structure?

Answer 1

Nucleotides –> Strand –> Double helix –> Chromosomes –> Genome

Question 2

What are the pyrimidines?

Answer 2

CUT

Question 3

What are the purines?

Answer 3

AG

Question 4

What is the structure of a nucleic acid?

Answer 4

Phosphate group, 5-carbon sugar, Nitrogenous base

Question 5

What carbon is the nitrogenous base bonded to?

Answer 5

1st carbon

Question 6

What carbon is the phosphate group bonded to?

Answer 6

5th carbon

Question 7

What bond makes up the sugar-phosphate backbone of DNA?

Answer 7

Phosphodiester bonds

Question 8

What is the direction of a nucleic acid?

Answer 8

5’ to 3’

Question 9

What are Chargaff’s 3 Rules?

Answer 9

1. [Thymine] = [Adenine]
2. [Cytosine] = [Guanine]
3. [T] + [C] = [A] + [G]

Question 10

Are the two strands of DNA parallel or anti-parallel?

Answer 10

Anti-parallel

Question 11

What are the three general steps of DNA replication?

Answer 11

1. strand separation
2. base pairing with template
3. polymerization

Question 12

What is step 1 of DNA replication?

Answer 12

Heating or enzyme-catalyzed reactions that cause the double helix to separate

Question 13

What are the two parts of step 2 of DNA replication?

Answer 13

1. Free deoxyribonucleotides form hydrogen bonds with complementary bases on the original strand of DNA
2. Sugar-phosphate groups form phosphodiester linkages to create a new strand

Question 14

What is the name for the new strand?

Answer 14

Complementary strand

Question 15

What are the two names for the original strand of DNA that is used as a basis for replication?

Answer 15

Parental strand and template strand

Question 16

What is the result of step 3 of DNA replication?

Answer 16

two identical daughter molecules

Question 17

What are the three hypotheses for how the old and new DNA strand interact during replication?

Answer 17

1. Semiconservative
2. Conservative
3. Dispersive

Question 18

Which enzyme catalyzes DNA synthesis?

Answer 18

DNA polymerase

Question 19

What is the role of the origin of replication?

Answer 19

It provides an opening called a replication bubble that forms two replication forks

Question 20

Bacteria have ___ origin of replication

Answer 20

One

Question 21

Eukaryotes have ___ origin of replication

Answer 21

Multiple

Question 22

DNA replication proceeds ____ from forks

Answer 22

Outward

Question 23

DNA polymerases add deoxyribonucleotides to what end of the growing DNA chain?

Answer 23

3’

Question 24

What direction does DNA synthesis proceed in?

Answer 24

5’ to 3’

Question 25

Is DNA polymerization exergonic or endergonic?

Answer 25

Exergonic