DNA Replication

Question 1

RNA Primer

Answer 1

a short segment of RNA used to initiate the synthesis of a new strand of DNA during replication

Question 2

DNA Polymerase I

Answer 2

an enzyme that removes RNA primers and replaces them with DNA

Question 3

What did Meselson and Stahl discover?

Answer 3

DNA replication is semi-conservative; each new strand contains one old and one new strand

Question 4

Semi-conservative model

Answer 4

• the two strands of the parental molecule separate
• each function as a template for the synthesis of a new complementary strand

Question 5

Allele

Answer 5

a variation of a gene

Question 6

Topoisomerase

Answer 6

relieves the “overwinding” strain ahead of replication forks by breaking, swivelling, and rejoining DNA strands

Question 7

Purine structure

Answer 7

double ringed

e.g. adenine and guanine

Question 8

Ligase

Answer 8

joins the end of DNA that make up the Okazaki fragments

Question 9

Replication bubble

Answer 9

an unwound and open region of a DNA helix where DNA replication occurs

Question 10

DNA Polymerase III

Answer 10

after seeing the RNA primer, it synthesizes the leading strand

Question 11

What is adenine (A) paired with?

Answer 11

thymine (T)

Question 12

What is the second step of DNA replication?

Answer 12

a new complementary strand is added

Question 13

Single-stranded binding proteins (SSBs)

Answer 13

stops the two separated parent strands from annealing

Question 14

Annealing

Answer 14

recombine DNA in the double-stranded form following separation by heat

Question 15

Okazaki fragment

Answer 15

small fragments of DNA produced on the lagging strand during DNA replication, later joined by DNA ligase to form a complete strand

Question 16

Pyrimidine structure

Answer 16

single ring

e.g. cytosine, thymine, uracil

Question 17

Helicase

Answer 17

unwinds DNA helix

Question 18

What did Hershey and Chase discover?

Answer 18

DNA was the genetic material; radioactively on viruses and proteins

Question 19

What bonds hold nucleotides together?

Answer 19

phosphodiester bonds

Question 20

Replication origin

Answer 20

specific sequence of DNA where DNA synthesis begins

Question 21

Nucleotide structure

Answer 21

• 5 carbon sugar
• phosphate group
• nitrogenous base

Question 22

What is guanine (G) paired with?

Answer 22

cytosine (C)

Question 23

What is the first step of DNA replication?

Answer 23

partial unwinding of the double helix

Question 24

Deoxyribose

Answer 24

a five-carbon sugar that is a component of DNA nucleotides

Question 25

Lagging strand

Answer 25

is copied 3’ to 5’

Question 26

Nuclease

Answer 26

DNA cutting enzyme

Question 27

What is the third step of DNA replication?

Answer 27

new strands are proofread and repaired

Question 28

Gene

Answer 28

a segment of DNA that codes for a specific trait

Question 29

RNA primase

Answer 29

an enzyme that creates an RNA primer for the initiation of DNA replication

Question 30

What did Griffith discover?

Answer 30

transformation: a change in genotype and phenotype due to assimilation of foreign DNA

Question 31

Genome

Answer 31

the complete set of genes or genetic material present in a cell or an organism

Question 32

Replication fork

Answer 32

a y-shaped region on a replication DNA molecule where new strands are growing

Question 33

Leading strand

Answer 33

continuous complementary DNA strand synthesized along the template strand in the direction 5’ to 3’

Question 34

Gyrase

Answer 34

reduces topological strain in an ATP dependent manner