DNA

Question 1

What is a purine?

Answer 1

A and G (double ringed)

Question 2

What is a pyrimidines?

Answer 2

T and C (single ringed)

Question 3

What is meant by 3’ and 5’?

Answer 3

The carbon it connects to. 5’ to a phosphate group, 3’ to a hydroxyl group

Question 4

What are the sides of the DNA ladder made of?

Answer 4

sugar and phosphate.

Question 5

What are rungs of ladder made of?

Answer 5

nitrogenous bases connected by H bonds

Question 6

What are 2 main functions of DNA?

Answer 6

expression and replication

Question 7

Monomers of nucleic acid?

Answer 7

nucleotides

Question 8

Polymers of nucleic acid?

Answer 8

DNA and RNA

Question 9

What part of nucleotide contains genetic code?

Answer 9

Nitrogenous bases

Question 10

The sequence of N bases is __________ for almost all organisms.

Answer 10

different

Question 11

What is the purpose of DNA replication.

Answer 11

Replication (make proteins), keep it fresh

Question 12

The location where DNA is unzipped is called . . . ?

Answer 12

replication fork

Question 13

What is a replication bubble?

Answer 13

The region where 2 rep. forks are close producing a bubble in the DNA.

Question 14

The ________ strand is made continuously.

Answer 14

leading

Question 15

The ________ strand is made in short segments called what?

Answer 15

lagging and Okazaki fragments

Question 16

What is semiconstructive replication?

Answer 16

Produces DNA molecule with 1 new and 1 old strand.

Question 17

What is constructive replication?

Answer 17

Leaves the original copy in tack and makes a new copy.

Question 18

What is dispersive replication?

Answer 18

Produces 2 DNA with segments of both old and new.

Question 19

What is the first step of DNA rep?

Answer 19

Unwinding and separation of parent strand.

Separation is initiated in multiple places.

Question 20

What enzyme breaks the bonds that connect N bases allowing the double helix to unwind?

Answer 20

DNA helicase

Question 21

What enzyme relieves tension produced by unwinding DNA?

Answer 21

DNA gyrase

Question 22

What is the second step of DNA rep?

Answer 22

DNA synthase. Rep begins in different directions on each strand.

Question 23

What repairs DNA mistakes?

Answer 23

DNA polymerase III and I

Question 24

Summarize the first half of DNA rep.

Answer 24

The helix is unwound. Single stranded binding proteins prevent it from rewinding. DNA Polymerase III adds triphosphates to help drive the process. The leading strand is built toward the rep fork and the lagging away.

Question 25

Summarize the second half of DNA rep.

Answer 25

DNA polymerase I excises the RNA primers and replaces them with the right deoxynucleotides. DNA ligase fills the gaps of the lagging strand. Proofreading is done.

Question 26

What enzyme fills in the gaps between the Okazaki fragments?

Answer 26

DNA ligase

Question 27

What does DNA ligase use to fill in the gaps between the Okazaki fragments?

Answer 27

Phosphodiester bonds

Question 28

Why is DNA rep. important for every cell?

Answer 28

mitosis and meiosis

Question 29

Why is it important to proofread DNA?

Answer 29

A mistake could kill the cell or cause it to malfunction and cause damage.

Question 30

What is anneal?

Answer 30

The pairing of complementary strands of DNA through H bonding.

Question 31

What do single stranded binding proteins (SSBs) do?

Answer 31

Keeps separated strands of DNA apart

Question 32

What base pairs have a double H bond and which have a triple H bond?

Answer 32

A and T have a double

G and C have a triple

Question 33

What does DNA polymerase take?

Answer 33

Free nucleotides found within cell and adds them to 5’ -> 3’ direction to form new strand.

Question 34

Which strand is faster?

Answer 34

Leading strand

Question 35

How does DNA return to original shape?

Answer 35

Once the H bonds are formed again it automatically goes back.