QUIZ 5 BIOCHEM

Question 1

3 stages of interphase

Answer 1

G1 (growth and metabolism)
S (DNA Replication)
G2 (Preparation for cell division)

Question 2

Mitosis

Answer 2

short phase following interphase

Question 3

DNA replication

Answer 3

the process of making a copy of DNA, chain will split and put matching nucleotides in

Question 4

Epigenetics

Answer 4

as DNA is replicated, tags are copied too (ex. methyl coping enzymes place methyl tags on newly synthesized strand)

Question 5

Bacterial Replication

Answer 5

circular DNA, DNA replication begins at the origin in both directions

Question 6

Eukaryotic Replication

Answer 6

multiple origins, replication bubbles arise and synthesis proceeds along a fork in each direction

Question 7

in order to replicate DNA …

Answer 7

the double helix must be unwound and opened

Question 8

Helicase

Answer 8

will open the helix, untwisting the double helix

Question 9

single strand binding proteins

Answer 9

keep DNA from re-annealing

Question 10

Topoisomerase

Answer 10

enzyme that breaks and rejoins strands to relieve tension from twisting

Question 11

what bonds will topoisomerase cut allowing for the helix to relax and spin freely?

Answer 11

phosphodiester bonds

Question 12

DNA synthesis in what direction

Answer 12

5’ to 3’

Question 13

bonds easy to break during DNA synthesis

Answer 13

the hydrogen bonds between nucleotides

Question 14

Direction of reading DNA

Answer 14

3’ to 5’

Question 15

exonuclease

Answer 15

cuts incorrect bases and replaces with the correct base

Question 16

RNA primers

Answer 16

synthesized to start replication

Question 17

primase

Answer 17

enzyme that adds the RNA bases in a 5’ - 3’ direction, coping from the template strand

Question 18

leading strand

Answer 18

continuous synthesis of DNA replication, DNA polymerase synthesizing 5’ to 3’

Question 19

lagging strand

Answer 19

opposite from the leading strand, made out of Okazaki fragments, discontinuous

Question 20

Okazaki fragments

Answer 20

synthesized, RNA primers used to start each and is replaced by DNA

Question 21

Ligase

Answer 21

enzyme that joins Okazaki fragments together

Question 22

telomeres

Answer 22

caps at the end of each chromosome that ensure coding regions aren’t lost when chromosomes shorten during replication

Question 23

telomerase

Answer 23

RNA-dependent DNA polymerase, lengthens the ends of chromosomes

Question 24

reverse transcriptase

Answer 24

in telomerase, a single strand of RNA is reverse transcribed to single-stranded DNA and complementary DNA, RNA is removed and DNA is made double-stranded

Question 25

mutations

Answer 25

a random error in gene replication that leads to a change, repair mechanisms in place

Question 26

4 steps of DNA repair

Answer 26

1. Damaged DNA recognized 2. Enzymes break phosphodiester bond and remove damaged area 3. DNA polymerase designed to repair, rebuilds the damaged area 4. DNA ligase seals the nicks

Question 27

Transcription

Answer 27

RNA synthesis from a DNA template

Question 28

Polymerase

Answer 28

joins nucleotides to form a single stand

Question 29

RNA Polymerase

Answer 29

able to initiate synthesis, primer not needed, lack of exonuclease

Question 30

Changes in RNA bases

Answer 30

A will change places with T and U will replace T's place

Question 31

RNA polymerase in prokaryotes

Answer 31

One RNA transcribes all RNA in the cell

Question 32

RNA polymerase in eukaryotes

Answer 32

an individual RNA polymerase for each rRNA, mRNA, tRNA

Question 33

RNA polymerase I

Answer 33

transcribes rRNA

Question 34

RNA polymerase II

Answer 34

transcribes mRNA

Question 35

RNA polymerase III

Answer 35

transcribes tRNA

Question 36

promoter region

Answer 36

site of attachment for the RNA polymerases and identify thee start point for transcription

Question 37

operons

Answer 37

a number of genes all under the control of a single promoter in RNA

Question 38

TATA box

Answer 38

many A and T at the start point of transcription, with only 2 bonds, easier to separate

Question 39

polycistronic transcript

Answer 39

produced by an operon, translates several proteins

Question 40

what cells contain introns and axons?

Answer 40

eukaryotic

Question 41

Bacterial Transcription

Answer 41

1. Initiation 2. Elongation 3. Termination

Question 42

Sigma factor

Answer 42

controls the binding of RNA polymerase to the promoter, allows for bacterial transcription to occur

Question 43

5' capping

Answer 43

Addition of methyl guanosine to the 5' end of a eukaryotic mRNA during processing.

Question 44

what methylates guanosine? how is it regenerated?

Answer 44

S-adenosylmethionine (SAM) regenerated by folate and vitamin B12

Question 45

Poly A polymerase

Answer 45

catalyzes the addition of adenines from ATP after transcription is finished

Question 46

Poly (A) tails

Answer 46

post transcriptional modification, is a protein binding site that protects mRNA transcript from being degraded in the cytosol

Question 47

removal of introns

Answer 47

a sequence signals the borders of the intron, spliceosomes attach and cut the introns out between the borders

Question 48

a-Amanitin

Answer 48

poisonous mushroom, binds to RNA polymerase II, halting transcription and translation so the cells die