QUIZ 5 BIOCHEM Flashcards

1
Q

3 stages of interphase

A

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

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2
Q

Mitosis

A

short phase following interphase

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3
Q

DNA replication

A

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

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4
Q

Epigenetics

A

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

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5
Q

Bacterial Replication

A

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

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6
Q

Eukaryotic Replication

A

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

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7
Q

in order to replicate DNA …

A

the double helix must be unwound and opened

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8
Q

Helicase

A

will open the helix, untwisting the double helix

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9
Q

single strand binding proteins

A

keep DNA from re-annealing

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10
Q

Topoisomerase

A

enzyme that breaks and rejoins strands to relieve tension from twisting

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11
Q

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

A

phosphodiester bonds

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12
Q

DNA synthesis in what direction

A

5’ to 3’

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13
Q

bonds easy to break during DNA synthesis

A

the hydrogen bonds between nucleotides

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14
Q

Direction of reading DNA

A

3’ to 5’

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15
Q

exonuclease

A

cuts incorrect bases and replaces with the correct base

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16
Q

RNA primers

A

synthesized to start replication

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17
Q

primase

A

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

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18
Q

leading strand

A

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

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19
Q

lagging strand

A

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

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20
Q

Okazaki fragments

A

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

21
Q

Ligase

A

enzyme that joins Okazaki fragments together

22
Q

telomeres

A

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

23
Q

telomerase

A

RNA-dependent DNA polymerase, lengthens the ends of chromosomes

24
Q

reverse transcriptase

A

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

25
Q

mutations

A

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

26
Q

4 steps of DNA repair

A
  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
27
Q

Transcription

A

RNA synthesis from a DNA template

28
Q

Polymerase

A

joins nucleotides to form a single stand

29
Q

RNA Polymerase

A

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

30
Q

Changes in RNA bases

A

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

31
Q

RNA polymerase in prokaryotes

A

One RNA transcribes all RNA in the cell

32
Q

RNA polymerase in eukaryotes

A

an individual RNA polymerase for each rRNA, mRNA, tRNA

33
Q

RNA polymerase I

A

transcribes rRNA

34
Q

RNA polymerase II

A

transcribes mRNA

35
Q

RNA polymerase III

A

transcribes tRNA

36
Q

promoter region

A

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

37
Q

operons

A

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

38
Q

TATA box

A

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

39
Q

polycistronic transcript

A

produced by an operon, translates several proteins

40
Q

what cells contain introns and axons?

A

eukaryotic

41
Q

Bacterial Transcription

A
  1. Initiation
  2. Elongation
  3. Termination
42
Q

Sigma factor

A

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

43
Q

5’ capping

A

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

44
Q

what methylates guanosine? how is it regenerated?

A

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

45
Q

Poly A polymerase

A

catalyzes the addition of adenines from ATP after transcription is finished

46
Q

Poly (A) tails

A

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

47
Q

removal of introns

A

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

48
Q

a-Amanitin

A

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