Unit 6? Flashcards

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1
Q

What are the purines

A

A and G

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2
Q

What are the pyrimidines

A

C and T

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3
Q

Are purines or pyrimidines wider

A

Purines

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4
Q

DNA strands run (direction)

A

Antiparallel

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5
Q

Where does the replication of chromosomal DNA begin

A

Origins of replication

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6
Q

What is at each end of a replication bubble

A

Replication fork

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7
Q

What untwists the double helix at the replication forks

A

Helicases

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8
Q

What keeps the DNA open in the replication bubble

A

Single-strand binding proteins

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9
Q

What breaks and rejoins dna strands during dna replication before the replication bubble

A

Topoisomerase

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10
Q

How does the Antiparallel arrangement of the double helix affect replication?

A

Because of their structure, DNA polymerases can add nucleotides only to the free 3’ end of a primer or growing DNA strand, never to the 5’ end

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11
Q

DNA strands can only elongate in the direction of

A

5’ -> 3’

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12
Q

What enzyme synthesizes new complementary strands

A

DNA polymerase III

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13
Q

What’s the DNA strand made by DNA polymerase called

A

The leading strand

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14
Q

What strand is synthesized discontinuously

A

Lagging strand

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15
Q

The lagging strand is made of little segments. What are the segments called?

A

Okazaki fragments

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16
Q

Three stages of translation?

A

Initiation, elongation, termination

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17
Q

Initiation begins when…

A

Small ribosomal subunit binds to mRNA and charged tRNA binds to start codon on mRNA

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18
Q

What is the start codon?

A

AUG

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19
Q

What’s the second step of initiation

A

Large ribosomal subunit binds to mRNA

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20
Q

What starts elongation?

A

Next tRNA comes to the A site, mRNA is moved through the ribosome and it’s codons are read

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21
Q

What does all organisms using the same genetic machinery imply?

A

THERE IS COMMON ANCESTRY ‼️‼️

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22
Q

First part of elongation?

A

The appropriate anticodon of the next tRNA goes to the A-site

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23
Q

Second part of elongation

A

Peptide bonds are formed that transfer the polypeptide to the A site tRNA

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24
Q

Third part of elongation

A

the tRNA in the A site moves to the P site, the tRNA in the P site goes to the E site. The A site is open for the next tRNA

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25
Q

What is the A site

A

Amino acid site

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26
Q

What is the P site

A

Polypeptide site

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27
Q

What is the e site

A

Exit site

28
Q

Where are the three sites?

A

On the large ribosomal subunit

29
Q

What happens in termination

A

A stop codon in the mRNA reaches the A site of the ribosome

30
Q

How does transcription work in retro viruses

A

Information flows from RNA to DNA, enzyme used called reverse transcriptase, viral RNA is coupled to DNA, DNA becomes part of RNA

31
Q

What is gene expression

A

The process by which DNA directs the synthesis of proteins

32
Q

What is transcription

A

The synthesis of RNA using information from DNA

33
Q

Where does transcription occur

A

Nucleus

34
Q

What is translation

A

The synthesis of a polypeptide using information from RNA

35
Q

Where does translation occur

A

At the ribosome

36
Q

Functions of tRNA

A

They carry amino acids and can attach to mRNA via their anticodon. They allow information to be translated into a peptide sequence

37
Q

What is the DNA strand that gets transcribed called

A

Template strand

38
Q

Transcribed mRNA strands are

A

Antiparallel and complementary to the DNA nucleotides

39
Q

What are the mRNA nucleotide triplets are called

A

Codons. Codons code for amino acids

40
Q

For most amino acids, there are multiple codons that can code for them. What is this called?

A

Redundancy

41
Q

Three steps of transcription

A

C Initiation
C Elongation
C Termination

42
Q

What happens in C Initiation

A

RNA polymerase attach to a promoter region of DNA (no primer needed)

43
Q

Where are promoter regions (transcription)

A

Upstream of the desired gene to transcribe

44
Q

C Initiation in eukaryotes

A

Promoter region is called TATA box, transcription factors help RNA polymerase bind

if DNA can’t unwind, no initiation can happen

45
Q

C initiation prokaryotes

A

RNA polymerase can bind directly to promoter

46
Q

Why is there a lagging strand

A

The strand runs in the 3’ to 5’ direction, but it must be built in the 5’ to 3’ direction. The lagging strand has to wait for a long segment of DNA to become unwound and exposed before replication can start with the addition of a primer

47
Q

What puts together the Okazaki fragments

A

Ligase

48
Q

What’s mismatch repair

A

A protein complex binds to mispaired bases, the mispaired base it cut out with enzymes and replaced by DNA polymerase

49
Q

What has to happen before dna replication can occur

A

Primase has to put RNA primers on the DNA template strand

50
Q

What’s the role of microRNA (mrRNA) in gene expression

A

microRNA helps pick which genes are expressed

51
Q

How does the process of horizontal/lateral gene transfer lead to genetic diversity

A

Organisms can acquire new genetic information from other organisms

52
Q

What’s transformation?

A

when cells can take in DNA that is placed near them, transformation is often used in experiments

53
Q

What are nucleotides made of

A

Nitrogen base, sugar, phosphate group

54
Q

How many rings do purines have

A

2

55
Q

DNA is made of

A

A sugar-phosphate backbone, nucleotides paired with hydrogen bonds

56
Q

How many bonds between A and T

A

2 hydrogen bonds

57
Q

How many bonds between C and G

A

3 hydrogen bonds

58
Q

Are plasmids part of the prokaryotic cells DNA

A

they are distinct from the chromosomal DNA

59
Q

Which strand is the leading strand

A

The one that runs 5 to 3 toward the replication fork

60
Q

Operons are only in

A

Prokaryotes

61
Q

Difference between DNA Polymerase I and DNA Polymerase III

A

DNA polymerase III does most of the replicating,Polymerase I removes RNA primers

62
Q

What does telomerase do

A

Adds DNA to the ends of chromosomes to keep them from being damaged, it also adds RNA bases to the 3’ end of the DNA strand in replication

63
Q

RNA primers function

A

It attaches to leading strand of DNA and allows DNA polymerase to add new nucleotides to the strand

64
Q

What’s morphogenesis

A

The shaping of an organism by embryological processes of differentiation

65
Q

What’s DNA sequencing

A

Determining the order of the bases that make up the DNA molecule

66
Q

What’s the 5’ cap on mRNA for

A

It keeps the mRNA from degrading

67
Q

Where do transcription factors bind

A

Enhancer on rna