Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Genetics > Lecture 9 > Flashcards

Lecture 9 Flashcards

1
Q

what enzymes and proteins are essential to DNA synthesis?

A

DNA polymerase 3, SSBPs, DNA gyrase, DNA helicase, and RNA primers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

DNA polymerase 3

A

elongates and edits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

SSBPs

A

single stranded binding proteins; keeps ssDNA template ss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

DNA gyrase

A

relieves the coiling tension created by unwinding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

DNA helicase

A

pushes open the replication fork; unwinds to create single strands to be used as templates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

RNA primers

A

polymerase needs a 3’ end to add onto

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what features are similar in eukaryotic and bacterial DNA replication?

A
  • dsDNA unwounded at ORI
  • replication fork formed
  • bidirectional synthesis creates leading and lagging strands
  • eukaryotic polymerases also require 4 deozyribonucleoside triphosphates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

how does eukaryotic DNA differ from bacterial DNA?

A
  • more DNA
  • DNA is complexed with nucleosomes
  • linear chromosomes
  • have multiple ORIs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

bacterial and viral chromosomes

A
  • single nucleic acid molecule
  • largely devoid of associated proteins
  • much smaller
  • contain less genetic information
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

viral chromosomes

A
  • DNA or RNA; ds or ss
  • circular or linear
  • genetic material is nactive until released into host
  • packages long DNA into a small volume
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

bacterial chromosomes

A
  • circular, ds DNA
  • associated with histone proteins
  • readily replicated and transcribed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

supercoiled DNA

A
  • closed-circular molecules

- more compact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

topoisomerases

A
  • enzymes that cut one or both DNA strands

- wind or unwind helix before releases strands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

histones

A

-positively charged proteins associated with chromosomal DNA in eukaryotes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

at what phase can DNA make RNA?

A

when the chromatin is a relaxed structure; when it is tightly wound no transcription can be occur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

methylation

A

activates genes
can also repress genes
depends on what chemistry you are altering

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

phosphorylation

A

can promote demethylation

-can recruit proteins, those proteins can bind to this region and undo the work of the methyl group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

acetylation

A

represses genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

euchromatin

A

-uncoiled and active

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

heterochromatin

A

condensed areas, mostly inactive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

pseudogenes

A

single copy noncoding regions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

codon

A

triplet code, every three ribonucleotides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what does unambiguous mean in the genetic code?

A

each triplet codon specifies for only one amino acid

24
Q

what does degenerate mean in the genetic code?

A

a given amino acid can be specified by more than one triplet codon

25
what does commaless in genetic code mean?
once translation begins, there are no breaks in codons
26
mRNA
messenger RNA | serves as intermediate in transferring genetic information from DNA to proteins
27
how many codons are there? how many code for amino acids? what do the others do?
- 64 codons - 61 coding - the other 3 are termination signals
28
how many amino acids do the codons code for?
20
29
frameshift mutation
-insertions or deletions shift the reading frame and change the codons downstream
30
what are termination codons?
UAG, UAA, and UGA
31
reading frame
-contiguous sequence of nucleotides
32
nonoverlapping
- genetic code reads three nucleotides at a time in a continuous, linear manner - during translation, genetic code is nonoverlapping
33
triple binding assay
- developed by Nitenberg and Leder - ribosomes bind to a single codon of three nucleotides - complementary amino acid charged tRNA can bind
34
how does the genetic code show order?
chemically similar amino acids share one or two middle bases in triplets encoding them
35
wobble hypothesis
- the initial two ribonucleotides of triplet codons are often more critical than the third - the third position is less spatially constrained; need not adhere as strictly to established base-pairing rules
36
initiation codons
- methionine (AUG) - initial amino acid incorporated into all proteins - AUG is the only one to code for methionine
37
overlapping genes
- single mRNA has multiple initiation points - creates different reading frames - specifies more than one polypeptide
38
Open Reading Frame (ORF)
- overlapping genes - DNA sequence produces RNA with start and stop - series of triplet codons specify amino acids to make a polypeptide
39
transcription
- RNA synthesized on DNA template - genetic info stored in DNA transferred to RNA - serves as intermediate molecule between DNA and proteins - each triplet codon is complementary to anticodon of tRNA
40
what does transcription result in?
- in ssRNA - template is transcribed - transcription begins with template binding by RNA polymerase at promoter - alpha subunit is responsible for promoter recognition
41
promoter
specific DNA sequences in 5' region upstream of initial transcription point
42
RNA polymerase
- enzyme directs synthesis of RNA using DNA template - nucleotides contain ribose - no primer needed for initiation
43
transcription start site
- DNA double helix is unwound to make template strand accessible for RNA pol - interaction of promoter and RNA polymerase regulates efficiency of transcription
44
how does transcription differ in eukaryotes?
- occurs within a nucleus - mRNA must leave nucleus for translation - chromatin remodeling - RNA polymerase rely on transcription factors to scan/bind to DNA - enhancers and silencers control transcription regulation
45
chromatin remodeling
chromatin must uncoil to make DNA accessible to RNA pol
46
what are the three forms of RNA pol in eukaryotes?
RNA Polymerases 1,2,3
47
RNA Polymerase 2
-responsible for transcription of wide range of genes in euk -activity of RNAP2 is dependent on cis-acting elements and trans-acting transcription factors RNAP2 core-promoter determines where RNAP2 binds to DNA
48
what are the regulation sequences that influence the efficiency of transcription by RNAP2?
- proximal-promoter elements - enhancers - silencers
49
TATA box
- core promoter element | - determines start transcription site
50
enhancers
- binds activators | - increase transcription levels
51
silencers
- binds repressors | - decrease transcription factors
52
enhancers and silencers
- found unpstream, within, or downstream of a gene | - modulate transcription from a distance
53
posttranscriptional factors
- addition of 5' cap (7-mG cap) - addition of 3' tail (poly-A tail) - excision of introns
54
introns
- regions of initial RNA transcript not expressed in amino acid sequence of protein - DNA sequence not represented in final mRNA product - prokaryotes do not have them
55
heteroduplexes
introns present in DNA but not mRNA loop out
56
splicing
- introns are removed by splicing - exons are joined together in mature mRNA - mature mRNA is smaller than initial RNA

Genetics (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions