Ch 7: RNA and the Genetic Code Flashcards

1
Q

Central Dogma

A

DNA -> RNA -> proteins

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

degenerate code allows

A

multiple codons to encode for the same amino acid

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

Initiation (start) codon

A

AUG

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

Termination (stop) codon

A

UGA, UAA, UAG

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

redundancy and wobble (third base codon) allows

A

mutations to occur without effects in the protein

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

point mutations can cause

A

silent, nonsense (truncation), missense

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

silent mutations

A

with no effect on protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

nonsense (truncation) mutations

A

produce a premature stop codon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

missense mutations

A

produce a codon that codes for a different amino acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

frameshift mutations

A

result from nucleotide addition or deletion, and change the reading frame of subsequent codons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

RNA is structurally similar to DNA except

A

substitution of a ribose sugar for deoxyribose
substitution of uracil for thymine
single-stranded instead of double-stranded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

3 types of RNA with separate jobs during transcription

A

messenger, transfer, and ribosomal

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

messenger RNA (mRNA)

A

carries the message from DNA in the nucleus via transcription of the gene; travels into the cytoplasm to be translated

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

transfer RNA (tRNA)

A

brings in amino acids, recognizes the codon on the mRNA using its anticodon

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

Ribosomal RNA (rRNA)

A

makes up the ribosome; enzymatically active

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

unwind the DNA double helix

A

helicase and topoisomerase

17
Q

RNA polymerase II

A

binds to the TATA box within the promoter region the gene (25 bp upstream from first transcribed base)

18
Q

hnRNA is synthesized from

A

DNA template (Antisense) strand

19
Q

posttranscriptional modifications include

A

7-methylguanylate triphosphate cap added to the 5’ end

polyadenosyl (poly-A) tail is added to the 3’ end

20
Q

Spicing is done by ___ and ____ in the ___ ; introns are removed in the ___ structure, and exons are ligated together

A

snRNA
snRNPs
lariat

21
Q

polycistronic genes

A

allows prokaryotic cells to increase their variability of gene products from one transcript through this; starting transcription in different sites the gene leads to different gene products

22
Q

alternative splicing

A

how eukaryotic cells increase variability of gene products ; by combining different exons in a modular fashion to acquire different gene products

23
Q

translates the codon into the correct amino acid

A

tRNA

24
Q

factories where translation (protein synthesis) occurs

A

ribosomes

25
Q

3 stages of translation are

A

initiation, elongation, and termination

26
Q

Initiation in prokaryotes

A

occurs when the 30S ribosome attaches to the Shine-Dalgarno sequence and scans for a start codon; it lays down N-formylmethionine in the P site of the ribosome

27
Q

Initiation is eukaryotes

A

occues when the 40S ribosome attaches to the 5’-cap and scans for a start codon; it lays down methionine on the P site of the ribosome

28
Q

Elongation involves the addition of

A

a new aminoacyl-tRNA into the A site of the ribosome and transfer of the growing polypeptide chain from the tRNA in the P site to the tRNA in the A site. The now uncharged tRNA pauses in the E site before exiting the ribosome

29
Q

Termination occurs when the codon in the

A

A site is a stop codon, release factor places a water molecule on the polypeptide chain and thus releases the protein

30
Q

help with each step in the recruitment and assembly/disassembly of the ribosome

A

initiation, elongation, and release factor

31
Q

posttranslational modifications include

A

folding by chaperones
formation of quaternary structure
cleavage of proteins or single sequence
covalent addition of other biomolecules (phosphorylation, carboxylation, glycosylation, prenylation)

32
Q

Jacob-Monad model explains

A

how operons work with repressors and activators

33
Q

operons

A

are inducible or repressible clusters of genes transcribed as a single mRNA

34
Q

inducible systems

A

bound by a repressor under normal conditions; they can be turned on by an inducer pulling the repressor from the operator site

lac operon

35
Q

repressible systems

A

transcribed under normal conditions; they can be turned off by a corepressor coupling with the repressor from the operator site

trp operon

36
Q

search for promoter and enhancer regions in the DNA

A

transcriptional factors (promoters, enhancers)

37
Q

within 25 base pairs of the transcription start site

A

promoter

38
Q

more than 25 bp away from the transcription start site

A

enhancers

39
Q

modifications of _____ affects the ability of transcriptional enzymes to access the DNA through ___ or ___

A

chromatin structure

histone acetylation (increases accesibility)
DNA methylation (decreases accessibility)