9.3 - 9.4 Flashcards

1
Q

Transfer RNA nucleotides

A

74-95 nucleotides (short)

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2
Q

Transfer RNA

A

small RNA adapter moelcule that, through complementary base pairing with codons in mRNA, places a specific amino acid at the correct position in a growing polypeptide chain at the ribosome

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3
Q

tRNA secondary structur

A

cloverleaf

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4
Q

tRNA tertiary structure

A

looks compact letter L

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5
Q

anticodon

A

codon in tRNA molecules that recognize codon on the mRNA by complementary base pairing and wobble

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6
Q

Amino acid is attached on

A

3’ end of tRNA

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7
Q

Aminoacyl-tRNA synthetases

A

enzymes that catalyze the attachment of tRNAs to the amino acids that corresponds to tRNA’s anticodon, forming charged tRNAs

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8
Q

Only molecules that read both nucleic acid and protein language

A

Aminoacyl-tRNA synthetases

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9
Q

One Aminoacyl-tRNA synthetases exists for

A

each of the 20 common amino aicds

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10
Q

Charged tRNA

A

a tRNA molecule to which the corresponding amino acid has been attached y an aminoacyl-tRNA synthetase (uses ATP)

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11
Q

Bond between the amino acid and tRNA contains substantial energy that is later used to form

A

peptide bonds

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12
Q

Amino acid attached to tRNA treated with nickel hydride

A

changes amino acid

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13
Q

Treatment with nickel hydride on anticodon

A

leaves anticodon unchanged

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14
Q

Specific interaction between a tRNA’s anticodon and mRNA’s codon determines

A

which amino acid is added to growing polypeptide chain

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15
Q

Wobble

A

the ability of the 5’-most base of an anticodon to pair with more than one type of base at the 3’ ends of codons

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16
Q

possible codon triplets in genetic code

A

61 possible codons

17
Q

E. Coli makes tRNAs containing 42 different anticodon

A

61-42 =19 of potential anticodons are not represented

18
Q

Do cells carry tRNA with anticodons complementary to all possible codons

A

no

19
Q

How can an organism construct proper polypeptides if some of the codon in its mRNAs cannot locate tRNAs with complementary anticodons?

A

Some tRNAs can recognize more than one codon for the amino acid with which they are charged

20
Q

U in the 5’ end of tRNA can bind

A

A or G in the codon 3’ end

21
Q

G in the 5’ end of the tRNA can

A

U or C in the codon’s 3’ end

22
Q

I (inosine) in the 5’ end pf tRNA can bind

A

A, U or C in the codon’s 3’ end

23
Q

Ribosome in eukaryotic

A

80S

24
Q

Ribosome in prokaryotic

A

70S

25
Q

Small subunit of ribosome

A

binds to mRNA

26
Q

Site of polypeptide synthesis

A

ribosomes

27
Q

Large subunit of ribosome

A

has peptidy transferase activity

28
Q

Parts of karge subunit of rubosome

A

Aminoacyl (A) site, Peptidy (P) site, Exit (E) site

29
Q

in prokaryotic what is the first amino acid in the polypeptide chain

A

N-formyl-methionine

30
Q

Translation of mRNAs on ribosomes for prokaryotes, during initiation phase what does ribosomes bind to

A

Shine-Dalgarno box and an AUG

31
Q

Shine-Dalgarno box

A

5’ - AGGAGG - 3’

32
Q

Translation of mRNAs on ribosomes for eukaryotes, during initiation

A

small ribosomal subunits binds to 5’ cap, then migrates to the first AUG codon

33
Q

Elongation phase in ribosomes

A

addition of AA to C-terminus of polypeptide

34
Q

Termination phase in ribosomes

A

No normal tRNAs carry anticodons for the stop codons
Release factors bind to the stop codon
Release of ribosomal subunits, mRNA, and polypeptide

35
Q

Posttranslational processing

A

Enzymatic cleavage
Addition of chemical constituents

36
Q

Enhancers can be located

A

upstream, downstream or within coding region
or intron of a gene

37
Q

Enhancers

A

Stabilize RNA polymerase at promoter and enhancers clear histones from promoter

38
Q

Prokaryotic translation

A

Multiple ribosomes binding sites and can direct synthesis of several different polypeptide and immediatiely binds to binding site of mRNA