Lesson 5 - RNA Translation

Question 1

the process in which a sequence of nucleotide triplets in a messenger RNA give rise to a specific sequence of amino acids during the synthesis of a polypeptide chain or protein

Answer 1

RNA translation

Question 2

Ribosomes translate the genetic message of mRNA into ____

Answer 2

Proteins

Question 3

The mRNA is translated 5’→3’, producing a corresponding _____ → _____ polypeptide

Answer 3

N-terminal
C-terminal

Question 4

Amino acids bound to tRNAs are inserted in the proper sequence due to (2)

Answer 4

Specific binding of each amino acid to its tRNA.

Specific base pairing between the mRNA codon and tRNA anticodon

Question 5

Translational Machinery (4)

Answer 5

mRNAs
tRNAs
Aminoacyl tRNA synthetase
Ribosome

Question 6

Provides an intermediate that carries the copy of DNA sequence that represents protein

Answer 6

Messenger RNA (mRNA)

Question 7

Protein coding region of mRNA is composed of a contiguous, non- overlapping string of codons called _____

Answer 7

Open Reading Frame (ORF)

Question 8

the site of attachment of the specific amino acid

Answer 8

Acceptor ARM

Question 9

involved in binding of the aminoacyl-tRNA to the ribosomal surface at the site of protein synthesis

Answer 9

Ribothymidine Pseudouridine Cytidine ARM

Question 10

recognition of a given tRNA species by its proper aminoacyl-tRNA synthase

Answer 10

D ARM

Question 11

(2) attachments of amino acids to RNA

Answer 11

Adenylation
Charging

Question 12

Provide specificity in joining amino acids to their RNAs

Answer 12

Amino Acyl tRNA Synthetase

Question 13

It directs the synthesis of proteins

Answer 13

Ribosome

Question 14

contains the peptidyl transferase center which is responsible for the formation of peptide bonds

Answer 14

Large subunit

Question 15

contains the decoding center in which charged tRNAs read or decode the codons of mRNA

Answer 15

Small subunit

Question 16

undergo association and dissociation during each cycle of translation

Answer 16

Large subunit and small subunit

Question 17

Prokaryotic Ribosome = ___S
Eukaryotic Ribosome = ____S

Answer 17

70; 80

Question 18

An mRNA bearing multiple ribosome is known as ____ or ____

Answer 18

Polyribosome; polysome

Question 19

binding site for the first aminocylated tRNA

Answer 19

A-site

Question 20

binding site for the first peptidyl tRNA

Answer 20

P-site

Question 21

binding site for the first uncharged tRNA

Answer 21

E-site

Question 22

Large subunit has an exit channel for ____

Answer 22

Newly synthesized polypeptide chain

Question 23

ordered series of three nucleotides specific for amino acids

Answer 23

Codon

Question 24

last codon of an ORF at the 3’end which define the signal termination of protein synthesis

Answer 24

Stop codon

Question 25

Features of Genetic Code (5)

Answer 25

Degenerate Unambiguous Non-overlapping Not punctuated Universal

Question 26

Feature of Genetic Code The reading of the genetic code during the process of protein synthesis does not involve any overlap of codons

Answer 26

Non-overlapping

Question 27

Feature of Genetic Code The code is the same in all organisms from viruses and bacteria to humans with few exceptions

Answer 27

Universal

Question 28

Steps of RNA Translation (3)

Answer 28

Initiation Elongation Termination

Question 29

The initiator tRNA is charged with with ____

Answer 29

Methionine

Question 30

(3) key events for correct addition of each amino acids

Answer 30

Correct aminoacyl-tRNA is loaded to the A site of the ribosome as dictated by the A site codon Peptidyl transferase reaction Translocation of peptidyl tRNA from A site of ribosome to the P site of ribosome

Question 31

Stop codons are recognized by proteins called ____

Answer 31

Release factors (RF)

Question 32

(2) classes of RF

Answer 32

Class 1 RFs Class 2 RFs

Question 33

recognize stop codon and trigger the hydrolysis of peptide chain from the peptidyl tRNA

Answer 33

Class 1 RFs

Question 34

stimulate the dissociation of class 1 RFs from the ribosome after the release of polypeptide

Answer 34

Class 2 RFs

Question 35

UGA Universal Code and Unusual Code

Answer 35

Stop; Trp

Question 36

CUG Universal Code and Unusual Code

Answer 36

Leu; Thr

Question 37

UAA, UAG Universal Code and Unusual Code

Answer 37

Stop; Gln

Question 38

UGA Universal Code and Unusual Code

Answer 38

Stop; Cys

Question 39

Occurrence in UGA

Answer 39

Mycoplasma Spiroplasma Mitochondria of many species

Question 40

Occurrence in CUG

Answer 40

Mitochondria in yeasts

Question 41

Occurence in UAA and UAG

Answer 41

Acetubularia Tetrahymena Paramecium Etc.

Question 42

Occurence in UGA

Answer 42

Euplotes

Question 43

Multiple codons must decode the same amino acid

Answer 43

Degenerate

Question 44

Once the reading is commenced at a specific codon, the message is read in a continuing sequence of nucleotide triplets until a stop codon is reached.

Answer 44

No punctuation

Question 45

For a given codon in the mRNA, only a ____ species of tRNA molecule possesses the proper anticodon

Answer 45

Single

Question 46

In general, the third nucleotide in a codon is less important than the ____ in determining the specific amino acid to be incorporated

Answer 46

First two

Question 47

First codon of an ORF present at the 5’ end

Answer 47

Start codon

Question 48

Entry and exit channel for mRNA

Answer 48

Ribosome

Question 49

an endergonic process that occurs at the expense of ATP, which loses two phosphate groups, becoming AMP

Answer 49

Linkage

Question 50

base pair complementary to mRNA codons

Answer 50

Anti-codon loop

Question 51

5’-CC—3’ which is the binding site of amino acids

Answer 51

Acceptor stem

Question 52

Consists of anti-codon loop and acceptor stem

Answer 52

Transfer RNA (tRNA)

Question 53

tRNA contains unusual and modified bases such as (5)

Answer 53

Uridine Thymine Pseudouridine Methyguanine Hypoxanthine Etc.