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Protein Synthesis MCQ Questions & Answers

Protein Synthesis MCQs : This section focuses on the "Protein Synthesis". These Multiple Choice Questions (MCQs) should be practiced to improve the Protein Synthesis skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.




Question 1

A polysome could be best described as

A. an active site of DNA synthesis.
B. an active site of protein synthesis.
C. an active site of lipid synthesis.
D. all of the above.

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Question 2

Phosphorus is taken up by the cell during the process of

A. carbohydrate synthesis.
B. protein synthesis,
C. lipid synthesis.
D. ATP synthesis.

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Question 3

The following set of RNA is required in the translation process except one, mark the INCORRECT?

A. Si RNA
B. rRNA
C. mRNA
D. tRNA

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Question 4

The eukaryotic mRNA binding to the ribosomes is facilitated by ____________

A. T-RNA
B. Poly-A tail
C. Shine Dalgarno sequence
D. 7-methyl guanosine cap

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Question 5

Mark the one, which is NOT a stop codon?

A. UAA
B. UAG
C. UGA
D. GGA

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Question 6

Name the drug which inhibits the initiation step of translation.

A. Cyclohexamine
B. Tetracycline
C. Ricin
D. Streptomycin

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Question 7

Bacteria have ____________

A. 70S ribosomes
B. 60S ribosomes
C. 50S ribosomes
D. 80S ribosomes

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Question 8

Which of the following is not a necessary component of translation?

A. Anticodon
B. mRNA
C. Ligase
D. Amino acid

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Question 9

What is the size of the prokaryotic ribosome?

A. 80S
B. 70S
C. 40S
D. 60S

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Question 10

Proteins contain __________ different amino acids, whereas DNA and RNA are composed of __________ different nucleotides

A. 20,64
B. 3,20
C. 4,20
D. 20,4

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Question 11

Which of the following catalyzes ADP-ribosylation of a diphthamide residue?

A. Chloramphenicol
B. Cycloheximide
C. Diphtheria toxin
D. Ricin

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Question 12

Degenerated codon differs mostly in

A. the identities of their second base
B. the identities of their third base
C. the wobble position
D. both (b) and (c)

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Question 13

Which of the following is not true to the nature of the genetic code?

A. Codon is triplet
B. Codons are commaless
C. Codons are overlapping
D. Codons are universal

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Question 14

Which is the third elongation step in bacteria?

A. Peptide bond formation
B. Binding of an incoming aminoacyl t-RNA
C. Translocation
D. None of the mentioned

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Question 15

Name the inhibitor which blocks translation in both prokaryotes as well as eukaryotes?

A. Chlorophenicol
B. Tetracycline
C. Puromycin
D. Streptomycin

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Question 16

The lac operon contains the z, y and a structural genes

A. encoding p-galactosidase, galactose permeases and thio-galactosidase transacetylase respectively
B. encoding p-galactosidase and galactose permeases
C. encoding P-galactosidase only
D. None of the above

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Question 17

Processive synthesis is a characteristic feature of

A. all DNA polymerases.
B. DNA Pol III at a replication fork.
C. removal of RNA primers on Okasaki fragments.
D. DNA mismatch repair

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Question 18

Ribosomes select the correct tRNAs

A. then bind to the appropriate mRNA
B. solely on the basis of their anticodons
C. depending on their abundance in the cytosol
D. with the least abundant anticodons

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Question 19

Which of the following has unusual bases?

A. mRNA
B. tRNA
C. rRNA
D. hnRNA

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Question 20

The structure in a bacterium that indicates an active site for protein synthesis is

A. a chromosome.
B. a cell membrane,
C. a flagellum.
D. a polysome.

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Question 21

The pathway of a tRNA during polypeptide elongation on the ribosome is

A. A site → P site → E site
B. P site → entry site → exit site
C. A site → P site → entry site
D. P site → A site → E site

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Question 22

Type I proteins (plasma membrane) have a

A. cleavage N- terminal signal sequence and a hydrophobic stop transfer sequence
B. cleavaged N- terminal signal sequence that doubles as the membrane anchoring sequence
C. multiple signal sequence and a hydrophobic stop transfer sequence
D. multiple signal sequence that doubles as the membrane anchoring sequence

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Question 23

Which of the following inhibitor block translation in eukaryotes?

A. Cyclohexamine
B. Tetracycline
C. Puromycin
D. Streptomycin

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Question 24

The direction of amino acid transfer to the growing polypeptide chain is

A. from the A (aminoacyl tRNA site) site to the P (peptidyl tRNA site) site on the ribosome
B. from the P site to the A site on the ribosome
C. from the A site to the E (exit tRNA site) site on the ribosome
D. from the P site to the E site on the ribosome

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Question 25

The site of protein synthesis is

A. Ribosome
B. Nucleus
C. Endoplasmic reticulum
D. Chromosome

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Question 26

Which of the following inhibits initiation at higher concentrations?

A. Chloramphenicol
B. Streptomycin
C. Diphtheria toxin
D. Ricin

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Question 27

tRNA has peptidal transferase activity.

A. True
B. False

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Question 28

On the ribosome, mRNA binds

A. between the subunits
B. to the large subunit
C. to the small subunit
D. none of these

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Question 29

What is the role of small nuclear RNAs in protein synthesis?

A. It translates genetic code to a specific amino acid
B. It modifies mRNA molecules prior to protein synthesis
C. It provides a genetic blueprint for the protein
D. It catalyzes the process

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Question 30

Conversion of messages carried by mRNA into amino acid sequences is called___________

A. Replication
B. DNA repair
C. Translation
D. Transcription

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Question 31

Translation in prokaryotes begins by the formation of a 30S initiation complex between the

A. 30S ribosomal subunit, mRNA, initiation factors and N-fMet tRNA
B. 30S ribosomal subunit, tRNA and initiation factors
C. 30S ribosomal subunit and mRNA only
D. 30S ribosomal subunit, mRNA and initiation factors

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Question 32

The anticodon of tRNA

A. binds to rRNA
B. binds to an amino acid
C. binds to the Shine Dalgarno sequence
D. binds to an mRNA codon

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Question 33

The peptidyl transferase reaction occurs

A. on the large subunit
B. on the small subunit
C. between the subunit
D. none of these

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Question 34

How many bases of nucleic acid determine a single amino acid?

A. Four
B. One
C. Two
D. Three

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Question 35

Which of the following inactivates the 60S subunit of eukaryotic ribosomes?

A. Chloramphenicol
B. Cycloheximide
C. Diphtheria toxin
D. Ricin

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Question 36

Eukaryotic mRNA binding to the ribosomes is facilitated by __________ .

A. the Shine Dalgarno sequence
B. the 7-methyl guanosine cap
C. tRNA
D. poly A tail

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Question 37

Which of the following amino acid starts all proteins synthesis?

A. Glycine
B. Proline
C. Thymine
D. Methionine

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Question 38

Which is required for protein synthesis?

A. tRNA
B. mRNA
C. rRNA
D. All of these

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Question 39

The first step in translation is

A. binding of the two ribosomal subunits to each other
B. binding of mRNA to the two ribosomal subunits
C. binding of tRNA to the small ribosomal subunit
D. binding of mRNA to the small ribosomal subunit

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Question 40

Which of the following is considered as a start codon?

A. AUG
B. GUG
C. UAG
D. AGG

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Question 41

Which of the following RNAs bind to an amino acid?

A. mRNA
B. tRNA
C. rRNA
D. hnRNA

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Question 42

What is the role of mRNA in protein synthesis?

A. It translates genetic code to a specific amino acid
B. It modifies mRNA molecules prior to protein synthesis
C. It provides a genetic blueprint for the protein
D. It catalyzes the process

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Question 43

The ribosomes are composed of

A. proteins
B. RNA
C. both (a) and (b)
D. lipids

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Question 44

Which of the following blocks the peptidyl transferase of 80S eukaryotic ribosomes?

A. Chloramphenicol
B. Cycloheximide
C. Diphtheria toxin
D. Ricin

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Question 45

The growing polypeptide chain is released from the ribosomes when

A. a chain terminating codon is reached
B. a chain terminating tRNA binds to the ribosome
C. the 7-methyl guanosine cap is reached
D. the poly A tail is reached

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Question 46

The site on a bacterial chromosome that marks the termination point for chromosome replication is called

A. ter
B. a stop codon.
C. a stem-loop
D. pau

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Question 47

Protein synthesis rates in prokaryotes are limited by the rate of mRNA synthesis. If RNA synthesis occurs at the rate of 50 nucleotides/sec, then rate of protein synthesis occurs at

A. 10 amino acids/sec
B. 17 amino acids/sec
C. 25 amino acids/sec
D. 50 amino acids/sec

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Question 48

Who explained the wobble hypothesis?

A. Darwin
B. Watson and Crick
C. Samuel B. Weiss
D. Nirenberg

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Question 49

Which of the following recognize a specific amino acid and its cognate t-RNA molecule?

A. t-RNA synthetase
B. Ribososme
C. r-RNA
D. Topoisomerase

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Question 50

In how many steps protein biosynthesis takes place?

A. 2
B. 3
C. 4
D. 5

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Question 51

Which site of the tRNA molecule binds to the mRNA molecule?

A. Anticodon
B. Codon
C. Amino acid
D. 5 prime end

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Question 52

Amino acids are joined together into a protein chain by which of the following?

A. Transfer RNA
B. DNA polymerase
C. Hydrogen bonds
D. Messenger RNA

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Question 53

Signal peptide protein removal that is translocated across a membrane is accomplished by

A. fMet aminopeptidase
B. trypsin
C. signal peptidase
D. chymotrypsin

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Question 54

Which of the following is not necessary for protein synthesis to occur, once transcription is completed?

A. tRNA
B. Ribosomes
C. mRNA
D. DNA

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Question 55

Name the sequence of RNA, which is recognized by a small subunit of the ribosome.

A. Rho utilization site
B. Downstream sequence
C. Upstream sequence
D. Shine Dalgarno sequence

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