Translation and Regulation

Q1: Which of the following statement is correct?

A The size and sequence of introns can be deduced from the cDNA sequence

B Restriction endonuclease can cleave ss and dsDNA both

C Restriction fragment length polymorphism (RFLP) is usually formed in coding sequence of a gene

D Amino acid sequence of a protein can be deduced from corresponding cDNA nucleotide

ANS:D - Amino acid sequence of a protein can be deduced from corresponding cDNA nucleotide

No answer description is available.

Q2: The ribosome binding site

A forms a stem-loop structure in the RNA

B is located upstream of the promoter sequence

C is located immediately upstream of the start codon

D is more likely to be associated with an operon than with a gene encoding a single protein

ANS:C - is located immediately upstream of the start codon

No answer description is available.

Q3: Which of the following molecule catalyzes the transpeptidation reaction?

A RNA polymerase

B Peptidyl transferase

C DNA ligase

D DNA polymerase

ANS:B - Peptidyl transferase

No answer description is available.

Q4: Negative regulation of protein synthesis is accomplished by

A allosteric inhibition

B the binding of RNA polymerase to the promoter

C the binding of a repressor to the DNA

D the binding of a repressor to the RNA polymerase

ANS:C - the binding of a repressor to the DNA

How the negative regulation occurred?

Q5: What is the maximum number of different amino acids in a polypeptide chain coded by the synthetic polyribonucleotides (UCAG)5?

A One

B Two

C Three

D Four

ANS:C - Three

Isn't it 4, amino acids that can coded by (UCAG) 5?

UCA GUC AGU CAG.

Anyone, please clarify this.

Q6: The interaction between the mRNA and tRNA determined the position of amino acid in a polypeptide sequence. This is called the

A stagerivity

B Wobble hypothesis

C promiscuity

D adaptor hypothesis

ANS:D - adaptor hypothesis

No answer description is available.

Q7: Which of the termination codon is called amber?

A UAA

B UAG

C UGA

D AUG

ANS:B - UAG

It is the name of the codon.

UAG- amber.
UAA- ochre.
UGA- opal.

Q8: Which phage always carries a small piece ofE.coli genome?

A Lambda

B Mu

C T4

D T3

ANS:B - Mu

Explain the answer please.

Q9: Which binding is inhibited by pactamycin?

A Aminoacyl-tRNA to the A-site of 30S subunit

B Initiator-tRNA to 30S/40S initiation complexes

C Peptidyl t-RNA to the 50S subunit

D Formation of peptide bond in P site

ANS:B - Initiator-tRNA to 30S/40S initiation complexes

What is pactamycin?

Q10: The nonsense codon(s) is/are

A UAG

B UAA

C UGA

D all of these

ANS:D - all of these

A nonsense codon is UAA, UAG, UGA.

Q11: What is the direct cause of cell death by diphtheria toxin?

A Formation of an ion channel in the cell membrane

B Inactivation of a translational elongation factor

C Induction of apoptosis

D None of the above

ANS:B - Inactivation of a translational elongation factor

No answer description is available.

Q12: What are the Svedberg values for the subunits of the 70S ribosomes of E. colli?

A 40S and 30S

B 50S and 20S

C 50S and 30S

D 40S and 20S

ANS:C - 50S and 30S

No answer description is available.

Q13: Which of the following is a nontranslated sequence located between the transcription and the translation start site?

A Ending frame

B Leader sequence

C Trailer sequence

D Reading frame

ANS:B - Leader sequence

No answer description is available.

Q14: The development of global regulatory systems in prokaryotes

A determines the exact location of the cell on the globe

B aids in DNA replication

C determines the exact location of the replication site

D regulates many genes under varying environmental conditions

ANS:D - regulates many genes under varying environmental conditions

No answer description is available.

Q15: The final step of gene expression is protein synthesis, which is also known as

A replication

B translation

C transcription

D none of these

ANS:B - translation

No answer description is available

Q16: Which of the following act as the blueprint or template for the process of protein synthesis that takes place on ribosomes?

A rRNA

B DNA

C tRNA

D mRNA

ANS:D - mRNA

Protein synthesis in ribosome is called translation. During translation the ribosome binds to the mRna and reads along it. The information (codon) read from mRna is then transferred to tRna and then amino acids coded for are synthesized.

Q17: Which of the following defines an open reading frame (ORF)?

A A sequence of genome in bacteriophage

B The sequence of a complete genome

C A plasmid vector used in genome sequencing

D A possible gene predicted by DNA sequencing

ANS:D - A possible gene predicted by DNA sequencing

No answer description is available

Q18: During amino acid activation a(n)

A amino acid is bound to tRNA

B amino acid is bound to mRNA

C methyl group is attached to rRNA

D methyl group is attached to an amino acid

ANS:A - amino acid is bound to tRNA

No answer description is available.

Q19: The Shine-Dalgarno sequence is

A trailer sequence

B a stop codon

C the reading frame of a gene

D a short sequence that acts as a ribosomal binding site

ANS:D - a short sequence that acts as a ribosomal binding site

No answer description is available.

Q20: Site in the ribosome from which the tRNA donates amino acids to the growing polypeptide chain is

A P site

B O site

C T site

D A site

ANS:A - P site

Before the termination process, the growing polypeptide chain is located on the A site so according to this.

The site where the tRNA donates the amino acid to the growing chain will be the A site as the growing chain is present on the A site.

Q21: When was the genetic code completed?

A 1958

B 1952

C 1966

D 1968

ANS:C - 1966

Yes, the genetic code was completed in 1966.

Q22: Which of the following modified amino acid is used at the starting of most prokaryotic proteins?

A N-formylserine

B N-formylmethionine

C N-formylleucine

D N-formylalanine

ANS:B - N-formylmethionine

No answer description is available.

Q23: Three stop codons, which aids in termination of translation are also known as

A pause codons

B nonsense codons

C missense codons

D antisense codons

ANS:B - nonsense codons

No answer description is available.

Q24: The role of molecular chaperones is to

A facilitate binding of ribosomes to mRNA

B degrade newly synthesized polypeptides that contain inaccurate sequences

C facilitate binding of RNA polymerase to DNA

D aid a newly synthesized polypeptide in folding to its proper shape

ANS:D - aid a newly synthesized polypeptide in folding to its proper shape

No answer description is available

Q25: What was the first bacterial genome to be sequenced and made public?

A Bacillus subtilis

B Escherichia coli

C Haemophilus influenzae

D No bacterial genome has been sequenced yet

ANS:C - Haemophilus influenzae

It's a viral genome.

Q26: Which of the following three codons translate as serine (Ser)?

A AGU

B CGA

C CAU

D AUG

ANS:A - AGU

No answer description is available.

Q27: Which stop codon has been found to encode selenocysteine?

A UAA

B UAG

C UGA

D AGA

ANS:C - UGA

Is there any Aminoacid coding for the rest to stop codons?

Anyone, please explain about it.

Q28: What is the action of tetracycline in prokaryotes?

A It blocks translocation reaction on ribosomes

B It blocks peptidyl transferase reaction on ribosomes

C It blocks the binding of amino-acyl tRNA to the A site of ribosomes

D Not known with certainity

ANS:C - It blocks the binding of amino-acyl tRNA to the A site of ribosomes

Then what about Puromycin?

Q29: A quorum sensing system

A detects a signal from the external environment

B senses a compound produced by the bacterium itself

C consists of a sensor component that phosphorylates a regulatory protein

D controls the activity of ribosomes directly

ANS:B - senses a compound produced by the bacterium itself

No answer description is available.



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