Molecular Basis of Inheritance - Online Test
Q1. Write and codon for anticodon on the t-RNA
Answer : Option B
Explaination / Solution:
The codon for anticodon UCA on t-RNA is AGU. U bonds with A and G bonds with U in RNA. t-RNA carries specific amino acids to form protein molecules.
Q2. During protein synthesis, AUG functions as the initiator codon in mRNA. What should be the anticodon on the t-RNA molecule that picks up and brings the amino acid specified by this codon?
Answer : Option A
Explaination / Solution:
The anticodon on the t-RNA corresponding to AUG initiator codon on mRNA is UAC as A bonds with U and G bonds with C in RNA. Thymine (T) is absent in RNA.
Q3. According to the lac-operon concept, which functional unit of the bacterial gene material is responsible for suppressing the activity of the operator gene in the absence of lactose?
Answer : Option D
Explaination / Solution:
A regulator gene is a gene that codes for a repressor protein that inhibits the activity of an operator gene (a gene which binds repressor proteins thus inhibiting the translation of RNA to protein via RNA polymerase). In prokaryotes, regulator genes often code for repressor proteins.
Q4. Removal of introns and joining of exons in a defined order during transcription is called
Answer : Option C
Explaination / Solution:
The mRNA produced by transcription of DNA consists of exons and introns. The removal of introns and joining of exons to obtain mature mRNA is called splicing. It is followed by capping and tailing.
Q5. What does "lac" refer to in what we call the lac operon?
Answer : Option D
Explaination / Solution:
The lac operon (lactose operon) is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria. Although glucose is the preferred carbon source for most bacteria, the lac operon allows for the effective digestion of lactose when glucose is not available.
Q6. The primary control of gene expression takes place at the level of
Answer : Option D
Explaination / Solution:
Expression of gene starts with transcription of particular segment of DNA, so primary control of gene expression takes place at the level of transcription of DNA into m-RNA.
Q7. The sequence of structural gene in lac operon concept is
Answer : Option A
Explaination / Solution:
In lac operon concept the sequence of arrangement of structural gene is as lac Z, lac Y and lac A. The z gene codes for beta-galactosidase. The y gene code for permease and a gene encodes a transacytylase.
Q8. Removal of RNA polymerase III from nucleoplasm will affect the synthesis of
Answer : Option B
Explaination / Solution:
During transcription of m-RNA, removal of RNA polymerase III form nucleoplasm will affect the synthesis of t-RNA. The t-RNA transfers the amino acids to the site of translation to form protein.
Q9. Production of a human protein in bacteria by genetic engineering is possible because
Answer : Option C
Explaination / Solution:
Human protein can be produced in bacteria by genetic engineering because genetic code is universal i.e. same codon in different organism’s code for same amino acids.
Q10. What does X replesent in the followwing diagram:
Answer : Option C
Explaination / Solution:
Figure shown above represent translation process in which protein is produced. Ribosome provide site for protein synthesis and t-RNA brings the amino acids. The ‘x’ is the polypeptide chain produced.
