Which one of the following lacks active site of $\text{RNA}$ polymerase?
- A$\alpha\alpha\ '\beta2\sigma$
- B$\alpha\beta\beta\ '\sigma$
- C$\alpha\alpha\ '\beta,\beta\ '\sigma$
- ✓$\alpha_2\beta\beta\ '$
Answer: D.
View full solution →Question types
Molecular Basis of Inheritance question types
850 questions across 7 question groups — pick any mix to generate a BIOLOGY paper with step-by-step answer keys.
850
Questions
7
Question groups
5
Question types
01
M.C.Q (1 Marks)
270 Q→021 Marks Question
222 Q→032 Marks Questions
149 Q→043 Marks Question
116 Q→055 Marks Questions
62 Q→06Assertion (A) & Reason (B) MCQ
20 Q→07Case study (4 Marks)
11 Q→Sample Questions
Molecular Basis of Inheritance questions
One sample from each question group in this chapter. Select any group above to see the full set with answer keys.
Sex is determined in human beings:
- ABy ovum.
- ✓At the time of fertilization.
- C$40$ days after fertilization.
- DSeventh to eight week when genitals differentiate in foetus.
Answer: B.
View full solution →Which one of the following codons codes for the same information as $\text{UGC}?$
- ✓$\text{UGU}$
- B$\text{UGA}$
- C$\text{UAG}$
- D$\text{UGG}$
Answer: A.
View full solution →The experimental system used in studies of the discovery of replication of $\text{DNA}$ has been:
- ADrosophila melanogaster
- BPneumococcus
- ✓Escherichia coli
- DNeurospora crassa
Answer: C.
View full solution →A person with $47$ chromosomes due to an additional $Y-$chromosome suffers from a condition called:
- ADown’s syndrome.
- BSuper female.
- CTurner’s syndrome.
- ✓Klinefelter’s syndrome.
Answer: D.
View full solution →Briefly describe the following:
Transcription.
Transcription.
Explain (in one or two lines) the function of the following:
Promoter.
Promoter.
If the sequence of the coding strand in a transcription unit is written as follows:
5'-ATGCATGCATGCATGCATGCATGCATGC-3'
Write down the sequence of mRNA.
5'-ATGCATGCATGCATGCATGCATGCATGC-3'
Write down the sequence of mRNA.
Briefly describe the following:
Translation.
Translation.
Explain (in one or two lines) the function of the following:
tRNA.
tRNA.
Why is the Human Genome project called a mega project?
Group the following as nitrogenous bases and nucleosides:
Adenine, Cytidine, Thymine, Guanosine, Uracil and Cytosine.
Adenine, Cytidine, Thymine, Guanosine, Uracil and Cytosine.
If a double stranded DNA has 20 per cent of cytosine, calculate the per cent of adenine in the DNA.
List two essential roles of ribosome during translation.
Depending upon the chemical nature of the template (DNA or RNA) and the nature of nucleic acids synthesised from it (DNA or RNA), list the types of nucleic acid polymerases.
What is DNA fingerprinting? Mention its application.
Differentiate between the following:mRNA and tRNA.
Which property of DNA double helix led Watson and Crick to hypothesise semi-conservative mode of DNA replication? Explain.
How did Hershey and Chase differentiate between DNA and protein in their experiment while proving that DNA is the genetic material?
Differentiate between the following:Template strand and Coding strand.
In the medium where E. coli was growing, lactose was added, which induced the lac operon. Then, why does lac operon shut down some time after addition of lactose in the medium?
Differentiate between the genetic codes given below:
- Unambiguous and Universal.
- Degenerate and Initiator.
Define a cistron. Giving examples differentiate between monocistronic and polyeistronic transcription unit.
Who revealed biochemical nature of the transforming principle? How was it done?
Match the terms in Column I with those in Column II.
|
S. No.
|
Column I
|
|
Column II
|
|
A
|
Transcription
|
1
|
A set of three bases on RNA that is complementary to the bases of codon on mRNA.
|
|
B
|
Anticodon
|
2
|
A unit of DNA that codes for a polypeptide.
|
|
C
|
Cistron
|
3
|
Process of synthesis of polypeptide as dictated by mRNA.
|
|
D
|
Translation
|
4
|
Process by which mRNA carries the information from nucleus to ribosomes.
|
For two statements are given$-$one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below.
Assertion: Same $\text{tRNA}$ can recognise more than one codons differing only at the third position.
Reason : The specificity of a codon is particularly determined by the first two bases.
Assertion: Same $\text{tRNA}$ can recognise more than one codons differing only at the third position.
Reason : The specificity of a codon is particularly determined by the first two bases.
- ✓Both assertion and reason are true, and reason is the correct explanation of assertion.
- BBoth assertion and reason are true, but reason is not the correct explanation of assertion.
- CAssertion is true, but reason is false.
- DBoth assertion and reason are false
Answer: A.
View full solution →For two statements are given$-$one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below.
Assertion : Constitutive genes are continuously being expressed.
Reason : Constitutive genes are frequently needed for various metabolic functions.
Assertion : Constitutive genes are continuously being expressed.
Reason : Constitutive genes are frequently needed for various metabolic functions.
- ✓Both assertion and reason are true, and reason is the correct explanation of assertion.
- BBoth assertion and reason are true, but reason is not the correct explanation of assertion.
- CAssertion is true, but reason is false.
- DBoth assertion and reason are false
Answer: A.
View full solution →For two statements are given$-$one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below.
Assertion: Core enzyme catalyses chain elongation of $\text{RNA}.$
Reason: The presence of sigma factor is required for initiation of transcription.
Assertion: Core enzyme catalyses chain elongation of $\text{RNA}.$
Reason: The presence of sigma factor is required for initiation of transcription.
- ABoth assertion and reason are true, and reason is the correct explanation of assertion.
- ✓Both assertion and reason are true, but reason is not the correct explanation of assertion.
- CAssertion is true, but reason is false.
- DBoth assertion and reason are false.
Answer: B.
View full solution →For two statements are given$-$one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below.
Assertion: The genetic code is degenerate.
Reason : for a particular amino acid more than one codons can be used.
Assertion: The genetic code is degenerate.
Reason : for a particular amino acid more than one codons can be used.
- ✓Both assertion and reason are true, and reason is the correct explanation of assertion.
- BBoth assertion and reason are true, but reason is not the correct explanation of assertion.
- CAssertion is true, but reason is false.
- DBoth assertion and reason are false
Answer: A.
View full solution →For two statements are given$-$one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below.
Assertion: No lac $\text{mRNA}$ is made in the presence of glucose.
Reason: In the presence of glucose and lactose activity of lac operon is not needed.
Assertion: No lac $\text{mRNA}$ is made in the presence of glucose.
Reason: In the presence of glucose and lactose activity of lac operon is not needed.
- ✓Both assertion and reason are true, and reason is the correct explanation of assertion.
- BBoth assertion and reason are true, but reason is not the correct explanation of assertion.
- CAssertion is true, but reason is false.
- DBoth assertion and reason are false
Answer: A.
View full solution →Why are vectors needed for replication of DNA during rDNA technology?
Read the following and answer any four questions from (i) to (v) given below:DNA replication is a complex multistep process that requires enzymes, protein factors and metal ions. DNA replication in eukaryotes occurs in the nucleus during the S-phase of the cell cycle. It is semidiscontinuous in eukaryotes. in prokaryotes, replication takes place in the cytoplasm. DNA replication in bacteria occurs prior to fission. Nucleoid or viral chromosome is a single molecule of nucleic acid, it may be linear of circular. Nucleic acid in a virus is either DNA or RNA but never both.
View full solution →- In viral DNA, how many origin of replication are present?
- Single
- Twice
- Multiple
- None
- Select the main enzyme involved in DNA replication.
- DNA ligase
- DNA dependent DNA polymerase
- Topoisomerase
- Helicase
- Read the given statement and select the option that correctly fill in the blanks. Enzyme (i) acts over the Ori site and unwinds the two strands of DNA by destroying (ii) bonds.
- (i)-Helicase (ii) Glycosidic
- (i)-Helicase (ii)-Hydrogen
- (i)-Unwindase (ii)-Phosphodiester
- (i)-Unwindase (ii)-Glycosidic
- DNA strand, built up of Okazaki fragments, is called.
- Lagging strand.
- Leading strand.
- Complementary strand.
- Parental strand.
- Select the incorrect statement about DNA polymerase in eukaryotes.
- Polymerase $\alpha$ is required for initiation of replication.
- When the RNA primer gets removed the gap is filled by DNA polymerase $\beta$ in eukaryotes.
- Polymerase $\in$ helps in elongation of lagging strand.
- Polymerase $\delta$ is largest and main enzyme for DNA replication in eukaryotes.
Read the following and answer any four questions from (i) to (v) given below:
In prokaryotes, DNA is circular and present in the cytoplasm but in eukaryotes, DNA is linear and mainly confined to the nucleus. DNA or deoxyribonucleic acid is a long polymer of nucleotides. In 1953, the first correct double-helical structure of DNA was worked out by Watson and Crick. Based on the X-ray diffraction data produced by Maurice Wilkins and Rosalind Franklin. It is composed of three components, i.e., A phosphate group, a deoxyribose sugar and a nitrogenous base. Different forms of DNA are B-DNA, Z-DNA, A-DNA, C-DNA and D-DNA.
In prokaryotes, DNA is circular and present in the cytoplasm but in eukaryotes, DNA is linear and mainly confined to the nucleus. DNA or deoxyribonucleic acid is a long polymer of nucleotides. In 1953, the first correct double-helical structure of DNA was worked out by Watson and Crick. Based on the X-ray diffraction data produced by Maurice Wilkins and Rosalind Franklin. It is composed of three components, i.e., A phosphate group, a deoxyribose sugar and a nitrogenous base. Different forms of DNA are B-DNA, Z-DNA, A-DNA, C-DNA and D-DNA.
- Name the linkage present between the nitrogen base and pentose sugar in DNA.
- Phosphodiester bond
- Phosphodiester bond
- Hydrogen bond
- None of these
- The double helix structure of DNA was proposed by.
- James Watson and Francis Crick.
- Earwin Chargaff
- Federick Griffith
- Hershey and Chase.
- The double chain of B-DNA is coiled in a helical fashion. The spiral twisting of B-DNA duplex produces.
- Right and left part.
- Major and minor grooves.
- Upper and lower side.
- Linear and circular part.
- Assertion: The two strands of DNA helix have uniform distance between them.
- Both assertion and reason are true and reason is the correct explanation of assertion.
- Both assertion and reason are true but reason is not the correct explanation of assertion.
- Assertion is true but reason is false.
- Both assertion and reason are false.
- Which of the following describes the structure of B-DNA?
|
S.no
|
Polynudeotide chains
|
Polynudeotide chains
|
|
(a)
|
Parallel
|
5
|
|
(b)
|
Anti-parallel
|
10
|
|
(c)
|
Parallel
|
15
|
|
(d)
|
Anti-parallel
|
20
|
Read the following and answer any four questions from (i) to (v) given below:
Mutation explains the relationship between gene and DNA. The effects of large deletions and rearrangement in a segment of DNA results in loss or gain of gene and its function. Insertion or deletion of one or two bases changes the reading frame from the point of insertion or deletion. A classical example of point mutation is a change of single base pair in the gene for beta globin chain that results in change of amino acid residue glutamate to valine and results into a diseased condition called sickle cell anaemia.
Mutant A-G-C-A-T-G-C-A-T-C-C-T
The table shows six codons and the corresponding amino acids into which each is translated.
The mutation has changed the amino acid.
mRNA codons for these amino acids are
Glutamine (Glu) GAA GAG
Praline (Pro) CCU CCC
Threonine (Thr) ACU ACC
Valine (Val) GUA GUG
Which transfer RNA molecule is involved in the formation of this part of the sickle cell haemoglobin?
Mutation explains the relationship between gene and DNA. The effects of large deletions and rearrangement in a segment of DNA results in loss or gain of gene and its function. Insertion or deletion of one or two bases changes the reading frame from the point of insertion or deletion. A classical example of point mutation is a change of single base pair in the gene for beta globin chain that results in change of amino acid residue glutamate to valine and results into a diseased condition called sickle cell anaemia.
- A mutation is a change produced by an alteration in the genetic mechanism and.
- May arise spontaneously.
- Is always induced by the environment.
- Is never advantageous.
- Is not inherited.
- The DNA code for glutamic acid is CTC or CTT. The code for valine is CAA or CAT. In sickle cell haemoglobin, valine is present instead of glutamic acid.
- CUU
- GAA
- GAG
- GUA
- A mutation involving the substitution of one nitrogenous base for another has altered the base sequence of a DNA molecule, coding for four amino acids, as shown below.
Mutant A-G-C-A-T-G-C-A-T-C-C-T
The table shows six codons and the corresponding amino acids into which each is translated.
|
mRNA codon
|
Amino acid
|
|
AAG
|
Lysine
|
|
CUA
|
Leucine
|
|
GGA
|
Glycine
|
|
GUA
|
Valine
|
|
UAC
|
Tyrosine
|
|
UCG
|
Serine
|
- Leucine to valine.
- Lysine to glycine.
- Serine to leucine.
- Tyrosine to lysine.
- Assertion : Insertion or deletion of three or its multiple bases, insert or delete one or multiple codons and so one or multiple amino acids.
- Both assertion and reason are true, and reason is the correct explanation of assertion.
- Both assertion and reason are true, but reason is not the correct explanation of assertion.
- Assertion is true, but reason is false.
- Both assertion and reason are false.
- Part of the amino acid sequences in normal and sickle cell haemoglobin are shown.
| Normal haemoglobin | Sickle cell haemoglobin |
| Thr-Pro-Glu-Glu | Thr-Pro-Val-Glu |
Glutamine (Glu) GAA GAG
Praline (Pro) CCU CCC
Threonine (Thr) ACU ACC
Valine (Val) GUA GUG
Which transfer RNA molecule is involved in the formation of this part of the sickle cell haemoglobin?
Read the following and answer any four questions from (i) to (v) given below:
Translation is the process of polymerisation of amino acids to form a polypeptide. The order and sequence of amino acids are defined by the sequence bases in the mRNA. The amino acids are joined by a bond called peptide bond. Ribosome is the site of protein synthesis.
View full solution →Translation is the process of polymerisation of amino acids to form a polypeptide. The order and sequence of amino acids are defined by the sequence bases in the mRNA. The amino acids are joined by a bond called peptide bond. Ribosome is the site of protein synthesis.
- Which ion is essential for association of both units of ribosome at the time of protein formation?
- $\mathrm{Mg}^{2+}$
- $\mathrm{Mn}^{2+}$
- $\mathrm{Cl}^{-}$
- $\mathrm{Ca}^{2+}$
- During translation, how many initiation factors are required in eukaryotes for initiation reactions?
- 3
- 6
- 7
- 9
- Which part of mRNA contains untranslated regions (UTR)?
- 3' end
- 5' end
- Either 3' or 5' end
- Both 5' end and 3' end
- Name the enzyme that helps in combining amino acid to its particular tRNA?
- Activating enzyme
- Amino-acyl tRNA-synthetas
- PeptidyI transferase
- Both (a) and (b)
- From the given list, select the translation machinery.
- mRNA
- Ribosomes
- Amino acids
- tRNAs
- Peptidyl transferase
- Amino acyl tRNA synthetase
- Pyrophosphatase
- (1), (2), (3), (4) and (6)
- (1), (2), (3), (4) and (5)
- (1), (2), (3), (4), (5) and (6)
- (1), (2), (3), (4), (5), (6) and (7)
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