Question 1:
The sequence of nitrogenous bases in a segment of a coding strand of DNA is $5^{\prime} \text{-AATGCTAGGCAC- } 3^{\prime}$. Choose the option that shows the correct sequence of nitrogenous bases in the mRNA transcribed by the DNA.
Question 2:
The phosphoester linkage in the nucleotides is between
Question 3:
Given below is a heterogeneous RNA formed during Eukaryotic transcription : [Diagram is implied but not provided in text]. $5^{\prime} \rightarrow 3^{\prime}$. How many introns and exons respectively are present in the hnRNA?
Question 4:
Study the items of Column-I and those of Column-II:
Column-I: (a) RNA polymerase I, (b) RNA polymerase II, (c) RNA polymerase III.
Column-II: (i) $18s$ rRNA, (ii) SnRNAS, (iii) hnRNA.
Choose the option that correctly matches the items of Column-I with those of Column-II :
Column-I: (a) RNA polymerase I, (b) RNA polymerase II, (c) RNA polymerase III.
Column-II: (i) $18s$ rRNA, (ii) SnRNAS, (iii) hnRNA.
Choose the option that correctly matches the items of Column-I with those of Column-II :
Question 5:
If Meselson and Stahl's experiment is continued for $80$ minutes (till III generation) then what would be the ratio of DNA containing $N^{15}/N^{15} : N^{15}/N^{14}:N^{14}/N^{14}$ in the medium ?
Question 6:
What are minisatellites ?
Question 7:
The process of splicing in eukaryotes represents the dominance of the :
Question 8:
Regulation of lac operon by repressor is referred to as:
Question 9:
SNPs in Human Genome Project refers to :
Question 10:
The histone core in a nucleosome of chromatin thread is a/an:
Question 11:
During the process of transcription, after binding to a promoter, RNA polymerase catalyses and makes the bases in the template strand of DNA available for base pairing, with the bases of:
Question 12:
What would happen if a gene encoding a polypeptide of $50$ amino acids, $25^{th}$ Codon (UAU) is mutated to "UAA"?
Question 13:
The correct depiction of the centrifugation step of the experiment conducted by Alfred Hershey and Martha Chase on using radioactive labelled phages to prove that DNA is the genetic material is :
Options are complex table structures. Option (A) is the biologically correct outcome for the test.
No Radioactive ($^{35} ext{S}$) detected in cells + Radioactive ($^{35} ext{S}$) detected in supernatant AND Radioactive ($^{32} ext{P}$) detected in cells + No Radioactivity detected in supernatant
Options are complex table structures. Option (A) is the biologically correct outcome for the test.
No Radioactive ($^{35} ext{S}$) detected in cells + Radioactive ($^{35} ext{S}$) detected in supernatant AND Radioactive ($^{32} ext{P}$) detected in cells + No Radioactivity detected in supernatant
Question 14:
The histone core in a nucleosome of chromatin thread is a/an:
Question 15:
During the process of transcription, after binding to a promoter, RNA polymerase catalyses and makes the bases in the template strand of DNA available for base pairing, with the bases of:
Question 16:
What would happen if a gene encoding a polypeptide of $50$ amino acids, $25^{th}$ Codon (UAU) is mutated to "UAA"?
Question 17:
The correct depiction of the centrifugation step of the experiment conducted by Alfred Hershey and Martha Chase on using radioactive labelled phages to prove that DNA is the genetic material is :
Options are complex table structures. Option (A) is the biologically correct outcome for the test.
No Radioactive ($^{35} ext{S}$) detected in cells + Radioactive ($^{35} ext{S}$) detected in supernatant AND Radioactive ($^{32} ext{P}$) detected in cells + No Radioactivity detected in supernatant
Options are complex table structures. Option (A) is the biologically correct outcome for the test.
No Radioactive ($^{35} ext{S}$) detected in cells + Radioactive ($^{35} ext{S}$) detected in supernatant AND Radioactive ($^{32} ext{P}$) detected in cells + No Radioactivity detected in supernatant
Question 18:
The histone core in a nucleosome of chromatin thread is a/an:
Question 19:
During the process of transcription, after binding to a promoter, RNA polymerase catalyses and makes the bases in the template strand of DNA available for base pairing, with the bases of:
Question 20:
What would happen if a gene encoding a polypeptide of $50$ amino acids, $25^{th}$ Codon (UAU) is mutated to "UAA"?
Question 21:
The correct depiction of the centrifugation step of the experiment conducted by Alfred Hershey and Martha Chase on using radioactive labelled phages to prove that DNA is the genetic material is :
Options are complex table structures. Option (A) is the biologically correct outcome for the test.
No Radioactive ($^{35} ext{S}$) detected in cells + Radioactive ($^{35} ext{S}$) detected in supernatant AND Radioactive ($^{32} ext{P}$) detected in cells + No Radioactivity detected in supernatant
Options are complex table structures. Option (A) is the biologically correct outcome for the test.
No Radioactive ($^{35} ext{S}$) detected in cells + Radioactive ($^{35} ext{S}$) detected in supernatant AND Radioactive ($^{32} ext{P}$) detected in cells + No Radioactivity detected in supernatant
Question 22:
In its extended 'beads-on-string' form of chromatin, the 'beads' in the string represent:
Question 23:
The substrate used during DNA replication by the enzyme DNA-dependent DNA polymerase is :
Question 24:
Use the given information to select the amino acid attached to the $3^{\prime}$ end of tRNA during the process of translation, if the coding strand of the structural gene being transcribed has the nucleotide sequence TAC.
Codons for the amino acids :
AUC-Isoleucine
AUG-Methionine
UAC-Tyrosine
GUA - Valine
Codons for the amino acids :
AUC-Isoleucine
AUG-Methionine
UAC-Tyrosine
GUA - Valine
Question 25:
The correct depiction of the experiment performed by Matthew Meselson and Franklin Stahl to prove that DNA replicates semi-conservatively on separation of DNA by centrifugation after 40 minutes is: [Diagram is implied by the options in the source document]
Question 26:
Match the following genes of the lac operon listed in column 'A' with their respective products listed in column 'B' :
Select the correct option :
| A Gene | B Products |
|---|---|
| a. 'i' gene | (i) $\beta$-galactosidase |
| b. 'z' gene | (ii) lac permease |
| c. 'a' gene | (iii) repressor |
| d. 'y' gene | (iv) transacetylase |
Question 27:
If the sequence of nitrogen bases of the coding strand in a transcription unit is $5^{\prime} - ATGAATG - 3^{\prime}$, the sequence of bases in its RNA transcript would be
Question 28:
Assertion (A): One of the property of genetic code is degeneracy.
Reason (R): Some amino acids can be coded by more than one codon.
Question 29:
Assertion (A): Replication of DNA takes place in S phase of the cell cycle.
Reason (R): DNA replication and cell division cycle should be highly coordinated.
Reason (R): DNA replication and cell division cycle should be highly coordinated.
Question 30:
Study the given molecular structure of double-stranded polynucleotide chain of DNA and answer the questions that follow. [Diagram of DNA implied]
- (a) How many phosphodiester bonds are present in the given double-stranded polynucleotide chain ?
- (b) How many base pairs are there in each helical turn of double helix structure of DNA? Also write the distance between a base pair in a helix.
- (c) In addition to H-bonds, what confers additional stability to the helical structure of DNA?
Question 31:
Assume that the given mRNA (start site is not depicted) is theoretically translated in two reading frames.
(a) Translation starting from the first nucleotide (Reading frame 1)
$5^{\prime}$-CUCGCUUGCCGAUCAAGGGUUA - $3^{\prime}$
(b) Translation starting from the second nucleotide (Reading frame 2)
$5^{\prime}$-GUGGCACUCAGUCCUUAAUGGCG-3^{\prime}$
Answer the following question :
How many amino acids will be specified in case (a) and case (b) on translation? Justify your answer.
(a) Translation starting from the first nucleotide (Reading frame 1)
$5^{\prime}$-CUCGCUUGCCGAUCAAGGGUUA - $3^{\prime}$
(b) Translation starting from the second nucleotide (Reading frame 2)
$5^{\prime}$-GUGGCACUCAGUCCUUAAUGGCG-3^{\prime}$
Answer the following question :
How many amino acids will be specified in case (a) and case (b) on translation? Justify your answer.
Question 32:
If the base adenine constitutes $31\%$ of an isolated DNA fragment, then write what will be the expected percentage of the base cytosine in it. Explain how did you arrive at the answer given.
Question 33:
Study the diagram given below and answer the questions that follows: [Diagram].
(a) Identify the structure shown in the above figure.
(b) Identify the labels P and Q.
(c) Write the nature of histone proteins.
(d) Distinguish between Euchromatin and Heterochromatin.
Question 34:
A segment of DNA, 'TTG AGG GGG ATG' was translated into an oligopeptide with the amino acids, Lysine - Serine - Proline - Tyrosine.
- (a) Write the codons in correct sequence for the four amino acids.
- (b) If first adenine in DNA is substituted by guanine, what will be the sequence of amino acids in the new oligopeptide ?
- (c) Write the anticodons for these amino acids.
Question 35:
Explain how the addition of lactose in the medium regulates the switching on of the lac operon in bacteria.
Question 36:
Study the given below single strand of deoxyribonucleic acid depicted in the form of a "stick" diagram with $5^{\prime}$-$3^{\prime}$ end directionality, sugars as vertical lines and bases as single letter abbreviations and answer the questions that follow. [Diagram is implied with labels $5^{\prime}$, $3^{\prime}$, A, T, G, P, (OH), (a), (b)]
(a) Name the covalent bonds depicted as (a) and (b) in the form of slanting lines in the diagram.
(b) How many purines are present in the given "stick" diagram?
(c) Draw the chemical structure of the given polynucleotide chain of DNA.
(a) Name the covalent bonds depicted as (a) and (b) in the form of slanting lines in the diagram.
(b) How many purines are present in the given "stick" diagram?
(c) Draw the chemical structure of the given polynucleotide chain of DNA.
Question 37:
(a) Why does DNA replication occur within a replication fork and not in its entire length simultaneously?
(b) "DNA replication is continuous and discontinuous on the two strands within the replication fork." Explain with the help of a schematic representation.
(b) "DNA replication is continuous and discontinuous on the two strands within the replication fork." Explain with the help of a schematic representation.
Question 38:
Explain the processing of heterogeneous nuclear RNA (hnRNA) into a fully functional mRNA in eukaryotes. Where does this processing occur in the cell ?
Question 39:
According to Chargaff, almost all DNA-no matter what organism or tissue type it comes from maintains
certain properties, even as its composition varies. In particular, the amount of adenine (A) is usually
similar to the amount of thymine (T) and the amount of guanine (G) usually approximates the amount
of cytosine (C).
(i) A sample of DNA having 5375 nucleotides was analysed, out of which the propagation of different bases were : Adenine = 33%, Guanine 18%, Cytosine = 33%, Thymine = 17%. What can be concluded from this data?
(ii) If one strand of DNA has the following percentage. A = 26%, T = 23%, C = 24%, G = 27% What percentage will be found in the complementary strand?
(iii) If a sample of DNA has a cytosine content of 26%, what proportion of thymine do you expect?
Question 40:
OR (B) Explain with the help of well-labelled diagrams how lac operon operates in $\text{E. coli}$:
(i) In presence of an inducer.
(ii) In absence of an inducer.
Question 41:
(a) Write the features a molecule should have to act as a genetic material. In the light of the above features, evaluate and justify the suitability of the molecule that is preferred as an ideal genetic material.
OR
(b) Differentiate between the following :
OR
(b) Differentiate between the following :
- (i) Polygenic Inheritance and Pleiotropy
- (ii) Dominance, Codominance and Incomplete dominance
Question 42:
**OR**
(i) Why did Hershey and Chase use $^{35}S$ and $^{32}P$ in their experiment? Explain.
(ii) State the importance of (1) blending and (2) centrifugation in their experiment.
(iii) Write the conclusion they arrived at the end of their experiment.
(i) Why did Hershey and Chase use $^{35}S$ and $^{32}P$ in their experiment? Explain.
(ii) State the importance of (1) blending and (2) centrifugation in their experiment.
(iii) Write the conclusion they arrived at the end of their experiment.
Question 43:
The process of copying the genetic information from one strand of DNA into RNA is termed as transcription. The principle of complementarity of bases governs the process of transcription, also except that uracil comes in place of thymine.
Study the complete transcription unit given below and answer the following questions: [Diagram with labels A, B, C, D is implied]
A: $3^{\prime} \rightarrow 5^{\prime}$ strand
B: $5^{\prime} \rightarrow 3^{\prime}$ strand
(a) Name the main enzyme involved in the process of transcription.
(b) Identify coding strand and template strand of DNA in the transcription unit.
Attempt either sub-part (c) or (d) :
(c) Identify (C) and (D) in the diagram, mention their significance in the process of transcription.
OR
(d) Describe the location of (C) and (D) in the transcription unit.
Study the complete transcription unit given below and answer the following questions: [Diagram with labels A, B, C, D is implied]
A: $3^{\prime} \rightarrow 5^{\prime}$ strand
B: $5^{\prime} \rightarrow 3^{\prime}$ strand
(a) Name the main enzyme involved in the process of transcription.
(b) Identify coding strand and template strand of DNA in the transcription unit.
Attempt either sub-part (c) or (d) :
(c) Identify (C) and (D) in the diagram, mention their significance in the process of transcription.
OR
(d) Describe the location of (C) and (D) in the transcription unit.