Transcription Unit

Q. The DNA dependent DNA polymerases catalyse polymerisation only in one direction, that is ___(i)___. The replication is continuous on the template strand with polarity ___(ii)___ . Replication is discontinuous on the template strand with polarity ___(iii)___.

Select the correct option for (i), (ii) and (iii).
[0.7 mark]

1. (i)	(ii)	(iii)
   $3^{\prime }\to 5^{\prime }$	$3^{\prime }\to 5^{\prime }$	$5^{\prime }\to 3^{\prime }$

2. (i)	(ii)	(iii)
   $5^{\prime }\to 3^{\prime }$	$3^{\prime }\to 5^{\prime }$	$5^{\prime }\to 3^{\prime }$

3. (i)	(ii)	(iii)
   $3^{\prime }\to 5^{\prime }$	$5^{\prime }\to 3^{\prime }$	$3^{\prime }\to 5^{\prime }$

4. (i)	(ii)	(iii)
   $5^{\prime }\to 3^{\prime }$	$5^{\prime }\to 3^{\prime }$	$3^{\prime }\to 5^{\prime }$

Q. Can you explain how PCR can detect very low amounts of DNA?

Q. Which of the following enzymes has been incorrectly matched with their function?

1. DNA polymerase – Joins nucleosides
2. Ligase – Molecular glue
3. RNA polymerase – Joins nucleotides
4. Endonuclease – Chemical scalpel

Q. During transcription, RNA polymerase binds to which site of DNA

1. Regulator
2. Promoter
3. Enhancer
4. Receptor

Q. The Polymerase Chain Reaction (PCR) is a technique that is used for _______i______ of specific DNA sequence using ______ii________.

1. i - in vivo replication,
   ii - thermostable DNA polymerase
2. i - in vitro replication,
   ii - thermostable DNA polymerase
3. i - in vitro replication,
   ii - mRNA sequence
4. i - in vivo replication,
   ii - any DNA polymerase

Q.

Assertion : Lac operon is an inducible system.

Reason: The product of gene activity stops the activity of the gene itself.

1. Both Assertion and Reason are true and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are true but Reason is not the correct explanation for Assertion
3. Assertion is true but Reason is false

4. Both Assertion and Reason are false

Q. Enzyme which can break and seal the DNA strand

1. Restriction endonuclease
2. Topoisomerase II
3. Helicase
4. Primase

Q. Study the given figure and name the three phases of PCR indicated by 1, 2 and 3.

1. 1-Denaturation, 2-Annealing, 3-Extension
2. 1-Renaturation, 2-Annealing, 3-Extension
3. 1-Denaturation, 2-Renaturation, 3-Annealing
4. 1-Annealing, 2-Renaturation, 3-Extension

Q. A vial with 10 microlitres of PCR mix has 100 template DNA molecules. The polymerase chain reaction was performed for 10 cycles. How many molecules of amplicons will be generated?

1. 10
2. 102400
3. 1024
4. 100

Q. Which among the following statements is/are correct?

Statement 1: In the double-stranded DNA, only one strand serves as a template for the duplication of the new DNA.

Statement 2: Leading strand is continuously synthesised in 5’-3’ direction and lagging strand is discontinuously synthesised in 3’-5’ direction.

Statement 3: DNA polymerase reads the template strand in 5’-3’ direction.

Statement 4: Replication proceeds only in 5’-3’ direction

Choose the correct option

1. Statement 1 only
2. Statement 1 and statement 3
3. Statement 2 and statement 4
4. Statement 4 only

Q.

Briefly describe the following:

(a) Transcription

(b) Polymorphism

(c) Translation

(d) Bioinformatics

Q. Which of the following statements are correct?
(i) RNA polymerase I transcribes rRNAs.
(ii) RNA polymerase II transcribes snRNAs.
(iii) RNA polymerase III transcribes hnRNA.
(iv) RNA polymerase II transcribes hnRNA.

1. (i) and (ii) are correct
   
2. (i) and (iii) are correct
3. (i) and (iv) are correct
4. (i), (ii) and (iv) are correct

Q.

Which RNA can induce gene silencing?

Q. Enzyme responsible for DNA chain elongation is

1. DNA polymerase
2. RNA polymerase
3. REN
4. DNA ligase

Q.

Do Eukaryotic cells have chromosomes?

Q. The cells in a culture plate were treated with a compound X. However, it was observed that the DNA replication was not occurring properly. On exploring the underlying defects by experiments, it was observed that the replication fork was not formed. Predict the enzyme that has been degraded by compound X.

1. Ligase
2. Helicase
3. Topoisomerase
4. DNA polymerase

Q. cDNA is copied from mRNA molecule the help of

1. Adenosine deaminase
2. DNA polymerase
3. Reverse transcriptase
4. Restriction enzyme

Q. Which gene in lac operon is active all the time and its product is responsible to switch off the operon?
[0.7 mark]

1. Promotor gene
2. Operator gene
3. Structural gene
4. Regulator gene

Q. Which among the following is a characteristic of a monocistronic mRNA

1. Has codons capable of synthesizing only a single protein
2. Combines with only a single tRNA
3. Has codons capable of synthesizing multiple protein.
4. Has multiple codons

Q. State the difference between the structural gene in a transcription unit of prokaryotes and eukaryotes.

Q. Which of the following is wrongly matched between column I and column II, with respect to Polymerase Chain Reaction (PCR)?

Column I	Column II
1. Primer	Oligonucleotide
2. Template	Double-stranded DNA
3. Polymerase	Taq polymerase
4. Synthesis	5’ to 3’ direction

1. 1 only
2. 1 and 3 only
3. 2 only
4. 2 and 4 only

Q. The direction in which new strand is synthesized during the process of replication is

1. 3’ $\to$ 5’
2. 5’ $\to$ 3’
3. Both a and b
4. None of the above

Q. A group of molecular biologists performed an experiment of transcription in which they used RNA polymerase without sigma (σ) factor. Which of the below statements will be more correct in this case?

1. Transcription will initiate from the initiation codon
2. Transcription will not take place
3. Sequence specific transcription will be taking place
4. RNA Polymerase will not work

Q. What is transcription? What are the different parts of a DNA transcription unit? What is their role in the process of transcription?

Q. What will be the number of bivalents present in typical human meiocyte?

Q. What is linkage group?

Q. Assertion :Transcription unit is often monocistronic in eukaryotes and polycistronic in prokaryotes . Reason: Exons do not appear in mature RNA, introns appear in mature RNA.

1. Assertion and Reason are true, Reason is correct explanation of Assertion.
   
2. Assertion and Reason are true, Reason is not the correct explanation of Assertion.
   
3. Assertion is true, Reason is false.
   
4. Assertion is false, Reason is true.

Q. During transcription, holoenzyme RNA polymerase binds to DNA sequence and DNA assumes a saddle like structure at that point. The sequence is called as

1. TATA box
2. GGCC box
3. AAAT box
4. CAAT box

Q. What is the function of DNA polymerase in RDT?

Q. Briefly describe the following:
(a) Transcription
(b) Polymorphism
(c) Translation
(d) Bioinformatics