Okazaki Fragments

Q.

Match the RNA polymerase types in column I with that of the product they synthesize in column II.

Column I	Column II
a. RNA pol. I	i. Synthesizes mRNA and hnRNA
b. RNA pol. II	ii. Synthesizes tRNA , 5 srRNA, Sn RNA in nucleolus
c. RNA pol. III	iii. Synthesizes rRNA (28S, 18S) in nucleolus

1. a- i, b – ii, c - iii

2. a – ii, b – iii, c – i
3. a – iii, b – i, c – ii
4. a – iii, b – ii, c – i

Q.

What is the unit of replication?

Q. The site on DNA where replication starts is called _______________.

1. GC region
2. parental strand
3. origin of replication or (ORI)
4. daughter strand

Q. How many of the following statements are correct?
I. If a linear DNA molecule is digested with a restriction enzyme at four recognition sites, 4 fragments would be produced.
II. If a closed circular DNA molecule is digested with a restriction enzyme at six recognition sites, 6 fragments would be produced.
III. If a linear DNA molecule is digested with a restriction enzyme at four recognition sites on the DNA, 5 fragments would be produced.
IV. If a closed circular DNA molecule is digested with a restriction enzyme at six recognition sites, 7 fragments would be produced.

1. 1
2. 2
3. 3
4. 4

Q.

Why do we need PCR primers?

Q.

An Okazaki fragment includes:

1. Only short fragments of deoxyribonucleotides

2. Only short RNA fragments

3. RNA primer + short fragments of deoxyribonucleotides

4. Only RNA primer

Q. Cohesive ends of DNA are produced by restriction endonuclease when

1. they cleave both strands of DNA so as to leave no unpaired bases on either end
2. they make staggered cuts on the two DNA strands leaving two to four nucleotides of one strand unpaired
3. they cut the methylated strand of host DNA by error
4. enzymatic digestion of DNA strand leave unpaired bases on both ends of the two strands

Q. Restriction endonucleases

1. synthesizes DNA
2. cuts the DNA molecule randomly
3. cuts the DNA molecule at specific sites
4. restricts the synthesis of DNA inside the nucleus

Q. The area of unwinding and separation of DNA strands during replication is called

1. Origin
2. Initiation point
3. Primer
4. Replication fork

Q. Which of the following statements given below are correct?
(A) BamHI and EcoRI have five and six base pair long recognition sequences, respectively.
(B) Roman number in the restriction enzyme name indicates the order in which it was isolated from the bacteria.
(C) Restriction endonuclease function by inspecting the length of a DNA molecule for recognition sequences.
(D) The palindrome in DNA reads the same on the two strands when orientation is kept the same.

Choose the correct option.

1. A, B, C
   
2. B and C only
   
3. B, C, D
   
4. All of the above
   

Q. A specific recognition sequence identified by endonucleases to make cuts at specific positions within the DNA is:

1. Poly (A) tail sequences
2. Degenerate primer sequence
3. Okazaki sequences
4. Palindromic Nucleotide sequences

Q. Which of the following is true for eukaryotic transcription?

1. In capping, nucleotide methyl cytosine triphosphate is added to 5’ end of hnRNA
2. RNA splicing is the removal of exons and joining of introns
3. 5S rRNA is transcribed by RNA polymerase I
4. Tailing at 3’ end of RNA is a template-independent process

Q. Which of the following DNA sequences is the recognition site for EcoR I enzyme?

1. 5’ GAATTC 3’
2. 5’ GGATCC 3’
3. 5’ AAGCTT 3’
4. 5’ CAGCTG 3’

Q. During replication of DNA, Okazaki fragments are formed in the direction of

1. $3^{\prime }\to 5^{\prime }$
2. $5^{\prime }\to 3^{\prime }$
3. $5^{\prime }\to 5^{\prime }$
4. $3^{\prime }\to 3^{\prime }$

Q. Which of the following statements regarding EcoR I is not correct?
I. It is isolated from Escherichia coli RY13.
II. Its recognition sequence is
5' GAATTC 3'
3' CTTAAG 5'
III. It produces complementary blunt ends.
IV. It was the first restriction endonuclease to be characterised.

1. I and II
2. II and IV
3. III and IV
4. I and IV

Q. Which of the following correctly depicts the endonuclease activity of EcoR I?

1. 
2. 
3. 
4. 

Q. How the sequence of origin of replication is responsible for controlling the copy no. of the linked dna?

Q.

During DNA replication, the lagging strand gets copied as short segments of 100-200 base pairs in length, which are known as

1. Okazaki fragments

2. Ori site

3. RNA primers

4. Replication fork

Q. Okazaki fragments form

1. Leading strand
2. Lagging strand
3. Sense strand
4. None of the above

Q. Semi-conservative replication of DNA was first demonstrated in

1. Drosophila melanogaster
2. Streptococcus pneumoniae
3. Salmonella typhimurium
4. Escherichia coli

Q.

An Okazaki fragment includes

1. Only short fragments of deoxyribonucleotides

2. Only short RNA fragments

3. RNA primer + short fragments of deoxyribonucleotides

4. Only RNA primer

Q. The site on DNA where replication starts is called _______________.

1. GC region
2. parental strand
3. origin of replication or (ORI)
4. daughter strand

Q. A DNA double helix is $340nm$ long. The number of nucleotides in this DNA is

1. $2000$
2. $200$
3. $1000$
4. $20$

Q. Which of the following correctly depicts the endonuclease activity of EcoR I?

1. 
2. 
3. 
4. 

Q. Name the scientists who generated first recombinant DNA molecules.

Q. During DNA replication, Okazaki fragments are used to elongate :

1. The leading strand towards replication fork
2. The lagging strand towards replication fork
3. The leading strand away from replication fork
4. The lagging strand away from replication fork

Q. Which of the following statements regarding EcoR I is not correct?
I. It is isolated from Escherichia coli RY13.
II. Its recognition sequence is
5' GAATTC 3'
3' CTTAAG 5'
III. It produces complementary blunt ends.
IV. It was the first restriction endonuclease to be characterised.

1. I and II
2. II and IV
3. III and IV
4. I and IV

Q. How many of the following statements are correct?
I. If a linear DNA molecule is digested with a restriction enzyme at four recognition sites, 4 fragments would be produced.
II. If a closed circular DNA molecule is digested with a restriction enzyme at six recognition sites, 6 fragments would be produced.
III. If a linear DNA molecule is digested with a restriction enzyme at four recognition sites on the DNA, 5 fragments would be produced.
IV. If a closed circular DNA molecule is digested with a restriction enzyme at six recognition sites, 7 fragments would be produced.

1. 1
2. 2
3. 3
4. 4

Q. The length of one full turn of DNA is

1. 3.4 $\mathring{A}$
2. 20.0 $\mathring{A}$
3. 34.0 $\mathring{A}$
4. 3.04 $\mathring{A}$

Q.

An Okazaki fragment includes

1. Only short fragments of deoxyribonucleotides

2. Only short RNA fragments

3. RNA primer + short fragments of deoxyribonucleotides

4. Only RNA primer