Palindrome Sequences

Q. How many fragments will be generated if you digest a linear DNA molecule with a restriction enzyme having four recognition sites on the DNA?

1. 3
2. 6
3. 5
4. 4

Q.

What are the major grooves and minor grooves of DNA?

Q.

What are molecular scissors?

Q. The antiparallel nature of DNA strands helps in the formation of

1. Phosphate bonds
2. Phosphodiester bonds
3. Hydrogen bonds
4. Glycosidic bonds

Q.

The restriction enzyme EcoRI from E.coli is expected to cleave DNA at the following sequence

1. AAGTTC

2. GAATTC

3. AAGCTT

4. GTATATC

Q. Which one of the following is a palindromic base sequence in DNA that can be easily cut at at the middle by some particular restriction enzyme?

1. 5’-------------CATTCG--------------------3’
   3’-------------GTAAGC-------------------5’
2. 5’------------GATATG------------------3’
   3’------------CTATAC-------------------5’
3. 5’------------GAATTC-------------------3’
   3’-------------CTTAAG-------------------5’
4. 5’-------------CACGTA------------------3’
   3’-------------CTGCAT------------------5’

Q. The two strands of DNA are

1. Complementary and antiparallel
2. Complementary and parallel.
3. Similar and parallel
4. Similar but antiparallel

Q. Which one of the following represents a palindromic sequence in DNA?

1. 5'- GAATTC-3'
   3'-CTTAAG-5'
2. 5' -CATTAG-3'
   3'-GATAAC-5'
3. 5' - CCAATG - 3'
   3' - CAATCC - 5'
4. 5' - GATACC - 3'
   3' - CCTAAG - 5'

Q.

Collect five examples of palindromic DNA sequences by consulting your teacher.
Better try to create a palindromic sequence by following base-pair rules.

Q. How many fragments will be generated if you digest a linear DNA molecule with a restriction enzyme having four recognition sites on the DNA?

1. 3
2. 6
3. 5
4. 4

Q. Assertion :Restriction enzymes cut the strand of DNA to produce sticky ends. Reason: Stickiness of the ends facilitates the action of the enzyme DNA polymerase.

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

Q. Which of the following statements does not hold true for restriction enzymes?

1. It can produce the same kind of sticky ends in different DNA molecules
2. It is isolated from viruses
3. It is an endonuclease
   
4. It recognises a palindromic nucleotide sequence
   

Q. How many fragments will be generated if you digest a linear DNA molecule with a restriction enzyme having four recognition sites on the DNA?

1. 3
2. 6
3. 5
4. 4

Q. Which of the following sequences can be recognised by a restriction enzyme?

1. 5' GTTA 3'
   3' CAAT 5'
2. 5' GATC 3'
   5' CTAG 3'
3. 5' CATGG 3'
   5' GTACC 3'
4. 5' GAATTC 3'
   3' CTTAAG 5'

Q. Restriction enzymes can cleave the DNA at any site randomly.

1. True
2. False

Q. Which of the following statements are correct?
(i) Restriction enzymes may cut the DNA strand a little away from the centre of the palindromic sequence, but between the same two bases on the opposite strands.
(ii) Hind ll always cuts DNA molecules at a particular site by recognising a specific sequence of six base pairs.
(iii) DNA is a positively charged molecule.

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

Q.
Identify the incorrect statement given below.

1. Each restriction endonuclease recognises a specific palindromic nucleotide sequences in the DNA
2. Restriction enzymes cut the strand of DNA a little away from the centre of the palindrome sites, but between the same two bases on the opposite strand
3. The ends cut by restriction enzymes can be joined together (end-to-end) using DNA ligases
4. Endonucleases remove nucleotides from the ends of the DNA whereas, exonucleases make cuts at specific positions within the DNA

Q.

What are the four bases of human DNA?

Q. A geneticist finds the sequences of the coding strands in transcription units as follows:
(a) 5'-TGAACTGTAGCATGC-3'
(b) 5'-TGATACTGGTACATTC-3'
Find out the correct sequences of the mRNAs transcribed from them.

1. (a) 5'-UGAACUGUAGCAUGC-3'
   (b) 5'-UGAUACUGGUACAUUC-3'
2. (a) 3'-CGUACGAUGACAAGU-5'
   (b) 3'-TGATACTGGTACATTC-5'
3. (a) 3'-CGUACGAUGUCAAGU-5'
   (b) 3’-TGATACUGGTACAUTC-5'
4. (a) 5'-UGACUGUAGCUUGCC-3'
   (b) 5'-TGATACTGGTACATTC-3'

Q. What is special of base sequence of two strands of DNA segment 5’- GAATTC -3’ 3’- CTTAAG -5’

1. Deletion mutation
2. Start condition at 5’ end
3. Replication completed
4. Palindromic sequence of base

Q.

Which enzyme is known as genetic scissors?

Q. Which of the following statements are correct?

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

Q. Which of the following statements are correct?
(i) Restriction enzymes may cut the DNA strand a little away from the centre of the palindromic sequence, but between the same two bases on the opposite strands.
(ii) Hind ll always cuts DNA molecules at a particular site by recognising a specific sequence of six base pairs.
(iii) DNA is a positively charged molecule.

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

Q. Which of the following are correctly matched?
1. Ligase - Joins short segments of DNA together
2. DNA polymerase - cuts DNA at specific site
3. Helicase breaks hydrogen bond between complementary pairs during DNA replication

1. 1, 2, and 3 are correct
2. 1 and 2 are correct
3. 2 and 3 are correct
4. 1 and 3 are correct

Q. Illustrate the recognition sequence of EcoRI and mention what such sequences are called.

Q. REN are called as molecular scissors. Why?

Q. The enzyme that reduces the tension during the unwinding of DNA helix in front of the replication folk is

1. Ligase
2. Topoisomerase
3. Endonuclease
4. Helicase
5. Polymerase

Q. (a) Why are restriction endonucleases so called ? (b) What is a palindromic nucleotide sequence ? How do restriction endonucleases act on palindromic sites to create sticky ends ?

Q. As indicated in the gel image, lanes X and Y represent samples obtained from a circular plasmid DNA after complete digestion using restriction enzyme X or Y with different recognition sites, respectively. How many sites for X and Y are present in the plasmid (sizes of the bands in kilo base pairs(kb) is shown)?

1. $1$ for X, $1$ for Y
2. $2$ for X, $1$ for Y
3. $1$ for X, $2$ for Y
4. $2$ for X, $2$ for Y

Q. Read the given statements and select the correct option.
Statement 1 : Restriction endonuclease enzymes recognise a specific palindromic nucleotide sequence in the DNA.
Statement 2 : Restriction endonuclease enzymes are called as molecular scissors or biological scissors.

1. Both statements 1 and 2 are correct
2. Statement 1 is correct but statement 2 is incorrect
3. Statement 1 is incorrect but statement 2 is correct
4. Both statements 1 and 2 are incorrect