Base Pairing

Q.

Given the DNA sequence 5’ CCTAGAA 3’, the complementary strand would read:

1. 3’ GGATCTT 5’

2. 3’ AAGATCC 5’

3. 5’ GGTATTC 3’

4. 5’ GGATCTT 3’

Q. The base sequence of DNA is CAT, TAG, CAT, CAT, GAC. What would be the base sequence of its complementary mRNA?

1. GUA, GUA, CUG, AUC, CUG
2. AUG, CUG, CUC, GUA, CUG
3. GUA, AUC, GUA, GUA, CUG
4. GUC, CUG, CUG, CUA, CUU

Q.

If the sequence of one strand of DNA is written as follows
5' - ATGCATGCATGCATGCATGCATGCATGC - 3'
Write down the sequence of complementary strand in 5' $\to$ 3' direction.

Q. The given figure is the representation of a certain event at a particular stage of a type of cell division. Which is this stage.

1. Prophase – I during meiosis
2. Prophase – II during meiosis
3. Prophase of mitosis
4. Both prophase and metaphase of mitosis

Q. In one polynucleotide strand of a DNA molecule the ratio of A + T/G + C is 0.3, What is the A + G/T + C ratio of the entire DNA molecule?

1. $0.6$
2. $0.3$
3. $1$
4. $1.2$

Q. Which one of the following palindromic base sequences in DNA can be easily cut at about the middle by some particular restriction enzyme?

1. 5’ ........GATATG........ 3’
   3’ ........CTACTA........ 5’
2. 5’ ........CACGTA........ 3’
   3’ ........CTCAGT........ 5’
3. 5’ ........GAATTC........ 3’
   3’ ........CTTAAG........ 5’
4. 5’ ........CGTTCG........3’
   3’ ........ATGGTA........5’

Q. Give a schematic labelled diagram to represent oogenesis (without descriptions)

Q. If the base sequence in one strand of double stranded DNA is 3′ TGATCAT 5′, then the base sequence of its complementary strand would be
[0.7 mark]

1. 3′ TACTAGT 5′
2. 3′ ACTAGTA 5′
3. 3′ ATGATCA 5′
4. 3′ GACGTCG 5′

Q. If there are 120 adenine molecules in a DNA double helical structure showing 20 coils, what is the number of pyrimidine nucleotides forming three hydrogen bonds in it?

1. 80
2. 200
3. 160
4. 240

Q. If an antisense strand of DNA in the transcription unit has 3’ ATCTG 5’ sequence, what will be the sequence of nitrogenous bases in the newly synthesized RNA strand?

1. 5’ TAGAC 3’
2. 5’ UAGAC 3’
3. 3’ AUCUC 5’
4. 3’ AUGAC 5’

Q. Adenine and thymine have hydrogen bonds binding them in a double helix.

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

Q. Which of the following is correct for DNA?

1. Adenine pairs with guanine by covalent bonds
2. Adenine pairs with thymine by 3 hydrogen bonds
3. Guanine pairs with cytosine by 3 covalent bonds
4. A purine always pairs with a pyrimidine

Q.

Identify the mismatched purine-pyrimidine pair among the following options.

1. Adenine - Thymine

2. Thymine - Adenine

3. Guanine - Cytosine

4. Thymine - Cytosine

Q. A student was looking at a gamete and he found that the gamete is exhibiting n+1 condition. Which of the following phenomenon leads to this condition?

1. Disjunction
2. Non–disjunction
3. ​​​​Crossing over
4. Linkage

Q. Assertion :Complementary pairing between nucleotides is used to diagnose presence of a specific DNA segment in a mixture. Reason: DNA probes having radioactive isotopes help to detect DNA by autoradiography.

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.

Given the DNA sequence 5’ CCTAGAA 3’, the complementary strand would read:

1. 3’ GGATCTT 5’

2. 3’ AAGATCC 5’

3. 5’ GGTATTC 3’

4. 5’ GGATCTT 3’

Q.

Give the biological/technical term for the following

The repeating components of each $DNA$ strand lengthwise.

Q.

Identify the mismatched purine-pyrimidine pair among the following options.

1. Adenine - Thymine

2. Thymine - Adenine

3. Guanine - Cytosine

4. Thymine - Cytosine

Q.

Give technical term for repeated units of $DNA$ molecule.

Q.

A nitrogenous base present in the DNA

1. Adenine

2. Uracil

Q. If the sequence of one strand of DNA is written as follows:

Q. A tetrad is made of:

1. Four non-homologous chromatids
2. Four homologous chromosomes with four chromatids
3. Four non-homologous chromosomes
4. Two homologous chromosomes each with two chromatids

Q.

DNA is the abbreviated form of ____________.

Q.

If the sequence of one strand of DNA is written as follows:

5-ATGCATGCATGCATGCATGCATGCATGC-3

Write down the sequence of complementary strand in 5→3 direction

Q. Which of the following are nucleosides?

1. A and B
2. B and C
3. A and D
4. C and D

Q. If an antisense strand of DNA in the transcription unit has 3’ ATCTG 5’ sequence, what will be the sequence of nitrogenous bases in the newly synthesized RNA strand?

1. 5’ TAGAC 3’
2. 5’ UAGAC 3’
3. 3’ AUCUC 5’
4. 3’ AUGAC 5’

Q.

If the percentage of cytosine is 18%, then the percentage of adenine will be

1. 32%

2. 36%

3. 23%

4. 64%

Q. A purine and a pyrimidine together form a __.

Q. If one strand of DNA has the nitrogenous base sequence as ATCTG, what would be the complementary RNA strand sequence?

1. TTAGU
2. AACTG
3. ATCGU
4. UAGAC

Q. The base sequence on one of the strands of DNA is TAC TAG GAT.
(i) Give the base sequence of its complementary strand.
(ii) What is the distance maintained between the two consecutive paired bases in the DNA molecule?
(iii) Who contributed the base complementarity rule?
(iv) Categorise these bases using their full names.
(v) What holds these base pairs together?