Class XII · Biology practice

Molecular Basis of Inheritance MCQs

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668 questions in this collection · Page 25 of 67

Question 241 of 668

📘 CLASS XII

Molecular Basis Of Inheritance

DNA as an acidic substance present in the nucleus was first identified by _______

Friedrich Miescher identified DNA in 1869 and named it Nuclein.

Question 242 of 668

📘 CLASS XII

Molecular Basis Of Inheritance

Based on X-ray diffraction data, _______ and _______ proposed the Double Helix model.

James Watson and Francis Crick proposed the double helix model in 1953.

Question 243 of 668

📘 CLASS XII

Molecular Basis Of Inheritance

Erwin Chargaff observed that for a double-stranded DNA, the ratio between Adenine and Thymine is _______

Chargaff's rule states A=T and G=C, so the ratio is one.

Question 244 of 668

📘 CLASS XII

Molecular Basis Of Inheritance

The two chains of DNA have _______ polarity.

One strand runs 5'->3' and the other 3'->5'.

Question 245 of 668

📘 CLASS XII

Molecular Basis Of Inheritance

Adenine forms _______ hydrogen bonds with Thymine.

Adenine pairs with Thymine via two hydrogen bonds.

Question 246 of 668

📘 CLASS XII

Molecular Basis Of Inheritance

Guanine is bonded with Cytosine with _______ hydrogen bonds.

Guanine and Cytosine are connected by three hydrogen bonds.

Question 247 of 668

📘 CLASS XII

Molecular Basis Of Inheritance

The pitch of the DNA helix is _______ nm.

The pitch (one complete turn) of the B-DNA helix is 3.4 nm.

Question 248 of 668

📘 CLASS XII

Molecular Basis Of Inheritance

There are roughly _______ base pairs in each turn of the helix.

One turn of the helix contains approximately 10 base pairs.

Question 249 of 668

📘 CLASS XII

Molecular Basis Of Inheritance

The distance between a base pair in a helix is approximately _______ nm.

The rise per base pair is 0.34 nm.

Question 250 of 668

📘 CLASS XII

Molecular Basis Of Inheritance

In DNA, a purine always comes opposite to a _______

Purine pairing with pyrimidine ensures a uniform distance between strands.

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