1
MCQ (Single Correct Answer)

AIPMT 2008

In DNA, the complimentary bases are
A
adenine and guanine; thymine and cytosine
B
uracil and adenine; cytosine and guanine
C
adenine and thymine; guanine and cytosine
D
adenine and thymine; guanine and uracil.

Explanation

DNA contains two types of nitrogeneous bases

Purine $$ \to $$ Adenine (A) and guanine (G)

Pyrimidine $$ \to $$ Cytosine (C) and thymine (T)

The purine and pyrimidine bases pair only in certain combination. Adenine pairs with thymine (A : T) by two hydrogen bonds and guanine with cytosine (G : C) by three hydrogen bonds.
2
MCQ (Single Correct Answer)

AIPMT 2007

RNA and DNA are chiral molecules, their chirality is due to
A
chiral bases
B
chiral phosphate ester units
C
$$D$$-sugar component
D
$$L$$-sugar component

Explanation

Each nucleic acid consists of a pentose sugar a heterocyclic base, and phosphoric acid. The sugar present in DNA is -D (–) -2-deoxy ribose and the sugar present in RNA is D (–)- ribose. The chirality of DNA and RNA molecules are due to the presence of sugar components.
3
MCQ (Single Correct Answer)

AIPMT 2007

Which of the following vitamins is water-soluble?
A
Vitamin E
B
Vitamin K
C
Vitamin A
D
Vitamin B

Explanation

Vitamin B is water soluble whereas all other are water insoluble.
4
MCQ (Single Correct Answer)

AIPMT 2006

During the process of digestion, the proteins present in food materials are hydrolysed to amino acids. The two enzymes involved in the process-

are respectively
A
invertase and zymase
B
amylase and maltase
C
diastage and lipase
D
pepsin and trypsin

Explanation

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