NCERT Class 11-Biology Exemplar Chapter –9 Biomolecules Part 1

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Multiple Choice Questions

Question 1:

It is said that elemental composition of living organisms and that of inanimate objects (like earth’s crust) are similar in the sense that all the major elements are present in both. Then what would be the difference between these two groups? Choose a correct answer from among the following:

a. Living organisms have more gold in them than inanimate objects

b. Living organisms have more water in their body than inanimate objects

c. Living organisms have more carbon, oxygen and hydrogen per unit mass than inanimate objects.

d. Living organisms have more calcium in them than inanimate objects.

Answer: (c)

Question 2:

Many elements are found in living organisms either free or in the form of compounds. One of the following is not, found in living organisms.

a. Silicon

b. Magnesium

c. Iron

d. Sodium

Answer: (d)

Question 3:

Aminoacids, as the name suggests, have both an amino group and a carboxyl group in their structure. In addition, all naturally occurring aminoacids (those which are found in proteins) are called L-aminoacids. From this, can you guess from which compound can the simplest be made?

a. Formic acid

b. Methane

c. Phenol

d. Glycine

Answer: (b)

Question 4:

Many organic substances are negatively charged e.g., acetic acid, while others are positively charged e.g., ammonium ion. An aminoacid under certain conditions would have both positive and negative charges simultaneously in the same molecule. Such a form of aminoacid is called

a. Positively charged form

b. Negatively charged form

c. Neutral form

d. Zwitterionic form

Answer: (d)

Question 5:

Sugars are technically called carbohydrates, referring to the fact that their formulae are only multiple of C(H2O). Hexoses therefore have six carbons, twelve hydrogens and six oxygen atoms. Glucose is a hexose. Choose from among the following another hexose.

a. Fructose

b. Erythrose

c. Ribulose

d. Ribose

Answer: (a)

Question 6:

When you take cells or tissue pieces and grind them with an acid in a mortar and pestle, all the small biomolecules dissolve in the acid. Proteins, polysaccharides and nucleic acids are insoluble in mineral acid and get precipitated. The acid soluble compounds include aminoacids, nucleosides, small sugars etc. When one adds a phosphate group to a nucleoside one gets another acid soluble biomolecule called

a. Nitrogen base

b. Adenine

c. Sugar phosphate

d. Nucleotide

Answer: (d)

Question 7:

When we homogenise any tissue in an acid the acid soluble pool represents

a. Cytoplasm

b. Cell membrane

c. Nucleus

d. Mitochondria

Answer: (a)

Question 8:

The most abundant chemical in living organisms could be

a. Protein

b. Water

c. Sugar

d. Nucleic acid

Answer: (b)

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