Chapter 2 test

What are the three most common elements in living organisms?

• oxygen, hydrogen and nitrogen

• nitrogen, carbon and phosphorus

• oxygen, hydrogen and carbon

• carbon, sulphur and nitrogen

Water is important to humans because

(1) it provides turgidity to maintain the body shape.

(2) it acts as a medium of transport in the human body.

(3) it helps maintain a relatively constant body temperature.

• (1) and (2) only

• (1) and (3) only

• (2) and (3) only

• (1), (2) and (3)

Which of the following descriptions about minerals is incorrect?

• They are essential to the regulation of metabolism.

• They are broken down during respiration to provide energy to organisms.

• They are inorganic in nature.

• They are transported by water in the human body.

Which of the following statements about glycogen is correct?

• It is a storage form of carbohydrate in animals.

• It is a component of plant cell walls.

• It can form brick-red precipitate in Benedict’s test.

• It is a polysaccharide found in both animals and plants.

Which of the following substances is the most soluble in water?

• sucrose

• cellulose

• glucose

• glycogen

What is the function of cholesterol in the human body?

• as a component of cell membranes

• protecting internal organs

• as an insulating layer to reduce heat loss

• as an energy reserve

Which of the following chemical substances can provide energy to the body?

(1) carbohydrates

(2) lipids

(3) minerals

• (1) and (2) only

• (2) and (3) only

• (1) and (3) only

• (1), (2) and (3)

The specificity of amino acids is determined by the

• amino group.

• side chain.

• carboxyl group.

• peptide bond formed between amino acids.

Which of the following is not the primary function of proteins?

• as cell component

• growth and tissue repair

• form enzymes

• energy storage

Which of the following comparisons about DNA and RNA is correct?

• A

• B

• C

• D