IB Biology Molecules

Which molecule is shown?

• Amino acid

• Glucose

• Ribose

• Fatty acid

Which is an effect of protein denaturation?

• The order of amino acids is changed when the protein overheats.

• The bonds between amino acids are broken by condensation.

• Parts of the protein become linked together by hydrolysis.

• The three-dimensional structure of the protein is altered.

Which type of reaction is the breakdown of starch into sugars?

• Denaturation

• Reduction

• Catabolic

• Condensation

The diagram shows a molecular structure. What is it?

• Amino acid

• Lipid

• Carbohydrate

• Nucleotide

Which properties explain the ability of water to dissolve solutes?

I. Polarity of water molecules

II. High specific heat capacity of water

III. Hydrogen bonding

• I and II only

• I and III only

• II and III only

• I, II and III

What is a similarity between DNA and RNA?

• Both are polymers of nucleotides.

• Both are composed of antiparallel strands.

• Both contain adenine, cytosine and thymine.

• Both contain ribose sugar.

A polymer of alpha-D-glucose found in plants has mostly 1,4 linkages and some 1,6 linkages. Which molecule fits this description?

• Glycogen

• Cellulose

• Amylose

• Amylopectin

The most abundant structural protein in the human body is found in ligaments and skin. What is the name of this protein?

• Collagen

• Hemoglobin

• Myoglobin

• Immunoglobulin

The graph shows the effect of increasing the substrate concentration on the rate of an enzyme-catalysed reaction. What is occurring during the phase indicated by section Y of the graph?

• The active site of the enzyme is saturated.

• The enzyme becomes denatured.

• The substrate concentration has risen too high.

• The optimum rate is reached.

The diagram shows the structure of palmitic acid. What type of fatty acid is palmitic acid?

• It is monounsaturated.

• It is polyunsaturated.

• It is saturated.

• It is a trans-fatty acid.