Biological Molecules 2 - As level

What is the maximum number of hydrogen bonds that can form between two single water molecules?

• 1

• 2

• 3

• 4

Which part of the structure of haemoglobin carries oxygen?

• four polypeptide chains

• haem groups

• hydrogen bonds

• hydrophilic R groups

What describes cellulose?

• a branched chain of 1-4 α-glucose

• a branched chain of 1-4 β-glucose

• an unreactive linear chain of 1-4 α-glucose

• an unreactive linear chain of 1-4 β-glucose

Which molecules contain at least two double bonds?

• A

• B

• C

• D

A sample of a solution was tested for reducing sugar and the result was negative. Another sample of the same solution was then tested for non-reducing sugar and the result was positive. Which step in the test for non-reducing sugar breaks the glycosidic bonds?

• addition of Benedict’s reagent

• addition of sodium hydroxide

• boiling with hydrochloric acid

• heating to 80 °C

What are the features of triglycerides?

• A

• B

• C

• D

The diagram shows the structure of the polysaccharide chitin which is found in the cell wall of fungi. Which statements are correct for chitin and for cellulose?

1 The monomers are joined by 1,4 glycosidic bonds.

2 Every second monosaccharide in the polysaccharide chain is rotated by 180°.

3 The polysaccharide contains the elements carbon, hydrogen, oxygen and nitrogen.

• 1, 2 and 3

• 1 and 2 only

• 1 and 3 only

• 2 and 3 only

Some of the molecules found in animal tissues are grouped into three lists.

1 glucose, cholesterol, triglycerides, water

2 glycogen, antibodies, adenine, phospholipids

3 haemoglobin, carbon dioxide, mRNA, monosaccharides

Which lists include one or more molecules that always contain nitrogen atoms?

• 1, 2 and 3

• 1 and 2 only

• 1 and 3 only

• 2 and 3 only

Which row gives the correct description of both a collagen molecule and a collagen fibre?

• A

• B

• C

• D

The diagrams show the structures of two amino acids, each of which has two amine (–NH₂) groups. A peptide bond is formed between the two amino acids. Which groups could form the peptide bond?

• 1 and 4

• 1 and 5

• 2 and 6

• 3 and 5