Food Chemistry Quiz - 3

0.001 mole of which molecule will react completely with 0.320g of bromine?

• Compound D

• Compound G

• Compound F

• Compound A

The tertiary structure of proteins may be maintained by

• hydrogen bonding

• ionic interactions

• covalent bonds.

• all of the above

The following diagram is a simplified illustration of the protein insulin. Insulin consists of 51 amino acids arranged in two individual chains linked by disulfide bridges.

The two chains have 21 and 30 amino acids respectively.

How many peptide links are present in one molecule of insulin?

• 48

• 49

• 50

• 51

The following diagram is a simplified illustration of the protein insulin. Insulin consists of 51 amino acids arranged in two individual chains linked by disulfide bridges.

Disulfide bridges are formed when the side chains of two amino acid residues react.

The pair of amino acids that form the disulfide bridges could be

• cysteine and serine.

• cysteine and glycine.

• cysteine and cysteine

• cysteine and glutamic acid.

Many biological compounds are large molecules made of many smaller units joined together. Each of the units has the same basic structure. Such molecules are called polymers.

Biological polymers include:

• glycogen composed of glycerol.

• proteins composed of fatty acids

• cellulose composed of glucose

• starch composed of amino acids

The diagrams below represent three of the major macromolecule groups in living things.

Synthesis of macromolecules from these groups

• Result from energy-generating condensation reactions requiring an input of water molecules

• Result from energy-generating reactions requiring an input of carbon dioxide molecules

• Are energy-requiring condensation reactions with an output of water molecules

• Are energy-requiring reactions with an output of oxygen molecules

Starch consists mainly of amylose, which is a polymer made from glucose, C₆H₁₂O₆

A particular form of amylose has a molar mass 3.62×10⁵g/mol. A molecule of this amylose can be described as:

• an addition polymer of 2235 glucose molecules

• an addition polymer of 2011 glucose molecules.

• a condensation polymer of 2235 glucose molecules.

• a condensation polymer of 2011 glucose molecules.

A substance that could be formed as a product, when a polysaccharide undergoes enzyme catalysed hydrolysis, is:

• H₂O

• CO₂

• C₆H₁₂O₆

• CH₂OHCHOHCH₂OH

What type of bonds are broken when a triglyceride is hydrolysed?

• Glycosidic links

• Ester links

• Peptide links

• Amide functional groups

The side chains of some amino acids are able to form amide (peptide) bonds. Glutathione is a tripeptide that protects cells in humans by acting as an antioxidant. The structure of glutathione is:

The molecule of glutathione contains residues from the amino acids cysteine and glycine.

The name of the third amino acid found in glutathione is:

• asparagine

• aspartic acid

• glutamine

• glutamic acid