Simple Proteins questions

Question 1

What are the roles of proteins?

Answer 1

Enzymes - breakdown and synthesise molecules
Antibodies - Immune response
Transport - Move molecules/ions across membranes
Structural components - Keratin and collagen used to create strong fibres
Hormones - chemical messengers in the body
Muscle contractions - muscles made up of proteins

Question 2

Amino acid structure: draw

Answer 2

…

Question 3

Amino acid structure: describe

Answer 3

Central carbon atom
Amino group
Carboxylic group
Hydrogen atom
variable R group

Question 4

What is the role of the R-group?

Answer 4

To determine the properties of the amino acid.

Question 5

Test for proteins:

Answer 5

1. Place food sample in a test tube.
2. Add equal volume of Biuret solution (sodium hydroxide and copper sulfate)
3. If proteins present, the solution will turn from blue to purple. No protein present, solution remains blue.

Question 6

Levels of protein structure?

Answer 6

Primary
Secondary
Tertiary
Quaternary

Question 7

Feature of hydrogen bonds?

Answer 7

Individually weak but provide strength in large numbers

Question 8

Features of ionic bonds?

Answer 8

Form between positive and negative R-groups

Question 9

Features of disulfide bridges?

Answer 9

Form between R groups that contain sulfur (cysteine)

Question 10

Features of hydrophobic and hydrophilic interactions?

Answer 10

Weak interactions between polar and non-polar R groups.

Question 11

Globular protein metabolic roles in the body:

Answer 11

• Enzyme (speed up chemical reactions in body)
• Hormones (chemical messengers that travel in the bloodstream)
• Antibodies (binds to and prevent the spread of pathogens)

Question 12

Examples of Fibrous proteins?

Answer 12

• Keratin (found in skin, hair and nails)
• Collagen (found in connective tissues such as bond and muscle)
• Elastin (elastic connective tissue)

Question 13

Features of haemoglobin:

Answer 13

• Four polypeptide chains (means that 4 molecules of oxygen can be carried at a time)
• Haem group (contains iron that reversibly binds to oxygen)
• Compact globular structure (allows haemoglobin to fit inside red blood cells)

Question 14

Structure of insulin:

Answer 14

Made up of 2 polypeptide chains held together by disulfide bonds.

Question 15

Amylase structure:

Answer 15

Made up of a single polypeptide chains folded using both alpha-helixes and beta-pleated sheets.

Question 16

Name of collagen structure?

Answer 16

Triple-helix