Proteins C3

Question 1

Explain properties of a globular protein

Answer 1

Compact, water soluble, spherical in shape. Form when hydrophobic R groups are kept away from their environment as they form inwards.

Question 2

What is an example of a globular protein

Answer 2

Insulin, hormone involved in regulation of blood glucose concentration. Hormones need to be soluble as they are transported in the blood stream.

Question 3

Explain properties of a conjugated protein

Answer 3

Proteins that contain a non protein component called a prosthetic group. E.g. Haemoglobin, each subunit has iron, each molecule of irom carries a molecule of oxygen.

Question 4

Explain properties of a fibrous protein.

Answer 4

Long, insoluble molecules, due to presence of many hydrophobic r groups in primary structure, they contain a limited no. Of AA and their AA sequence is usually repetitive. These proteins are usually not folded.

Question 5

Name 2 and explain 1 example of a fibrous protein

Answer 5

Keratin - Large proportion of sulfur AA and so many disulfide bonds, making it strong.

Elastin - Quaternery protein, made from strcehy molecules called tropoelastin

Collagen - Made up of 3 polypeptide wound together in a long, rope-like structure

Question 6

What is the primary structure of a protein

Answer 6

Sequence in which amino acids are joined

Question 7

What is the secondary structure of a protein

Answer 7

The protein is either an Alpha helix or beta pleated sheat. It depends on their h bonds

Question 8

What is the tertiary structure of a protein

Answer 8

Folding of the protein into its final shape.

Question 9

What interactions occur between R groups to determine the tertiary structure

Answer 9

• Hydrophobic and hydrophilic, these are weak interactions between polar and non polar R groups.
• Hydrogen bonds - Weakest of all ponds formed.
• Ionic bonds, form between oppositely charged R groups.
• Disulfide bonds - Form between R groups that contain sulfur