Biochemistry - Proteins and Nucleic acids

Question 1

What are proteins?

Answer 1

• Carbon, hydrogen, oxygen and nitrogen

- Approx. 100,000 different human proteins and each has a specific function

Question 2

What are amino acids?

Answer 2

There are 20 different amino acids

- amino group of 1 amino acid binds the carboxyl group of another amino acid

Question 3

Which amino acids are added together in a chain is controlled by what?

Answer 3

Genes (DNA). Ingested proteins provides the amino acids for the body to make its own proteins

Question 4

What is the first level of protein structure?

Answer 4

Primary

- amino acid sequence

Question 5

What is the second level of protein structure?

Answer 5

Secondary
 - amino acid chain (polypeptide) folds and twists to produce shapes 
Either:
Alpha helix  - repeated clockwise twists
Beta pleated sheets - repeated folding

Question 6

What is the third level of protein structure?

Answer 6

Tertiary

• arrangement of the secondary structures
• produces a unique 3 dimensional shape
• final shape determines function

Question 7

What is the fourth level of protein structure?

Answer 7

Quarternary

- In some cases proteins join together to form functional protein complexes

Question 8

What is the function of proteins in the body?

Answer 8

• Important structural components of the body
• enzymes
• some hormones and hormone receptors
• molecular motors
• antibodies and other components of the immune system

Question 9

Protein function:

Answer 9

Regulation
- Enzymes and hormones 
Transport
- haemoglobin
Protection 
- antibodies
 Contraction 
- actin and myosin
Structure
- collagen and keratin 
Energy
- relatively minor role compared to crabs and lipids