2.2 Biological Molecules (PROTEINS)

Question 1

What are proteins made up of?

Answer 1

Long chains of amino acids
- One or more polypeptides

Question 2

What are amino acids?

Answer 2

Monomers in proteins

Question 3

What is a dipeptide?

Answer 3

formed when 2 amino acids are joined together

Question 4

What is a polypeptide?

Answer 4

formed when more than 2 amino acids join together

Question 5

Amino acid structure?

Answer 5

Same carboxyl group (COOH), Amino Group (NH^2)
- Attached to Carbon atom (C),

Different variable groups!

Question 6

What are the chemical elements that all amino acids contain?

Answer 6

Carbon, Oxygen, Hydrogen and Nitrogen
(Some = sulfur)

Question 7

What bonds are amino acids joined by?

Answer 7

Peptide bonds

Question 8

Proteins: four structure levels?

Answer 8

Primary, Secondary, Tertiary and Quaternary

Question 9

Primary structure?

Answer 9

Sequence of amino acids in the polypeptide chains

Question 10

Secondary structure?

Answer 10

Polypeptide chain isn’t flat + straight.
H bonds form between nearby amino acids
Alpha = coil
Beta = fold

Question 11

Tertiary structure?

Answer 11

Coiled or folded chains of amino acids
(coiled + folded further)
- More bonds
- Last stage for single polypeptide chain
- 3D

Question 12

Quaternary structure?

Answer 12

• Several polypeptide chains held by bonds
• 3D structure
• Tertiary but more chains!

Question 13

Primary structure bonds?

Answer 13

Peptide

Question 14

Secondary structure bonds?

Answer 14

Hydrogen

Question 15

Tertiary structure + Quaternary structure bonds?

Answer 15

Ionic, Disulphide, Hydrophobic + Hydrophilic interactions, Hydrogen

Question 16

Globular Proteins?

Answer 16

Round and Compact
- Soluble, easily transported

Question 17

Fibrous Proteins?

Answer 17

Tough and Rope shaped
- Insoluble, strong, unreactive

Question 18

Globular Proteins FUNCTIONS?

Answer 18

Haemoglobin - carries O around body in RBC. (conjugated protein)
Insulin - hormone secreted by pancreas, regulates blood glucose levels. (two polypeptide chains)
Amylase - catalyses the breakdown of starch. (single chain amino acid)

Question 19

Fibrous Proteins FUNCTIONS?

Answer 19

Collagen - animal connective tissues, v strong, rigid
Keratin - external structure of animals, flexible or hard and strong
Nails - elastic connective tissue (skin) , elastic

Question 20

What is a conjugated protein?

Answer 20

Protein with a non protein group attached to it.
- Non protein group = prosthetic group.
For haemoglobin: it is haem, it contains iron (with O binds to)