Proteins

Question 1

What are the 7 classes of amino acids?

Answer 1

Aliphatic, aromatic, acidic, basic, sulfur-containing, polar and miscellaneous

Question 2

What is a protein?

Answer 2

A macromolecule consisting of amino acids

Question 3

How does DNA link to protein?

Answer 3

DNA tells cells how to make mRNA, which acts as a blue print for amino acid chain formation

Question 4

How many naturally occurring amino acids are there?

Answer 4

20

Question 5

How many nucleotides code for an amino acid?

Answer 5

3

Question 6

What are the nucleotides in DNA and mRNA?

Answer 6

ATCG and AUCG

Question 7

What is the structure of an amino acid?

Answer 7

Central carbon attached to an amine (NH2), carboxyllic acid (-COOH), hydrogen and R-group

Question 8

Do amino acids have any charge at a pH of 7?

Answer 8

They are zwitterions so there is a (NH3)+ and -(COO-) at a pH of 7

Question 9

What are the two types of proteins in use and an example of each?

Answer 9

Structural - keratin and Functional - antibodies/enzymes

Question 10

What is the primary protein structure?

Answer 10

Chain of amino acids bound by peptide bonds - polypeptide chain

Question 11

What is the secondary protein structure? What are the 2 types?

Answer 11

3D spacial structure relying on hydrogen bonding between partially negative -O and -H. Can be Alpha helix or Beta plaited sheet

Question 12

What is the tertiary protein structure?

Answer 12

Still 1 polypeptide chain but -R groups interact with ionic bonding, hydrogen bonding, disulphides bridges and hydrophilic and hydrophobic interactions.

Question 13

What is the quaternary protein structure?

Answer 13

Involves +1 polypeptide chain, e.g. haemoglobin (4)

Question 14

What is denaturation?

Answer 14

When a protein can no longer fulfil its function due to disruption or destroyed bonds. The amino acid retains its identity, but cannot function.

Question 15

What features do protein channels have that assist their function?

Answer 15

The proteins amino acids can be hydrophilic or hydrophobic, assisting specific molecules, e.g. water, in passing through

Question 16

What are three forms of conjugated protein?

Answer 16

Glycoproteins, lipoproteins, metalloproteins

Question 17

What is a conjugated protein?

Answer 17

A protein which undergoes an additional post-transitional change and gains a non-protein group.

Question 18

What is a glycoprotein?

Answer 18

A protein with 1+ carbs attached. If a few are in a chain its an oligosaccharide.

Question 19

What qualities do glycoproteins have?

Answer 19

Increased stability, altered solubility, folds/bends in chain, cell-cell communication

Question 20

What is a lipoprotein and its benefits?

Answer 20

Proteins combines with lipids. Transport hydrophobic molecules around the blood, like cholesterol

Question 21

What are metalloproteins and an example?

Answer 21

Proteins with a metal ion in its structure. E.g. Iron ion (Fe+) in haem

Question 22

What are the 3 classifications of protein structure?

Answer 22

Globular, Fibrous and Membranous proteins

Question 23

What is an example of a globular protein?

Answer 23

Immunoglobulin and enzymes

Question 24

How does solubility vary between globular and fibrous proteins?

Answer 24

Globular - high solubility in water. Fibrous - low solubility in water

Question 25

What are some examples of fibrous proteins?

Answer 25

Keratin, collagen, fibril, elastin

Question 26

What are the uses of fibrous proteins?

Answer 26

Have a rope like structure so form connective tissue, muscle fibres and tendons. High tensile strength

Question 27

What are membranous proteins with examples?

Answer 27

Proteins embedded in cell membrane. Aquaporins in cell membrane or glycoproteins

Question 28

What is a G protein?

Answer 28

Peripheral proteins found on the inner membrane, responsible for translocate messages for receptor proteins to other proteins on the membrane - e.g. enzymes or ion channels