Proteins

Question 1

How many genetically amino acids are there?

Answer 1

20

Question 2

What are the 4 basic categories of natural amino acids?

Answer 2

Acidic, basic, uncharged polar and non-polar

Question 3

What are examples of acidic proteins?

Answer 3

Aspartic acid and glutamic acid (AG)

Question 4

What are examples of basic proteins?

Answer 4

Lysine, arginine and histidine (LAH)

Question 5

What are examples of uncharged polar proteins?

Answer 5

Asparagine, glutamine, serine, threonine and tyrosine (AGSTT)

Question 6

What are examples of non-polar proteins?

Answer 6

Glycine, alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan and cysteine (GAVLIPPMTC)

Question 7

How to proteins function?

Answer 7

By interacting with other biomolecules

Question 8

What are the functions of protein?

Answer 8

Movement, protection, transport, enzymes, receptors, structural, storage, hormones and control of gene expression

Question 9

What protein groups can be charged at biological pH?

Answer 9

Alpha-amino group, alpha-carboxyl group and R groups of some amino acid residues

Question 10

What is the basic structure of proteins?

Answer 10

Unbranched linear polymer of L-amino acid residues linked by peptide bonds forming a polypeptide

Question 11

What is the primary structure of proteins?

Answer 11

The sequence of amino acids in a polypeptide chain which is determined by gene encoding

Question 12

What is the function of primary structured proteins?

Answer 12

They allow versatility in protein structure and function

Question 13

What is the secondary structure of proteins?

Answer 13

The spatial arrangement of amino acid residues that are near each other in the linear sequence

Question 14

What is an amino acid residue?

Answer 14

What remains of each amino acid after water is removed from the peptide

Question 15

What are the 2 examples of secondary protein structures?

Answer 15

Alpha helices and beta sheets

Question 16

What are alpha helices?

Answer 16

Telephone cord shape held in place by H bonds between the N-H group and the C=O group of each amino acid in the turn of the helix

Question 17

What are beta sheets?

Answer 17

Pleated structure held together by H bonds between amide groups of linear polypeptide chains

Question 18

What is the tertiary structure of proteins?

Answer 18

The spatial arrangement of amino acid residues that are far apart in the linear chain

Question 19

What does the tertiary structure depend on?

Answer 19

Van der Waals, ionic interactions, H bonding, disulphide bridges and hydrophobic interactions

Question 20

What is the quaternary structure of proteins?

Answer 20

The spatial arrangement of individual polypeptide chains in a multi-subunit protein

Question 21

What are the properties of the quaternary structure?

Answer 21

Contains more than one polypeptide, can be fibrous or globular

Question 22

What causes a loss in 3D structure?

Answer 22

Denaturation

Question 23

What is denaturation?

Answer 23

Loss of 3D structure due to acid, heat or solvents. The primary structure is unaffected, while the secondary and tertiary structures are

Question 24

What does denaturation cause?

Answer 24

A decrease in solubility and a loss of function

Question 25

What is renaturation?

Answer 25

The gain of 3D structure

Question 26

What is the structure of fibrous proteins?

Answer 26

Beta-pleared sheet due to the interaction of many individual protein chains

Question 27

What determines the function of fibrous proteins?

Answer 27

It's structure

Question 28

Where do fibrous proteins occur?

Answer 28

Bone matrices, muscle fibres, tendons and connective tissue

Question 29

What are examples of fibrous proteins?

Answer 29

Collagen, eleastins, keratins and fibrinogen

Question 30

What is the structure of globular proteins?

Answer 30

Clumped into a ball

Question 31

What are the functions of globular proteins?

Answer 31

Enzymes, messengers (hormones), transporters, amino acid storage and structural function

Question 32

What is an example of globular proteins?

Answer 32

Haemoglobin

Question 33

What are the 3 different types of modified proteins?

Answer 33

Glycoproteins, lipoproteins and metalloproteins

Question 34

What are glycoproteins?

Answer 34

They are carbohydrates that have joined to proteins which are formed by post-trasnlational modification. They are important integral membrane proteins and play a role in cell-cell interactions

Question 35

What are lipoproteins?

Answer 35

They are lipids joined to proteins. They transport water-insoluble fats in the blood e.g. HDL and LDL

Question 36

What are metalloproteins?

Answer 36

They are metals joined to proteins. They are used for enzymes, storage, signalling and transport

Question 37

What are examples of protein disorders?

Answer 37

Sickle cell anaemia, FH and scurvy

Question 38

What cases sickle cell anaemia?

Answer 38

One amino acid change

Question 39

What causes FH?

Answer 39

Decrease in LDL receptors

Question 40

What causes scurvy?

Answer 40

Weakened collagen

Question 41

What is an alpha-keto-acid?

Answer 41

The C skeleton of an alpha-amino-acid

Question 42

What is the difference between an alpha-keto-acid and an alpha-amino acid?

Answer 42

Alpha-keto-acids have been deaminated, although they have the same structure. The H and amino groups have been removed and replaced by an O group. The carbonyl and R groups are still there