Protein Structure

Question 1

What are properties of the peptide bond?

Answer 1

Very stable
Cleaved by proteolytic enzymes
Partial double bond
Flexibility around C atoms

Question 2

What is the ‘backbone’?

Answer 2

A line following the peptide bonds

Question 3

What is a ‘cartoon’?

Answer 3

A representation showing the fundamental secondary structures

Question 4

What forces hold proteins together?

Answer 4

Van der Waals
Hydrogen bonds
Hydrophobic forces
Ionic bonds
Disulphide bonds

Question 5

What are Van der Waals?

Answer 5

Weak attractive interactions between atoms due to fluctuating electrical charges.

Question 6

What are hydrogen bonds?

Answer 6

Interaction between dipoles, involving a hydrogen and a oxygen/nitrogen

Question 7

What are hydrophobic forces?

Answer 7

Uncharged and non-polar side chains

Question 8

What are ionic bonds?

Answer 8

Occur between fully or partially charged groups

Question 9

What are disulphide bonds?

Answer 9

Bonds between cysteine

Question 10

What is the primary structure?

Answer 10

Linear sequence of amino acids linked by peptide bonds

Question 11

What is the secondary structure?

Answer 11

Bonds forming between the primary structure, hydrogen bonds etc…

Question 12

What is the alpha helix?

Answer 12

Hydrogen bonds between each carbonyl group

Question 13

What is the beta sheet?

Answer 13

Hydrogen bonds between linear regions of polypeptide chains
Parallel or anti parallel sheets

Question 14

What is the tertiary structure?

Answer 14

The overall 3D conformation of the protein?

Question 15

What is the quaternary structure?

Answer 15

3D structure of a protein composed of multiple subunits
Same non-covalent interactions as tertiary structures

Question 16

How to determine the structure of a protein?

Answer 16

Crystallography
X-ray diffraction

Question 17

What are enzymes?

Answer 17

Biological catalysts, accelerate a reaction and provide a way to regulate the rate of reactions

Question 18

What enzymes are used to indicate liver function?

Answer 18

Acid phosphatase
Alanine aminotransferase

Question 19

What enzymes are used to indicate prostate cancer?

Answer 19

Alkaline phosphatase

Question 20

What enzyme is used to indicate pancreas function?

Answer 20

Amylase

Question 21

What enzyme is used to indicate renal function?

Answer 21

Angiotensin converting enzyme

Question 22

What enzyme is used to indicate liver function?

Answer 22

Aspartate aminotransferase

Question 23

What enzyme is used to detect muscle damage or myocardial infarction?

Answer 23

Creatinine kinase

Question 24

What factors influence haemoglobin saturation?

Answer 24

Temperature
H+
P CO2

Question 25

What is sickle cell anemia?

Answer 25

Genetic disorder characterised by the formation of hard, sticky, sickle shaped red blood cells

Question 26

What is sickle cell caused by?

Answer 26

Single nucleotide mutation From GAG to GTG

Question 27

What is glutamic acid in haemoglobin substituted for?

Answer 27

Valine

Question 28

At what condition is the haemoglobin in sickle cell affected?

Answer 28

Low oxygen concentration

Question 29

With the eradication of malaria in some geographical areas, why does sickle cell trait persist in the population at such a high frequency?

Answer 29

It takes many generations to change gene frequencies

Question 30

What is truncation?

Answer 30

Premature termination, stop code where it doesn't belong

Question 31

What is substitution?

Answer 31

Changing the amino acids

Question 32

What is Conservative substitution?

Answer 32

Amino acid is changed with a similar amino acid, charged with charged, hydrophilic with hydrophilic etc...

Question 33

What is Non-conservative substitution?

Answer 33

Mutation causes a completely different amino acid to be inserted

Question 34

What are deletions?

Answer 34

When part of the protein is removed, or stops

Question 35

What is misplacing?

Answer 35

When RNA is edited incorrectly, instead of removing an intron it carries on

Question 36

What are immunoglobulins?

Answer 36

Antibodies, produced to bind to antigens typically toxins or proteins on the surface of microbial agents

Question 37

What structure do antibodies have?

Answer 37

Beta sheets

Question 38

How do antibodies bind to antigens with high affinity?

Answer 38

Close proximity of the antibody CDR regions and the antigen surface Intimate contact allows the combination of relatively weak interactions to produce a strong binding surface

Question 39

What is the portion of antigen bound known as?

Answer 39

Epitope

Question 40

What forces are used for the antigen-antibody bind?

Answer 40

Van der Waals Hydrogen bonds

Question 41

What factors affect complementarity

Answer 41

Van der Waals Hydrogen bonds Charge Bulk Hydophobicity