VETS-111 Cell Biology Flashcards
(75 cards)
0
Q
How is iron stored?
A
Complex with ferritin in the liver.
1
Q
What is Transferrin?
A
Carries iron in blood plasma.
2
Q
Functions of proteins
A
1) enzymology catalysts
2) transport and storage
3) movement
4) structural materials
5) immune protection antibodies
6) membranes
7) regulators and receptors
3
Q
Structure of an amino acid in neutral solution
A
Zwitterion
4
Q
Name if pH where amino acid has no net charge
A
Isoelectric
5
Q
Two enantiomers of an amino acid
A
L and D-isomers
6
Q
Which form of amino acids do proteins contain
A
L-isomer
7
Q
Amino acids are joined by…
A
Peptide bonds
8
Q
A polypeptide starts at which end?
A
Amino terminal residue
9
Q
An amino acid ends at what end?
A
The carboxyl terminal residue
10
Q
Is arginine an essential amino acid?
A
Yes
11
Q
Is Histidine an essential amino acid?
A
Yes
12
Q
Is Isoleucine an essential amino acid?
A
Yes
13
Q
Is leucine an essential amino acid?
A
Yes
14
Q
Is lycine an essential amino acid?
A
Yes
15
Q
Is methionine an essential amino acid?
A
Yes
16
Q
Is phenylalanine an essential amino acid?
A
Yes
17
Q
Is threonine an essential amino acid?
A
Yes
18
Q
Is tryptophan an essential amino acid?
A
Yes
19
Q
Is valine an essential amino acid?
A
Yes
20
Q
Is alanine an essential amino acid?
A
No
21
Q
Is asparagine an essential amino acid?
A
No
22
Q
Is aspartic acid an essential amino acid?
A
No
23
Q
Is cysteine an essential amino acid?
A
No
24
Is glutamic acid an essential amino acid?
No
25
Is glutamine an essential amino acid?
No
26
Is glycine an essential amino acid?
No
27
Is proline an essential amino acid?
No
28
Is serine an essential amino acid?
No
29
Is tyrosine an essential amino acid?
No
30
Which amino acid should be avoided by diabetics as a supplement
Cysteine (interacts with insulin)
31
Which amino acid is a precursor for serotonin?
Tryptophan
32
Rigidity In the primary structure of polypeptides
Caused by carbon-nitrogen bond having partial double bond character.
33
Interactions in the secondary structure of amino acids
Hydrogen bonds:
Beta pleated sheets
Alpha helix
34
Which amino acid is a helix breaker
Proline
35
Interactions within the tertiary structure
```
Disulphide bridges (2 cysteine)
Hydrogen bonding
Electrostatic/ionic
Hydrophobic
Polar (OH)
```
36
What is the quaternary structure
Multiple chains interacting forming subunits
37
Types of super secondary structures
BaB unit
| Greek key of B-pleats
38
What is denaturation
Loss of proteins structure and thus function
39
Causes of denaturation
Changes in pH
Salt conc
Temp
Environmental changes
40
What aids protein folding
Chaperonins
41
Ways to determine protein structure
X-Ray crystallography
| NMR spectroscopy
42
Result of protein misfolding
Loss or modification of activity
| Aggregation
43
Cause of sickle cell disease
Amino acid substitution in harmoglobin causes aggregation and fibres. Deformed RBCs
44
Cause of Cystic fibrosis
Deletion of Phe in CFTR protein which is degraded.
45
What is p53
Tumour suppression gene. Mutations present in tumour cells
46
Cause of Alzheimers
B-amyloid cleaved from APP produces aggregations of plaques in the brain
47
What is PrPc
Native form of prion protein mainly a-helix.
48
What is PrPSc
Amyloidogenic form. Mix of B-sheets and a-helices. Aggregates form insoluble plaques in brain
49
What causes huntingdons?
Huntingtin protein is longer than normal and end is cleaved to form aggregates and inclusions.
50
What causes Parkinson's?
Inclusions in the cytoplasm called Lewy bodies formed from multiple proteins.
51
Cause of cataracts
Aggregation of crystallins due to environmental factors (UV or oxidising agents)
52
Fibrous proteins
Filamentous elongated held by strong bonding
53
Globular proteins
Compact structures that interact with other molecules e.g enzymes, antibodies
54
Membrane proteins
Embed in membranes and transmit molecules in and out cell
55
Structure of collagen
Triple helix. Repeating triplet of glycine, X (often proline) and Y (often hydroxyproline)
56
Structure of glycerophospholipid
Two hydrophobic fatty acid tails joined to hydrophilic head (glycerol, phosphate and choline)
57
Define steroid
Lipids with a carbon skeleton consisting of four fused rings
58
Define ligand
Extra cellular signalling molecules
59
Define a catalyst
Increases the rate of a chemical reaction without being changed itself. Cannot alter the position of equilibrium but allows equilibrium to be reached quicker.
60
Define free energy of activation
Equal to the difference in free energy between the transition state and the substrate.
61
Define induced fit of an enzyme
Frequent binding of substrate induces a conformational change in the active site.
62
Factors affecting enzyme activity
```
Substrate concentration
Enzyme concentration
Temperature
Post translational modification (e.g phosphorylation, Proteolytic activation)
Coenzymes and cofactors
pH
```
63
Most coenzymes are related to what structural group
Vitamin B group
64
What is end product feedback
Inhibits the committed step (first step to produce an intermediate unique to the pathway) earlier in the pathway.
65
What is allosteric regulation
Molecules that regulate an enzymes activity by binding to a site remote from the active site.
66
Define cooperativity
Binding of a substrate can trigger the same conformational change in all other subunits of the enzyme
67
Define isoenzyme
Different forms of an enzyme which catalyse the same reaction
68
What does LDH stand for
Lactate dehydrogenase
69
Structure of LDH
2 subunits H and M. 5 different combinations
70
Where is H4 and H3M found?
Mainly heart and RBCs
71
Where is H2M2 LDH found?
Brain and kidney
72
Where is HM3 and M4 LDH found?
Skeletal muscle and liver
73
What does LDH isoenzymes in the blood indicative of?
Cell death. E.g myocardial infarction, infectious hepatitis and muscle diseases.
74
What is a multi-enzyme complex
Aggregation of several enzymes/coenzymes into a single functional unit. Usually perform a multi-step transformation
