Extra

Question 1

What does auricular cartilage contain and what is its function?

Answer 1

Resists compression by drawing in water by several negative charges. Has collagen II fibrils.

Question 2

What direction do tendons resist force?

Answer 2

All directions

Question 3

What is TATA?

Answer 3

A sequence found at the beginning of gene promoter sequences that work by binding to TF-II D and promoting gene expression and transcription.

Question 4

Do influenza virus undergo recombination?

Answer 4

Yes - it has a segmented genome.

Question 5

What does glucose-6-phosphatase do?

Answer 5

Present in liver and muscle. Converts glycogen into glucose (hydrolyses glucose-6-phosphate to glucose) in the ER, so important in glycogenolysis.

Question 6

Why do proteins naturally form R-alpha helices?

Answer 6

The use of R-proteins naturally arranges into a conformation of the lowest energy. L-proteins counter steric hindrance in a L-handed helix.

Question 7

What is at the core of a microvilli?

Answer 7

An actin core

Question 8

How do bacteria affect actin?

Answer 8

Can cause actin polymerisation which can be helpful for the invasion of host cells.

Question 9

Why can cysteine form disulphide bridges?

Answer 9

Has a sulphydryl group which can be oxidised to form disulphide bridges.

Question 10

What does FAD stand for?

Answer 10

Flavine adenine dinucleotide

Question 11

What is the point of transamination?

Answer 11

Produce new pair of keto and amino acids that are able to enter the TCA cycle.

Question 12

Why are triacylglycerides good energy stores?

Answer 12

Highly reduced and have optimal packing in adipocytes due to their straight carbon chains.

Question 13

What is Orlistat?

Answer 13

A medication that inhibits gastric and pancreatic lipase so that fat passes undigested through the gut, resulting in steatorrhea.

Question 14

What two enzymes are responsible for fatty acid synthesis?

Answer 14

Fatty acid synthase and acetyl CoA carboxylase.

Question 15

How are cholesterol requirements met?

Answer 15

De novo biosynthesis from acetyl co-A (lipogenesis)

Question 16

What are isoprenoids?

Answer 16

Wide class of natural compounds derived from terpenes (isoprene units). They can be covalently-attached to proteins to help anchor them to biological membranes via cysteine residues.

Question 17

How is calcitriol produced from cholesterol?

Answer 17

UV light is required to generate calcitriol from 8-dehydrocholesterol.

Question 18

How are lipoproteins categorised?

Answer 18

On their density.

Question 19

How do we know if a protein is destined for lysosomes?

Answer 19

Will be phosphorylated on the mannose sugar molecules (mannose-6-phosphate) which is recognised boy M-6-P receptor, which is then targeted by lysosomes.

Question 20

What is I-cell disease?

Answer 20

Disorder resulting from mutations in phosphotransferase enzymes that catalyse the phosphorylation of mannose sugar molecules. Results in mental retardation, skeletal abnormalities and coarse facial features.

Question 21

What is Robinow syndrome?

Answer 21

Extremely rare disorder causing dysmorphic facial appearance and vertebral malformations. Caused by defects in signalling with tyrosine kinase receptors ROR2 caused by a misfolded protein.

Question 22

What appearance are clatharin vesicles associated with?

Answer 22

Basket-like appearance

Question 23

Why is a carboxyl group added to glutamate in the blood?

Answer 23

Increases affinity for calcium ions which is needed for clotting. Forms gamma-carboxylglutamate.

Question 24

What is meant by MHC restriction?

Answer 24

Refers to the fact that T cells can interact with MHC molecules and the attached antigen to the MHC molecule but can only recognise and respond to the antigen once it is bound to the MHC molecule.

Question 25

What is the couple reaction used for the detection of CK levels?

Answer 25

1) Creatine phosphate + ADP forms creatine and ATP, catalysed by creatine kinase.
2) D-glucose + ATP forms ADP and glucose-6-phosphate, catalysed by hexokinase.
3) G6P +NADP+ = 6-PG + NADPH + H+, catalysed by G6P dehydrogenase.

Question 26

Describe action of lysozyme.

Answer 26

Depends upon Glu-35 and Asp-52.

1) Glu-35 protonates oxygen (in glycosidic link between two sugars)
2) Water molecule deprotonated by Glu-35
3) Asp-52 stabilised positive charge in transition state
4) Hydroxide ion attacks the remaining sugar molecule, adding OH group to it.
5) Proton transferred to Glu-35 to return to original state
6) Glu-35 ad Asp-52 both in original states

Question 27

What is the step that produces isoprene in cholesterol biosynthesis?

Answer 27

Mevalonate is synthesised from 3 acetyl-coA subunits, which is then activated to form isoprene (C5).

Question 28

What is the process of the link reaction?

Answer 28

1) Decarboxylation of pyruvate to give hydroxyethyl TPP.
2) Oxidation and transfer of hydroxyethyl TPP to lipoamide to give acetylipoamide.
3) Transfer of acetyl group acetylipoamide to coA to give acetyl CoA
4) Regeneration of the oxidised lipoamide generating FADH2
5) Regeneration of oxidised fAD, by NAD+ regenerating NADH.

Question 29

How is calcium released from the SR in smooth muscle?

Answer 29

Gq receptors for endothelin, adrenaline or Act are present on the smooth muscle membrane, causing the production of IP3. IP3 is directly responsible for the calcium influx into cytoplasm from SR, opening Ca channels on the surface of smooth muscle membrane.
- Allows smooth muscle to contract even in the absence of an AP.