Extra Flashcards
What does auricular cartilage contain and what is its function?
Resists compression by drawing in water by several negative charges. Has collagen II fibrils.
What direction do tendons resist force?
All directions
What is TATA?
A sequence found at the beginning of gene promoter sequences that work by binding to TF-II D and promoting gene expression and transcription.
Do influenza virus undergo recombination?
Yes - it has a segmented genome.
What does glucose-6-phosphatase do?
Present in liver and muscle. Converts glycogen into glucose (hydrolyses glucose-6-phosphate to glucose) in the ER, so important in glycogenolysis.
Why do proteins naturally form R-alpha helices?
The use of R-proteins naturally arranges into a conformation of the lowest energy. L-proteins counter steric hindrance in a L-handed helix.
What is at the core of a microvilli?
An actin core
How do bacteria affect actin?
Can cause actin polymerisation which can be helpful for the invasion of host cells.
Why can cysteine form disulphide bridges?
Has a sulphydryl group which can be oxidised to form disulphide bridges.
What does FAD stand for?
Flavine adenine dinucleotide
What is the point of transamination?
Produce new pair of keto and amino acids that are able to enter the TCA cycle.
Why are triacylglycerides good energy stores?
Highly reduced and have optimal packing in adipocytes due to their straight carbon chains.
What is Orlistat?
A medication that inhibits gastric and pancreatic lipase so that fat passes undigested through the gut, resulting in steatorrhea.
What two enzymes are responsible for fatty acid synthesis?
Fatty acid synthase and acetyl CoA carboxylase.
How are cholesterol requirements met?
De novo biosynthesis from acetyl co-A (lipogenesis)
What are isoprenoids?
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.
How is calcitriol produced from cholesterol?
UV light is required to generate calcitriol from 8-dehydrocholesterol.
How are lipoproteins categorised?
On their density.
How do we know if a protein is destined for lysosomes?
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.
What is I-cell disease?
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.
What is Robinow syndrome?
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.
What appearance are clatharin vesicles associated with?
Basket-like appearance
Why is a carboxyl group added to glutamate in the blood?
Increases affinity for calcium ions which is needed for clotting. Forms gamma-carboxylglutamate.
What is meant by MHC restriction?
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.
What is the couple reaction used for the detection of CK levels?
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.
Describe action of lysozyme.
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
What is the step that produces isoprene in cholesterol biosynthesis?
Mevalonate is synthesised from 3 acetyl-coA subunits, which is then activated to form isoprene (C5).
What is the process of the link reaction?
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.
How is calcium released from the SR in smooth muscle?
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.
