Question Add Ons Flashcards
What happens to lactose when lactase is not present?
It moves on in the intestine and is fermented by gut bacteria to give organic acids
= lower water potential
= irritate lining
Give an overview of the digestion of carbs.
Starch and glycogen in mouth - salivary amylase and glycosidase enzymes = maltose, disaccharides, dextrins.
MOVE ON TO JEJEUNUM AND DUODENUM
Disaccharides etc. broken down by glycosidase enzymes in brush border
What bonds does glycogen contain?
Alpha 1-4 and alpha 1-6 glycosidic bonds
What happens to lactate in the heart?
It is converted to pyruvate and then into acetyl CoA, before being fed into TCA.
What happens to lactate in the liver?
It is converted to pyruvate, then:
- into glucose by gluconeogeneic pathway
- oxidised into acetyl CoA for TCA
What is lactic acidosis?
When plasma lactate builds up to a level where it affects the plasma buffering capacity.
What is the purpose of glycolysis in RBCs?
Only form of ATP generation
Makes 2,3BPG which regulates Hb’s affinity for oxygen by decreasing it.
What is the purpose of glycolysis in adipose tissue?
It is a minor route for ATP generation
It can produce DHAP which can be converted back to glycerol phosphate and used in the production of TAGs (esterifies FA)
What is the purpose of glycolysis in skeletal muscle?
Enables production of ATP under anaerobic conditions.
What may increased LDLs and a family history of heart disease indicate?
Familial hypercholesterolaemia.
What do bile salt sequestrants do?
Increase disposal of cholesterol from the body.
How does NADPH oxidase work and where is it found?
Found in cell membranes.
It uses electron from NADPH to transfer over the membrane and generate its own ROS.
Would hyperventilation aid a free diver?
No because:
1) . This rids of CO2 = Hb affinity for O2 increases and therefore won’t release O2 at tissues as easily.
2) . High CO2 = urge to breathe, so ridding of CO2 surpresses this urge and may lead to unconsciousness.
How does acidosis lead to sickle cell crisis?
More H+ in blood than normal = decreases Hb affinity for O2.
Hb is now more likely to polymerise and this leads to sickle cell crisis.
How do hydrophobic interactions affect entropy?
More hydrophobic interactions decrease disorder and therefore decrease entropy
Why do marfans and homocystinuria appear similar?
Marfans is a mutation which causes Fibrillin 1 to mutate. In homocystinuria, homocysteine binds to lysine residues on Fibrillin1, also altering its shape and therefore, changing its function.
Define diabetes
A group of metabolic disorders characterised by chronic hyperglycaemia. It can be caused by insulin resistance or beta cell destruction.
What is a sign and a symptom?
Symptom is so ring they tell you, a sign is something you see.
What effect does metformin have?
It inhibits gluconeogenesis
What is glaucoma?
It is pressure in the eye from increased osmotic pressure
What is amylin?
From beta cells and surpresses appetite whilst slowing gastric emptying.
What does overproduction of adrenaline and noradrenaline do?
Tremors, hyperglycaemic, hypertension, sweating, palpitations.
Where is noradrenaline in the CNS?
Post ganglionic neurone of the sympathetic pathway
What is backers dystrophy?
Deficiency of dystrophin rather than lack of it
What are the effects of TH?
- increases bone uptake of calcium
- ovulation
- increase BMR = weight loss, increased motility of GI tract and heat intolerance
What is the proper name for galactose transferase?
Galactose 1 phosphate uridyl transferase
What are the main carbs found in a western diet and what digests them?
Cellulose - undigested Sucrose - sucrase Lactose - lactase Glycogen - numerous enzymes Starch - amylase
Why would cardiac arrest affect the heart and CNS more than skeletal muscle?
Heart and CNS don’t have stores of glycogen etc for anaerobic respiration, so whereas the skeletal muscle can continue to respire anaerobically for a short time to produce ATP, the heart and CNS cannot = not oxygen stops them from respiring and therefore functioning.
Why may weak aromatic acids cause death?
They act as uncoupling proteins and dissipate the pmf in mitochondria.
At first, the victim would lose fat stores, as glucose is used up very quickly due to quick dissipation = subcutaneous fat reserves used next. Heat would rise and eventually a coma and death would occur.
What does production of ketone bodies require?
1) . Low insulin to glucagon ratio
2) . Mobilisation of fatty acids and availability to be oxidised in liver
Compare and contrast TAGs and glycogen.
TAGS - in adipose tissue, biggest energy store, more stored energy per C atom
Glycogen - in liver, small energy store, less energy per C atom
Why is fatty acid synthesis not simply a reversal of beta oxidation, and why is this good?
Beta oxidation contains irreversible reactions and is exergonic, so can’t be the same as synthesis.
This is good as it allows better control (they can be done independently) and greater flexibility by using different substrates and enzymes
What happens to the carbon skeleton in amino acid metabolism?
It becomes glucogenic amino acids (for carb metabolism) or ketogenic amino acids (for lipid metabolism, ketone body generation or acetyl CoA production).
What does glutamate dehydrogenase do?
Converts glutamate to alpha keto glutarate to produce NH4+ and NADH
What is a synonymous mutation?
One in which the amino acid isn’t changed
Why may autosomal recessive diseases persist in humans?
There may be an advantage to carrier status
Reproductive compensation - parents have more children
What is the difference between mutations in BMD and DMD?
BMD usually has a mutation which remains in frame, DMD causes a frame shift
What is a polysome?
A cluster of ribosomes attached to a mRNA molecule
What is an inversion?
A rearrangement of the linear DNA in a chromosome
What are the 2 types of intercalated disc in cardiac muscle?
1) . Gap junctions - allow passage of ions so action potential can spread
2) . Adherens junctions - anchor actin to the nearest sarcomere
What are telomeres?
They are the ends of the chromosome which protect it from damage
