Flashcards in MEH Deck (40)
Name low energy signals
NAD, inuslin, ADP, pyruvate
Name high energy signals
NADH, citrate, acetyl CoA, ATP
ADP + Pi --> ATP
Substrate level phosphorylation
When do we use LDH
To rexoxidise NADH to NAD when we can't carry out ETC or don't have enough oxygen (RBCs, exercising muscle)
Which proton carrier can be damaged by CO?
PTC IV- has a haem group to bind O2 and convert to H2O
What are uncouplers?
Uncouple electron transport from ATP synthesis. UCPs do this
Which is higher energy, FADH2 or NADH?
Brown adipose contains
UCP1 (thermogenin), an uncoupler
Name types of lactase deficiency
Primary is lack of lactase persistance allele, found in adults.
Secondary is due to SI injury and is reversible e.g. IBD, coeliac
Congenital is very rare AR can't digest breast milk
Name enzymes that if deficient would cause galactosemia
Galactokinase, UDP-galactose epimerase or uridyl transferase
Deficiency in which enzyme would cause fructosuria and which would cause fructose intolerance?
Essential fructosuria: fructokinase
Fructose intolerance: aldolase (F1P accumulates in liver to cause liver damage)
Which pathway makes NADPH and ribose?
Pentose phosphate pathway
What is used for GSH regeneration?
NADPH from pentose phsphate pathway
If you're starving, what activates ketone production?
Low insulin:glucagon activates lyase (enzyme in ketone production) and low glucose causes FA release from tissues to make acetyl CoA for ketones
How does alcohol change liver metabolism?
Uses up NAD in metabolising alcohol so then no NAD to break down FAs so they accumulate to give fatty liver. No NAD to break down glycerol for gluconeogenesis so hypoglycemia. No NAD to convert lactate to pyruvate so lactic acidosis and also build up of uric acid to causes gout.
What drug treats alcoholism
Disulfiram- inhibits aldehyde dehydrogenase so aldehyde builds up
Name some sources of free radicals
NADPH oxidase, ETC, radiation
Name three protectors of free radical damage
SOD: converts O2- --> H202 + O2
Glutathione: ROS react with it and form safe disulphide bonds, recycled back using NADPH
Catalase: H202 --> H20 + O2
Name some anti-oxidants
Vitamin E (regenerated by vitamin C) is a free radical scavenger
Consequences of galactosemia? (or indeed G6PDH deficiency!)
Galactose has to be converted to galctitol which uses up NADPH so NADPH not available to regenerate glutathione so prone to oxidative damage so cataracts
G6PDH needed for pentose phosphate pathway which produces NADPH so also get oxidative stress plus HEINZ bodies
What are Heinz bodies?
G6PDH deficiency sign- dark staining in RBCs frpm precipitated Hb. Forms a blister cell, spleen removes them to make a bite cell --> haemolysis
Describe metabolism of paracetamol
Metabolised to NAPQI (toxic metabolite), made safe by glutathione
Treatment for paracetamol OD
acetylcysteine- precursor to glutathione that makes NAPQI safe
Name ketogenic and glucogenic amino acids
Ketogenic: lysine and leucine (essential)
Glucogenic: alanine, glycine
Both: tyrosine, tryptophan
What hormones stimulate glucose production and which inhibit?
Insulin and growth hormone
What is transamination?
Transfer an amine group from an amino acid to a keto acid (and a keto acid gains an amine group to become an amino acid)
What's a keto acid?
An amino acid without an amine group
Name enzymes in gluconeogenesis
PEPCK, F16BPTase, G6Ptase
What goes into the urea cycle
Ammonia from deamination, CO2 and aspartate and glutamate from transamination