MEH

Question 1

Name low energy signals

Answer 1

NAD, inuslin, ADP, pyruvate

Question 2

Name high energy signals

Answer 2

NADH, citrate, acetyl CoA, ATP

Question 3

ADP + Pi –> ATP

Answer 3

Substrate level phosphorylation

Question 4

When do we use LDH

Answer 4

To rexoxidise NADH to NAD when we can’t carry out ETC or don’t have enough oxygen (RBCs, exercising muscle)

Question 5

Which proton carrier can be damaged by CO?

Answer 5

PTC IV- has a haem group to bind O2 and convert to H2O

Question 6

What are uncouplers?

Answer 6

Uncouple electron transport from ATP synthesis. UCPs do this

Question 7

Which is higher energy, FADH2 or NADH?

Answer 7

NADH

Question 8

Brown adipose contains

Answer 8

UCP1 (thermogenin), an uncoupler

Question 9

Name types of lactase deficiency

Answer 9

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

Question 10

Name enzymes that if deficient would cause galactosemia

Answer 10

Galactokinase, UDP-galactose epimerase or uridyl transferase

Question 11

Deficiency in which enzyme would cause fructosuria and which would cause fructose intolerance?

Answer 11

Essential fructosuria: fructokinase

Fructose intolerance: aldolase (F1P accumulates in liver to cause liver damage)

Question 12

Which pathway makes NADPH and ribose?

Answer 12

Pentose phosphate pathway

Question 13

What is used for GSH regeneration?

Answer 13

NADPH from pentose phsphate pathway

Question 14

If you’re starving, what activates ketone production?

Answer 14

Low insulin:glucagon activates lyase (enzyme in ketone production) and low glucose causes FA release from tissues to make acetyl CoA for ketones

Question 15

How does alcohol change liver metabolism?

Answer 15

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.

Question 16

What drug treats alcoholism

Answer 16

Disulfiram- inhibits aldehyde dehydrogenase so aldehyde builds up

Question 17

Name some sources of free radicals

Answer 17

NADPH oxidase, ETC, radiation

Question 18

Name three protectors of free radical damage

Answer 18

SOD: converts O2- –> H202 + O2
Glutathione: ROS react with it and form safe disulphide bonds, recycled back using NADPH
Catalase: H202 –> H20 + O2

Question 19

Name some anti-oxidants

Answer 19

Vitamin E (regenerated by vitamin C) is a free radical scavenger

Question 20

Consequences of galactosemia? (or indeed G6PDH deficiency!)

Answer 20

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

Question 21

What are Heinz bodies?

Answer 21

G6PDH deficiency sign- dark staining in RBCs frpm precipitated Hb. Forms a blister cell, spleen removes them to make a bite cell –> haemolysis

Question 22

Describe metabolism of paracetamol

Answer 22

Metabolised to NAPQI (toxic metabolite), made safe by glutathione

Question 23

Treatment for paracetamol OD

Answer 23

acetylcysteine- precursor to glutathione that makes NAPQI safe

Question 24

Name ketogenic and glucogenic amino acids

Answer 24

Ketogenic: lysine and leucine (essential)
Glucogenic: alanine, glycine
Both: tyrosine, tryptophan

Question 25

What hormones stimulate glucose production and which inhibit?

Answer 25

Insulin and growth hormone

Question 26

What is transamination?

Answer 26

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)

Question 27

What's a keto acid?

Answer 27

An amino acid without an amine group

Question 28

Name enzymes in gluconeogenesis

Answer 28

PEPCK, F16BPTase, G6Ptase

Question 29

What goes into the urea cycle

Answer 29

Ammonia from deamination, CO2 and aspartate and glutamate from transamination

Question 30

What is phenylketonuria

Answer 30

Deficiency AR in phenylalanine hydroxylase which converts phenylalanine to tyrosine, which we need to make NA, adrenaline, dopamine, thyroid hormones, melanin (so get intellectual disability, hypopigmentation, microcephaly)

Question 31

What is homocysteinuria

Answer 31

Problem with methionine breakdown that results in homocysteine accumulation

Question 32

Triglycerides are broken down into what two things

Answer 32

FAs and glycerol

Question 33

Name 3 ketone bodies

Answer 33

Acetoacetate, acetone, B-hydroxybutyrate

Question 34

What are normal, starvation, and untreated type 2 DM ketone levels

Answer 34

Normal less than 1, starvation 2-10, DM more than 10

Question 35

How do statins work

Answer 35

Decrease cholesterol synthesis by inhibiting HMG CoA reductase

Question 36

Describe iron uptake into enterocytes

Answer 36

Only enters as Fe2 (ferrous) via transferrin, then converted to Fe3 (ferric), can be stored as ferritin or transferred out via ferroportin (which is inhibited by hepcidin)

Question 37

Where is haemosiderin and ferritin

Answer 37

Haemosiderin- Kupffer cells, MO (stores iron) | Ferritin only in hepatocytes

Question 38

What is anisopoikilocytosis

Answer 38

Change in size and shape of cells e.g. pencil, target

Question 39

What tests would you do for anemia

Answer 39

Ferritin tests long term Fe storage (low means deficiency, if normal/high doesn't mean you're okay) CHR tests content of Hb in reticulocytes, how much iron is functionally available for RBC production

Question 40

In treating anemia what rise in Hb are we looking for

Answer 40

20g/L in 3 weeks