KFP and EMQ MTC revision related questions

Question 1

What are the two ketone bodies?

Answer 1

acetoacetate and beta-hydroxybutryate

Question 2

What is the purpose of ketone bodies?

Answer 2

means for recycling CoA when glucose is low

Question 3

In cases of Diabetes Mellitus, what pathway is blocked and what is alternatively used?

Answer 3

Glucose metabolism is impacted due to reduced insulin leading the body to store and seek energy in the form of ketones. It initiates ketosis (breakdown of ketones) and ketogenesis.

Question 4

What are Activation-transfer co-enzymes and what are their characteristics?

Answer 4

Class of co-enzyme

What: Participate in catalysis by binding with the substrate

Characteristics = functional group (forms covalent bond) and binding group (binds to enzyme)

Question 5

Name three Activation-transfer-co-ensyme examples, their related vitamin and their main function

Answer 5

Thiamine Pyrophosphate = B1 = involved in carbohydrate metabolism (makes metabolites from carbs and keto analogues from amino and fatty acid metabolism = production of energy)

Co-Enzyme A = pantothenate = energy production (krebs cycle), fatty acid synthesis (transfers acetyl groups in elongation and carriers in oxidation), drug and enzyme functioning

Tetrahydrofolate = folate = carrier unit, versatile carbon donor and used in reactions involing amino and nucleic acids.

Question 6

Explain why a person who has comsumed alcohol presents with histamine release, facial flushing, nausea, headache, tachycardia and general physical discomfort.

Answer 6

80% have hyperactive ADH or reduced ALDL activity = increased serum levels of toxic acetaldehyde = these symptoms

Question 7

What is the reaction for Alcohol metabolism

Answer 7

Ethanol –(ADH)–> Acetaldehyde –(ALDH)–> acetate

Question 8

What is the enzyme used in alcohol metabolism and describe its presence in drinkers vs non-drinkers

Answer 8

Synthesis of alcohol DH (breakdown of ethanol) is stimulated by the presence of alcohol in bloodstream.

Those who don’t drink alcohol will not have this enzyme. When they drink for the first time = effects of alcohol in nervous system (as it can diffuse across membranes) will be noticed.

Heavy drinkers have high levels of the enzyme in liver = rapid metabolism of blood alcohol.

Question 9

Outline the regulation of glycolysis.

Answer 9

Hexokinase = inhibited by G7P

PFK1= inhibited by ATP and Citrate, Activated by = F2,6BP, AMP and ADP, allosteric regulators = insulin (activates) and Glucagon (inhibits PFK1)

Pyruvate kinase = Inhibitor = ATP and Acetyl CoA, Activator = F1,6BP,

Question 10

What is needed for glycolysis and what is produced?

Answer 10

Glucose + 2NAD+ + 2ADP + 2Pi⟶ 2 pyruvate + 2NADH + 2H+ +2ATP + 2H2O

Question 11

Describe the regulation, precursors, products and ATP production of gluconeogenesis.

Answer 11

Regulation
Allosteric= ATP
Hormonal = insulin (inhibits), glucagon (stimulates)

Precursors = lactate, amino acids and glycerol

6 ATP produced

Question 12

What is the purpose of ketone body synthesis?

Answer 12

Alternative source of energy when low BGL and can’t meet metabolic demands.

occurs in a fasting/starving state

Question 13

what are the inputs and outputs of ketogenesis?

Answer 13

input = acetyl CoA

outputs= acetoacetate and beta-hydroxybutryate

Question 14

outline the regulation of fatty acid synthesis

Answer 14

The switch from lipolysis –> lipogenesis is regulated via ATP, Citrate and malonyl CoA

Step 2 is only regulated step:
hormonal (insulin = active form) (glucagon = inactive form)
allosteric activators (Citrate and ATP)
allosteric inhibitors (palmitoyl CoA and AMPK)

Note- the allosteric activators and hormonal regulators are OPPOSITE to that of glycolysis.

Question 15

What is LDL and what hormone activates it and what can be the impact of this?

Answer 15

catalyses lipolysis of TG in chylomicrons or HDL

activated by insulin

diabetes = LDL not activated = can’t breakdown fats

Question 16

What is lipolysis stimulated by?

Answer 16

catecholamines, noradrenaline (release in adipose), Adrenaline in circulation, glucagon, cortisol and GH

Question 17

What is the major activator of lipolysis in a fasting-induced state?

Answer 17

Catecholamines

Question 18

What are the major hormones involved in lipolysis?

Answer 18

Adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HASL) and monoglyceride lipase (MGL)

Question 19

How many ATPs are produced in anaerobic glycolysis?

Answer 19

2

Question 20

What do RBCs always produce?

Answer 20

lactate - which is then recycled in the liver

Question 21

What does glucagon increase in a fasting state?

Answer 21

Gluconegensis

Glycogenolysis

Lipolysis

Beta oxidation

Ketone body production

Protein breakdown

Increased urea genreation

Question 22

What does insulin increase in a fed state?

Answer 22

Glycolysis

Glycogenesis

Lipogenesis

Protein production

Question 23

what is the mechanism of insulin?

Answer 23

initiates binding to glycoprotein receptor – binds to alpha subunit which is continuous with the beta subunit = tyrosine kinase receptor

Question 24

Glucagon stimulates glyogenolysis. What is this?

Answer 24

increase conversion of stored glycogen to glucose

Question 25

What is the role of amino acids?

Answer 25

Glucogenic = makes glucose from TCA and pyruvate

Ketogenic = makes acetyl-CoA or used to synthesise ketone bodies or fatty acids

Question 26

Where are amino acids made?

Answer 26

Fed state = Gut and liver

Fasting = muscle, gut, kidney and liver

Question 27

What are amino acids made from?

Answer 27

Essential – amino acids CAN’T be synthesized in human body – need to come in diet

Non-essential – can synthesis via metabolic intermediates (from TCA cycle) or other amino acids.

From TCA, glycolysis and PPP intermediates

Question 28

Describe regulation of TCA

Answer 28

A-ketoglutarate –> Succinyl CoA: NADH inhibits, Ca2 stimulates

Isocitrate –> A-KTG: NADH inhibits, ADP and Ca2 stimulates

Malate -> OAA: NADH inhibits

Overall: NADH inhibits, Ca2 stimulates