KFP and EMQ MTC revision related questions Flashcards
all wks
What are the two ketone bodies?
acetoacetate and beta-hydroxybutryate
What is the purpose of ketone bodies?
means for recycling CoA when glucose is low
In cases of Diabetes Mellitus, what pathway is blocked and what is alternatively used?
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.
What are Activation-transfer co-enzymes and what are their characteristics?
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)
Name three Activation-transfer-co-ensyme examples, their related vitamin and their main function
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.
Explain why a person who has comsumed alcohol presents with histamine release, facial flushing, nausea, headache, tachycardia and general physical discomfort.
80% have hyperactive ADH or reduced ALDL activity = increased serum levels of toxic acetaldehyde = these symptoms
What is the reaction for Alcohol metabolism
Ethanol –(ADH)–> Acetaldehyde –(ALDH)–> acetate
What is the enzyme used in alcohol metabolism and describe its presence in drinkers vs non-drinkers
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.
Outline the regulation of glycolysis.
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,
What is needed for glycolysis and what is produced?
Glucose + 2NAD+ + 2ADP + 2Pi⟶ 2 pyruvate + 2NADH + 2H+ +2ATP + 2H2O
Describe the regulation, precursors, products and ATP production of gluconeogenesis.
Regulation
Allosteric= ATP
Hormonal = insulin (inhibits), glucagon (stimulates)
Precursors = lactate, amino acids and glycerol
6 ATP produced
What is the purpose of ketone body synthesis?
Alternative source of energy when low BGL and can’t meet metabolic demands.
occurs in a fasting/starving state
what are the inputs and outputs of ketogenesis?
input = acetyl CoA
outputs= acetoacetate and beta-hydroxybutryate
outline the regulation of fatty acid synthesis
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.
What is LDL and what hormone activates it and what can be the impact of this?
catalyses lipolysis of TG in chylomicrons or HDL
activated by insulin
diabetes = LDL not activated = can’t breakdown fats
What is lipolysis stimulated by?
catecholamines, noradrenaline (release in adipose), Adrenaline in circulation, glucagon, cortisol and GH
What is the major activator of lipolysis in a fasting-induced state?
Catecholamines
What are the major hormones involved in lipolysis?
Adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HASL) and monoglyceride lipase (MGL)
How many ATPs are produced in anaerobic glycolysis?
2
What do RBCs always produce?
lactate - which is then recycled in the liver
What does glucagon increase in a fasting state?
Gluconegensis
Glycogenolysis
Lipolysis
Beta oxidation
Ketone body production
Protein breakdown
Increased urea genreation
What does insulin increase in a fed state?
Glycolysis
Glycogenesis
Lipogenesis
Protein production
what is the mechanism of insulin?
initiates binding to glycoprotein receptor – binds to alpha subunit which is continuous with the beta subunit = tyrosine kinase receptor
Glucagon stimulates glyogenolysis. What is this?
increase conversion of stored glycogen to glucose
What is the role of amino acids?
Glucogenic = makes glucose from TCA and pyruvate
Ketogenic = makes acetyl-CoA or used to synthesise ketone bodies or fatty acids
Where are amino acids made?
Fed state = Gut and liver
Fasting = muscle, gut, kidney and liver
What are amino acids made from?
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
Describe regulation of TCA
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
