Metabolism ew Flashcards
What the diagram that summarises metabolism?
What type of reaction mainly are the breakdowns of protein, fat and carbohydrates?
Oxidative processes= reactions that involve the transfer of 1 or more electrons from an electron donor (reductant) to an electron acceptor
What is ATP mainly used for?
Ion pumping
Biosynthetic reactions
Muscle contraction
Where is ATP produced?
Mainly through the electron transport chain, TCA cycle (respiration), amino acid breakdown, fatty acid oxidation and glycolysis (glucose breakdown)
What is the actual and effective free energy of hydrolysis of ATP?
Hydrolysis of ATP= releases energy
Actual= 60 kJ/mol but ATP is not 100% effective so effective= ~40 kJ/mol
Where is NADPH produced from?
Produced in the pentose-phosphate pathway from NADP+
What is NADPH used for?
Fatty acid synthesis, ribonucleitode reduction and cholesterol synthesis
At what stage of life do you need the most energy per kg?
Baby, then slowly decreases, unless are an athlete
What energy source has the biggest energy yield?
What are the different energy stores in the body?
Glucose (plasma, liver, muscle)
Triacylglycerol (adipose and muscle)
Protein
What are the pros and cons of the different glucose stores?
Plasma- very small store, used by all cells
Liver- highly hydrated so heavy and not efficient storage
Muscle- can be mobilised rapidly in fight and flight and provide glucose anaerobically, store can only be used for muscle and also heavy
What are the pros and cons of triacylglycerol energy storage?
Not hydrated- less heavy and big energy yield
However, fat oxidation requires oxygen and free fatty acids cannot be used by the brain as fuel
What are the pros and cons of protein energy storage in the body?
It is convertible to both glucose and ketone bodies
All protein is functional however, there is no excess storageq
What are the different fuels present in the blood?
Glucose, fatty acids, ketone bodies, amino acids and lactate (breakdown product of glucose in anaerobic respiration)
What are ketone bodies made of?
Breakdown of fatty acids or proteins in starvation
What parts of the body require glucose as a fuel?
Brain- mainly uses glucose cannot use fatty acids
Erythrocytes- metabolise only glucose as they do not have mitochondria
Some other tissues e.g. renal medulla
What can amino acids be broken down into?
Some are glucogenic- can be broken down into glucose
Some are ketogenic- broken down into ketones
Some are both
How is fat metabolised? (diagram)
Triacylglycerol in diet converted to chylomicrons then stored as TG in adipose and be broken down when needed to FFAs in the plasma
FFA taken up by muscles (for energy) and in the liver (for energy and to be converted to ketone bodies for brain)
What are the differences between fast twitch and slow twitch muscles?
Red=fast twitch, white= slow twitch
What is a source of ATP in muscle?
Creatine phosphate can be converted to creatine by creatine kinase and in the process ATP is produced
When energy is not needed, creatine can be rephosphorylated back
What fuels are used for muscle contraction (in anaerobic and aerobic exercise)?
Anaerobic e.g. sprinting= muscle ATP, creatine phosphate and muscle glycogen
Aerobic e.g. marathon running- fatty acids, ATP, glycogen, creatine P, and plasma glucose
What is the pathway of glucose metabolism in muscle in aerobic and anerobic conditions?
What is the cori cycle?
Where the liver converts lactate back to glucose, however comes at an ATP cost
What fuel is used in different times of moderate exercise?
Firstly running on muscle glycogen, but runs out
Plasma glucose not initially a big contributor but increases as liver glycogen breaks down
Fatty acids are major fuel towards end of exercise