Karteikarten
Metabolism
Karten in diesem Stapel (60)
- 1What is catabolism?Breakdown of complex molecules into smaller ones, releasing energy
- 2What is anabolism?Sythesis of new complex molecules from its smaller constituents, using energy
- 3Why should we study metabolism?Often the basis of disease - therefore we need to know how the body NORMALLY uses nutrients. In a disease state, metabolism can change (e.g. cancer)
- 4The body needs to re-synthesise ____ from ____ to meet demand, as the body only has ____g - this is one fifth of the required amount during exercise.ATP,
ADP,
100 - 5How is most ATP in the body synthesised?Through oxidative phosphorylation in the mitochondria
- 6Name 4 major oxidative pathways1. glycolysis
2. fatty acid oxidation
3. TCA cycle (Krebs cycle)
4. Electron transport chain and oxidative phosphorylation - 7Glycolysis is an _________ process converting _________ to 2 x _________. It occurs in the ___________anaerobic,
glucose,
pyruvate,
cytoplasm - 81. Glucose is _________ using ____ by __________ (or in the liver, ___________). This maintains a _______ _______.phosphorylated,
ATP,
hexokinase,
glucokinase,
concentration gradient. - 92. G-6-P is then converted to _________ __ ________ and then phosphorylated again using ____ by _____________________. This is the ____ _______ ____ of glycolysis.Fructose 6 phosphate,
ATP,
phosphofructokinase,
rate limiting step - 103. The resulting ________ __ __ _________ splits into 2 x 3 carbon compounds, which undergo dephosphorylation to produce _________.fructose 1,6 bisphosphate,
pyruvate - 11How many ATP molecules are used and gained in glycolysis, and what is the resultant net gain?2 used, 4 made = 2 gained
- 12How many molecules of NAD+ are used in glycolysis, and at what stage?2, in the conversion of the unstable 3 carbon compound to pyruvate.
- 13Which enzyme converts phosphoenol pyruvate to pyruvate?Pyruvate kinase
- 14What inhibits the action of hexokinase?G-6-P (it's own product)
- 15What inhibits the action of phosphofructokinase?ATP, Citrate and H+ (low pH) = (the products of oxidative phosphorylation)
- 16What stimulates the action of phosphofructokinase?AMP and Fructose 6 phosphate
- 17What inhibits the action of pyruvate kinase?ATP
- 18How does ATP inhibit phosphofructokinase?Lowers the affinity of PFK for fructose 6 phosphate
- 19What does inhibiting PFK lead to?Build up of G-6-P and therefore also inhibition of hexokinase
- 20In the liver, there is _________ as well as hexokinase. It is not inhibited by a build up of ___ ___ ___ like hexokinase.glucokinase,
G-6-P - 21In muscles and tumours, most energy is gained through glycolysis, which is ________.anaerobic
- 22In anaerobic glycolysis in muscle and tumours, there needs to be a supply of NAD+ for formation of pyruvate. As there is no oxidative phosphorylation, where does it come from?Pyruvate is converted to lactate, which also converts NADH to NAD+ which is used in the earlier stages of glycolysis.
- 23What are 2 dangers in a build up of lactate?1. Lactate is toxic - it must be broken down in the liver
2. It is acidic so causes fall in pH, which inhibits PFK - 24Tumours exist in a _______ environment, which activates __ __ __ __. This stimulates ______ _______ to grow and an increase in ___________ _______ so tumours can overcome the usual regulatory processes and survive.hypoxic,
HIF1,
blood vessels,
glycolytic enzymes - 25Apart from lactate, what is the other fate of pyruvate?Acetyl CoA
- 26What is an advantage and disadvantage of this?Advantage = yields more ATP
Disadvantage = requires O2 - 27Where does aerobic respiration take place?The mitochondria
- 28Where does the TCA cycle take place?Mitochondrial matrix
- 29Pyruvate is converted to ________ ___ in the presence of ______. It is a __ carbon compound, and the by-products of the reaction are ______ and ______Acetyl CoA,
oxygen,
2,
CO2,
NADH - 30What does Acetyl CoA react with on its entry to the TCA cycle?Oxaloacetate (4C)
- 31What does this form?Citrate (6C)
- 32Citrate undergoes 3 main reactions: 1. a 5C compound is obtained by the loss of ____ and _____. 2. a 4C compound is obtained by the loss of ____ and _____. 3. The 4C compound is converted back to oxaloacetate, losing a molecule each of ____, _____ and _____.CO2 and NADH,
CO2 and NADH,
GTP, NADH and FADH2 - 33Which enzyme helps convert pyruvate to Acetyl CoA?pyruvate dehydrogenase
- 34How does it control entry to the TCA cycle?Build up of NADH and Acetyl CoA causes production of a kinase which phosphosylates pyruvate dehydrogenase and makes it inactive
- 35When a muscle in exercising, there is increased ____. This stimulates a _________ enzyme which activates __________ __________ and allows conversion of ________ to ______ ___.Ca++,
phosphatase,
pyruvate dehydrogenase,
pyruvate,
Acetyl CoA - 36Which enzyme helps make citrate from acetyl CoA and oxaloacetate?Citrate synthase
- 37Which enzymes helps convert citrate into the 5C compound (alpha-ketogluterate)?Isocitrate dehydrogenase
- 38Which enzyme helps convert the 5C alpha ketogluterate into the 4C Succinyl CoA?alpha ketogluterate dehydrogenase
- 39What is beriberi and what does it do?Deficiency of vitamin B1 (thiamine). Thiamine is a prosthetic group in pyruvate and alpha-ketogluterate dehydrogenase - lack of these causes difficulties in generating energy from glucose so causes cardiac and neurological symptoms
- 40The FADH2 and NADH produced in the TCA cycle then goes to the ________ ___________ ________ to take part in the _________ __________ _________.inner mitochondrial membrane,
electron transport chain - 41NADH is oxidised by _____ ____________ to give _____ + ____ + ___. The ______ enter the chain at complex I and travel through complexes II, III and IV, gradually losing ______. They are then used in a reduction reaction to form _____ at complex IV.NADH dehydrogenase,
NAD+,
H+,
2e-,
electrons,
energy,
H2O - 42The FADH2 is oxidised by ________ ________ and the _______ enter the chain at complex II, taking the same course as those from NADH.succinate dehydrogenase,
electrons - 43As the electrons pass along the chain, their ______ allows ___ ions across the membrane into the ____________ _____. This creates an ____________ _______.energy,
H+,
intermembrane space,
electrochemical gradient - 44For each NADH molecule, ___ H+ ions are pumped out. For every FADH2 molecule, ___ H+ ions are pumped out.10,
6 - 45____ ______ molecules exist on the membrane, which are molecular motors. They have a channel which allows ____ ions into the matrix down the __________ _________. This movement causes a rotation of part of the protein, and the synthesis of ____ from ___ + ___.ATP synthase,
H+,
electrochemical gradient,
ATP,
ADP + Pi - 46If the protein is uncoupled, ___ ions enter the matrix without synthesising ____. This generates _____ (used in newborns in brown fat molecules, as they cannot shiver).H+,
ATP,
heat - 47What is the main regulator of the electron transport chain?ATP - when there is excess, electron flow can be scaled down, but when there is need for ATP it can be increased.
- 48What processes provide the energy for a 100m sprint? (4)1. ATP stores in muscle
2. Glycolysis
3. Glycogenolysis
4. Creatine phosphate + ADP --> ATP + creatine - 49Why can creatine phosphate and glycolysis only be used for short bursts of exercise?We only have small stores of creatine phosphate, and glycolysis produces lactate and therefore a fall in pH.
- 50What substances provide energy while running a marathon?Glycogen and fatty acids
- 51In the fed state, where are most nutrients going?1. From gut to liver
2. From liver to adipose stores
3. From liver to muscle
4. From liver to kidneys
5. From liver to brain - 52Which pathways are stimulated in the fed state? (3)1. Glycolysis
2. Glycogenesis
3. Lipogenesis - 53Which pathways are inhibited in the fed state? (3)1. Glycogenolysis
2. Lipolysis
3. Gluconeogenesis - 54Which molecules are abundant in the fed state?1. Glycogen
2. Fatty acids - 55Which molecules are few in the fed state?1. Glucose
2. Ketones - 56In starvation, where are most nutrients going?1. From muscle to liver
2. From adipose stores to liver
3. From liver to brain
4. From liver to kidneys - 57Which pathways are stimulated in the starved state? (4)1. Glycogenolysis
2. Gluconeogenesis
3. Lipolysis
4. Ketogenesis - 58What pathways are inhibited in the starved state? (3)1. Glycolysis
2. Glycogenesis
3. Lipogenesis - 59Which molecules are abundant in the starved state? (2)1. Glucose
2. Ketones - 60Which molecules are few in the starved state? (2)1. Glycogen
2. Fatty acids
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- Degree MCBHD Karteikarten am Metabolism, erstellt von Hannah Tribe am 27/04/2014.
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- Hannah Tribe
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