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Biochem 10-Exercise&Metabolism

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winniesmith1's version from 2017-05-16 14:04

Section 1

Question Answer
StarvationGradual process of adaptation
Exercisemassive metabolic flux (est 1000fold Δ)
What is the whole-body energy expenditure18 x change
Exercise causes a major increase in substrate transport- how?(3xchange) increased circulation, increased respiration, increased metabolism.
What are the two types of exerciseAnaerobic and aerobic
What is anaerobic exerciseRapid energy generation over a short time period
Energy is generated too rapidly for the diffusion into the muscle of which substratesOxygen and NEFA
How do muscles generate energyATP-PC- Muscle Glycogen- Muscle TriG
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Section 2

Question Answer
What is aerobic exerciseProlonged exercise at reduced intensity.
What energy do we use in aerobic exerciseDuration is such that muscle stores alone are not suffice. So we use the bodies other energy store: Adipose tissue, triglycerides- liver glycogen.
How does energy stored in other parts of the body help the muscleTransport of substrate to muscle via blood
Why is aerobic respiration more efficient than anaerobicSubstrates fully oxidised aerobically = max energy output Substrates partially oxidised = less energy (but faster)
How is exercise or work usually calculated Externally. That is the movement of the whole body or part of the body sometime carrying a weight. But can also look at energy expended as metabolic rate
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Section 3

Question Answer
(AN)Workers exercise beginIn the brain
What does cognitive function do decides to move
What do somatic nerves dosignal muscle to contract
What does skeletal muscle docontraction -> movement
What do nerve impulses doneurotransmitter= acetylcholine
What does acetylcholine do nicotinic receptors (in somatic nervous system). Stimulates ATP hydrolysis and muscle contraction.
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Section 4

Question Answer
(AN) ATP only exist in small quantities so..It has to be re-synthesised (0.1mmol)
How is ATP resynthesisedby phospho creatine (ATP+CP=Phosphagen store)
What is the method of phosphagen store re-synthesis ? Breakdown of ?Glycogen and glucose
What breakdown is the most important during high intensity exerciseGlucose-6-phosphate via Glycogenolysis.
How is glycogenolysis and contraction co-ordinated2 methods: 1) increased Ca2+ in SR activates glycogen synthase 2) Glycogen phosphorylase only works with increased Pi
Where does Pi come from ATP--> ADP+Energy+Pi. But as ATP is continually re-synthesised where does Pi really come from ? PC (phospho creatine).
If Pi actually comes from PC - what does this meanno real need for rapid hormone stimulation as glycogen breakdown and muscle contraction are so closely linked.
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Section 5

Question Answer
(AN)What else is needed other than substrates for the massive change in glycolysisenzymes
What enzymes are needed in anaerobic metabolic regulation (for massive change in glycolysis)Phosphofructo kinase. Adenylate kinase. Creatine kinase. AMP deaminase
What does Phosphofructo kinase doF-6-P → F-1-6BiP
What does Adenylate kinase doATP → ADP + Pi
What does Creatine kinase doPC + ADP → Cr + ATP
What does AMP deaminase doAMP + H2O → IMP + NH3
What is the change in glycolysis1000 fold flux - massive change. Caused by enzyme increase and substrate cycles.
What are substrate cycles see UNI folder -> Biochem2 -> exercise metabolism word sheet
In ANaerobic, is a 36 fold increase realistic?Not instantly. 25 fold increase is stretching things but combined it means a 1000 fold change.
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Section 6

Question Answer
AEROBIC exercise can be sustained for a long period of time so fuels must beFully oxidised to prevent partial breakdown products such as Lactate. Also requires oxygen.
in aerobic- what else must happen apart from the supply of substrates and oxygen ?Removal of CO2.
How much ATP is used during a marathonapprox. 70kg. Therefore ATP must be re-synthesised many times over.
How is ATP resynthesis brought about in light intensity exerciseNEFA (from adipose tissue)
How is ATP resynthesis brought about in higher intensity exerciseGlucose (initially) shifting to NEFA.
Why does glucose needs to be conservedas Fats and AA burn in CHO flame
Where does the glucose come from in aerobic exercise Muscle glycogen and Liver glycogen (liver Gluconeogenesis kinda)
Why is Liver Gluconeogenesis limited during exercise ? Blood flow to Liver limited, as skeletal muscles steal all the blood.
With fat metabolism- why don't we just run and runFat only contributes to about 60% of muscle oxygen consumption ! Leaving Glucose as the number 1 important factor in exercise metabolism !
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