Extended metabolism Flashcards
how can you use measurement of inspired and expired gas to measure RMR? What is this methodology called?
Indirect calorimetry
Measure oxygen inspired, and CO2 expired
Understand amount of fat and CHO being burned
Every l oxygen burns 5 kcal
Measure amount of oxygen used over 24h and know kcal
Several equations to allow for calculation
what practical method of dietary assessment would you use to assess an athletes diet? why?
3 day weighed food diary - 2 weekdays and 1 weekend
Most accurate and 7 day too long
Allow kcal/macro and micro nutrient intake
what are the different ways to describe energy efficiency?
Gross
Work
Net
Delta
(+formulas)
list the external factors that may not have been controlled when measuring RMR and how they would have influenced RMR - state the direction
Temp (cold) - increases
Starvation - decreases
Caffeine - increases
Carb - increases
Ex - increases
Protein - increases
Food pre lab - increases
Muscle mass - increases
what is the energy currency of the cell and describe the immediate energy systems that can be used to generate it
ATP (some UTP and GTP)
Some ATP stores
Phosphocreatine - combines with ADP to form ATP and Cr
Adenylate kinase - myokinase reaction - 2ADP form ATP and AMP
what are the 3 main adenylates in cells, how do you calculate the energy charge of the cell and what does this mean?
ATP, ADP, AMP
[ATP] + 0.5[ADP]/[ATP] + [ADP] + [AMP]
as AMP continues to increase exercise cannot continue, why and how?
If AMP accumulates energy charge of cell falls and wouldn’t have enough energy - stop exercising
Amp converted to IMP through purine nucleotide cycle
Presence AMP deaminase
what are the 6 stages of digestion and absorption and explain them
Ingestion - Taking food in
Secretion - Of water, acids, buffers and enzymes
Motility - Contraction and relaxation of smooth muscle, e.g. peristalsis
Digestion - Larger molecules into smaller ones through mechanical and chem digestion
Absorption - Products of digestion enter cells within body, from SI
Defecation - Indigestible substances, cells, digested materials not absorbed leave body as faeces
what are the 3 main disaccharides, the monosaccharides that make them up and the enzymes which hydrolyse them?
Sucrose - glucose and fructose - sucrase
Maltose - glucose - maltase
Lactose - glucose and galactose - lactase
what are the 2 forms of starch in the human diet, what is their prevalence and how do they differ?
Amylose (coiled for storage, 15-20% diet, 1,4 bonds) and amylopectin (branched for release of energy, 80-85% diet, 2 types bonds, 1,4 and 1,6)
what are the part of the digestive system and how long is the food/bolus/chyme at each stage?
Mouth (10s)
oesophagus (few s)
stomach (2-4h)
SI (3-12h)
LI (24-72h)
name and state the function of 3 hormones involved in digestion
Gastrin - stomach - stimulates glands to secrete HCl and pepsinogen
Secretin - SI - stimulates pancreatic bicarb-rich juices to neutralise acid
Cholecystokinin (CCK) - SI - stimulated when fat present stimulates gall bladder to release bile
how does exercise intensity effect gastric emptying?
Rate of gastric emptying not affected up to 80% VO2 max
Above this a reduction in delivery of fluid and nutrients to SI may occur
May not matter as unlikely can sustain activity at high levels for long periods
may be imp in intermittent type activity where low average VO2 max but lots of short intermittent bouts of hight intensity
why might the gall bladder be removed and what happens when it is?
A surgeon will remove your gallbladder if gallstones cause significant pain and other complications.
Other conditions that could make you a candidate for gallbladder removal include: Biliary dyskinesia.
This occurs when the gallbladder doesn’t empty bile correctly due to a defect in its motion
Inflammation of gall bladder
Bile less concentrated when coming straight from liver
Fat may not be broken down effectively
Up to 40% less dietary lipid
Lost in faeces
Reduced capacity to absorb fats
Alli is an over the counter weight loss pill that acts on lipases, how does it work?
Fat released as waste - not absorbed - become dehydrated
what is alpha amylase and how would alpha amylase inhibitors work to combat ever growing overweight and obesity problem
In saliva and pancreas
Breaks down amylose
Impedes digestion starch and wouldn’t be available for absorption
role of kinases
Transfer of phosphate group from ATP to specific molecule
role of isomerases
Catalyses conversion of compound to isomer - change structure
role of dehydrogenases
Oxidise substrate by reducing electron acceptor
role of synthases
Catalyses synthesis process
role of mutases
Catalyses the movement of a functional group from one position to another within the same molecule
role of decarboxylases
Add or remove carboxyl group from compound
role of phosphatases
Removes phosphate group from a protein
role of phosphorylase
Catalyse the addition of a phosphate group from an inorganic phosphate (phosphate + hydrogen) to an acceptor
role of deaminases
Removal of an amine group from a molecule
during exercise PDH is activated, describe how
PDH active form can be activated by PDH phosphatase
Get more active PDH when large amounts of pyruvate, CoA and NAD+ (metabolites) and product amounts low: acetyl CoA, NADH and CO2
Calcium also stimulant as released during muscle contraction
McArdle’s patients are missing glycogen phosphorylase. what does this mean for their everyday life and exercising?
No access to muscle glycogen
Max HR reached after climbing 5-6 steps
Not able to sprint - explosive ex results in severe problems
Larger energy disturbances occur
Measurable decreases in ATO
Rely more on fat met
what effect would an increase in glycogenolysis have on glucose uptake and why?
Glucose uptake will decrease because there’s large amount of G6P present from glycogenolysis
Increased levels of G6P inhibit enzyme hexokinase - therefore less glucose uptake into cell
how and where do we store fat, protein and carbohydrate?
Fat - intramuscular triglycerides and adipose tissue
Carb - glycogen in muscle and liver
Protein - not stored
antimycin A is a specific inhibitor of cytochrome C - describe the effects of the drug on OP and ATP synthesis
Antimycin A causes TP synthesis and Op inhibited
Electrons transferred from protein to protein until reach cytochrome c where stops
never reaching oxygen and not producing enough energy for translocation of protons
what are the 3 steps involved in protein synthesis, name them and give a brief overview
Transcription - DNA mRNA
Translation - initiation, elongation/termination
Post translational modifications - folding into useful structure
what is the difference between saturated and unsaturated FAs and what effect does this have?
Saturated = no double bonds - pack more tightly together - solids - don’t break down as easily
Unsaturated = at least one double bond - liquids at room temp
Double bond makes kink in chain - easier to break down
what is the difference between essential and non-essential nutrients
Essential - cannot be synthesised in the body - need to be taken in from external sources
How AAs referred to
describe the 4 main classes of nutrients and give an example of each
Essential - vitamins and minerals
Non-essential - AAs - alanine
Macronutrients - carbs and fat
Micronutrients - vitamins and minerals
name the item of equipment you need to measure indirect calorimetry with a cortex
Mask
Hair net
Turbine
Turbine casting (housing)
