Extended metabolism

Question 1

how can you use measurement of inspired and expired gas to measure RMR? What is this methodology called?

Answer 1

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

Question 2

what practical method of dietary assessment would you use to assess an athletes diet? why?

Answer 2

3 day weighed food diary - 2 weekdays and 1 weekend

Most accurate and 7 day too long

Allow kcal/macro and micro nutrient intake

Question 3

what are the different ways to describe energy efficiency?

Answer 3

Gross

Work

Net

Delta
(+formulas)

Question 4

list the external factors that may not have been controlled when measuring RMR and how they would have influenced RMR - state the direction

Answer 4

Temp (cold) - increases

Starvation - decreases

Caffeine - increases

Carb - increases

Ex - increases

Protein - increases

Food pre lab - increases

Muscle mass - increases

Question 5

what is the energy currency of the cell and describe the immediate energy systems that can be used to generate it

Answer 5

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

Question 6

what are the 3 main adenylates in cells, how do you calculate the energy charge of the cell and what does this mean?

Answer 6

ATP, ADP, AMP

[ATP] + 0.5[ADP]/[ATP] + [ADP] + [AMP]

Question 7

as AMP continues to increase exercise cannot continue, why and how?

Answer 7

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

Question 8

what are the 6 stages of digestion and absorption and explain them

Answer 8

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

Question 9

what are the 3 main disaccharides, the monosaccharides that make them up and the enzymes which hydrolyse them?

Answer 9

Sucrose - glucose and fructose - sucrase

Maltose - glucose - maltase

Lactose - glucose and galactose - lactase

Question 10

what are the 2 forms of starch in the human diet, what is their prevalence and how do they differ?

Answer 10

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)

Question 11

what are the part of the digestive system and how long is the food/bolus/chyme at each stage?

Answer 11

Mouth (10s)

oesophagus (few s)

stomach (2-4h)

SI (3-12h)

LI (24-72h)

Question 12

name and state the function of 3 hormones involved in digestion

Answer 12

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

Question 13

how does exercise intensity effect gastric emptying?

Answer 13

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

Question 14

why might the gall bladder be removed and what happens when it is?

Answer 14

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

Question 15

Alli is an over the counter weight loss pill that acts on lipases, how does it work?

Answer 15

Fat released as waste - not absorbed - become dehydrated

Question 16

what is alpha amylase and how would alpha amylase inhibitors work to combat ever growing overweight and obesity problem

Answer 16

In saliva and pancreas

Breaks down amylose

Impedes digestion starch and wouldn’t be available for absorption

Question 17

role of kinases

Answer 17

Transfer of phosphate group from ATP to specific molecule

Question 18

role of isomerases

Answer 18

Catalyses conversion of compound to isomer - change structure

Question 19

role of dehydrogenases

Answer 19

Oxidise substrate by reducing electron acceptor

Question 20

role of synthases

Answer 20

Catalyses synthesis process

Question 21

role of mutases

Answer 21

Catalyses the movement of a functional group from one position to another within the same molecule

Question 22

role of decarboxylases

Answer 22

Add or remove carboxyl group from compound

Question 23

role of phosphatases

Answer 23

Removes phosphate group from a protein

Question 24

role of phosphorylase

Answer 24

Catalyse the addition of a phosphate group from an inorganic phosphate (phosphate + hydrogen) to an acceptor

Question 25

role of deaminases

Answer 25

Removal of an amine group from a molecule

Question 26

during exercise PDH is activated, describe how

Answer 26

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

Question 27

McArdle’s patients are missing glycogen phosphorylase. what does this mean for their everyday life and exercising?

Answer 27

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

Question 28

what effect would an increase in glycogenolysis have on glucose uptake and why?

Answer 28

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

Question 29

how and where do we store fat, protein and carbohydrate?

Answer 29

Fat - intramuscular triglycerides and adipose tissue

Carb - glycogen in muscle and liver

Protein - not stored

Question 30

antimycin A is a specific inhibitor of cytochrome C - describe the effects of the drug on OP and ATP synthesis

Answer 30

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

Question 31

what are the 3 steps involved in protein synthesis, name them and give a brief overview

Answer 31

Transcription - DNA mRNA

Translation - initiation, elongation/termination

Post translational modifications - folding into useful structure

Question 32

what is the difference between saturated and unsaturated FAs and what effect does this have?

Answer 32

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

Question 33

what is the difference between essential and non-essential nutrients

Answer 33

Essential - cannot be synthesised in the body - need to be taken in from external sources

How AAs referred to

Question 34

describe the 4 main classes of nutrients and give an example of each

Answer 34

Essential - vitamins and minerals

Non-essential - AAs - alanine

Macronutrients - carbs and fat

Micronutrients - vitamins and minerals

Question 35

name the item of equipment you need to measure indirect calorimetry with a cortex

Answer 35

Mask

Hair net

Turbine

Turbine casting (housing)