Metabolism - Introduction Flashcards
What energy is gained from alcohol, carbs, protein and fats?
Fats 37000kJ/kg
Alcohol 29000kJ/kg
Carbs 17000kJ/kg
Protein 17000kJ/kg
What is energy used for?
1) . Resist entropy - breakdown of cells and tissues
2) . Maintain body temperature in mammals
3) . Support and activity of cells and tissues
- -> biosynthesis
- -> mechanical
- -> electrochemical
- -> transport
What does BMR maintain?
1) . Digestion of food/other organs function
2) . Body temp
3) . Maintenance of cells (ion transport etc)
What affects BMR?
Body size Gender Environmental temperature Endocrine status (thyroid hormones etc) Factors that affect body temp (fever etc)
What stores can the body gain energy from?
1) . Glycogen - immediately used
2) . Triacylglycerides - long term store
3) . Proteins from muscle - during starvation
What are the components of energy expenditure?
BMR
Exercise
Processing food
What are the categories in the diet and what do they provide?
1) . Fats
- 2.2x more energy than from carbs
- absorb fat soluble vitamins
- some fatty acids are essential
2) . Proteins
- can be metabolised for energy
- can be broken down to provide amino acids required for N containing compounds
3) . Carbs
- metabolised for energy
4). Vitamins
5) . Fibre
- maintains healthy gut function
6) . Water
- maintains hydration
What are the 2 protein deficiencies and their function?
1) . Marasmus -
- no proteins or carbs
- no oedema
- anaemic, diarrhoea, thin and dry hair
- muscle wasting
- cant make amino acids
2) . Kwashiorkor -
- carbs but no proteins
- oedema
- apathetic, lethargic, anorexia
- carbs are converted into lipids, but due to lack of protein, there is no carrier, so the lipid is stored in the liver = accumulates = damage
What is the BMI calculation and categories?
Weight (kg)
BMI = —————
Height (m2)
< 18.5 = underweight 18.5 - 24.9 = average 25 - 29.9 = overweight 30 - 34.9 = obese > 35 = severely obese
What are the comorbidities of obesity?
Type II diabetes
Cancer
CV disease
Hypertension
How does obesity occur?
When energy expenditure is less than energy intake?
What is homeostasis?
The maintenance of the internal environment in order to sustain life.
It is a dynamic equilibrium
What are some examples of what homeostasis controls?
Blood flow Blood pH Body temp Supply of nutrients and O2 Removal of CO2 and waste
How does homeostasis affect the blood?
The blood needs its conc of nutrients kept constant but need fluctuates = cells store and interconvert
What are the levels of TAGS, a/a, cholesterol, fatty acids and glucose in the blood?
Cholesterol ~ 5mmol/L Glucose ~ 5mmol/L TAGs ~ 2mmol/L A/a ~ 2mmol/L Fatty acids ~ 0.5mmol/L
What is metabolism?
The process in which energy and raw materials are derived from food stuff, in order to support the growth, repair and activity of tissues to sustain life.
What are the types of metabolism?
Anabolic
- reductive
- builds things up from metabolites
- uses ATP
Catabolic
- oxidative
- breaks down fuel molecules to gain metabolites
- generates ATP
What is the function of metabolism?
Provides the energy we use for:
- support activity and growth of cells
- -> biosynthesis
- -> mechanical
- -> electrochemical
- -> transport
- resisting entropy
- manta inning body temp
What does exergonic and endergonic mean?
Exergonic
- release energy = spontaneous so deltaG < 0
- energy released often drives substrate level phosphorylation
Endergonic
- takes in energy = non spontaneous so deltaG > 0
How is the energy in bonds of fuel molecules released, and therefore, what is required?
Released via oxidation so carriers are needed for the electrons released
= NAD+
= FAD
Why is NAD+ and FAD recycled?
Because the total concentration of NAD+/NADH and FAD/FAD2H is constant in the body = would run out
What are the features of carriers?
Complex
Contain components from vitamins
What happens when ATP levels are high/low?
High - energy levels are high, anabolic systems activated.
Low - energy levels are low, catabolic systems activated.
What does adenylate kinase do?
Converts 2ADP —-> ATP + AMP
How is energy released from ATP?
Via hydrolysis of the high energy bond between ADP and Pi.
Why does ADP need recycling?
It is not a store
Concentration on body is constant
Why is it important that ATP is a stable molecule?
It is vital for the flow of energy.
What is creating phosphate and how is it created?
Creatine + ATP —————-> ADP + CrP
Creatine kinase
It is a reserve of high energy stores for periods of sudden metabolic activity.
How is ATP generated through CrP?
If conc of ATP falls quickly, creatine kinase quickly uses CrP and ADP to formATP and creatine.
What is the clinical importance of CrP?
1). Released by cardiac myocytes during a heart attack = can be measured in blood a few hours later as diagnosis.
2). Creatine and CrP both break down spontaneously at a constant rate to give creatinine.
Creatinine concentration in urine over 24hours is proportional to muscle mass, and therefore, can be a measure of dilution of urine, to estimate true urinary loss of a substance.
