Metabolism Flashcards
Define Metabolism
The set of processes which DERIVE ENERGY and raw MATERIALS from food and use them to support REPAIR, GROWTH and ACTIVITY of the tissues to sustain life
What are the domains in the overview of metabolism
The GI TRACT where nutrients are absorbed from and lost in faeces.
The BLOOD where nutrients are transported and WASTE PRODUCTS from UTILISATION are lost (kidneys and lungs).
The TISSUES where nutrients are INTERCONVERTED for STORAGE or UTILISATION (also via SYNTHESIS). UTILISATION produces ENERGY and WASTE PRODUCTS
How are metabolic pathways organised within tissues
Some occur in ALL CELLS
Some a restricted to SOME CELLS
Some may be further restricted to COMPARTMENTS within cells
Metabolic maps show what?
they show start and end points as well as intermediates/metabolites also interconnections
Name the two main metabolic pathways and outline their functions
CATABOLIC- BREAKDOWN of larger molecules to smaller molecules releasing large amounts of FREE ENERGY and are usually OXIDATIVE (releasing protons and electrons).
ANABOLIC- SYNTHESIS of larger important cellular components from intermediary metabolites USING ENERGY via usually REDUCTIVE pathways
What are fuel molecules metabolised to supply
‘Building blocks’- i.e sugars, amino or fatty acids. A dynamic state of cell components, cell growth, division and repair
Organic precursors- i.e Acetyl CoA for interconversion
Biosynthetic reducing power (NADH NADPH)
Energy for cell function (ATP)
What is energy and what is it used for
The capacity to do work
BIOSYNTHETIC (anabolism)
TRANSPORT (membranes- nutrient uptake and ion gradients)
SPECIALISED (mechanical eg contraction, electrical eg nervous, osmotic eg kidneys)
True or False, in a normal healthy adult the average daily energy intake is equal to the average daily expenditure?
True, food in is equal to work and heat out roughly
What is the standard unit of energy and what is it per gram for fat, carbs, protein and alcohol in Kcal (1 calorie is 4.2 SI Units)
SI UNIT of energy is the Joule (J). Dividing by 4.2 gives calories
Fat is 9 kcal, carb is 4 kcal, protein is 4 kcal, alcohol is 7 kcal.
What is the base metabolic rate for a 70KG male and a 58KG woman per day at 18C?
1700kcal for men and 1400kcal for women
How many calories are expended through activity (muscular work) roughly per day
1000 to 300 kcal through skeletal and cardiac muscle
How much energy is used per day to ingest, digest and absorb food?
150kcal
Excess energy is stored when intake exceeds energy required. What is it used for and what if it is less than the energy required?
Growth occurs (new tissue, repair, children, pregnancy) or production of adipose tissue.
TISSUE LOSS occurs if intake < energy required
Can survive 20-70 days with water
List one types of energy and which is most predominantly used in the body.
Heat, light, mechanical, electrical, osmotic. CHEMICAL BOND ENERGY most used form.
What does the term isothermal mean and how does it apply to man?
Heat energy is not used to drive reactions in man
What are the two energy changes associated with chemical reactions and how do they relate to Gibbs free energy?
Exergonic- release energy with a NEGATIVE Delta G
Reaction is ‘spontaneous/feasible’
Endergonic- require energy with a POSITIVE Delta G
Reaction is not ‘spontaneous/feasible’ and requires energy input
True or false, the value of delta G indicates whether a reaction is spontaneous and indicates the rate?
False, it only indicates its spontaneity
What is a redox reaction. Explain redox in terms of electrons and hydrogen.
A reaction where a species is oxidised and another is reduced.
OIL RIG- Ox is loss, Red is gain
Name three major carrier molecules in the oxidised and reduced forms.
Nicotinamide adenine dinucleotide (NAD, NADH + H+)
Nicotinamide adenine dinucleotide phosphate (NADP+, NADPH +H+)
Flavin adenine dinucleotide (FAD, FADH2)
True or false, the concentration of oxidised or reduced carries is constant, cyclical, and they act as carriers of reducing power.
True, the concentrations are constant and must be cycled to maintain this. They act as carriers of reducing powers for ATP production and biosynthesis (NADH and NADPH)
Briefly outline H carrier molecules
Complex molecules with components from vitamins (B vitamins) that are converted to reduced form by adding two H atoms (proton and electron). The proton dissociates into solution.
How can energy released during oxidative metabolism be used?
Energy from oxidation stored in reducing equivalents used COUPLING SYSTEMS directly or indirection such as NADPH and NADH in the mitochondrial system respectively.
Through what process is reducing power converted to an energy currency (ATP)
Oxidative phosphorylation
Outline the ATP/ADP cycle?
OXYGEN and FUELS are used to combine ADP and Pi producing WATER and CARBON DIOXIDE as waste productions (aerobic respiration). This produces ATP which is used for WORK and dissociates into ADP and Pi again.
