lecture 22 - energy balances in cells/organisms Flashcards
What is metabolism the basis for in cells?
Aids in the ways cells sense and respond to environment, make and break molecules, access energy and divide
What are the 3 ways to achieve loss of stored energy in the body - weight loss?
Reducing energy intake, increasing activity, increasing basal metabolism
What peptide is made in fat cells and signals to the brain that enough food has been consumed, reducing hunger?
Lectin
What is anabolism?
The synthesis of complex molecules, which requires an input of energy
What is catabolism?
The breakdown of molecules and the utilisation of the energy released.
Is ATP hydrolysed or synthesised in anabolism?
Hydrolysed
Is ATP hydrolysed or synthesised in catabolism?
Synthesised
What are 2 key energy sources that are not able to be utilised in the body?
Fibre lost in faeces, nitrogen is oxidised and excrete in urine
What is direct calorimetry?
Measuring the heat output from individuals in order to determine basal metabolic rate (BMR)
What is indirect calorimetry?
Measures O2 consumption and CO2 usage to determine the ‘respiration exchange ratio’
What does direct calorimetry determine?
Basal metabolic rate
What does indirect calorimetry determine?
Respiration exchange ratio
What is the equation for respiration exchange ratio?
RER = Co2 produced / O2 consumed
What does the respiration exchange ratio reveal?
The type of fuel being used by the body - as carbohydrates and fatty acids use different stoichiometric ratios of CO2 and O2
What does basal metabolism include?
Energy expenditure at rest for: muscle contraction, nerve conduction, ion transport, macromolecule synthesising, body heat
