Bioenergetics and ATP synthesis Flashcards
What is Gibb’s free energy?
Amount of energy in a system available to do work
G=H-T.S
What does it tell us if delta G is negative?
Energy is liberated and the reaction is exergonic
A reaction can occur spontaneously
What does it tell us if delta G is positive?
Reaction is endergonic
Reaction will need an energy input
What does it tell us if delta G is 0?
System is at equilibrium
No net change can take place
What does it mean if an organism is a chemoorganotroph?
Extracts energy from organic compounds by oxidation
What should extraction of energy from food by controlled?
Don’t want to release all the energy at once because would increase body temp too much
Coupled reactions more efficient
Small carrier molecules are more mobile to travel around body
What do dehydrogenase do?
Oxidise organic compounds by abstracting protons and electrons and passing them to a mobile carrier in biodegradation and energy abstraction
Can reduce organic compounds by adding protons and electron from mobile electron carrier
Name 3 electron carriers.
NADH
NADPH
FADH2
What is ATP?
Energy rich molecule with high phosphoryl transfer potential
What does a catabolic reaction do?
Transforms fuels into usable cellular energy
What does an anabolic reaction do?
Utilise the useful energy formed by catabolism to generate complex structures from simple ones
What are the 3 principal ways that metabolic pathways are regulated?
Levels and accessibility of substrates
Amounts of metabolic enzymes
Modulation of catalytic activities of enzymes
What does an allosteric enzyme do?
Has a site distinct from the substrate-binding site. Ligands bind to this causing conformational changes so affinity for substrate and ligands changes
What is glycolysis?
Conversion of glucose to pyruvate
Anaerobic
Happens in cytosol
What are the 2 steps of glycolysis?
Trapping and destabilising glucose to produce 2 X 3C molecules
Oxidation of the 3C molecules to pyruvate
What is gluconeogenesis?
Glucose formation from non-carbohydrate precursors
What is the major site of gluconeogenesis?
Liver
Why do animals store energy as glycogen?
Controlled breakdown and synthesis helps maintain blood-glucose levels
Important: glucose only fuel for brain under non-starvation conditions
Where is glycogen mainly stored?
Liver and muscle
What is glycogenesis?
Glycogenesis Convert glucose to glucose 6-P Glucose 6-P converted to glucose 1-P Activated to produce UDP-glucose Glycosyl units added to non-reducing end of glycogen molecule
What does ubiquitin do?
Attaches to proteins and marks them for degradation
