Chapter 4 Flashcards
Cellular respiration
Glucose molecules are oxidized
Products are water, CO2, heat and ATP
Centre of all metabolism
Overall change in energy of cellular respiration
-2870kJ/ mol glucose rather by composition or cellular respiration
Respiration steps
1) Glycolysis- 10 steps- cytoplasm
2) Pyruvate oxidation- 1 step- mitochondrial matrix
3) Krebs cycle- 8 steps- mitochondrial matrix
4) Electron transport and chemiosmosis- multistep process ON inner mitochondrial membrane
Obligate aerobe
Can not live without oxygen
Substrate level phosphorylation
Formation of ATP by the direct transfer of a phosphate group from a siubstrate to ATP
Happens in glycolysis and krebs cycle
Forms ATP directly without O2
Pi and energy come from substrate
Oxidative phosphorylation
Forms ATP using energy transferred indirectly from a series of redox reactions
Happens in ETS via chemosmosis
Energy comes from oxidation of NADH and FADH2
Metabolic rate
The amount of energy that is expended per unit time in an organism
Basal metabolic rate (BMR)
The metabolic rate of an organism at rest. Accounts for 60-70% of human activities
Anaerobic respiration
Uses an inorganic molecule other than oxygen as the final oxidizing agent. Uses electron transport system
Fermentation
Uses an organic compound as the final oxidizing agent to produce energy
Beta oxidation
A process in which fatty acids are broken down into acetyl-CoA through catabolism
ATP contains ___ kJ/ mol
31
Uncoupling electron transport
The energy released is turned into thermal energy used to regulate body temperatures instead of being used as ATP
What does cellular respiration do?
Extracts energy from food.
Glycolysis
10 steps. in glycolysis 1 glucose is turned into dihydroxy phosphate and 2 glyderaldehyde 3 phosphate molecules (steps 1-5, initial energy investment phase)
The 2 G3P molecules both form pyruvate in glycolysis 3 (steps 6-10, energy payoff phase)
When glycolysis forms pyruvate what does it do?
Diffuses into mitochondrial membrane through a transport protein
Pyruvate oxidation
1) Pyruvate is decarboxylized
2) Pyruvate looses e- by being oxidized by NAD+ and produces an acetyl group
3) Acetyl group reacts with the sulphur atoms of coenzyme A and produces acetyl co-A
Citric acid cycle (basics)
Acetyl Co-A —–> Citrate (6C) —–> oxaloacetote
Proton motive force
moves protons because of a chemical gradient of protons across a membrane
Proton gradient
A difference in proton (H+) concentration across a membrane
Chemiosmosis
A process in which ATP is synthesized using the energy of an electrochemical gradient and the ATP synthase enzyme
Actual yield
30 ATP because:
1) Some H+ leak through inner membrane
2) Some H+ in revision are used by cell for other activities
3) Some cells use less efficient glycerol- phosphate shuttles
Aerobic respiration is still much more efficient than glycolysis
Theoretical yield of cellular respiration
38 ATP (41%)
Protein catabolism
Amino group is removed: deamination in the liver
The remaining carbon skeletons enter various components of glycolysis or krebs cycle
