Bio U4 Respiration Flashcards
The outer membrane of the mitochondria
Contains proteins to transport PYRUVATE from the cytoplasm into the mitochondria
The inner membrane of the mitochondria
Highly folded into cristae to increase surface area, allowing more electron carriers to fit into the membrane
Define ANABOLISM
The building up of complex molecules from simpler ones
Amino acids to proteins
Define catabolism
The breaking down of complex molecules to simpler ones
Proteins to amino acids
Metabolic processes that need energy
Cell transport processes - active transport Muscle contractions DNA replications Protein synthesis Digestion
NAD
Coenzyme that accepts hydrogen and carries it to where it is needed.
NAD accepts hydrogen in glycolysis, the links reaction and the Krebs cycle and releases it at the electron transport chain (OXIDATIVE PHOSPHORYLATION)
Coenzyme A
CoA
Carries a ACETATE group from the link reaction to the KREBS CYCLE
Here the ACETATE group combines with OXALOACETATE to form CITRATE
Respiration
The process whereby energy stores in complex molecules is used to make ATP. Occurs in living cells
What are the four stages respiration occurs in
Glycolysis
The Link Reaction
Krebs Cycle
Oxidative Phosphorylation
The last three stages of respiration only take place under …
Aerobic conditions
Under ANAEROBIC conditions PYRUVATE is…
Converted to either ETHANOL or LACTATE
Glycolysis
Happens in the CYTOPLASM of all cells
Doesn’t need O2 and can take place in aerobic or anaerobic conditions
During glycolysis, glucose-6C- is broken down into 2 molecules of PYRUVATE 3C
The link reaction
Happens in the MATRIX of the mitochondria
PYRUVATE is dehydrogenated and decarboxylated and converted into acetate
PYRUVATE is combines with coenzyme A to give acetylcoenzyme A (ACoA)
Krebs cycle
Takes place in the MATRIX of mitochondria
Citrate is converted back into OXALOACETATE
ACETATE is dehydrogenated and decarboxylated
Oxidative phosphorylation
Takes place on the folded inner membranes (CRISTAE) of mitochondria
This is where ADP is phosphorylated into ATP
Products of glycolysis
2x PYRUVATE
2x NADH
Net gain of 2xATP
Products of the Krebs Cycle
2x CO2
3x NADH
1x FADH2
1x ATP
Process of oxidative phosphorylation
Hydrogen atoms from reduced NAD and FAD are split into protons and electrons and donated to the electron carriers
The electrons are passed along the chain of electron carriers and then donated to molecular oxygen-the final electron acceptor
Energy is released as the electrons flow across the electron transport chain and is used to pump the protons across the membrane into the inter-membrane space
This builds up a PROTON GRADIENT and an ELECTROCHEMICAL GRADIENT
this results in a build up of potential energy in the inter-membrane space and causes protons to diffuse through the channels associated with the enzyme ATP synthase - CHEMIOSMOSIS
flow of protons through the channel causes the enzyme to rotate leading to the production of ATP from ADP and an inorganic phosphate
Some hydrogen ions are also donated to molecular oxygen forming water
What is CHEMIOSMOSIS
The flow of hydrogen ions through ATP synthase enzymes
Force of this flow allows the production of ATP
Occurs in the thylakoid membranes during the light-dependent stage of photosynthesis
Occurs across the inner mitochondrial membrane during oxidative phosphorylation in respiration
Products of oxidative phosphorylation
H2O
ATP
Define Oxidative phosphorylation
The formation of ATP by adding a phosphate group of ADP in the presence of oxygen (the final electron acceptor)
How much ATP is made during oxidative phosphorylation
20-Krebs cycle
7-glycolysis
5- link reaction
=32 ATP made
What are the two ways in which NAD can be reoxidised in eukaryotic cells
Fungi - ethanol fermentation
Animals - lactate fermentation
Products of alcohol fermentation
CO2
Ethanol
Products of lactate pathway
Lactate
The Cori cycle
Lactate is produced during strenuous muscle activity and is taken up from blood plasma by the liver- where it is converted to PYRUVATE and then glucose/glycogen
The cori cycle rescues lactate and prevents the wasteful loss of some of it’s chemical bond energy
Prevents a potentially disastrous fall in plasma pH
Define Respiratory substrate
Organic substrate that can be used in respiration
E.g glucose
Respiratory quotient
Volume of O2 consumed
RQ of glucose
1
RQ of lipids
0.7
RQ of protein
0.9
Lower pH in the inter membrane space if the mitochondrial matrix
Because there are many H+ ions present
The more negative potential on the matrix side of the inner mitochondrial membrane
Because the positive H+ ions have moved out of the matrix into the intermembrane space
No ATP made in mitoblasts
H+ ions would spread out and the concentration gradient could not be established
No ATP made if the headpieces are removed from the stalked particles
The headpieces contain ATP synthase which is needed for ATP production
No ATP made in the presence of OLIGOMYCIN
OLIGOMYCIN inhibits the electron transport chain so not electrons can be transported
The matrix of the mitochondrion
Contains all the enzymes and reactants needed for the Krebs cycle and link reaction
