5A - photosynthesis and respiration Flashcards
what are the 4 stages of aerobic respiration and where do they occur?
Glycolysis - cytoplasm
link reaction - mitochondrial matrix
krebs cycle - mitochondrial matrix
oxidative phosphorylation - inner membrane / cristae
describe gylcolysis
glucose (6C) is phosphorylated due to the hydrolysis of 2ATP into 2ADP +2Pi forming glucose phosphate (6C) . this molecules splits into triose phosphate ( 3C X 2). this molecule is oxidised, losing a hydrogen which is picked up by the co - enzyme, 2NAD being reduced into 2NADH. 2ADP and 2Pi forms 2ATP in a condensation reaction. 2 3C pyruvates are formed.
what is the gain of molecules at the end of glycolysis
2ATP, 2NADH and 2 3C pyruvate molecules.
describe the link reaction
pyruvate molecule is oxidised and NAD is reduced forming NADH. the pyruvate is decarboxylated releasing CO2 and producing an acetate molecule. acetate reacts with co-enzyme A forming acetyl coenzyme A
describe the krebs cycle
acetyl CoA reacts with a 4C molecule producing a 6C moleucle. the 6C molecule is decarboxylated releasing 2 carbons and producing 2 CO2 molecules. it is oxidised releasing hydrogens which are taken up by by 3 NAD enzymes and 1 FAD enzyme, producing 3NADH and 1FADH2. an ATP molecule is produced via substrate level phosphorylation. this will reproduce a 4C molecule.
what are the products of the krebs cycle
2CO2, 3NADH,1FADH2 and 1ATP
describe oxidative phosphorylation
NADH and FADH2 are oxidised releasing the H. the H splits into an electron and a proton. the electron moves across the etc through cattier proteins, releasing energy which is used in the active transport of protons across the inner membrane space, this forms an electro-chemical gradient. protons move back to the matrix through ATP synthase via facilitated diffusion. this causes rotation- for every 1 proton there is 1 rotation, and 1 ATP molecule is made every 3 rotations-
oxygen acts as the final electron acceptor, joining with 2 electrons and 2 protons to produce 1 water molecule.
what happens to lipids before they are used as products
they are hydrolysed by lipase into fatty acids and glycerol. the glycerol is phosphorylated and then converted into triose phosphate, entering glycolyis
what happens to the glycerol before entering the process of respiration
the glycerol is phosphorylated and then converted into triose phosphate, entering glycolyis
what happens to the fatty acids before entering the process of respiration
the fatty acids are converted into acetyl conenzyeme A, entering the krebs cycle
when is protein used at respiratory substrate
severe starvation
what happens to proteins inorder to be used as a respiratory substrate
proteins are hydrolysed into amino acids. excess amino acids are deaminated and converted into urea and excreted
what is deamination
removal of the amine group NH2
what happens to the remaining molecules of a protein
they enter the respiratory pathway depending on the number of carbon atoms. 3C are converted to pyruvates, 4C and 5C enter the krebs cycle directly
pathway of alcohol fermentation in anaerobic respiration
occurs in yeast and some plants.
pyruvate will lose a molecule of CO2 and accepts a hydrogen from NADH. this produces ethanol and regenerates NAD
