Respiration Module 5 Flashcards
What are the 4 stages in Aerobic respiration?
glycolysis, the link reaction, krebs cycle, oxidative phosphorylation
where do the stages in respiration occur?
glycolysis is in the cytoplasm. The link reaction, krebs cycle and oxidative phosphorylation take place in the mitochondria
structure of a mitochondrion?
Has inner and outer mitochondrial membrane, has matrix within with crista (folds) and mitochondrial DNA
What can cells use to respire?
All use glucose to respire, but can also break down other complex inorganic molecules such as fatty acids or amino acids
what does glycolysis do in general?
splits one molecule of glucose (6C), to form 2 smaller molecules of pyruvate (3C). Process occurs in cytoplasm of cells. It’s an anaerobic process so is the first step of aerboic and anaerobic respirarion
What are the 2 steps of glycolysis?
Phosphorylation, Oxidation
What occurs in phosphorylation in glycolysis?
Glucose is phosphorylated by adding 2 phosphates from 2 molecules of ATP. Forming 1 molecule of hexose Biphosphate and 2 molecules of ADP. Tje hexose biphosphate is then split into 2 molecules of triose phosphate
What occurs in the oxidation stage of glycolysis?
Triose phosphate is oxidised (loses hydrogen) forming 2 molecules of pyruvate, NAD collects thr hydrogen forming 2 reduced NAD. 4 ATP are produced, but 2 were used up in stage one sp theres a net gain of 2 ATP
What takes place in the link reaction?
Occurs in mitochondrial matrix. Pyruvate is decarboxylated, one carbon atom is removed in the form of CO2. NAD is reduced, it collects hydrogen from pyruvate, changing pyruvate into acetate. Acetate is combined with coenzyme A to form acetyle coenzyme A. No ATP is formed in this reaction
How many times does the link reaction occur for every glucose molecule?
Twice as 2 molecules of pyruvate are formed in glycolysis
What occurs in the Kreb’s cycle?
Acetyl CoA from the link reaction combines with oxaloacetate to form citrate (citric acid), this is catalysed by citrate synthase. Coenzyme A goes back to the link reaction to be used again
The 6C citrate molecule converted to 5C molecule as decarboxylation occurs removing CO2, dehydrogenation also occurs so hydrogen lost to turn NAD into reduced NAD
5C molecule then turned into a 4C molecule as decarboxylation and dehydrogenation occur producing one molecule of reduced FAD and 2 of reduced NAD. ATP is produced via direct transfer of phosphate group from an intermediate compound to ADP, this is called substrate level phosphorylation.
Citrate has now been converted to oxaloacetate
What’s oxidative phosphorylation in general?
Process where the energy carried by electrons from reduced coenzymes reduced FAD and reduced NAD, is used to make ATP.
Takes place in the inner mitochondrial membrane
Describe oxidative phosphorylation in depth?
Hydrogen atoms are released from reduced NAD and reduced FAD as they’re oxidised to NAD and FAD. The H atom splits into H+ and e-
The electrons move along the electron transport chain (made up of 3 electron carriers, located in the inner mitochondrial membrane), losing energy at each carrier.
The energy is used by the electron carriers to pump protons from the mitochondrial matrix into the intermembrane space
The conc of protons now higher in intermembrane space than matrix, so electrochemical gradient formed
Protons move back down the electrochemical gradient, into the matrix via ATP synthase, which bonds Pi and ADP to form ATP
In the mitochondrial matrix at the end of the transport chain, the protons, electrons and O2(from the blood), combine to form water, as O2 is the final electron acceptor
Why is the inner mitochondrial membrane folded into cristae?
To increase surface area for respiration
What’s the process of ATP production driven by the movement of H+ ions across a membrane due to electron transport chains known as?
Chemiosmosis
