3.5.2 respiration Flashcards
what is a phosphorylation reaction?
transfer of a phosphate group to make it more reactive
what is a decarboxylation reaction?
removal of CO2
outline aerobic respiration
uses oxygen
produces more ATP
glucose completely broken down
carbon dioxide and water produced
outline anaerobic respiration
without oxygen
produces less ATP
glucose partially broken down
lactic acid produced
what are the 4 stages of aerobic respiration?
glycolysis
link reaction
krebs cycle
oxidative phosphorylation
where does glycolysis take place?
the cytoplasm
what are the 2 stages in glycolysis?
phosphorylation
oxidation
outline phosphorylation in glycolysis
glucose is phosphorylated by adding 2 phosphates from 2 molecules of ATP this produces 2 molecules of TP and 2 ADP
outline oxidation in glycolysis
TP is oxidised forming 2 molecules of pyruvate
NAD is reduced forming 2NADH
4 ATP are produced
why must glycolysis take place in the cytoplasm?
because glucose cannot cross the outer mitochondrial membrane
it breaks down into pyruvate because this can cross the membrane
what are the products of glycolysis?
2 reduced NAD
2 pyruvate
2 ATP (net gain)
where does the reduced NAD produced in glycolysis go?
to oxidative phosphorylation
where does the pyruvate produced in glycolysis go?
actively transported into the mitochondrial matrix for use in the link reaction
where does the ATP produced in glycolysis go?
used for energy
how many C atoms are in pyruvate?
3 carbon atoms
outline what happens during the link reaction
pyruvate is decarboxylated ( carbon dioxide is removed)
NAD is reduced it collects hydrogen from pyruvate
pyruvate is converted into acetate
no ATP is produced
acetate combines with coenzyme A to form acetyl coenzyme A
where does the link reaction take place?
mitochondrial matrix
in an anaerobic respiration what is the only stage that happens?
glycolysis
what are the products of anaerobic respiration in plants and yeast?
carbon dioxide and ethanol
what are the products of anaerobic respiration in animals and bacteria?
lactic acid
how is anaerobic respiration able to continue?
production of lactic acid, CO2 and ethanol regenerate NAD
this means glycolysis can continue even when oxygen is in short supply
how many carbon atoms are in acetyl coenzyme A?
2 carbon atoms
what are the 2 types of reaction that occur in the link reaction?
oxidation
decarboxylation
what are the products of the link reaction?
2 acetyl coenzyme A
2 carbon dioxide
2 reduced NAD
where does the acetyl coenzyme A produced in the link reaction go?
to the krebs cycle
where does the carbon dioxide produced in the link reaction go?
released as a waste product
where does the reduced NAD produced in the link reaction go?
to oxidative phosphorylation
outline the Krebs cycle
- acetyle coenzyme A (from the link reaction) joins with a 4C compound to form a 6C compound. Coenzyme A goes back to the link reaction
- decarboxylation occurs forming a 5C compound dehydrogenation also occurs, the hydrogen is used to form reduced NAD from NAD
- decarboxylation and dehydrogenation of the 5C compound occur to form a 4C compound
- ATP is made by the removal of a phosphate group, as the phosphate group is directly transferred from 1 molecule to another we say the ATP has been formed by substrate level phosphorylation
what are the products from ONE Krebs cycle?
1 coenzyme A
oxaloacetate (4C)
2 carbon dioxide
1 ATP
3 reduced NAD
1 reduced FAD
where does the coenzyme A produced in the Krebs cycle go?
reused in the next link reaction
where does the oxaloacetate produced in the Krebs cycle go ?
regenerated for use in next Krebs cycle
where does the carbon dioxide produced in the Krebs cycle go?
released as a waste product
where does the ATP produced in the Krebs cycle go?
used for energy
where does the reduced NAD produced in the Krebs cycle go ?
to oxidative phosphorylation
where does the reduced FAD produced in the Krebs cycle go?
to oxidative phosphorylation
where does the Krebs cycle take place?
mitochondrial matrix
where does oxidative phosphorylation take place?
mitochondrial cristae
what happens in oxidative phosphorylation?
the process wheee the energy carried by electrons, from reduced coenzymes is used to make ATP
outline what happens in oxidative phosphorylation
- hydrogen atoms are released from reduced NAD and reduced FAD which are oxidised to NAD and FAD, hydrogen atoms split into protons and electrons
- electrons move down electron transport chain losing energy at each carrier
- energy used by the electron carriers to pump protons from the mitochondrial matrix into the intermembrane space
- conc. of protons is higher in the intermembrane space than in mitochondrial matrix forms an electrochemical gradient
- protons move down electrochemical gradient back across inner mitochondrial membrane and into mitochondrial matrix via ATP synthase
- process of ATP production driven by movement of H+ ions across the membrane
- in mitochondrial matrix the protons, electrons and oxygen combine to form water
