respiration Flashcards
cellular respiration
process in which cells break down organic molecules to synthesis ATP
stages of respiration
glycolysis
link
krebs cycle
oxidative phosphorylation
where does glycolysis occur
cytoplasm of cells
stage one of glycolysis
phosphorylation
glucose is phosphorylated by adding 2 phosphates from 2 molecules of ATP
this produces hexose bisphosphate and 2 molecules of ADP
then hexose bisphosphate is split up into 2 molecules of triose phosphate
stage 2 of glycolysis
oxidation
triose phosphate is oxidised forming 2 pyruvate molecules
NAD collects the hydrogen forming 2 reduces NAD
4 ATP is produced but net yield of 2
products of glycolysis
2 pyruvate
2 ATP
2 reduced NAD
what happens to pyruvate after glycolysis
they are actively transported into the matrix of the mitochondria for the link reaction
where does the link reaction occur
mitochondrial matrix
steps of link reaction
pyruvate is decarboxylayed - one carbon atom is removed in the form of carbon dioxide
pyruvate is dehydrogenated changing pyruvate into acetate
NAD is reduced to NADH
acetate is combined with coenzyme a to form acetyl coA
no ATP is produced
products of link reaction
2 molecules of acetyl coenzyme A
two molecules of carbon dioxide
two molecules of reduced NAD
where does kreb cycle occur
mitochondrial matrix
steps for krebs cycle
- acetyl group detaches from acetyl coA and combines with oxaloacetate to form citrate( citric acid) this is catalysed by citrase synthase. Coenzyme a goes back into the link reaction to be used again
- the 6C citrase molecule is converted to a 5C molecule. decarboxylation occurs where carbon dioxide is removed. dehydrogenation occurs where hydrogen is removed. the hydrogen binds with NaD to for reduced NAD
- the 5C molecule is converted to 4C. decarboxylation and dehydrogenation occurs producing one molecule of reduced FAD and two of reduced NAD
ATP is produced by the direct transfer of phosphate group from an intermediate compound to ADP. this is known as substrate level phosphorylation
products of each kreb cycle
2 cycle for each glucose but each cycle produces
1 conenzyme a
oxaloacetate reforms
2 carbon dioxide
1 ATP
3 reduced NAD
1 reduced FAD
where does oxidative phosphorylation occur
inner mitochondrial membrane
steps for oxidative phosphorylation
- hydrogen atoms are reflexes from reduced NaD and reduced FAD as they get oxidised to NAD and FaD. the hydrogen atoms split into protons H+ and electrons
- the electrons move along the electron transport chain losing energy at each carrier
- the energy is used by the electron carrier to pump protons from the mitochondrial matrix into the inter membrane space
- the concentration of protons is now higher in the inter membrane space then in the mitochondrial matrix. this forms an electrochemical gradient
- protons move down the electrochemical gradient back into the mitochondrial matrix via ATP synthase. this movement drives the synthesis of ATP from ADP and inorganic phosphate
what happens at the end of the electron transport chain
in the mitochondrial matrix the protons, the electrons and oxygen combine to form water.
oxygen is said to be the final electron acceptor
how much ATP is produced from reduces NAD
2.5 for each one
how ATP is produced for each reduced FaD molecule
1.5
how much ATP can be produced from one glucose molecule
32
2 types of anaerobic respiration
alcoholic fermentation
lactate fermentation
where does kactate fermentation. occurs
in mammals
steps of lactate fermentation
reduced NAD from glycolysis transfers hydrogen to pyruvate to form lactate and NAD
NAD can be reused in glycolysis
small amount of ATp is produced during glycolysis
liver takes up lactate from bloodstream and coverts it back into glucose in process called gluconeogenesis
steps for alcoholic fermentation
carbon dioxide is removed from pyruvate to form ethanal
Reduced NAD from glycolysis transfers hydrogen to ethanal to form ethanol and NAD
NAF can then be reused in glycolysis
non reversible
RQ for carbohydrates
1.0
RQ for lipids
0.7
RQ for proteins
0.9
what are obligate anaerobes
cannot survive in the presence of oxygen
what are facultative anaerobes
can do anaerobic and aerobic respiration
what are obligate areobes
can only synthesise ATP from aerobic respiration so in the presence of oxygen
