oxidative phosphorylation and respiratory substrates

Question 1

Where to oxidative phosphorylation occur

Answer 1

in the cristae of the inner folder membrane

Question 2

how does an electron transfer occur in oxidative phosphorylation and how does result in the formation of ATP (steps of oxidative phosphorylation)

Answer 2

•electrons and protons are released from reduced co enzymes (NADH= e- + H+ + NAD and same for FADH)
• the electrons flow along an electron transport chain in a series of redox reactions
•the energy released causes the active transport of protons across the inner mitochondrial membrane and into the inter membrane space
• here protons accumulate before defusing because into the matrix through ATP synthase channels
• the energy released by electrons is also used to join ADP + Pi into ATP
• at the end of the chain electrons combine with these protons and oxygen to form water so oxygen is the final accepter of electrons in the electron transfer chain

Question 3

why is energy released in stages?

Answer 3

the greater the energy released in a single step the more of it is released as heat and so less is available for useful purposes. when released a little at a time more can be harvested for the benefit of the organism. Why electrons carrier by NAD and FAD are passed along a series of alex fron transfer carrier molecules

Question 4

how does respiration of lipids occur?
(probably don’t need to know)

Answer 4

hydrolysed to glycerol and fatty acids. the glycerol is phosphorylated and converted to triose phosphate which enters the glycolysis pathway and the krebs cycle. fatty acid component is broken down into 2C fragments which are converted im to acetyl coenzyme A which enters the krebs cycle.

the oxidation of lipids produced 2C fragments of carbohydrates and many hydrogen atoms, H atoms are used to produce ATP during oxidative phosphorylation so release over double energy than carbohydrates

Question 5

how does respiration of protein occur
(probably don’t need to know)

Answer 5

hydrolysed to it’s constituent amino acids. these have their amino group removed before entering the respiratory pathway at different points depending on number of carbon atoms. 3C converted to pyruvate, 4 and 5C converted to intermediates in krebs cycle

Question 6

respiratory substrate definition

Answer 6

any biological molecule that can be respired to release energy e.g. carbohydrates lipids and proteins

Question 7

why does every cell respire?

Answer 7

•respiration is essential to life
•ATP needed for all metabolic processes e.g. active transport
• minimum amount of ATP needed to maintain metabolism
• different respiratory substrates has different energy values
•proteins only respired when there’s no lipid or carbohydrates