respiration Flashcards
respiration definition
the process by which the energy in food molecules is made available to organisms to do biological work
what type of reaction is respiration
catabolic (breaking things up)
how does respiration make energy available
the energy released in respiration is used to make ATP, which releases energy when broken down, allowing small manageable amounts of energy to be released which don’t cause damage
give the equation for respiration
C6C12O6 + 6O2 <> 6CO2 + 6H2O
give the equation for the break down of ATP
ATP»_space; ADP + Pi
removing the third phosphate releases the most energy, the other phosphates are rarely removed
what does the body need ATP for
- active transport
- cell division
- DNA synthesis
- DNA replication
- vesicle movement
- metabolic reactions
- synthesis of other large molecules
where does respiration take place
cytoplasm + mitochondria
outline the structure of the mitochondria
- 2 membranes - an outer membrane and a highly folded inner membrane called the cristae
- between the outer membrane and the cristae is the inter membrane space
- within the cristae is a fluid called the matrix
- floating in the matrix is ribosomes, granules, mitochondrial DNA
1 adaptation of mitochondria
highly folded cristae has a high SA:V so lots of space for reactions to occur and energy can be produced at a faster rate
1 adaptation of cells with mitochondria
very active cells have lots of mitochondria, which is also often larger/longer
how many stages are there in respiration + what are they
4
glycolysis
link reaction
kerbs cycle
oxidative phosphorylation
why are there 4 stages to respiration
if oxidation of glucose happened in 1 step the body cells would burn as so much heat is generated
where does glycolysis occur
cytoplasm
outline the process of glycolysis
- glucose - not very reactive, so it is phosphorylated - ATP > ADP
- this forms glucose-6-phosphate, which undergoes phosphorylation again - ATP > ADP
- this forms hexose bisphosphate - can no longer be transported out of the cell
- it is very unstable so it splits into 2 3C sugars - GALP and DHAP
- these sugars are then both dephosphorylated twice - ADP > ATP - and oxidised once by the removal of H+
- this H+ goes to reduce NAD+ > NADH
- the end product is pyruvate
what is NAD
an electron carrier in mammals
what are the final products of glycolysis
2NADH + net 2 ATP + 2 pyruvate
where does the link reaction occur
mitochondrial matrix
outline the process of the link reaction
- pyruvate is decarboxylated to produce CO2 and oxidised by the removal of H+
- this H+ goes to reduce NAD+ > NADH
- this forms a 2C molecule, which is added to coenzyme A
- this forms acetyl coenzym A
remember this occurs twice per glucose molecule, as 2 pyruvate are produced in glycolysis
what is the structure of pyruvate
CH3 - [C=O] - [C=O] -[O-]
what are the final products of both runs of the link reaction
2 acetyl coA + 2 NADH + 2CO2
where does the krebs cycle occur
mitochondrial matrix
what is the main purpose of the krebs cycle
to feed electrons into stage 4 of respiration
outline the process of the krebs cycle
- acetyl coA - a 2C molecule is converted to citrate 6C by the removal of CoA
- citrate is decarboxylated to produce CO2 and oxidised by the removal of H+
- this H+ goes to reduce NAD+ > NADH
- this forms a 5C intermediate, which is decarboxylated to produce CO2, oxidised by the removal of H+, dephosphorylated - ADP > ATP - oxidised twice by the removal of H+ and then oxidised again by the removal of H+
- the H+ removed go to reduce NAD+ > NADH, reduce FAD2+ > FADH2, and reduce NAD+ > NADH
- this forms oxaloacetate 4C
- this then combines with acetate 2C to reforms citrate 6C, cycle repeats
remember for each glucose molecule the cycle runs twice
what are the final products of both runs of the krebs cycle
4CO2 + 6 NADH + 2 FADH2 + 2 ATP
tune to remember krebs cycle
DeNa DeNa A Fa Na
where does oxidative phosphorylation occur
on the inner membrane of the mitochondria
outline the process of oxidative phosphorylation
- NADH and FADH2 release electrons + H+ ions
- electrons are passed along a chain of carriers within the inner membrane of mitochondria (electron transport chain)
- H+ is pumped out of matrix into the intermembrane space, using energy from electron transport chain
- protons accumulate and build an electrochemical gradient across membrane
- the movement of H+ down proton gradient as it moves through a transmembrane protein channel provides energy for ATP synthesis - chemiosmosis
- oxygen acts as the final electron acceptor, it combines with e- from the electron transport chain to make water
how many electrons does NADH carry
2 e-
how many electrons does FADH2 carry
2 e-
why is it important that NADH and FADH2 release their electrons in oxidative phosphorylation
this regenerates NAD+ and FAD2+, allowing glycolysis to take place so the cycle to continue
chemiosmosis definition
the process by which the movement of protons/H+ down their concentration gradient releases energy which is then used for ATP synthesis
give the equation for oxygen acting as the final electron acceptor
2e- + 2H+ + 1/2O2»_space; H2O