paper 2: Respiration Flashcards
give three properties of an ATP molecules that make it suitable as an immediate source of energy in cells.
- it releases energy in small managable amounts
- to release energy it requires a single reaction so energy is available immediately
- it can be reformed
- it adds phosphate to molecules to make them more reactive
define the terms oxidation and reduction
oxidation is loss of electrons/ hydrogen atoms
reduction is gain of electrons/ hydrogen atoms
draw a labelled diagram of the mitochondrion and label location of 4 main stages in respiration
glycolysis: cytoplasm
link reaction: matrix
kreb cycle: matrix
oxidative phosphorylation: inner membrane
draw out the stage of glycolysis for one glucose molecule
- glucose is phosphorylated to glucose phosphate using phosphates from 2 ATP molecules
- this makes the glucose more reactive
- the glucose phosphate splits into 2 molecules of triose phosphate
- each triose phosphate is oxidised to pyruvate
- a hydrogen reduces the coenzyme NAD to reduced NAD
- 2 ATP molecules are produced for each triose phosphate that is oxidised
- 2 ATP used, 4 ATP produced = net gain of 2 ATP molecules
- ATP is formed by substrate level phosphorylation.
draw out stages of the link reaction for one glucose molecule
- takes place in the matrix
- pyruvate enters the matrix by active transport
- pyruvate us oxidised to acetate, releasing a hydrogen which reduces NAD to produce reduced NAD
- carbon dioxide is also produced
- acetate combines with coenzyme A to produce acetylcoenzyme A
draw out the stages of the kreb cycle for one glucose molecule
- occurs in the matrix
- acetylcoenzyme A recats with a 4C compound, releasing CoA, to make a 6C molecule
- coenzymes NAD and FAD are reduced to NADH and FADH
- CO2 is lost
- 2 molecules of ATP are produced by substrate level phosphorylation from ADP + Pi
draw out the stages of oxidative phosphorylation for one glucose molecule and describe what happens
- takes place in the inner membrane
- the reduced NAD and FAD are oxidised, donating a hydrogen and the hydrogen dissociates into a proton and an electron
- the electrons pass down a series of electron carriers on the inner membrane via redox reactions
- the electrons lose enrgy, which is used to pump the protons throught he inner membrane intot he intermembrane space, forming a proton gradient
- some energy is lost as heat
- the protons diffuse back through the inner membrane via ATP synthase. this is called chemiosmosis
- this releases energy to form ATP from ADP + Pi
- 34 ATP is formed
- the electrons and the protons combine with oxygen to form water
- oxygen is the terminal electron acceptor.
describe the role of the co enzymes FAD and NAD within the process of aerobic respiration
NAD and FAD help transport hydrogen atoms from molecules to become reduced NAD or FAD and then drop them off elsewhere
define the term chemiosmosis
electrons from are passed down a series of electron carriers in the inner membrane of the mitochondria via redox reactions. electrons lose enrgy and the enrgy is then used to pump protons across the thylakoid membrane forming a proton gradient.
describe the process of anaerobic respiration in plants and fungi
NAD must be regenerated from reduced NAD.
the H from reduced NAD reduces pyruvate to form ethanol and carbon dioxide.
describe the process of anaerobic respiration in animals
NAD must be regenerated from reduced NAD.
the H from reduced NAD reduces pyruvate to form lactic acid
describe and explain what happens to the liquid in a manometer when measuring the rate of aerobic respiration in an organism.
- as organism aerobically respires it absorbs O2 and releases CO2
- the co2 is absorbed by the potassium hydroxide
- this reduces the pressure and volume in the flask causing the coloured liquid tomove towards the organism.
