Respiration (Chapter 12) Flashcards
What is the equation for making ATP?
ADP + Pi > ATP
Why is ATP useful?
- Releases energy in small suitable amounts.
- Broken down in one step.
- Makes energy available rapidly.
- Makes phosphorylated substances more reactive/lower activation energy.
- Can be reformed/made again.
Why do plants make ATP in respiration as well as photosynthesis?
- In the dark no ATP is produced in photosynthesis.
- Some tissues unable to photosynthesis/ produce ATP.
- ATP cannot be moved from cell to cell/stored.
- Plants use more ATP than produced in photosynthesis.
- ATP needed for active transport.
- ATP for synthesis e.g. protein.
What happens when there is oxidation during respiration?
Lose electrons, lose H, gain O2
What happens when there is reduction during respiration?
Gains electrons, gains H, lose O2
Where does glycolysis take place?
In the cytoplasm
Describe the stages of glycolysis
1) Pi added to 6 glucose (ATP needed)
2) Glucose splits into 2x 3C triose phosphate (TP)
3) Triose phosphate is oxidised and gives H to NAD to form reduced NAD.
4) TPs are made into pyruvate (3C), releasing ATP
Describe the stages of the Link Reaction
1) Pyruvate is oxidised and gives H to NAD.
2) Pyruvate loses CO2 and becomes 2C acetyl group.
3) 2C acetyl joins with co-enzyme A to form acetyl coenzyme A (2C)
Where does the Link Reaction take place?
In the matrix of the mitochondria
What is made in glycolysis?
Makes ATP, NADH, and Pyruvate (needs ATP).
What is made in the Link Reaction?
Makes CO2, NADH, acytyl coenzyme A (no ATP)
Where does the Krebs Cycle take place?
In the matrix of the mitochondria
Describe the stages of the Krebs Cycle
1) Acetyl coenzyme A joins with 4C molecule (releases CoEnzyme A to form a 6 carbon molecule)
2) NAD and FAD are reduced,
3) Substrate level phosphorylation (makes 2 ATP).
What is made in the Krebs Cycle?
ATP, NADH, FADH, CO2 (4C molecule recycled)
Where does the Electron Transport Chain take place?
On the inner membrane of the mitochondria.
Describe the process of the Electron Transfer Chain (Chemeosmotic Theory)
1) NADH and FADH release their H which splits into protons and electrons.
2) Electrons move along carrier in ELT using oxidation-reduction reactions which release energy.
3) Protein channels use this energy to actively transport H ions into intermembrane space.
4) These then diffuse back down concentration gradient through ATP synthase into matrix and release ATP in oxidative phosphorylation (combine ADP and Pi)
Describe the process of Oxidative Phosphorylation
1) Protons and electrons combine with O2 to make water
2) O2 acts as terminal acceptor of electrons and stops build up of electrons.
What is made from the ELT and Oxidative Phosphorylation together?
ATP, Water, NAD, FAD (needs ATP)
What happens in anaerobic respiration?
There is no O2. NAD is regenerated/ pyruvate removed so glycolysis continues.
What is the equation for anaerobic respiration in plants?
Pyruvate + Reduced NAD > Ethanol + CO2 + NAD
What is the equation of anaerobic respiration in animals?
Pyruvate + Reduced NAD > Lactate + NAD
What is used as an artificial electron acceptor in experiments and what is the positive result?
Methylene Blue which becomes colourless when reduced.
Why are respiratory substances other than glucose used to investigate stages of respiration?
Glucose cannot cross the mitochondrial membrane and is usually broken down in glycolysis.
How are manometers used?
They are used to measure the rate of gas exchange.
1) Organisms use O2 and release CO2 in respiration.
2) CO2 is absorbed by a substance such as potassium hydroxide.
3) Pressure in tube is lowered so level of liquid moves.
What values are needed to calculate the rate of respiration?
- Volume of the tube
- The distance moved by the water
- Time taken
- Mass of respiring organisms
Why is the manometer left for a while after setting up?
- Allows an equilibrium to be reached
- Allows for expansion/pressure change in apparatus
- Allow respiration rate of seed to stabilise.
What order so the stages of respiration take place?
1) Glycolysis
2) Link Reaction
3) Krebs Cycle
What is the equation for the Link Reaction?
Pyruvate + NAD + CoEnzyme A > Acetyle CoEnzyme A + NADH + CO2
What happens between the Link Reaction and Krebs cycle?
Acetyl CoEnzyme A reacts with 4 carbon molecule and releases CoEnzyme A to form a 6 carbon molecule which enters the Krebs cycle.
Why do we make such large amounts of ATP?
ATP is unstable
ATP cannot be stored/is an immediate source of energy
Named process uses ATP e.g. active transport, muscle contraction, glycolysis
ATP only releases a small amount of energy at a time
Which process moves pyruvate into the mitochondria?
Active transport
