ATP: Respiration & Photosynthesis Flashcards
(25 cards)
What is the structure of ATP?
Adenosine (adenine and ribose)
Phosphate groups (3)
By what process is ATP formed?
Phosphorylation (of ADP)
What are the roles of ATP?
- Active transport
- Muscle contraction
- Polymer synthesis
How is ATP suited to its function?
- Easily broken up (unstable bonds)
- Simple reaction (single step)
- Small and soluble (easily transported around cells)
- Small amounts of energy released
- More manageable
- Less wastage
What are the three types of ATP formation?
- Photophosphorylation (photosynthesis)
- Oxidative phosphorylation (electron transport chain)
- Substrate-level phosphorylation (transfer of a phosphate from a donor molecule)
What are the stages of photosynthesis? Where do they occur?
- LDR - across the thylakoid membranes (in the grana)
- LIR - stroma
What happens during the light dependent reaction?
- Light strikes the chlorophyll molecule and excites an electron
- This electron is taken up by and electron carrier
- The electron passes down the electron transport chain in a series of redox reactions, releasing energy
- This energy is used to phosphorylate ADP to ATP
- Light is also used to split water into protons, electrons and oxygen (photolysis)
- The electrons replace those lost lost by the chlorophyll
- The protons and electrons (from the ETC) combine with NADP to form NADPH
What happens during the light independent reaction?
- RuBP combines with CO2 (catalysed by rubsico) to form two molecules of GP
- Each molecule of GP is reduced to TP by ATP and NADPH (from LDR)
- Either:
- Carbohydrates and other complex molecules are made
- TP is used to reform RuBP (uses ATP)
What are the stages of aerobic respiration? Where do they occur?
- Glycolysis - cytoplasm
- Link reaction - mitochondrial matrix
- Krebs cycle - mitochondrial matrix
- Electron transport chain - inner mebrane of the mitochondrion
What happens during glycolysis?
- Glucose → phosphorylated glucose
- Uses ATP
- Phosphorylated glucose → 2x pyruvate
- Produces ATP and NADH
What happens during the link reaction?
- Pyruvate + CoA → Acetyl CoA + CO2
- Produces NADH
What happens during the krebs cycle?
- Acetyl CoA + 4C compound → 6C compound + CoA
-
6C compound → 5C compound + CO2
- Produces NADH
-
5C compound → 4C compound + CO2
- Produces FADH2, ATP and 2x NADH
What happens during the electron transport chain?
- Electrons are taken up by electron carriers
- They pass down the ETC in a series of redox reactions, releasing energy
- This energy is used to actively transport protons across the inner mitochondrial membrane (into the intermembrane space)
- The protons diffuse back into the matrix through ATP synthase resulting in ADP being phosphorylated to ATP
- The protons and electrons combine with oxygen to form whater
- Oxygen is the final acceptor
Where during aerobic respiration is ATP produced?
- Glycolysis
- Krebs cycle
- ETC
Where during aerobic respiration is NADH produced?
- Glycolysis
- Link reaction
- Krebs cycle
Where during aerobic respiration is FADH2 produced?
- Krebs cycle
Where during aerobic respiration is CO2 produced?
- Link reaction
- Krebs cycle
What happens during anaerobic respiration in:
- Animals
- Plants
Animals:
- Pyruvate → lactic acid
- NADH → NAD
Plants:
- Pyruvate → ethanol
- NADH → NAD
What is the purpose of anaerobic respiration?
To regenerate NAD so that glycolysis can continue
When using free mitochondria, why isn’t glucose used as the respiratory substrate?
- Glucose is broken down during glycolysis
- Glcolysis occurs in the cytoplasm
- Glucose cannot cross the mitochondrial membrane
How can the rate of respiration be measured?
Using a manometer
What are the units for rate of respiration when using a manometer?
mm3g-1h-1
How do manometers work?
- The organism respires aerobically and produces and releases CO2
- This is absorbed by the KOH which decreases the pressure
- The decrease in pressure draws a coloured liquid towards the test tube
What is the setup for measuring rate of respiration?
