|How is the chloroplast adapted for photosynthesis?
|- The chloroplast envelope keeps the reactants for photosynthesis close to their reaction sites. - The thylakoids have a large surface area to allow as much light energy to be absorbed as possible. - Lots of ATP synthase molecules are present in the thylakoid membranes to produce ATP in the light-dependent reaction. - The stroma contains all the enzymes, sugars and organic acids for the light-independent reaction to take place.
|What are the two stages of photosynthesis?
|1. The light-dependent stage 2. The light-independent stage (The Calvin Cycle)
|What are the three limiting factors of photosynthesis?
|The three factors that can limit the speed of photosynthesis are: 1. Light intensity 2. Carbon dioxide concentration 3. Temperature
|What effect does having light intensity as a limiting factor have on the light-independent reaction (the Calvin cycle)?
|In low light intensities, the products of the light-dependent stage will be in short supply. This means the conversion of GP to TP and RuBP is slow. GP will rise as it's still being made, but it isn't being used up quickly. Levels of TP and RuBP will decrease as they are being used to make GP, but aren't being remade quickly.
|What effect does having temperature as a limiting factor have on the light-independent reaction (the Calvin cycle)?
|All the reactions in the Calvin cycle are catalysed by enzymes. At low temperatures, all of the reactions will be slower as the enzymes work more slowly. The levels of RuBP, GP and TP will fall as a result of this. RuBP, TP and GP are effected similarly by very high temperatures, because enzymes will start to denature.
|What effect does having carbon dioxide concentration as a limiting factor have on the light-independent reaction?
|At low concentrations, conversion to RuBP to GP is also slow as there's less carbon dioxide to combine with RuBP to make GP. So levels of RuBP will rise as it's still being made, but isn't being used. The levels of GP and TP will fall as they're used up to make RuBP, but aren't being remade.
|What is a co-enzyme? Name a co-enzyme used in photosynthesis. What does this co-enzyme do?
|A co-enzyme is a molecule that aids the function of an enzyme. They work by transferring a chemical group from one molecule to another. The co-enzyme NADP is used in photosynthesis. NADP transfers hydrogen from one molecule to another.
|How is the mitochondria adapted for respiration?
|- The inner mitochondrial membrane is folded into cristae, which increases the membrane's surface area to maximise respiration. - There are lots of ATP synthase molecules in the inner mitochondrial membrane to produce lots of ATP in the final stage of respiration. - The mitochondrial matrix contains all the reactants and enzymes needed for the Krebs cycle to take place.
|What is a co-enzyme? Name three co-enzymes used in respiration. What do these co-enzymes do?
|A co-enzyme is a molecule that aids the function of an enzyme by transferring a chemical group from one molecule to another. Co-enzymes used in respiration include NAD, co-enzyme A and FAD. NAD and FAD transfer hydrogen from one molecule to another. Co-enzyme A transfers acetate between molecules.
|What are the four stages in aerobic respiration?
|The four stages of aerobic respiration are: 1. Glycolysis 2. The link reaction 3. The Krebs cycle 4. Oxidative phosphorylation
|What are the products of glycolysis and where do they go?
|2 reduced NAD - To oxidative phosphorylation 2 pyruvate - To the link reaction 2 ATP (net gain) - Used for energy
|What are the products of the link reaction and where do they go?
|2 acetyl co-enzyme A - To the Krebs cycle 2 carbon dioxide - Released as a waste product 2 reduced NAD - To oxidative phophorylation
|What are the products of the Krebs cycle and where do they go?
|1 co-enzyme A - Reused in the next link reaction Oxaloacetate - Regenerated for use in the next Krebs cycle 2 carbon dioxide - Released as a waste product 1 ATP - Used for energy 3 reduced NAD - To oxidative phosphorylation 1 reduced FAD - To oxidative phosphorylation
|What are the two processes of oxidative phosphorylation?
|The two processes involved in oxidative phosphorylation are: 1. The electron transport chain 2. Chemiosmosis
|What is the final electron acceptor in oxidative phosphorylation?
|The final electron acceptor in oxidative phosphorylation is oxygen.
|How much ATP is produced in one cell, from one molecule of glucose, in aerobic respiration?
|A cell can make 32 ATP from one molecule of glucose in aerobic respiration.
|Why is the actual yield of ATP from one glucose molecule lower than the expected yield of ATP?
|The actual yield is lower because: - Some of the reduced NAD formed during the first three stages of aerobic respiration is used in other reduction reactions in the cell instead of in oxidative phosphorylation. - Some ATP is used up by actively transporting substances into the mitochondria during respiration. - The inner mitochondrial membrane is leaky - some protons may leak into the matrix without passing through ATP synthase and without making ATP
|ATP (adenosine triphosphate) is a molecule made up of adenine, a ribose sugar and three phosphate groups. It is the immediate source of energy in a cell.
|What is photosynthesis?
|Photosynthesis is the process where energy from light is used to make glucose from carbon dioxide and water.
|What is the Krebs cycle?
|The third stage of aerobic respiration. It is a series of oxidation-reduction reactions that produces reduced coenzymes and ATP.
|What is chemiosmosis?
|Chemiosmosis is the movement of protons (H+ ions) across a membrane which generates ATP.
|What properties of ATP make it a good energy source?
|- ATP stores or releases only a small, manageable amount of energy at a time, so no energy is wasted. - It's small, soluble molecule so it can be easily transported around the cell. - It's easily broken down, so energy can be easily released. - It can transfer energy to another molecule by transferring one of its phosphate groups. - ATP can't pass out of the cell, so the cell always has an immediate supply of energy.
|What is the chemical equation for photosynthesis?
|What is the chemical equation for aerobic respiration?
|What is the difference between aerobic respiration and anaerobic respiration?
|Aerobic respiration is respiration using oxygen. Anaerobic respiration is respiration without using oxygen.
|What is respiration?
|Respiration is the process in which plant and animal cells release energy from glucose. The energy is then used to power all the biological processes in a cell.
|What is glycolysis?
|Glycolysis is the first stage in aerobic respiration. It is where glucose is converted into pyruvate.
|What is the link reaction?
|The link reaction is the second stage of aerobic respiration where pyruvate is converted into acetyl coenzyme A
|What is the electron transport chain (ETC)?
|The electron transport chain is a chain of proteins through which excited electrons flow.
|What happens during the first stage (phosphorylation) of glycolysis?
|Glucose is phosphorylated by adding a phosphate from a molecule of ATP. This creates one molecule of hexose phosphate and one molecule of ADP. Hexose phosphate is phosphorylated by ATP to form hexose bisphosphate and ADP. Hexose bisphosphate is then split into 2 triose phosphate?
|What happens during the second stage (oxidation) of glycolysis?
|Triose phosphate is oxidised (loses hydrogen), forming 2 molecules of pyruvate. NAD collects the hydrogen ions, forming 2 reduced NAD. 4 ATP are produced, but 2 were used up in stage one, so there's a net gain of 2 ATP.
|What is phosphorylation?
|Phosphorylation is the process of adding phosphate to a molecule.
|What is oxidative phosphorylation?
|Oxidative phosphorylation is the final stage in aerobic respiration. Energy carried by electron, from reduced coenzymes, is used to make ATP.
|What is oxidation?
|Oxidation is a chemical reaction where a molecule loses electrons and may have lost hydrogen or gained oxygen.
|What is the initial electron donor of non-cyclic photophosphorylation?
|Water is the initial electron donor of non-cyclic photophosphorylation.
|What is photolysis?
|Photolysis is the splitting of a molecule using light energy.
|What is an autotroph?
|An autotroph is an organism which can generate its own food.