Essay Prep

Question 1

Explain the Light Dependant Stage of Photosynthesis.

Answer 1

1. Chlorophyll molecules in thylakoid membrane absorb light. Electrons become energised
2. Energy used to split H20 in to H and O2. ATP Formed
3. Electrons donated to NADP to make NADP-H which is transferred to Light Independent.

Question 2

Explain the Light Independant Stage of Photosynthesis.

Answer 2

1. Occur in Stroma. Glucose mol prod. Req supply of CO2, Hydrogen ions in NADP-H and chem energy in the form of ATP
2. ATP provide chem energy for CO2 to Glucose mol. Anabolic reaction and result in carbon being stored in glucose.
3. Chloroplasts convert new glucose mol to sucrose or starch. Sucrose easily transported, starch most common storage.

Question 3

What are 3 factors that affect the rate of photosynthesis? Why?

Answer 3

CO2 Concentration - The more the better, saturation point gets reached, photo reaches max rate

Light Intensity - The more the better, saturation point gets reached, photo reaches max rate

Temperature - Will affect enzyme activity, also availability of water which can directly effect opening of the stroma for water conservation.

Question 4

Explain the Glycolysis Stage of Cellular Respiration.

Answer 4

Glycolysis: ANAEROBIC, NO OXYGEN. 1 mol glucose is broken down into 2 3-C mol. Energy is invested to intial value of 2 ATP. The process gives a net gain of 2 ATP. During the process, 2 NAD are given 2 H atoms to form 2 NADH. 2 provic acid is also prod. If not oxygenated, this turns to lactic acid which causes muscle cramps and fatigue.

Question 5

Explain the Citric Acid Cycle Stage of Cellular Respiration.

Answer 5

Citric Acid Cycle: When oxygenated, pyruvate mol mol enter mitoch into citric cycle. For each pyruvate, CAC prod 3 NADH, 1 FADH2 and releases 2 CO2. For each glucose mol, tot yield from citric is 2 ATP, 6NADH, 2 FADH2. Energy in NADH and FAD will lead to more ATP in electron transport.

Question 6

Explain the Electron Transport Chain Stage of Cellular Respiration.

Answer 6

Elec trans by energy carrying mol NADH and FADH2 from CAC. Energy prod chem gradient across inner mitoch membrane. Oxidative Phosphorylation occurs as ATP is gen from ADP+P, Ox and H ions combine to form H2O. Approx 28 ATP released .

Question 7

How are biofuels (bioegas) made?

Answer 7

Biogas is made when micro organisms such as bacteria and other organisms anaerobically digest feedstock to produce biogas. Tanks knows as digesters are like big stomachs where the bacterias and micro organisms break down food such as cow shit, foodwaste, waste water and sewage. tank set to 35C (enzyme). Prod 60% methane, 40% carbon. Can make electricity and fuel for car.