Topic 5: Learn And Churns Flashcards
In the light dependent reaction of photosynthesis, light energy generates ATP.
Describe how (5 marks)
- Light(energy) excites/ raises energy level of electrons in chlorophyll
- Electrons pass down the electron transfer chain
- Electrons reduce carriers/passage involves redox reactions
- ETC/role of chain associated with chloroplast membranes/in thylakoids/grana eg. Chemiosmosis
- Energy released/carriers at decreasing energy levels
- ATP generated from ADP and Phosphate/phosphorylation of ATP
ATP is useful in many biological processes. Explain why (4 marks)
- Releases energy in small/manageable amounts
- Single bond broken/immediate energy compound
- Phosphorylates substances/more reactive/ lowers activation energy
- Reformed
Describe how ATP is made in mitochondria (6 marks)
- Substrate level phosphorylation/ATP produced in the Krebs cycle
- Krebs cycle/ link reaction produces reduced NAD/FAD
3/ electrons released from reduced NAD/FAD - Electrons passed along carriers/through ETC
- Energy released
- ADP+ Pi
- Proteins move into the inter membrane space
- ATP synthase
Plants produce ATP in their chloroplasts during photosynthesis. They also produce ATP during respiration. Explain why it is important for plants to produce ATP during respiration in addition to photosynthesis (5 marks)
- In the dark, no ATP is produced in photosynthesis
- In photosynthetic tissue/leaves
- Some tissues are unable to photosynthesise/produce ATP
- ATP cant be moved from cell to cell/stored
5.Plants use more ATP than produced in photosynthesis - ATP for active transport
During the light-independent reaction of photosynthesis, carbon dioxide is converted into organic substances. Describe How (6 marks)
- Carbon dioxide combines with RuBP
- Produces 2 GP
- GP reduced to TP
- Using reduced NADP
- Using energy from ATP
- Tríese phosphate is converted to glucose/ruBP/ named organic substances
The concentration of carbon dioxide in the air at different heights above ground in a forest changes over a period of 24 hours. Use your Knowledge of photosynthesis to describe these changes and explain why they occur (5 marks)
- High CO2 linked with night/darkness
2.Light required for light dependent reaction of photosynthesis - In darkness plants/other organisms respire
- In light, planks use more CO2 than they produce/ rate of photosynthesis greater than respiration
- Decrease in carbon dioxide concentration with height
- At ground level, fewer leaves photosynthesising/ less light
In the light- independent reaction of photosynthesis, the carbon in carbon dioxide becomes carbon in triose phosphate. Describe how. (5 marks)
- CO2 combines with RuBP
- Produces 2 molecules of GP
- Reduced to TP
- Requires reduced NADP
- Energy from ATP
Anolis Sagrei, is a species of lizard that is found on some of the smallest Caribbean islands. Describe how you could use the mark-release-recapture method. To estimate the number of Anolis Sagrei on one of these islands (4 marks)
- Capture/collect sample, mark and release
- Method of marking that doesn’t harm the lizard/ make it more visible to predators
- Leave sufficient time for lizards to randomly distribute before collecting second sample
- Population = no. In 1st sample x no in 2nd sample/ number recaptures
In forests, nitrogen in dead leaves is made available to growing plants by the action of Bacteria. Describe the role of bacteria in making the nitrogen in dead leaves available to growing plants (5 marks)
- Saprobionts
- Digest/ breakdown proteins/DNA/ nitrogen-containing substances
- Extra cellular digestion/release of enzymes
- Ammonia/ammonium produced
- Ammonia converted to nitrite to nitrate
- Nitrifying bacteria/nitrificaiton
- Oxidation
Explain how farming practices increase the productivity of agricultural crops (5 marks)
- Fertilisers/minerals/named ion added to soil
- Role of named nutrient. E.g. nitrogen for proteins/phosphorous for ATP
- Selective breeding/genetic modification of crops
- Ploughing/aeration allows nitrificaiton/decreases denitrification
- Benefit of crop rotation in terms of soil nutrients/ pest reduction
Describe how the action of microorganisms in the soil produces a source of nitrates for crop plants (5 marks)
- Protein/amino aids/DNA into ammonia
- By saprobionts
- Ammonia to nitrite
- Nitrite to nitrate
- By nitrifying bacteria/microorganisms
- Nitrogen to to ammonia
- By nitrogen-fixing bacteria/microorganisms in soil
Nitrate from fertilisers applied to crops may enter ponds/lakes. Explain how nitrate may cause the death of fish in fresh water (5 marks)
- Growth of algae/surface plants blocks lights
- Reduced/ no photosynthesis so submerged plants die
3.saprobiotic bacteria/microorganisms - Aerobically respire
- Less oxygen for fish to respire/ aerobic organisms die
A large lake is surrounded by fields, which are separated by hedges. The lake was a habitat for many plants, invertebrates, and fish, but no longer
Explain how the increased use of inorganic fertilisers on the field may have led to these changes (5 marks)
- Run off/leaching of nitrates
- Increased growth of algae/plants
- Competition for light
- Death of algae/plants
- Increased food supply/ increased microorganisms/decomposers
- Respiration of microorganisms uses up oxygen/ Increases BOD
- Fish/animals die due to lack of oxygen
