Biology B4 Flashcards
(36 cards)
What is photosynthesis?
Photosynthesis is a process by which plants use light energy to produce glucose and oxygen from carbon dioxide and water.
State the word and symbol equation for photosynthesis?
Carbon + Water —-> Glucose + Oxygen
dioxide
6CO2 + 6H2O ——> C6H1206 + 6O2
Is photosynthesis exo or endo?
Photosynthesis is endothermic, takes in energy from the surroundings, in the form of sunlight.
Where does photosynthesis take place?
Take place in the chloroplast, inside the leaf, where chlorophyll absorbs light.
Which 4 factos affect the rate of photosynthesis?
- Light intensity
- CO2 conc
- Temperature
- chlorophyll
Explain the relationship between light intensity and the rate of photosynthesis.
As light intensity increase, so does the rate, until the CO2 or the temp is the limiting factor.
Explain the relationship between CO2 conc and the rate of photosynthesis.
As CO2 conc increases, the rate increases, until light or temp become the limiting factor.
Explain the relationship between temperature and the rate of photosynthesis.
Temp too low = enzymes work too slowly
Temp too high = enzymes denature
Explain the relationship between chlorophyll and the rate of photosynthesis.
A disease infects the plant eg TMV. causes lack of nutrients chloroplasts get damaged less light absorbed rate of photosynthesis decreases
Give 5 uses of glucose?
- Respiration
- Cellulose for strong cell walls
- Making amino acids
- Stored as oils or fats
- Stored as starch
Why is glucose stored as starch during the winter?
Because plants don’t receive as much light during the winter, they use the starch by converting it back into glucose. Starch is insoluble, meaning that it is good for storage as it doesn’t draw in liquid or swell the cell otherwise it would burst.
How are conditions optimised inside a greenhouse?
- Greenhouse traps sun’s heat so temp is not a limiting factor.
- Artificial lighting after the sun goes down.
- paraffin heaters to produce CO2.
- Plants stay away from pests and diseases.
Describe the process of respiration?
Exothermic.
Process of transferring energy from glucose.
Happens in every cell continuously.
What is Aerobic Respiration?
Using Oxygen.
Inside mitochondria.
Equation for aerobic respiration.
C6 H12 06 + 6 O2 —> 6 CO2 + 6 H2O
Glucose + Oxygen —-> Carbon dioxide + Water
When does Anaerobic respiration take place?
When body cannot supply muscles with sufficient oxygen.
E.g during vigorous exercise.
Equation for Anaerobic Respiration.
glucose —-> lactic acid
C6 H12 06 —> 2 C3 H6 O3
What is the diff between aerobic and anaerobic.
Aerobic
- with oxygen
- produces more energy (ATP)
- produces C02 and O2
- in multicellular organisms eg animals and humans
Anaerobic
- without oxygen
- Produces less ATP
- Glucose is not fully oxidised.
- Produces lactic acid.
- in unicellular organisms e.g bacteria and fungi.
What is the process of fermentation?
Chemical process where glucose is broken down anaerobically to produce ethanol and carbon dioxide.
Equation for anaerobic respiration in yeast.
Glucose —-> ethanol + carbon dioxide
C6 H12 O6 —> 2 C2 H5 OH + 2CO
What are the uses of ethanol and CO2.
Ethanol is used in alcoholic drinks.
Carbon dioxide makes the bread rise.
How does the body respire during normal exercise.
Aerobically.
To exercise, muscles need energy to contract, which increases the rate of respiration and more oxygen given to cells.
How does the body respire during vigorous exercise?
Anaerobically.
In vigorous exercise, energy not supplied quickly enough to muscles —> anaerobic resp —-> lactic acid causes pain.
What is oxygen debt.
The amount of oxygen your body needs to react with the build up of lactic acid and remove it from cells.
