Topic 4 - Bioenergetics Flashcards
(15 cards)
What is photosynthesis and where in the plant does it take place?
Uses energy to change carbon dioxide and water into glucose and oxygen.
They take place in the chloroplasts in green plant cells they contain pigments like chlorophyll that absorb light.
Energy transferred to the chloroplasts from the environment by light.
What is the word equation for photosynthesis?
Carbon dioxide + water –> glucose + oxygen
What is the symbol equation for photosynthesis?
6CO2 + 6H2O → C6H12O6 + 6O2
What ways do plants use glucsoe?
For respiration - transfers energy from glucose.
Making Cellulose - Glucose is converted into cellulose for making strong plant cell walls.
Making amino acids - Glucose is combined with nitrate ions, which are absorbed from the soil, to make amino acids, which are then made into proteins.
Stored as oils or fats - Glucose is turned into lipids for storing in seeds.
Stored as starch - Glucose is turned into starch and stored in roots, stems and leaves as it is long term storage. It is insoluble will not draw water into cell via osmosis.
Define a limiting factor?
Limmiting factors affect the rate of photosynthesis.
What are the four limiting factors that affect the rate of photosynthesis?
Light intensity, CO2 concentration, Temperature, Amount of chlorophyll
What do farmers do to create conditions for photosynthesis?
Use greenhouses to trap sun’s heat this increases the temperature in colder conditions.
Use artificial light so photosynthesis can continue through day and night.
Pump carbon dioxide inside the greenhouse.
Use paraffin heater releases heat and carbon dioxide.
This all costs money so farmers have to consider cost vs yield.
Define respiration.
The process of transferring energy from glucose which goes on in every cell.
How do organisms use their energy?
Build up larger molecules from smaller ones.
For muscular contraction.
Maintaining body temperature.
What is aerobic respiration?
Respiration using oxygen, it is the most efficient way to transfer energy from glucose.
Most reactions for aerobic respiration takes place in the mitochondria.
What is the word and symbol equation for aerobic respiration?
What is anaerobic respiration?
Respiration without oxygen.
It is the incomplete breakdown of glucose making lactic acid (toxic).
Anaerobic respiration does not transfer as much energy as aerobic respiration.
Glucose —> Lactic acid.
What is the word equation for the anaerobic respiration of yeast?
Glucose –> ethanol + carbon dioxide
Define metabolism.
Sum of all the chemical reactions in an organism.
What is the method to show the effect of light intensity on photosynthesis.
Set up a boiling tube with pondweed (e.g. Elodea) in sodium hydrogen carbonate solution (provides CO₂).
Place the boiling tube 10 cm from a lamp (use a ruler to measure accurately).
Allow the pondweed to adjust for 2 minutes.
Count the number of bubbles released per minute (or measure volume of oxygen with a gas syringe).
Repeat the experiment at different distances from the lamp (e.g. 20 cm, 30 cm, 40 cm).
Keep other variables constant: temperature, CO₂ concentration, and same piece of pondweed.
Record results and calculate the rate of photosynthesis.
