B4 Flashcards
bioenergetics (22 cards)
Define respiration
The process of transferring energy from the breakdown of glucose.
Is respiration an EXOthermic reaction or an ENDOthermic reaction?
EXOthermic - energy is transferred to it’s surroundings.
Give the 3 ways how organisms use the energy transferred by respiration.
- Build up larger molecules from smaller molecules (proteins from amino acids)
- In animals, muscles can contract
- In mammals and birds, the energy is used to keep their body temperature steady.
What is the equation for aerobic respiration?
glucose + oxygen = carbon dioxide + water
Where does aerobic respiration happen?
Mitochondria
What is the equation for anaerobic respiration?
glucose = lactic acid
Where does anaerobic respiration take place?
Cytoplasm
Why doesn’t anaerobic respiration transfer as much energy as aerobic respiration?
Glucose isn’t fully oxidised
What does the incomplete breakdown of glucose make?
Lactic acid
What’s the equation for anaerobic respiration in PLANTS and YEAST?
glucose = ethanol + carbon dioxide
What is fermentation?
Anaerobic respiration in yeast cells
Define metabolism
All of the chemical reactions that happen in a body or cell
What controls the chemical reactions in a body/cell?
Enzymes (biological catalysts)
Give 3 examples of metabolism in the body
- digestion of food
- protein synthesis
- anaerobic respiration
- aerobic respiration
How is energy used for photosynthesis gained by plants?
Light is absorbed by chlorophyll
Why do plants use glucose? (give 3 ways)
Respiration
Making cellulose
Making amino acids
Stored as oils/fats
Stored as starch
What are the 3 limiting factors in photosynthesis?
Light intensity
Carbon dioxide
Temperature
Explain light intensity as a limiting factor
Not enough light slows the rate of photosynthesis because light provides energy for photosynthesis. So light increases photosynthesis but only up to a point because co2 or temperature will be the limiting factor
Explain carbon dioxide as a limiting factor
Carbon dioxide is fundamental for photosynthesis as it is one of the reactants. Carbon dioxide increases photosynthesis up to a point because it will no longer be the limiting factor - it will be temperature or light intensity.
Explain temperature as a limiting factor
The temperature has to be just right for photosynthesis.
If temperature is a limiting factor then it is too low - the enzymes needed work slower.
However… if the plant gets too hot, the enzymes will damage
This is usually at 45 degrees
Why do plants store glucose as starch?
Because starch is insoluble in water.
If glucose was stored, water would move into the plant cells via osmosis and burst.
Why do we put sodium bicarbonate in the beaker with water in the pondweed required practical?
Make sure that CO2 isn’t a limiting factor
