biology
- Created by: olivia
- Created on: 22-09-17 17:39
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- Biology-topic B4: Bioenergetics
- rates of photosynthesis
- factors = light, CO2, chlorophyll and Temperature
- carbon dioxide + water __________ glucose + oxygen
- takes place in chloroplasts in green plant cells
- energy is transferred to chloroplasts from the environment by light
- process is endothermic (energy transferred in from surroundings)
- uses glucose for: respiration, making cellulose, making amino acids, stored as oils/fats, stored as starch.
- amount of chlorophyll can depend on disease or environmental stress such as lack of nutrients.
- not enough light or too little CO2 slows down the rate of reaction
- Respiration and Metabolism
- respiration = the process of transferring energy from glucose which goes on in every cell.
- respiration is exothermic (energy transferred out to the environment)
- metabolism = all the chemical reactions in an organism
- lots of small glucose molecules join together to form starch and cellulose
- glucose is combined with nitrate ions to make amino acids which are then made into proteins.
- excess protein is broken down in a reaction to produce urea. urea is then excreted as urine
- aerobic respiration needs plenty of oxygen
- anaerobic respiration is used if there isn't enough oxygen (incomplete breakdown of glucose)
- anaerobic respiration in yeast cells is called fermentation
- most aerobic reactions occur in mitochondria
- anaerobic respiration is used if there isn't enough oxygen (incomplete breakdown of glucose)
- Exercise
- when exercising you respire more
- muscles need energy from respiration to contract.
- increase in respiration means that muscles require more oxygen.
- breathing rate and breath volume increases to intake oxygen
- heart rate increases to carry oxygenated blood around the body faster.
- long periods cause muscle fatigue.
- carbon dioxide is removed quicker with faster respiration
- vigorous exercise means that oxygen can't be supplied therefore the body respirates anaerobically.
- anerobic respiration leads to oxygen debt
- Inverse Square Law
- links light intensity and distance
- as distance increases, light intensity decreases
- further away from lamp = dimmer light
- light intensity decreases in proportion to distance
- putting one over the distance shows the inverse
- you can use 1/d squared as a measure of light intensity
- rates of photosynthesis
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