Photosynthesis, Respiration And Metabolism Flashcards
Photosynthesis is an endothermic reaction, what does this mean?
It needs an input of energy from the environment
How to calculate light intensity
1/distance ^2
Key points on water in photosynthesis
- Taken into the plant through root hair cells by osmosis
- Travels to leaf through xylem cells
- Light intensity breaks the water molecules to create glucose with co2
Key points of carbon dioxide in photosynthesis
- Taken in through stomata by diffusion
- co2 atoms combine with H atoms to create glucose
Key points of sunlight in photosynthesis
-Light intensity splits water molecules into H+ ions and oxygen molecules, the H combines with co2 to create glucose, the oxygen is released through stomata by diffusion.
Key points of chlorophyll in photosynthesis
- Found in chloroplasts in cytoplasm, traps sunlight energy.
- Mostly found in palisade mesophyll layer.
Key points of glucose in photosynthesis
- Made in the leaf, stored as insoluble starch.
- Used for respiration to provide and release ATP energy.
- Used to produce fat or oil for storage.
- Produces cellulose for cell Wall.
- Used to produce amino acids for protein synthesis.
Key points of oxygen in photosynthesis
- Escapes plant through stomata by diffusion
- Some is kept for respiration.
Respiration definition
The enzyme controlled reaction whereby energy is released from glucose. Occurs in the mitochondria, and is a exothermic reaction, releasing energy.
What are the two types of respiration?
- Aerobic respiration
- Anaerobic respiration
Equation for aerobic respiration
Glucose + oxygen -> carbon dioxide + water + ATP
Equation for anaerobic respiration
Glucose -> lactic acid + small amount of energy
Equation for photosynthesis
Carbon dioxide + water ->(light) -> glucose + oxygen
Key points for Aerobic respiration
- Glucose is fully broken down, all the energy is released.
- Oxygen is in plentiful supply
Key points for anaerobic respiration
- Glucose is partially broken down, only some energy is released
- Oxygen is not in plentiful supply, meaning lactic acid is released
- Occurs during vigorous exercise
- Occurs in mitochondria
- Is a quick source of energy.
- Builds up oxygen debt
What is the energy released from respiration used for?
- Chemical reactions to build larger molecules from smaller ones
- Energy is needed for movement
- Maintaining a constant internal body temperature e.g. 37 degrees
How can glucose be used for respiration
- Glucose is absorbed by diffusion into the bloodstream from the small intestine.
- Then the blood delivers glucose to muscles by capillaries
- Glucose can be used for respiration.
How does the body respond to exercise?
- Our bodies require more oxygen and glucose when exercising in order to respire quicker, as the muscles are working harder and faster.
- Heart and lungs have to work harder, meaning:
- Heart rate increases to supply more oxygen and glucose to muscles
- Breathing rate increases to supply more oxygen
- Increases the rate of co2 and lactic acid removal.
- Stored up glycogen converted back to glucose for respiration.
- Higher rate of respiration.
Metabolic functions from the liver
- Detoxification of poisonous substances such as ethanol from alcohol.
- Passing the breakdown products into the blood so they can be excreted in the urine via the kidneys.
- Breaking down worn out red blood cells and storing the iron until it is need to synthesise more blood cells.
Key points of removing lactic acid:
- Blood flowing through the muscles transports lactic acid to the liver, where it is converted back to glucose.
- Once the lactic is converted to glucose, which is broken down to form carbon dioxide and water, the oxygen debt has been repaid.
Equation for Anaerobic respiration in plants and yeast cells:
Glucose -> ethanol + carbon dioxide
What is fermentation?
Anaerobic respiration in yeast cells
