bioenergetics

Created by

lily punter

Cards (23)

Plants absorb light energy through a green pigment called chlorophyll.
Chlorophyll is found in chloroplasts in the leaves.
Photosynthesis is an endothermic reaction.
An endothermic reaction is a reaction that takes in energy from the surroundings.
photosynthesis word equation
photosynthesis symbol equation
Plants use glucose from photosynthesis when they respire.
Plants also use glucose to make cellulose, which makes cell walls strong.
Plants can also store the glucose for later by converting it into starch they also store glucose vin fats and oils
The rate of photosynthesis is affected by light intensity, carbon dioxide concentration and temperature.
The higher the concentration of carbon dioxide in the air, the faster the rate of photosynthesis.
The more chlorophyll in the plant’s cells, the faster the rate of photosynthesis.
The higher the temperature, the faster the rate of photosynthesis. ( if temp is too high enzymes that control photosynthesis will denature
Photosynthesis needs certain conditions in order to happen.
If one of those conditions is in short supply it can prevent photosynthesis happening any faster. e.g. at night light is a limiting factor
Farmers sometimes use greenhouses to create the best conditions for their plants.
Greenhouses allow farmers to control the limiting factors of photosynthesis
In other words, when the distance to the light source increases, the light intensity decreases.
When plants photosynthesise, they release oxygen.
If the plant is aquatic (underwater), the oxygen floats to the surface in bubbles.
That makes it easy to measure the amount of oxygen being produced.
You can measure the rate of photosynthesis in a plant
place an aquatic plant in a test tube of water with a nearby light source.
Then count the number of bubbles the plant produces in one minute.
Then move the light source further away from the plant.
Count the number of bubbles produced in one minute again.
repeat then calculate mean
Cellular respiration transfers energy to an organism from food.
Cellular respiration happens in all living cells, all the time.
Respiration is an exothermic chemical reaction.
That means it gives out energy.
Respiration can be aerobic or anaerobic.
Aerobic respiration uses oxygen.
Anaerobic respiration doesn't involve oxygen.
In aerobic respiration, glucose and oxygen are converted into carbon dioxide and water.
In anaerobic respiration (with no oxygen) in muscles, glucose turns into lactic acid.
In anaerobic respiration, glucose is not completely oxidised.
This means that less energy is released than in aerobic respiration.
In yeast cells, anaerobic respiration is called fermentation. Fermentation is a valuable process in making bread.
This is because the carbon dioxide (CO2) gas makes the dough rise.
When exercising, your muscles need more energy. our body reacts to the increased demand for energy in various ways.
For instance, your heart rate increases, increasing the flow of blood to the muscles. You also breathe faster (increased breathing rate) and more deeply (increased breath volume). This means more oxygen reaches your muscles, so more aerobic respiration can happen.
During exercise, lactic acid builds up in the muscles.
If you exercise hard enough and long enough, the muscles will become fatigued When muscles are fatigued, they can’t contract very well.
When muscles respire without enough oxygen, lactic acid builds up.
Your blood transports the lactic acid from your muscles to your liver.
Your liver then converts lactic acid back into glucose using oxygen.
The extra oxygen your body needs to remove the lactic acid is called the oxygen debt.
the metabolism of a cell or the body is the combined total of all the reactions that take place in it. These processes are usually controlled by enzymes. e.g. respiration
Metabolism also includes reactions where larger molecules are broken down into smaller ones. One of these reactions is the breakdown of excess protein, which leaves the body in urine as urea.