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Videos uploaded by user “Science Signal”
Diffusion IGCSE/ GCSE/ O LEVEL/ AQA/ CHECKPOINT
 
06:59
Diffusion IGCSE/ GCSE/ O LEVEL/ AQA/ CHECKPOINT
Views: 10 Science Signal
Photosynthesis IGCSE/ GCSE/ AQA
 
03:02
In photosynthesis is that green plants and algae trap light from the sun to fix carbon dioxide with hydrogen and water. This makes organic compounds which then provide food for not only the plant itself but also all animals. Photosynthesis happens in leaf cells. They contain tiny organelles called chloroplasts, which contain a green substance called chlorophyll. Chlorophyll molecules sit on the surface of the chloroplasts and capture light energy from the sun, which is fundamental for photosynthesis. Photosynthesis is a chemical reaction, in which carbon dioxide and water are converted to glucose and oxygen, by the energy provided from the light energy absorbed by the chlorophyll. It is an endothermic reaction because it takes in energy from surroundings. carbon dioxide + water ( + light energy ) → glucose + water. The light energy is not a substance, but it is an essential requirement for photosynthesis to happen. So we know the light energy comes from the sun, and is absorbed by the chlorophyll. But where do the carbon dioxide and water come from? Plants absorb water through their roots, and it moves through the plant and into the leaves by transpiration. Watch our video on ‘Xylem and transpiration’ to learn more about this process. Carbon dioxide enters into leaves from the air, through the stoma on the underside of the leaf. What then happens to the glucose and oxygen that are made? Some of the glucose is used for respiration and some is converted into insoluble starch. This can then be stored and turned back into glucose to be used at a later date. Oxygen is actually just a by-product of photosynthesis. There are some useful by-products in this world. Green plants are called producers or autotrophs, because they have the ability to produce their own food. They are the start off the food chain, and every animal relies upon them either directly if they are a herbivore or indirectly if they are a carnivore.
Views: 32 Science Signal
Enzymes (IGCSE Biology/ GCSE/ AQA/ Checkpoint/ O Level)
 
07:45
Enzymes (IGCSE Biology/ GCSE/ AQA/ Checkpoint/ O Level)
Views: 10 Science Signal
helpful tips for taking notes; improve academic performance and grade
 
04:15
helpful tips for taking notes; improve academic performance and grade
Views: 7 Science Signal
Before Lecture Preparation- to improve your class performance and grades
 
02:40
Before Lecture Preparation- to improve your class performance and grades
Views: 4 Science Signal
Characteristics of Living Organisms
 
03:18
Seven Characteristics of Living Organisms
Views: 40 Science Signal