Cell Energy (Photosynthesis and Respiration) Notes

Unlock the secrets of cell energy! Learn about photosynthesis and respiration.

Energy Energy for living things comes from food. Originally, the energy in food comes from the sun.Organisms that use light energy from the sun to produce food—autotrophs (auto = self)Ex: plants and some microorganisms (some bacteria and protists)Organisms that cannot use the sun’s energy to make food—heterotrophsEx: animals and most microorganisms Photosynthesis Photosynthesis is the process by which the energy of sunlight is converted into the energy of glucosePhotosynthesis occurs in the chloroplasts of plantsLight absorbing compound is a pigment—pigments absorb some wavelengths of light and reflect others—the color our eyes see is the color that the pigment reflectsChlorophyll is the pigment inside the chloroplast that absorbs light for photosynthesis Cellular Respiration: (2 kinds- Aerobic and Anaerobic) Cellular respiration is the process by which the energy of glucoseis released in the cell to be used for life processes (movement, breathing, blood circulation, etc…)Your body converts chemical energy into energy for growth, warmth, and movement.Cells require a constant source of energy for life processes but keep only a small amount of ATP on hand. Cells can regenerate ATP as needed by using the energy stored in foods like glucose.The energy stored in glucose by photosynthesis is released by cellular respiration and repackaged into the energy of ATP.Respiration occurs in all cells and can take place either with or without oxygen present. Aerobic Respiration Requires oxygenOccurs in the mitochondria of the cellGeneral formula for aerobic respiration Anaerobic Respiration Occurs when no oxygen is available to the cell (2 kinds: Alcoholic and Lactic Acid)Also called fermentation which occurs when cells release energy from food without using oxygen.There are 2 types of fermentation: Alcohol and Lactic AcidAlcoholic fermentation—occurs in bacteria, yeast, and plants.It produces alcohol, carbon dioxide and a small amount of energy.Lactic acid fermentation—occurs in muscle cellsLactic acid is produced in the muscles during rapid exercise when the body cannot supply enough oxygen to the tissues—causes burning sensation in muscles