Life Processes

Thèmes abordés

Anaerobic respiration, burst activity, Triphosphate

Résumé du document

ATP: the energy currency of the cell
To pass energy from respiration to other process => through a substance called adenosine Triphosphate: organic molecule attached to three inorganic phosphate groups
-can be broken down, losing a phosphate and producing a similar molecule (Diphosphate)
+ ATP is made, using the energy from the oxidised glucose to add a phosphate back onto ADP
(some energy is lost as heat, some is used to keep bodies warm)

Anaerobic respiration: cells can respire without using oxygen => glucose not completely broken down, less energy released but advantage: situation where oxygen is in short supply

During "burst activity" (muscles overworked), glucose broken down into lactic acid
Takes about 30mns of rest for all the lactic acid to be used up

Extraits

[...] ATP: the energy currency of the cell To pass energy from respiration to other process through a substance called adenosine Triphosphate: organic molecule attached to three inorganic phosphate groups can be broken down, losing a phosphate and producing a similar molecule (Diphosphate) + ATP is made, using the energy from the oxidised glucose to add a phosphate back onto ADP (some energy is lost as heat, some is used to keep bodies warm) Anaerobic respiration: cells can respire without using oxygen glucose not completely broken down, less energy released but advantage: situation where oxygen is in short supply During “burst activity” (muscles overworked), glucose broken down into lactic acid Takes about 30mns of rest for all the lactic acid to be used up Movements of materials in and out of cells Three ways that molecules and ions can move through the membrane: - diffusion substance more concentrated in one place than in the other (concentration gradient) Ex: membrane permeable to CO2 in either direction; higher concentration within the cell so move from inside to outside: net movement of the molecules Oxygen: concentration gradient from outside to inside: net movement into the cell by diffusion - active transport: uses energy from respiration to take up particles - osmosis: net diffusion of water across a partially permeable membrane, from a solution with a high water potential to one with a lower one ,moves from the dilute diffusion to the more concentrated one Cell division Single fertilised egg cell = zygote. [...]

[...] Chapter Life Processes Cell structure Animal cell - nucleus - cell membrane - mitochondria - cytoplasm Organelle: structures in the cell Nucleus: contains chromosomes which carry the genetic material (genes) Cell membrane: controls which substances pass in/out the ce ll (selectively permeable to some) Endoplasmic reticulum: ribosome (where proteins are assembled) Mitochondrion: carry out some of the reactions of respiration, release energy Cell wall: made of cellulose (fixed shape) Vacuole: filled with cell sap (dissolved sugars, minerals ions) Chloroplast: absorb light energy photosynthesis (pigmented by chlorophyll in green) Enzymes Controlling reactions in the cell biological catalysts (speeds up a metabolic reaction) Without them the reactions in the cell would be far too slow Made of proteins The molecule that an enzyme acts on is a substrate, fits in the active site Extracellular enzymes (out of the cell), most of them intracellular Factors affecting enzymes: - (best work= optimum too heat= destroyed, denatured) - pH (optimum pH, often neutral), can affect structure = substrate don(t fit into it so well Energy Cell respiration = processes of breaking down food molecules to release the stored chemical energy that they contain oxygen is used to oxidise food, CO2 and water released as waste products = aerobic respirat° main food oxidised = glucose sugar) The chemical energy can be sued for: contraction of muscles cells, transport of molecules, building large molecules, cell division. [...]

[...] Divides into 2 cells, then then mitosis The chromosomes in the nucleus are copied, the nucleus spits into two (shared equally), cytoplasm then divides forming two smaller cells. [...]