Biology B3 revision mock.

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  • Created by: Kimberley
  • Created on: 03-12-11 16:57

Cells

  • The nucleus controls the activities of the cell.
  • The ribosomes function in the cell is to act as the protein factory.
  • The cell wall is usually found in the animal cell but NOT in the plant cell.
  • The nucleus is missing in the red blood cells.
  • Diffusion is the movement of particles from a high concentrated region to a low concentrated region.

Dissolved substances passes in and out of the cell by diffusion, and water passes in and out of the cell by osmosis....

Part of cells/function in both animal and plant cell.

Nucleus: contains genetic information and controls the activity of the cell. 

Cytoplasm: most chemical process happens here, controlled by enzymes.

Cell membrane: control the moment of substances in and out.

Mitochondria: most energy is realised here by respiration.

Ribosomes: protein synthesis happens here.

Extra parts of plant cells.

Cell wall: strengthens the cell

Chloroplasts: contains chorolphyll which absorbs light for photosynthesis.

Permanent vacuole: filled with sap to keep the cell turgid (enlarged and swollen with water).

Diffusion occurs when particles spread. They move from high concentration to low concentration, but this only happens when the particles are free to move. (This is how the smell of cooking travels, particles diffuses down a concentration level, from an area of high concentration to an area of low concentration.)

Osmosis

Because of osmosis water can move in and out of cell membranes. To do this it needs.

  • 2 solutions with different concentrations.

  • A partially permeable membrane to separate them.

Eventually the level on the more concentrated side of the membrane rises, while the one on the less concentrated side falls. When the concentration is the same on both sides of the membrane, the movement of water molecules will be the same in both directions.

Photosynthesis

  • the spongy layer - allows gases to diffuse through
  • xylem - transports the water
  • Stoma - where the carbon dioxide enters
  • Chloroplasts - where most of the photosynthesis happens.

Carbon dioxide + water = oxygen + glucose

Plants also need mineral ions, included nitrate (which helps with the growth of plants, by making amino acids.) and magnesium (which helps make chlorophyll.

Photosynthesis takes place in the leaf cells. These contain chloroplasts, which also contain chlorophyll.

Plants need to take in a number of elements to stay alive. The most important are:

Carbon, Hydrogen and Oxygen. The plants get hydrogen and oxygen from the

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