B2 1.1 Animal and Plant Cells
Cell Structures: Animal/Plant Plant
Nucleus to control the cell's activities
Cytoplasm where chemical reactions take place
Cell Membrane to control the movement of materials in and out of the cell
Mitochondria where energy is released during areobic respiration
Ribosomes where protein synthesis takes place
Cell Wall (made of cellulose) for suppport
Chloroplasts (contain chlorophyll) for photosynthesis
Vacuole containing cell sap
B2 1.2 Bacteria and Yeast
Bacteria Structure: Yeast Structure:
Cell Membrane Nucleus
Genetic Material Cell Wall
Cell Wall Cell Membrane
Genetic Material: The DNA which carries the instructions for making a new cell.
Bacterial Colony: A population of billions of bacteria grown in culture.
B2 1.3 Specialised Cells
Specialised: Adapted for a particular function.
The struture of a cell is linked to its function.
If a cell has...
many mitochondria it must need a lot of energy.
many ribosomes it is making a lot of protein.
a tail it is able to move.
Receptor cells have special structures which allow them to detect stimuli.
Neurons are specialised to carry impulses.
Plant cells with many chloroplasts will be photosynthesising.
Root Hair cells increase the surface area of the root so it can absorb water/mineral ions.
B2 1.4 Diffusion
Molecules in liquids and gases move randomly because of the energy they have.
Diffusion: the net movement of particles of a gas or a solute from an area of high concentration to an area of low concentration (along a concentration gradient)
Net Movement: the overall movement into and out of cells. It depends on the concentration of particles.
Concentration Gradient: the difference in concentration between two areas.
The larger the difference in concentration, the faster the rate of diffusion.
Substances such as oxygen, glucose and water move into cells and CO2, water and urea move out.
Dissolved substances move across the cells membrane in 3 ways: Diffusion, Osmosis, Active transport.
B2 1.5 Tissues and Organs
Multicellular Organisms: an organism made up of many different cells working together. Some cells are specialised.
Differentiation: Specialised for a particular function
Tissue: group of cells with a similar structure and function.
Organs are made of tissues e.g. stomach.
Organ system: a group of organs working together to carry out a particular function. e.g. digestive system.
3 Main Types of Tissue
Muscle tissue - contracts to allow movement
Glandular tissue - produces hormones/enzymes
Epithelial - lines the surface of organs for protection
B2 1.6 Organ Systems
The food you eat must be changed from insoluable molecules into soluable molecules. Then soluable molecules can be absorbed into the blood.
3 Stages of Digestion:
Ingestion - food taken in
Digestion - food broken down
Egestion - waste removed from body
Digestive System : mouth, salivary gland, gall bladder, liver, pancreas, small intestine, gullet, stomach, large intestine, rectum, anus.