B2.1 Cells, Tissues and Organs

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

Bacteria Structure:                                       Yeast Structure:

Cell Membrane                                              Nucleus

Genetic Material                                            Cell Wall

Cytoplasm                                                      Cytoplasm

Cell Wall                                                         Cell Membrane

Slime Capsule

Plasmids

Flagella 

Genetic Material: The DNA which carries the instructions for making a new cell.

Bacterial Colony: A population of billions of bacteria grown in culture.

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.

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.

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

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.