1.1 Animal and plant cells
All living things are made up of cells
Most cells have a common structure;
Nucleus - controls all activities of a cell. Contains the genes and information to create a new cell
Cytoplasm - a liquid in which most chemical reactions take place
Cell membrane - controls passage of subtances in and out of the cell
Ribosomes - protein synthesis takes place here
Mitochondria - where oxygen is used and energy is released during respiration
Plant and algae cells also have;
Cell wall - strengthens the cell and gives it support
Chloroplasts - contain chlorophyll which absorbs light energy to make food by photosynthesis
Permanent Vacuole - filled with cell sap, keeps the cells rigid to support the plant.
1.2 Bacteria and yeast
Bacterial -the genes in the cell are not contained in a nucleus, -may have a slime capsule around the outside of the cell, -some baterium have a flagellum (or more than one) that help them to move around
1.2 Bacteria and yeast
Yeast: -each yeast cell contains a nucleus (which contains the genetic material), cytoplasm and a membrane surrounded by a cell wall, -the main way the repsoduce is by assexual budding (a new yeast cell growing out from the original cell), -Yeast cels can aerobically respire and use oxygen to provide energy. -they can also respire anaerobically but now they break down sugar to produce ethanol and carbon dioxide
1.3 Specialised celss
Many types of animal and plant cells thata re specialised. The structure of a cells is linked to its function.
Lots of mitochondria it must need alot on energy - e.g. muscle cell, sperm cell
Many ribosomes it is making alot of protein - e.g. gland cells which produce enzymes.
Cells with tails are able to move - e.g. sperm cell
receptor cells have special structures which enable them to detect stimuli - e.g. cone eye cell, light sensetive
neurons are specialised to carry impulses from receptors to CNS
plant cells with lots of chloraplasts photosynthesise -e.g. mesophyll cells on a plant leaf
root hair cells increase surface area of the root to maximise abosorbtion of water/minerals
1.3 Specialised cells
The spreading out of a gas or any other substance in a solution
FROM AN AREA OF HIGH CONCENTRATION TO LOW
If there is a big difference in the two concentrations, diffusion will take place more quickly. (diffusion occurs down a concentration gradient)
NET MOVEMENT = PARTICLES MOVING IN - PARTICLES MOVING OUT
In your body, water and simple sugars need to move across your cell membranes by diffusion. AMINO ACIDS need to pass through cell membranes. The oxygen in your lungs pass into red blood cells by diffusion.
some cells may be adapted specificaly for diffusion (mainly increasing SA)
1.5 Tissue and organs
Tissue is a group of cells similar in function animal plant
Muscular Tissue contract to brign about movement
Glandular Tissue contain secretory cells that produce enzymes and hormones
Epithelial Tissue covers to outside of your body and organs
Epidermal Tissue covers and protexts plant's surfaces
Mesophyll Tissue contain chloroplasts and can carry out photosynthesis
Xylem and Phloem are the transport tissues which carry water and mineral ions
Organs are made up of tissues.
e.g. the stomach contains: muscular tissue to churn food and digestive juices; glandular tissue to produce digestive juices; and epithelial tissue to which covers the inside and outside of the organ
Groups of organs make up organ systems e.g. digestive system
1.6 Organ systems
The food we eat has to be changed from insoluble molecules to soluble molecules, only then cant hey be absorbed into our blood. This is what the digestive system is responcible for this.
The digestive system.
- glands, pancrease + salivary glands produce digestive juices
- stomach and small intestine where digestion occurs
- liver which produces bile
- small intestine where asorbtion of soluble food occurs
- large intestine where water is absorbed frm undigested foor, producing feaces
1.6 Organ systems