Cells Tissues and Organs

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

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.

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

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

Fat cells

• have a small amount of cytoplasm and lots of fat
• few mitochondria as they need little energy
• can expand - can end up 1000 times its original size (it fills with fat)

Cone Cells (eye)

• outer segment contains a chemical that changes in coloured light (involves energy)
• middle segment packed with mitochondria to provide lots of energy
• has a specialised synapse that connects to the optic nerve to send impulses

Root Hair Cells

• large surface area for water to move in and out
• large permanent vacuole that speeds up osmosis

The spreading out of a gas or any other substance in a solute.

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)

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 (can be several) working together to carry out important functions of your body.

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

First, the food is broken into large, insoluble molecules by chewing. Meanwhile, the salivary glands are producing juices that will digest the food. the food then goes through a muscular tube that squeezes it through the digestive system. It is digested in the stomach and small intestine by digestive juices containing enzymes that are produced in the salivary glands and the pancreas. The enzymes break down large insoluble food molecules into smaller soluble ones. Your small intestine (large surface area to increase diffusion) is also where the food is absorbed into the blood so it can be transported around the body. The muscular walls squeeze the undigested food on into the large intestine where water is absorbed into the blood. the remainder forms faeces which are stored then pass out through the rectum and anus.