B 2.1 Cells, tissues and organs

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  • Created by: Twins 1&2
  • Created on: 17-12-13 11:05

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.

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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(http://www.bode-science-center.com/uploads/pics/bacteria.jpg)

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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      (http://www.bbc.co.uk/schools/gcsebitesize/science/images/add_21c_bio_diag_yeast_cell.jpg)

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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

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1.3 Specialised cells


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1.4 Diffusion

The spreading out of a gas or any other substance in a solution


If there is a big difference in the two concentrations, diffusion will take place more quickly. (diffusion occurs down a concentration gradient)


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)

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1.4 Diffusion


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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

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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
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1.6 Organ systems


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