Topic 1 - Cell biology

ALL living things are made of cells

Cells can EITHER be PROKARYOTIC or EUKARYOTIC

Prokaryotic cells = Smaller and simpler e.g. bacteria

Eukaryotic cells = Complex and include ALL ANIMAL and PLANT cells

Eukaryotes = organisms made up of eukaryotic cells

Prokaryotes = prokaryotic cell (SINGLE CELL ORGANISM)

MOST animal cells have these subcellular structures:

NUCLEUS - Contains genetic material that controls activites of the cell

CYTOPLASM - Where most of the chemical reactions happen. Contains enzymes that control these reactions

CELL MEMBRANE - Holds the cell together and controls what goes in and out 

MITOCHONDRIA - Most of the reactions for aerobic respiration happen in these. Respiration gives the cells the energy they need to work.

RIBOSOMES - Where proteins are made

Plant cells have all the subcellular structures that animal cells have + a few extra.

Have :  Nucleus, Cytoplasm, Cell membrane, Mitochondria and Ribosomes...

CELL WALL - Rigid and made of cellulose. Supports and stregthens the cell.

PERMANENT VACUOLE - Contains cell sap, a weak solution of sugar and salts.

CHLOROPLASTS - Where photosynthesis occurs. Contain chlorophyll that absorbs the light needed to create food.

Algea cells such as seaweed also have a rigid cell wall and chloroplasts.

Bacteria = Prokaryotes

Bacteria cells include : 

• Cytoplasm
• Cell membrane
• Cell wall
• Single circular strand of DNA (instead of nucleus) that floats freely in the cytoplasm
• May contain one or more plasmids (small rings of DNA)

Don't have chloroplasts or mitochondria