National Biology

Cell Structure and the cell membrane summary

All living organisms are made of cells ; therefore cells are the basic units of life.

Stains e.g. iodine solution are used to show the parts of animal and plant cells more clearly.

Organelles are the structures found inside a cell.

MOST animal and plant cells have the following parts:

Nucleus controls all cell activities as it contains DNA which codes for all the proteins a cell makes

Cytoplasm where all the chemical reactions of the cell take place either directly in it or in organelles

suspended in it.

Cell membrane is the layer around the cytoplasm and controls what molecules can get into or out of the

cell and is selectively permeable.

The following organelles are not found in all cells.

Cell wall is the layer made of mainly cellulose that is around the cell membrane in

some cells, it gives support, prevents bursting and is fully permeable.

Vacuole is a bag like organelle, which can be filled with cell sap or other molecules depending on the cell.

It controls water content of the cell.

Chloroplasts are the organelles where the reactions for photosynthesis occur.

Mitochondria are the organelles where the reactions for aerobic respiration occur.

Ribosomes are the organelles that are the site of protein synthesis.

Plasmid rings of genetic information that can be used for genetic engineering.

The plasma membrane surrounding the living content

of all cells is selectively permeable.

It consists of a phospholipid bilayer and protein

molecules whose arrangement is described as the

fluid mosaic model.

cells ribosomes iodine solution clearly fluid mosaic

nucleus cytoplasm cell membrane units cell wall

chloroplasts vacuole organelles plasmid phospholipid

mitochondria selectively

ChromosomePlasmid

Name the following cells and label their organelles