You must be able to:
Describe the structure of a typical animal cell
Describe how a plant cell differs from an animal cell
Recall the main differences between prokaryotic and eukaryotic cells
Describe the structure of a typical bacterial cell
All cells have structures inside of them - these are called sub - cellular structures
In an animal cell, the sub - cellular structures include:
a nucleus, which controls the activities of the cell and contains the genetic material
cytoplasm, in which most of the chemical reactions take place
a cell membrane, which controls the passage of substances into and out of the cell
mitochondria, where aerobic respiration takes place
ribosomes, where proteins are synthesised (made)
Plant cells and algal cells contain all the sub - cellular structures found in animal cells
They also have:
a cell wall made of cellulose, which strengthens the cell
a permanent vacuole filled with cell sap, which supports the plant
Plants need to make their own food, so some of their cells contain chloroplasts
Chloroplasts absorb light to make food (glucose) by photosynthesis
Diapositiva 4
Prokaryotic and Eukaryotic Cells
There are two main types of cell:
prokaryotic
eukaryotic
Plant, animal and fungal cells are all eukaryotic
Bacterial cells are prokaryotic
Prokaryotic cells are much smaller in size and:
the genetic material is not enclosed in the nucleus
the genetic material is a single DNA loop and there may be one or more small rings of DNA, called plasmids
they do not contain mitochondria or chloroplasts
Key Point:
Prokaryotic cells are much simpler in structure then eukaryotic cells. That id why scientists think that they developed before eukaryotic cells
Key Point:
Plasmids have become very useful to scientists. They allow genes to be inserted into bacteria in genetic engineering.
Bacteria cells have many different shapes - some are round, some are rod-shaped and some are spiral - but they are all prokaryotic cells.
In bacterial cells, the roles of mitochondria and chloroplasts are taken over by the cytoplasm.
There may be one or more flagella, which are tail-like structures that move the bacterium,
Plasmids are present, which are loops of DNA that can be transferred from one cell to another.
Plasmids allow bacterial cells to move genes from one cell to another.