Cell Structure

Cell Structure

• 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

A Typical Animal 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)
• Legenda: Animal Cell

Plant cells

• 
• Legenda: Plant Cell
• 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

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.

A Typical Bacterial Cell

• 
• 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.
• Legenda: A Typical Bacterial Cell