Animal cells contain:
- Nucleus- contains genes and controls activity
- Cytoplasm- where most chemical reactions take place
- Cell membrane- controls passage of substances into and out of cell
- Mitochondria- where oxygen is used ad much enerygy released in respiration
- Ribosomes- where protein synthesis takes place.
bacterial and yeast cells
- Each bacterium is a single cell
- Genetic material is not contained in a nucleus- lies in loops within the cytoplasm
- Can contain plasmids (small circular pieces of DNA carrying extra genetic information), slime capsule (outside cell wall) and/or one or more flagellum/flagella (long protein strand that enables the cell to move)
- Some bacteri cause disease but man are harmless and can be useful.
- single celled fungi
- Contains nucleus, cytoplasm, cell membrane, vacuole, foodstorage granules and cell wall
- Bigger than bacteria
- Can respire aerobically or anaerobically
- reproduces by asexual budding
Some cells have special features that help them to carry out their functions.
Fat cells- small amount of cytoplasm to make room for fat and few mitochondria as cell does not need much energy
Cone cells from eye- many mitochondria to provide energy needed by visual pigment, specialised synapse that connects to the optic nerve.
Root hair cells- increased surfac area to allow water into the cell, large permenant vacuole to speed up movement of water by osmosis.
Sperm cells- long tail to aid movement, many mitochondria because much enegy is required, large nucleus containing genetics.