Cells

• Eukaryotic cells are complex. animal and plant cells are eukaryotic
• Prokaryotic cells are smaller and simpler. Bacteria are prokaryotic cells
• the nucleus in an animal cell contains DNA. DNA controls what the cell does and is stored in structures called chromosomes
• the cytoplasm in an animal cell is where most chemical reactions happen. it is a gel like substance
• the cell membrane in an animal cell holds the cell together and controls what goes in and out
• the mitochondria in an animal cell is where respiration happens. respiration releases energy for the cell which allows it to function
• the ribosomes in an animal cell join amino acids together to make proteins
• the cell wall in a plant cell is made of cellulose and it supports the cell and strengthens it
• the chloroplasts in a plant cell is where photosynthesis takes place. photosynthesis makes food for the plant
• the large vacuole in a plant cell stores cell sap. cell sap is a solution of salts and sugars
• the bacterial cell contains small loops of plasmid DNA, ribosomes, cell membrane, cytoplasm, chromosomal DNA which is a long circular strand of DNA and a hair like structure called the flagellum which allows the cell to move
• cells with a structure that makes them adapted to their function are called specialised cells
• the egg cell carries the female DNA and feeds the developing embryo
• the sperm cell carries the male DNA to the egg
• an egg cell contains nutrients in its cytoplasm. these feed the embryo.
• after fertilisation, the cell membrane changes structure. this stops more sperm getting in. only one sperm can fertilise the egg
• an egg cell contains a haploid nucleus which contains half the number of chromosomes found in a normal body cell
• the sperm cell has a tail so that it can swim to the egg
• a sperm cell has lots of mitochondria which releases energy the sperm cell needs to swim
• a sperm cell has an acrosome which stores enzymes that digest through the membrane of the egg cell
• a sperm cell has a haploid nucleus
• ciliated epithelial cells are specialised for moving materials e.g. moving mucus up the throat
• epithelial cells line the surfaces of organs
• cilia are tiny hair like structures. they can move substances by beating them along the surface of tissues