biology p1

• animal and plant cells are eukaryotic cells
• bacteria cells are prokaryotic cells
• nucleus- contains dna
• cytoplasm- where most chemical reactions happen
• cell membrane- hold the cell together and controls what goes in and out
• mitochondria- where most respiration happen
• ribosomes- join amino acids together to make protein
• a cell wall- supports cell and strengthens it
• chloroplasts- photosynthesis happens
• vacuole- stores cell sap
• bacterial cells don’t have a nucleus
• bacteria cells have a chromosomal dna, ribosomes, cell membrane and plasmid dna and flagellum
• multicellular organisms contain lots of different types of cells
• egg cells function is to carry the female dna and feed the developing embryo
• the sperm cells function is to carry the male dna to the egg
• after ferilisation egg cells changes structure so no more sperm can enter
• egg cells have a haploid nucleus
• haploid nucleus means the cells only have half the number of chromosomes found in a normal body cell.
• a sperm cell has a tail so it can swim to the egg cell
• a sperm cell has lots of mitochondria to provide energy for the journey
• sperm cell has an acrosome to store enzymes
• sperm cells have a haploid nucleus
• microscopes uses lenses to magnify things
• light microscopes can be used to look at cells
• electron microscopes can make specimens look bigger and show more detail, gives us a better understanding of what sub cellular structures do
• enzymes are catalysts produced by living things
• enzymes sped up chemical reactions in living things
• every enzyme has an active site which is the part of the enzyme that is specific to the substrate
• enzymes catalyse breakdown and synthesis reactions
• enzymes called carbohydrases break carbohydrates into simple sugars
• protease break down proteins into amino acids
• lipases break down lipids into glycerol and fatty acids
• temperature, Ph and substrate concentration affect enzymes activity
• a higher temp increases the rate of and enzyme catalysed reaction at first but if it gets too hot some of the bonds holding the enzyme together break
• temp changes the shape of the enzyme activity site so the substrate won’t fit anymore
• if temp changes the shape the enzyme is said to be denatured
• all enzymes have an optimum temp
• diffusion is the spreading out of particles from an area of higher concentration to an area of lower concentration
• osmosis is the movement of water molecules across a partially permeable membrane from a less concentrated solution to a more concentrated solution
• a partially permeable membrane is a membrane with very small holes in it