Biology unit 1

• The cell is the basic unit of life
• unicellular organisms are made from one cell
• Multicellular organisms are made from many cells
• Only the bacterial cell has a plasmid
• Cell membrane controls the exit and entry of materials
• Cytoplasm is the site of chemical reactions
• Nucleus controls cells activities
• Cell wall provides support to the cell and prevents it from bursting
• Chloroplasts are the site of photosynthesis
• Vacuole contains cell Sap
• Ribosome is the site of protein synthesis
• Plasmid is a small circle of additional DNA found in the cytoplasm
• Mitochondrion is the site of aerobic respiration
• Yeast is a microbe that is used to make beer bread and wine
• Bacteria is a microbe used to make cheese and yogurt
• Microorganisms have many properties such as rapid growth
• The cell membrane is selectively permeable
• Selectively permeable means the membrane only allows small molecules to pass through such as oxygen,glucose and amino acids
• The cell membrane is made up of proteins and phospholipids
• Diffusion is the movement of molecules from a high concentration to a low concentration down a concentration gradient
• Diffusion is passive and doesn’t require energy
• Osmosis is the movement of water molecules from a high water concentration to a lower water concentration through a selectively permeable membrane
• Osmosis is passive and doesn’t require energy
• When animal cells are exposed to a high water concentration they swell and burst
• When plant cells are exposed to a high water concentration they become turgid
• When animal cells are exposed to a low water concentration they shrink
• When plant cells are exposed to a low water concentration they become playmolysed
• High sugar concentration=low water concentration
• Active transport is the movement of molecules and ions against the concentration gradient by membrane proteins (molecules move from an Are of low concentration to an area of high concentration )
• Active transport requires energy stored in ATP
• Many different tissues undertake active transport such as the movement of sodium and potassium in nerve cells and the movement of iodine ions in seaweed
• Chromosomes are found in the nucleus
• Genes carry the instructions to make proteins
• Dna exists as a double helix
• Dna is made of individual units called nucleotides
• In dna there are 4 types of bases such as adenine, thymine, cytosine and guanine
• Proteins are long chains of amino acids that are folded into a specific shape
• Amino acids are the building blocks for proteins
• The order of amino acids in a protein is coded for the DNA base order in a gene
• mRNA takes a copy of DNa out of the nucleus and to the ribosome