cell biology

site of cell reactions

controls entry and exit of molecules to cells

controls cell activities (contains genetic information)

site of protein synthesis

site of aerobic respiration

gives the cell support and structure

contains cell sap

contains chlorophyll. Traps light for photosynthesis

additional rings of DNA

It is made up of proteins and phospholipids. It has a selectively permeable membrane which small molecules like glucose water and oxygen can pass through but larger molecules like starch and fat cannot

diffusion is a form of passive transport. Movement from high concentration to low concentration down a concentration gradient. No energy is required.

Osmosis is the diffusion of water molecules from a region of high water concentration to a region of lower water concentration through a selectively permeable membrane. Osmosis is a passive process, it does not require energy.

ions/ molecules move from low to high concentration against a concentration gradient. Energy is required, this is an active process.

The nucleus of the cell carries genetic information in structures called chromosomes - chromosomes contain DNA

a gene is a section of DNA which codes for making protein to give you a characteristic.

• DNA is a double stranded helix held together by complimentary base pairs • DNA carries the genetic information for making proteins • ATGC

proteins are made up of many subunits called amino acids linked together in long chains by peptide bonds

each proteins has its own sequence of amino acids. The sequence of amino acids determines the structure and function of the protein. - the DNA base sequence determines the amino acid sequence in proteins

mRNA is a molecule which carries a complimentary copy of the genetic code from the DNA in the nucleus to a ribosome where the protein is assembled from amino acids

the cell wall is made of cellulose fibres, it keeps the cell rigid. It resists the uptake of water to maintain the shape and support of the cell. Fungal and bacterial cell walls are not made up of cellulose fibres but do the same job.

antibodies, structural, enzymes, hormones, receptors

protein molecules

diffusion is important to cells and multi cellular animals because cells require glucose and oxygen to diffuse into them so they can release energy during aerobic respiration. During this respiration process cells make the waste product, carbon dioxide which must diffuse out of the cells so they can stay alive.

plasmolysed means when there’s low water the cell shrinks turgid means when theres too much water the cell swells