Module 2 - Keywords Flashcards
Resolution
The ability to be able to distinguish between two objects which are close together
Magnification
The degree to which the size of an image if larger than the object itself
Staining
The process which helps reveal or distinguish different features
Cytoskeleton
The network of protein fibres found within cells that give structure and shape to the cell
Organelle
A particular structure of a cell which has a specialised/specific function
Phospholipid bilayer
The basic structural components of plasma/cell surface membranes, consisting of two layers of phospholipid
Fluid mosaic model
Model of the cell surface/plasma membrane
Cell signalling
Cells communicate with one another by signals e.g. hormones, to help them work together and coordinate their actions
Diffusion
The net movement of molecules from a region of high concentration of that molecule to a region of lower concentration of that molecule down a concentration gradient. This is a passive process
Facilitated diffusion
The net movement of molecules from a region of high concentration of that molecule to a region of lower concentration of that molecule down a concentration gradient through carrier proteins (large molecules) or channel proteins (ions). This is a passive process
Active transport
The movement of molecules or ions across a membrane from a region of low concentration to a region of higher concentration of that molecule, against the concentration gradient. This process uses ATP to drive the protein ‘pumps’ within the membrane
Osmosis
The net movement of water molecules from a region of high water potential to an area of lower water potential, down the water potential gradient across a partially Permeable membrane. This is a passive process
Solute
A solid that dissolves in a liquid
Solvent
A liquid that dissolves solids
Solution
A liquid containing dissolved solids
Cell cycle
Describes the events that take place as one parent cell divides to produce two new daughter cells which then each grow to full size
Mitosis
The process of nuclear division where two genetically identical nuclei are formed from one parent cell nucleus
Clones
Genetically identical cells or organisms derived from one parent
Differentiation
The changes occurring in cells of a multicellular organism so that each different type of cell becomes specialised to perform a specific function
Cytokine
An example of a cell signal
Tissue
A group of similar, specialised cells of more than one type working together to perform a common specific function
Organ
A collection of tissues that work together to carry out a common specific function
Stem cells
Cells that are not differentiated and are capable of mitosis and differentiation to become other cell types
Metabolism
The sum total of all the biochemical reactions taking in cells of an organism
Polysaccharides
Polymers of monosaccharides. They consist of hundreds or thousands of monosaccharide monomers bonded together to form a single large molecule
Hydrolysis
Breaking a bond with the addition of a water molecule
Condensation
Forming a bond with the removal of a water molecule
Primary structure
Sequence or order of amino acids in a polypeptide chain
Secondary structure
The coiling/folding of the polypeptide into an alpha helix or beta pleated sheet held together with hydrogen bonds between the amino acids
Tertiary structure
The final 3D shape of the protein. The shape is held in place with hydrogen bonds, ionic bonds between oppositely charged R groups, disulphide bridges and hydrophobic and hydrophilic interactions
Quaternary structure
made up of more than one polypeptide chain joined together to make the final functional protein
Lipids
Substances that dissolved in organic solvents like alcohol but not water
Saturated fatty acids
Fatty acids with no double bonds in the hydrocarbon chain
Unsaturated fatty acids
Fatty acids with at least one double bond in the hydrocarbon chain
Triglyceride
3 fatty acids joined to a glycerol molecule with 3 ester bonds
Nucleotides
Monomers of nucleic acids. Made of a phosphate group, pentose sugar and a nitrogenous base
Gene
A length of DNA that codes for a specific protein
Enzyme
Biological catalysts which reduce the activation energy required for a reaction to take place. They are protein molecules
Activation energy
The required amount of energy for a chemical reaction to take place
Active site
A region on the surface of an enzyme molecule where a substrate can bind and where the reaction takes place
Enzyme specificity
One enzyme’s active site is complementary in shape to only one substrate molecule
Catalyst
A molecule which speeds up a reaction but remains unchanged and is not used up in the reaction
Extracellular
Chemical reactions taking place outside of the cell
Intracellular
Chemical reactions taking place inside of the cell
Denaturation
When the active site of an enzyme changes shape due to the breaking of bonds, losing its tertiary structure and complementary shape to the substrate
