Keywords Flashcards
Eyepiece graticule
A measuring device. It is placed in the eyepiece of a microscope and acts as a ruler when you view an object under the microscope
Stage graticule
A precise measuring device. It is a small scale that is placed on a microscope stage and used to calibrate the value of eyepiece divisions at different magnifications
Condensation reaction
Reaction that occurs when two molecules are joined together with the removal of water
Hydrogen bond
A weak interaction that can occur wherever molecules contain a slightly negatively charged atom bonded to a slightly positively charged atom
Hydrolysis reaction
Reaction that occurs when a molecule is split into two smaller molecules with the addition of water
Monomer
A small molecule which binds to other identical molecules to form a polymer
Polymer
A large molecule made from many smaller molecules called monomers
Carbohydrates
Group of molecules containing C, H and O
Glycosidic bond
A bond formed between two monosaccharides by a condensation reaction
Amino acids
Monomers of all proteins, and all amino acids have the same basic structure
Peptide bond
A bond formed when two amino acids are joined by a condensation reaction
Primary structure
The sequence of amino acids found in a molecule
Quaternary structure
Protein structure where a protein consists of more than one polypeptide chain. e.g. insulin
Secondary structure
The coiling or folding of an amino acid chain, which often arises as a result of hydrogen bonding between different parts of the chain . The main types of secondary structure are alpha helix and beta pleated sheet
Tertiary structure
The overall three dimensional shape of a protein molecule. Its shape arises due to interactions including hydrogen bonding, disulfide bonding, ionic bonds, and hydrophobic interactions
Fibrous protein
Has a relatively long, thin structure, is insoluble in water and metabolically inactive, often having a structural role within an organism
Globular protein
Has molecules of relatively spherical shape, which are soluble in water, and often have metabolic roles in an organism
Prosthetic group
A non-protein component that forms a permanent part of a functioning protein molecule
Double helix
Shape of a DNA molecule, due to coiling of two sugar-phosphate backbone strands into a right-handed spiral configuration
Monomer
Molecule that when repeated makes up a polymer. Amino acids are the monomers of proteins. Nucleotides are the monomers of nucleic acids
Nucleotide
Molecule consisting of a five-carbon sugar, a phosphate group and a nitrogenous base
Polynucleotide
Large molecule containing many nucleotides
DNA polymerase
Enzyme that catalyses formation of DNA from activated deoxyribose nucleotides, using single-stranded DNA as a template
Helicase
Enzyme that catalyses the breaking of hydrogen bonds between nitrogenous bases in a DNA molecule
Semi-conservative replication
How DNA replicates, resulting in two new molecules, each of which contains one old strand and one new strand. One old strand is conserved in each new molecule
Gene
A length of DNA that codes for a polypeptide or for a length of RNA involved in regulating gene expression
Polypeptide
A polymer made of many amino acid units joined together by peptide bonds. Insulin is a polypeptide of 51 amino acids
Protein
A large polypeptide of 100 or more amino acids. However, the terms are often used synonymously, and insulin may be described as a small protein
Transcription
The process of making messenger RNA from a DNA template
Translation
Formation of a protein, at ribosomes, by assembling amino acids into a particular sequence according to the coded instructions carried from DNA to the ribosome by RNA
Active site
Indented area on the surface of an enzyme molecule, with a shape that is complementary to the shape of the substrate molecule
Catalyst
Chemical that speeds up the rate of reaction and remains unchanged and reusable at the end of the reaction
Extracellular
Outside of the cell
Intracellular
Inside of the cell
Metabolic/metabolism
The chemical reactions that take place inside living cells or organisms
Product
Molecule produced from substrate molecules, by an enzyme catalysed reaction
Substrate
Molecule that is altered by an enzyme-catalysed reaction
Cofactor
A substance that has to be present to ensure that an enzyme catalysed reaction takes place at the appropriate site. Some cofactors (prosthetic groups) are part of the enzyme structure, and others (mineral ion cofactors and organic coenzymes) form temporary associations with the enzyme
Enzyme-substrate complex
Complex formed by temporary binding of enzyme and substrate molecules during an enzyme-catalysed reaction
Enzyme-product complex
Enzyme molecule with the product molecule in its active site. The two are joined temporarily by non-covalent forces
Q10
Temperature coefficient, calculated by dividing the rate of reaction at (T + 10) degrees C by the rate of reaction at T degrees C
Concentration
Number of molecules per unit volume
Competitive inhibition
Inhibition of an enzyme, where the inhibitor molecule has a similar shape to that of a substrate molecule and competes with the substrate for the enzyme’s active site. It blocks the active site and prevents formation of an enzyme substrate complex
Inhibitor
A substance that reduces or stops a reaction
Non-competitive inhibition
Inhibition of an enzyme, where the competitor molecule attached to a part of the enzyme molecule but not the active site. This changes the shape of the active site which prevents ES complexes forming, as the enzyme active site is no longer complementary in shape to the substrate molecule
Fluid mosaic model
Theory of cell membrane structure with proteins embedded in a sea of phospholipids
Glycolipid
Lipid/phospholipid with a chain of carbohydrate molecules attached
Glycoprotein
Protein with a chain of carbohydrate molecules attached
Plasma membrane
Cell surface membrane
Diffusion
Movement of molecules from an area of high concentration of that molecule to an area of low concentration; it may or may not be across a membrane; it does not involve metabolic energy (ATP)
Facilitated diffusion
Movement of molecules from an area of high concentration of that molecule to an area of low concentration of that molecule, across a partially permeable membrane via protein channels or carriers; it does no involve metabolic energy (ATP)
Osmosis
Passage of water molecules down their water potential gradient, across a partially permeable membrane
Water potential
Measure of the tendency of water molecules to diffuse from one region into another
