| active site/ˈæktɪv saɪt/ |
The region of an enzyme where the substrate binds and reacts. |
| Active transport/ˈæktɪv ˈtrænspɔːt/ |
The movement of substances across a cell membrane against their concentration gradient using energy and carrier proteins. |
| amylopectin/ˈæmɪləʊpktɪn/ |
A branched polymer of alpha-glucose that forms part of starch. |
| amylose/ˈæmɪləʊs/ |
An unbranched polymer of alpha-glucose that forms part of starch and coils into a helix. |
| Anticoagulants |
Substances that reduce or prevent blood clotting. |
| anticodons |
A sequence of three nucleotides in tRNA that pairs with a complementary codon in mRNA. |
| Antihypertensives |
Medicines used to lower high blood pressure. |
| Atherosclerosis |
The development of fatty deposits in artery walls, which can narrow the lumen and reduce blood flow. |
| Atrial systole |
Contraction of the atria, pushing blood into the ventricles. |
| Blood pressure |
The force per unit area exerted by blood on the walls of blood vessels. |
| Bohr effect |
The reduced affinity of haemoglobin for oxygen at higher carbon dioxide concentration and lower pH, promoting oxygen unloading. |
| Competitive inhibitors |
A molecule that blocks the active site by competing with the substrate; more substrate can overcome it. |
| Condensation/kɒndenˈseɪʃn/ |
A chemical reaction in which molecules join and a small molecule, commonly water, is eliminated. |
| confounders |
Variables associated with both an investigated factor and an outcome that can distort their apparent relationship. |
| cooperative binding |
Binding that changes a protein's affinity for further molecules, as when oxygen binding increases haemoglobin's affinity for additional oxygen. |
| Correlation is not causation. |
An observed association between variables does not by itself show that changing one causes a change in the other. |
| degenerate/dɪˈdʒenəreɪt/ |
Describing the genetic code because more than one codon can specify the same amino acid. |
| deletion/dɪˈliːʃn/ |
A mutation in which one or more nucleotides are lost from a DNA sequence. |
| Diastole/ˈdaɪəstəʊl/ |
The relaxation phase of a heart chamber's cycle, during which it can fill with blood. |
| Diffusion/dɪˈfjuːʒn/ |
Net movement down a concentration gradient, no ATP. |
| dipole/ˈdaɪpəʊl/ |
A pair or separation of opposite electric charges, producing a positive and a negative end. |
| DNA polymerase/ˌdiː en ˈeɪ ˌpɒlɪməˈreɪz/ |
An enzyme that synthesises DNA by adding nucleotides to a growing strand using a template. |
| endothelium |
The thin layer of cells lining the inside of blood vessels. |
| enzyme/ˈenzaɪm/ |
A biological catalyst that increases the rate of a reaction without being used up overall. |
| ester bonds |
A covalent linkage formed between a carboxyl-derived group and an oxygen attached to a carbon group, as in fats. |
| Facilitated diffusion/fəˈsɪlɪteɪtɪd dɪˈfjuːʒn/ |
Passive movement down a concentration or electrochemical gradient through a membrane channel or carrier protein. |
| fibrin/ˈfɪbrɪn/ |
The insoluble protein mesh that traps cells to form a blood clot. |
| fibrinogen/ˈfɪbrɪnədʒn/ |
The soluble blood protein converted to fibrin during clotting. |
| fluid mosaic model/ˈfluːɪd məˈseɪɪk ˈmɒdl/ |
The model of the cell membrane as a fluid phospholipid bilayer with proteins scattered through it like tiles. |
| frameshift/ˈfreɪmʃɪft/ |
A change in how codons are grouped after insertion or deletion of a nucleotide number that is not a multiple of three in a coding sequence. |
| Genetic screening/dʒɪˈnetɪk ˈskriːnɪŋ/ |
Testing for genetic variants or chromosome changes that may indicate a condition, carrier status or increased risk. |
| glycogen/ˈɡlaɪkədʒn/ |
A highly branched glucose polysaccharide used for energy storage in animals and fungi. |
| glycosidic bond/ˌɡlaɪkəˈsɪdɪk bɒnd/ |
A covalent linkage joining a sugar to another group, including the links between sugar units in carbohydrates. |
| hydrogen bonds/ˈhaɪdrədʒn bɒndz/ |
An attraction between a hydrogen atom bonded to an electronegative atom and a suitable electronegative atom with a lone pair. |
| Hydrolysis/haɪˈdrɒləsɪs/ |
Breaking chemical bonds by reaction with water. |
| induced-fit |
A model in which substrate binding changes an enzyme's active-site shape to favour the reaction. |
| insertion/ɪnˈsɜːʃn/ |
A mutation in which one or more nucleotides are added to a DNA sequence. |
| mass transport |
Bulk movement of substances over distances, as in blood circulation or transport through plant vessels. |
| mononucleotide |
A pentose (deoxyribose or ribose), a phosphate and a nitrogenous base. |
