Unit 1-Glossary Flashcards
Activation energy
The minimum energy required by reactants to allow a reaction to occur
ADH
Anti-diuretic hormone.
A hormone produced by the pituitary gland which promotes water retention by the kidney
Adipose
Connective tissue composed mainly of cells that store fat, found beneath the skin, around internal organs, in bone marrow, and in breast tissue
ADP
Adenosine diphosphate
Anabolic
A reaction which builds up complex molecules from simpler ones
ATP
Adenosine triphosphate
Bile
A liquid produced by the liver which helps the digestion of fats/lipids by emulsifying these molecules
Blastocyst
An embryo of about 150 cells (preimplantation) produced by cell division following fertilisation
Carcinogens
Any agent directly involved in causing cancer
Carrier
An individual who is heterozygous for a particular recessive characteristic and shows a dominant phenotype
Catabolic
A reaction which breaks down complex molecules to simpler ones
cDNA
Stands for complementary DNA, or copy DNA, and can be single-stranded or double-stranded; it is synthesized in vitro from an mRNA template
Centromere
Region of the chromosome where two chromosomes are closed together
Chiasma
The point where two homologous chromosomes are touching
Chromatid
Daughter chromosomes
Chromatin
A complex of DNA, histones, and non-histone proteins found in the nucleus of a human cell. This is the material from which chromosomes are made.
Codominant
Alleles, when they are both fully expressed in the phenotype of the heterozygote, e.g. in the AB blood group.
Codon
Set of three adjacent bases on messenger RNA which correspond to a DNA triplet of bases and an anticodon on transfer RNA
Co-enzyme
Organic molecule that acts as a temporary carrier of atoms being removed from or added to a substrate during a reaction. Aid the action of the enzyme to which they are loosely bound.
Collagen
A tough, fibrous protein that is a major component of connective tissue.
Covalent bond
Strong chemical bond involving the sharing of electrons between atoms
Cytokines
Substances secreted by specific cells of the immune system which will stimulate specific immune responses
Cytoskeleton
System of microfilaments and microtubules made of protein that give the cell its structure and shape
Differentiation
A process, which takes place after cell division, where cells become specialised cells
Endometrium
Inner lining of the uterus
Eukaryote
An organism in which the DNA of the cells is contained within a nucleus and enclosed in a membrane
FAD
Flavin adenine dinucleotide
Gall bladder
The organ in the body which stores bile
Gene
A unit in the hereditary materials of an organism
Glucagon
A hormone produced by the pancreas which raises blood glucose levels, acting in opposition to insulin
Glycolysis
Cell process which converts glucose to pyruvate and occurs in the cytoplasm of the cells of nearly all organisms
GTP
Guanosine triphosphate, which performs a similar role to ATP, but is more specific
Haploid cells
Contain only a single set of 23 chromosomes
Histones
The basic proteins around which DNA is coiled and supercoiled. Histones and non-histone proteins are the chief protein components of chromatin.
Homologous chromosome
A pair of chromosomes which share the same gene sequences, each derived from one parent
Homologous genes
Genes of the same type
Hydrolysis
The breaking of chemical bonds by reaction with water
Hydrophobic
A molecule which is repelled by water, e.g. lipids (oils and fats)
Insulin
Hormone produced by the pancreas which lowers blood glucose levels
In vitro fertilisation
A technique that unites the egg and sperm in a laboratory instead of inside the female body
Isomer
These are intermediates and products of metabolism
Isomer
Molecules with the same chemical formula but different molecular structure
Micrometre
μm
equal to 10-6m
Minisatellites
Highly repetitive DNA consisting of sequences between 10 and 100 base pairs long, repeated in tandem arrays which vary in size from 0.5 to 40 kbp
Multipotent stem cells
These are true stem cells that can only differentiate into a limited number of types
Mutation
DNA gene is damaged or changed in such a way as to alter the genetic message carried by that gene.
Myoglobin
A conjugated protein, resembling haemoglobin, involved in oxygen transport in muscles
Negative feedback mechanism
Self-regulating process in which the build-up of a product inhibits earlier steps in the pathway that generates it
Neurotransmitters
A range of chemicals which convey messages between neurons, or neurons and effectors
Nonsense mutation
A change to a single nucleotide in DNA which results in a non-functional protein being produced
Nucleolus
A small, generally spherical, body found within the nucleus of eukaryotic cells
Oxytocin
A hormone produced by the pituitary gland which stimulates the uterus to contract during childbirth
Phosphofructokinase
Enzyme which catalyses a key regulatory step in glycolysis
Phospholipid bilayer
Thin membrane made up of two layers of phospholipid molecules, orientated such that their hydrophilic (’water-loving’) heads are on the outside and their hydrophobic (’water-hating’) tails are on the inside
Pituitary gland
Small, pea-sized gland attached to the base of the brain which secretes many hormones and is central to several homeostatic processes in the body
Pluripotent stem cells
These are stem cells with the potential to make any differentiated cell in the body
Prokaryote
Organisms which do not have any organelles contained within membranes in their cytoplasm, e.g. bacteria
Prolactin
A hormone produced by the pituitary gland which stimulates milk production and secretion
Ribosomes
Structures found in the cytoplasm and attached to ER where protein synthesis occurs
Rough endoplasmic reticulum
Extensive double-membrane sheets in the cytoplasm which are studded with ribosomes and continuous with the nuclear membrane
Stem cells
Undifferentiated cells that can differentiate into specialised cells or divide by mitosis to produce more stem cells
Stem cells
Undifferentiated cells that can differentiate into specialised cells or divide by mitosis to produce more stem cells
