Definitions (all of them - brace yourself) Flashcards
electron micrograph
photograph of an image seen using an electron microscope
magnification
the number of times larger an image appears, compared with the size of the object
organelles
small structures within cells, each of which has a specific function
photomicrograph
photograph of an image seen using an optical microscope
resolution
the clarity of an image; the higher the resolution, the clearer the image
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 whenever molecules contain a slightly negatively charged atom bonded to a slightly positively charged hydrogen 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 many other identical molecules to form a polymer
polymer
a large molecule made from many smaller molecules called monomers
carbohydrates
a group of molecules containing C, H and O
glycosidic bond
a bond formed between two monosaccharides by a hydrolysis reaction
lipids
a group of substances that are soluble in alcohol rather than water - they include triglycerides, phospholipids, glycolipids and cholesterol
macromolecule
a very large, organic molecule
phospholipid
a molecule consisting of glycerol, two fatty acids and one phosphate group
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
secondary structure
the coiling or folding of an amino acid chain, which arises often as a result of hydrogen bond formation between different parts of the chain - the main forms of secondary structure are the helix and the pleated sheet
tertiary structure
the overall three-dimensional shape of a protein molecule. Its shape arises due to interactions including hydrogen bonding, disulfide bridges, ionic bonds and hydrophobic interactions
fibrous protein
has a relatively long, thin structure, it is insoluble in water and metabolically inactive, often having a structural role within an organism
globular protein
has molecules of a relatively spherical shape, which are soluble in water, and often have metabolic roles within the organism
prosthetic group
a non-protein component that forms a permanent part of a functioning protein molecule
double helix
shape of DNA molecule, due to coiling of the two sugar-phosphate backbone strands into a right-handed spiral configuration
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 the nitrogenous pairs of 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 that is involved in regulating gene expression
polypeptide
a polymer made of many amino acid units joined together by peptide bonds
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 mRNA
active site
indented area on the surface of an enzyme molecule, with a shape that is complementary to the shape of the substrate molecule
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 rate - 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-product complex
enzyme molecule with product molecule(s) in its active site - the two are joined temporarily by non-covalent forces
enzyme-substrate complex
enzyme molecule with substrate molecule(s) in its active site - the two are joined temporarily by non-covalent forces
competitive inhibition
inhibition of an enzyme, where the inhibitor molecule has a similar shape to that of the substrate molecule and competes with the substrate for the enzyme’s active site - it blocks the active site and prevents formation of enzyme-substrate complexes
inhibitor
a substance that reduces or stops a reaction
non-competitive inhibition
inhibition of an enzyme, where the competitor molecule attaches 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
glycolipid
(phospho)lipid with a chain of carbohydrate molecules attached
glycoprotein
protein with a chain of carbohydrate molecules attached
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, across a partially permeable membrane via protein channels of carriers; it does not involve 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 to another
active transport
the movement of substances against their concentration gradient across a cell membrane, using ATP and protein carriers
endocytosis
bulk transport of molecules, too large to pass through a cell membrane even via a channel of carrier proteins, into a cell
exocytosis
bulk transport of molecules, too large to pass through a cell membrane even via channel of carrier proteins, out of a cell
chromatids
replicates of chromosomes
cytokinesis
division of the cytoplasm of a cell following mitosis
mitosis
type of cell division that maintains the chromosome number; each new daughter cell contains the same genetic info as the parent cell - they are also genetically identical to each other
haploid
having only one set of chromosomes, represented by the symbol n
homologous chromosomes
matching chromosomes, containing the same genes at the same places (loci) - they may contain different alleles for some of the genes
meiosis
type of nuclear division that results in the formation of cells containing half the number of chromosomes of the parent cell
differentiation
process by which stem cells become specialised into different types of cell
epithelial cells
cells that constitute lining tissue
erythrocyte
red blood cell
neutrophil
type of white blood cell that is phagocytic
stem cell
unspecialised cell able to express all of its genes and divide by mitosis
guard cells
in leaf epidermis, cells that surround stomata
palisade cells
closely-packed photosynthetic cells within leaves
root-hair cells
epidermal cells of young roots with long hair-like projections
tissue
group of cells that work together to perform a specific function/set of functions
meristem
area of unspecialised cells within a plant that can divide and differentiate into other cell types
organ
collection of tissues working together to perform a function/related functions
phloem
tissue that carries products of photosynthesis, in solution, within plants
xylem
tissue that carries water and mineral ions from the roots to all parts of the plant
stem cell
unspecialised cell able to express all of its genes and divide by mitosis
gamete
sex cell, e.g. ovum/spermatozoon (LOL if that’s what you wanna call it…)
mesenchyme
connective tissue
mesoderm
the middle of the three layers in the early embryo; gives rise to connective tissue, muscles and part of the gonads (ovaries and testes)
ossification
process of changing cartilage to bone by depositing calcium phosphate
surface area to volume ratio
the SA of an organism divided by its volume, expressed as a ratio
alveoli
tiny folds of the lung epithelium to increase the SA
bronchi and bronchioles
smaller airways leading into the lungs
diaphragm
a layer of muscle beneath the lungs
intercostal muscles
muscles between the ribs - contraction of the external intercostal muscles raises the ribcage
trachea
the main airway leading from the back of the mouth to the lungs
cartilage
a form of connective tissue
ciliated epithelium
a layer of cells that have many hair-like extensions called cilia
elastic fibres
protein fibres that can deform and then recoil to their original size
goblet cells
cells that secrete mucus
smooth muscle
involuntary muscle that contracts without the need for conscious thought
vital capacity
the greatest volume of air that can be expelled from the lungs after taking the deepest possible breath
buccal cavity
the mouth
filaments
slender branches of tissue that make up the gill - they are often called primary lamellae
lamellae (sometimes known as secondary lamellae)
folds of the filament to increase SA - they are also called gill plates
operculum
a bony flap that covers and protects the gills
spiracle
an external opening or pore that allows air in or out of the tracheae
tracheal fluid
the fluid found at the ends of the tracheoles in the tracheal system
tracheal system
a system of air-filled tubes in insects
double circulatory system
one in which the blood flows through the heart twice for each circuit of the body
single circulatory system
one in which the blood flows through the heart once for each circuit of the body
arteries
vessels that carry blood away from the heart
arterioles
small blood vessels that distribute blood from an artery to the capillaries
capillaries
very small vessels with very thin walls
veins
vessels that carry blood back to the heart
venules
small blood vessels that collect blood from capillaries and lead into the veins
hydrostatic pressure
the pressure that a fluid exerts when pushing against the sides of a vessel or container
lymph
the fluid held in the lymphomatic system, which is a system of tubes that returns excess tissue fluid to the blood system
oncotic pressure
the pressure created by the osmotic effects of the solutes
plasma
the fluid portion of the blood
tissue fluid
the fluid surrounding the cells and tissues
atrio-ventricular valves
valves between the atria and the ventricles, which ensure that blood flows in the correct direction
cardiac muscle
specialised muscle found in the walls of the heart chambers
semilunar valves
valves that prevent blood re-entering the heart from the arteries
bradycardia
a slow heart rhythm
ectopic heartbeat
an extra beat or an early beat of the ventricles
electrocardiogram
a trace that records the electrical activity of the heart
fibrillation
uncoordinated contraction of the atria and ventricles
myogenic muscle
muscle that can initiate its own contraction
purkyne tissue
consists of specially adapted muscle fibres that conduct the wave of excitation from the AVN down the septum to the ventricles
sino-atrial node (SAN)
the heart’s pacemaker - it is a small patch of tissue that sends out waves of electrical excitation at regular intervals in order to initiate contractions
tachycardia
a rapid heart rhythm
affinity
a strong attraction
e.g. i have an affinity for Heppy but she can’t know because that would make our friendship weird because I’m gay and she’s not
dissociation
releasing oxygen from oxyhaemoglobin
fetal haemoglobin
the type of Hb usually found only in the fetus
carbonic anyhydrase
the enzyme that catalyses the combination of carbon dioxide and water
chloride shift
the movement of chloride ions into the erythrocytes to balance the charge as hydrogencarbonate ions leave the cell
bohr effect
the effect that extra carbon dioxide has on the Hb, explaining the release of more oxygen
haemoglobinic acid
the compound formed by the buffering action of Hb as it combines with excess hydrogen ions
dicotyledonous plants
plants with two seed leaves and a branching pattern of veins in the leaf
meristem
a layer of dividing cells, here it is called the pericycle
phloem
transports dissolved assimilates
vascular tissue
consists of cells specialised for transporting fluids by mass flow
xylem
transports water and minerals
companion cells
the cells that help to load sucrose into the sieve tubes
sieve tube elements
make up the tubes in the phloem tissue that carry sap up and down the plant - the sieve tube elements are separated by sieve plates
xylem vessels
the tubes which carry water up the plant
plasmodesmata
gaps in the cell wall containing cytoplasm that connects two cells
potometer
a device that can measure the rate of water uptake, as a leafy stem transpires
transpiration
the loss of water vapour from the aerial parts of a plant, mostly through the stomata in the leaves
adhesion
the attraction between water molecules and the walls of the xylem vessel
cohesion
the attraction between water molecules caused by hydrogen bonds
hydrophyte
a plant adapted to living in water or where the ground is very wet
xerophyte
a plant adapted to living in dry conditions
assimilates
substances that have become part of the plant
sink
a part of the plant where certain materials are removed from the transport system
source
a part of the plant that loads materials into the transport system; for example, the leaves photosynthesis and the sugars made are moved to other parts of the plant
translocation
the transport of assimilates throughout a plant
callose
a large polysaccharide deposit that blocks old phloem sieve tubes
antigen-presenting cell
a cell that isolates the antigen from a pathogen and places it on the plasma membrane so that it can be recognised by other cells in the immune system
clonal selection
selection of a specific B or T cell that is specific to the antigen
cytokines
hormone-like molecules used in cell signalling to stimulate the immune response
neutrophil
a type of white blood cell that engulfs foreign matter and traps it in a large vacuole (phagosome) which fuses with lysosomes to digest the foreign matter
opsonins
proteins that bind to the antigen on a pathogen and then allow phagocytes to bind
antibodies
specific proteins released by plasma cells that can attach to pathogenic antigens
B memory cells
cells that remain in the blood for a long time, providing long-term immunity
clonal expansion
an increase in the number of cells by mitotic cell division
interleukins
signalling molecules that are used to communicate between different white blood cells
plasma cells
derived from B lymphocytes, these are cells that manufacture antibodies
T helper cells
cells that release signalling molecules to stimulate the immune response
T killer cells
cells that attack and destroy our own body cells that are infected by a pathogen
T memory cells
cells that remain in the blood for a long time, providing long-term immunity
T regulator cells
cells that are involved with inhibiting or ending the immune response
agglutinins
antibodies that cause pathogens to stick together
anti-toxins
antibodies that render toxins harmless
opsonins
antibodies that make it easer for phagocytes to engulf the pathogen
active immunity
where the immune system is activated and manufactures its own antibodies
artificial immunity
immunity that is achieved as a result of medical intervention
natural immunity
immunity achieved through normal life processes
passive immunity
immunity achieved when antibodies are passed to the individual through breast feeding or injection
vaccination
a way of stimulating an immune response so that immunity is achieved
antibiotic
a chemical which prevents the growth of microorganisms
personalised medicine
the development of designer medicines for individuals
synthetic biology
the re-engineering of biology - this could be the production of new molecules that mimic natural processes, or the use of natural molecules to produce new biological systems that do not exist in nature
biodiversity
a measure of variation found in the living world
habitat
where an organism lives
species
a group of organisms that can freely interbreed to produce fertile offspring
allele
a version of a gene
locus
the position of a gene on a chromosome
polymorphic gene locus
a locus that has more than two alleles
species evenness
a measure of how evenly represented the species are
species richness
a measure of how many different species are present
monoculture
a crop consisting of one strain of one species
keystone species
one that has a disproportionate effect upon its environment relative to its abundance
soil depletion
the loss of soil fertility caused by removal of minerals by continuous cropping
conservation in situ
carrying out active management to maintain the biodiversity in a natural environment
conservation ex situ
conservation outside the normal habitat of the species
CITES
the Convention on International Trade in Endangered Species
countryside stewardship scheme
a scheme to encourage farmers to manage parts of their land in a way that promotes conservation
phylogeny
the study of the evolutionary relationships between organisms
interspecific variation
the differences between species
intraspecific variation
the variation between members of the same species
correlation coefficient
a measure of how closely two sets of data are correlated - a value of 1 means perfect correlation
standard deviation
a measure of the spread around a mean
students t-test
a test used to compare two means
cell signalling
the way in which cells communicate with each other
effector
a cell, tissue or organ that brings about a response
homeostasis
maintaining a constant internal environment despite changes in external and internal factors
negative feedback
the mechanism that reverses a change, bringing the system back to the optimum
positive feedback
the mechanism that increases a change, taking the system further away from the optimum
sensory receptors
cells/sensory nerve endings that respond to a stimulus in the internal or external environment of an organism and can create action potentials
ectotherm
an organism that relies on external sources of heart to maintain body temperature
endotherm
an organism that uses heat from metabolic reactions to maintain body temperature
excretion
the removal of metabolic waste from the body
metabolic waste
a substance that is produced in excess by the metabolic processes in the cells; it may become toxic
ornithine cycle
a series of biochemical reactions that convert ammonia to urea
nephron
the functional unit of the kidney
ultrafiltration
filtration of the blood at a molecular level under pressure
antidiuretic hormone (ADH)
a hormone that controls the permeability of the collecting duct walls
osmoreceptors
a sensory receptor that detects changes in water potential
glomerular filtration rate (GFR)
the rate at which fluid enters the nephrons
monoclonal antibodies
antibodies made from one type of cell - they are specific to one complementary molecule
renal dialysis
a mechanism used to artificially regulate the concentrations of solutes in the blood
pacinian corpuscle
a pressure sensor found in the skin
sensory receptors
cell/sensory nerve endings that respond to a stimulus in the internal or external environment of an organism and can create action potentials
transducer
a cell that converts one form of energy into another - in this case to an electrical impulse
motor neurones
neurones that carry an action potential from the cns to the effector
myelinated neurone
has an individual later of myelin around it
non-myelinated neurone
has no individual layer of myelin
relay neurones
join sensory neurones to motor neurones
sensory neurones
neurones that carry an action potential from the sensory receptor to the CNS
action potential
a brief reversal of the potential across the membrane of a neurone causing a peak of +40mV compared to the resting potential of -60mV
positive feedback
a mechanism that increases a change taking the system further away from the optimum
resting potential
the potential difference across the membrane while the neurone is at rest
