Definitions (all of them - brace yourself) Flashcards
1
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electron micrograph
A
photograph of an image seen using an electron microscope
2
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magnification
A
the number of times larger an image appears, compared with the size of the object
3
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organelles
A
small structures within cells, each of which has a specific function
4
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photomicrograph
A
photograph of an image seen using an optical microscope
5
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resolution
A
the clarity of an image; the higher the resolution, the clearer the image
6
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eyepiece graticule
A
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
7
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stage graticule
A
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
8
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condensation reaction
A
reaction that occurs when two molecules are joined together with the removal of water
9
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hydrogen bond
A
a weak interaction that can occur whenever molecules contain a slightly negatively charged atom bonded to a slightly positively charged hydrogen atom
10
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hydrolysis reaction
A
reaction that occurs when a molecule is split into two smaller molecules with the addition of water
11
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monomer
A
a small molecule which binds to many other identical molecules to form a polymer
12
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polymer
A
a large molecule made from many smaller molecules called monomers
13
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carbohydrates
A
a group of molecules containing C, H and O
14
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glycosidic bond
A
a bond formed between two monosaccharides by a hydrolysis reaction
15
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lipids
A
a group of substances that are soluble in alcohol rather than water - they include triglycerides, phospholipids, glycolipids and cholesterol
16
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macromolecule
A
a very large, organic molecule
17
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phospholipid
A
a molecule consisting of glycerol, two fatty acids and one phosphate group
18
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amino acids
A
monomers of all proteins, and all amino acids have the same basic structure
19
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peptide bond
A
a bond formed when two amino acids are joined by a condensation reaction
20
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primary structure
A
the sequence of amino acids found in a molecule
21
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quaternary structure
A
protein structure where a protein consists of more than one polypeptide chain
22
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secondary structure
A
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
23
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tertiary structure
A
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
24
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fibrous protein
A
has a relatively long, thin structure, it is insoluble in water and metabolically inactive, often having a structural role within an organism
25
globular protein
has molecules of a relatively spherical shape, which are soluble in water, and often have metabolic roles within the organism
26
prosthetic group
a non-protein component that forms a permanent part of a functioning protein molecule
27
double helix
shape of DNA molecule, due to coiling of the two sugar-phosphate backbone strands into a right-handed spiral configuration
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nucleotide
molecule consisting of a five-carbon sugar, a phosphate group and a nitrogenous base
29
polynucleotide
large molecule containing many nucleotides
30
DNA polymerase
enzyme that catalyses formation of DNA from activated deoxyribose nucleotides, using single-stranded DNA as a template
31
helicase
enzyme that catalyses the breaking of hydrogen bonds between the nitrogenous pairs of bases in a DNA molecule
32
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
33
gene
a length of DNA that codes for a polypeptide or for a length of RNA that is involved in regulating gene expression
34
polypeptide
a polymer made of many amino acid units joined together by peptide bonds
35
transcription
the process of making messenger RNA from a DNA template
36
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
37
active site
indented area on the surface of an enzyme molecule, with a shape that is complementary to the shape of the substrate molecule
38
substrate
molecule that is altered by an enzyme catalysed reaction
39
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
40
enzyme-product complex
enzyme molecule with product molecule(s) in its active site - the two are joined temporarily by non-covalent forces
41
enzyme-substrate complex
enzyme molecule with substrate molecule(s) in its active site - the two are joined temporarily by non-covalent forces
42
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
43
inhibitor
a substance that reduces or stops a reaction
44
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
45
glycolipid
(phospho)lipid with a chain of carbohydrate molecules attached
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glycoprotein
protein with a chain of carbohydrate molecules attached
47
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)
48
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
49
osmosis
passage of water molecules down their water potential gradient, across a partially permeable membrane
50
water potential
measure of the tendency of water molecules to diffuse from one region to another
51
active transport
the movement of substances against their concentration gradient across a cell membrane, using ATP and protein carriers
52
endocytosis
bulk transport of molecules, too large to pass through a cell membrane even via a channel of carrier proteins, into a cell
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exocytosis
bulk transport of molecules, too large to pass through a cell membrane even via channel of carrier proteins, out of a cell
54
chromatids
replicates of chromosomes
55
cytokinesis
division of the cytoplasm of a cell following mitosis
56
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
57
haploid
having only one set of chromosomes, represented by the symbol n
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homologous chromosomes
matching chromosomes, containing the same genes at the same places (loci) - they may contain different alleles for some of the genes
59
meiosis
type of nuclear division that results in the formation of cells containing half the number of chromosomes of the parent cell
60
differentiation
process by which stem cells become specialised into different types of cell
61
epithelial cells
cells that constitute lining tissue
62
erythrocyte
red blood cell
63
neutrophil
type of white blood cell that is phagocytic
64
stem cell
unspecialised cell able to express all of its genes and divide by mitosis
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guard cells
in leaf epidermis, cells that surround stomata
66
palisade cells
closely-packed photosynthetic cells within leaves
67
root-hair cells
epidermal cells of young roots with long hair-like projections
68
tissue
group of cells that work together to perform a specific function/set of functions
69
meristem
area of unspecialised cells within a plant that can divide and differentiate into other cell types
70
organ
collection of tissues working together to perform a function/related functions
71
phloem
tissue that carries products of photosynthesis, in solution, within plants
72
xylem
tissue that carries water and mineral ions from the roots to all parts of the plant
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stem cell
unspecialised cell able to express all of its genes and divide by mitosis
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gamete
sex cell, e.g. ovum/spermatozoon (LOL if that's what you wanna call it...)
75
mesenchyme
connective tissue
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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)
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ossification
process of changing cartilage to bone by depositing calcium phosphate
78
surface area to volume ratio
the SA of an organism divided by its volume, expressed as a ratio
79
alveoli
tiny folds of the lung epithelium to increase the SA
80
bronchi and bronchioles
smaller airways leading into the lungs
81
diaphragm
a layer of muscle beneath the lungs
82
intercostal muscles
muscles between the ribs - contraction of the external intercostal muscles raises the ribcage
83
trachea
the main airway leading from the back of the mouth to the lungs
84
cartilage
a form of connective tissue
85
ciliated epithelium
a layer of cells that have many hair-like extensions called cilia
86
elastic fibres
protein fibres that can deform and then recoil to their original size
87
goblet cells
cells that secrete mucus
88
smooth muscle
involuntary muscle that contracts without the need for conscious thought
89
vital capacity
the greatest volume of air that can be expelled from the lungs after taking the deepest possible breath
90
buccal cavity
the mouth
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filaments
slender branches of tissue that make up the gill - they are often called primary lamellae
92
lamellae (sometimes known as secondary lamellae)
folds of the filament to increase SA - they are also called gill plates
93
operculum
a bony flap that covers and protects the gills
94
spiracle
an external opening or pore that allows air in or out of the tracheae
95
tracheal fluid
the fluid found at the ends of the tracheoles in the tracheal system
96
tracheal system
a system of air-filled tubes in insects
97
double circulatory system
one in which the blood flows through the heart twice for each circuit of the body
98
single circulatory system
one in which the blood flows through the heart once for each circuit of the body
99
arteries
vessels that carry blood away from the heart
100
arterioles
small blood vessels that distribute blood from an artery to the capillaries
101
capillaries
very small vessels with very thin walls
102
veins
vessels that carry blood back to the heart
103
venules
small blood vessels that collect blood from capillaries and lead into the veins
104
hydrostatic pressure
the pressure that a fluid exerts when pushing against the sides of a vessel or container
105
lymph
the fluid held in the lymphomatic system, which is a system of tubes that returns excess tissue fluid to the blood system
106
oncotic pressure
the pressure created by the osmotic effects of the solutes
107
plasma
the fluid portion of the blood
108
tissue fluid
the fluid surrounding the cells and tissues
109
atrio-ventricular valves
valves between the atria and the ventricles, which ensure that blood flows in the correct direction
110
cardiac muscle
specialised muscle found in the walls of the heart chambers
111
semilunar valves
valves that prevent blood re-entering the heart from the arteries
112
bradycardia
a slow heart rhythm
113
ectopic heartbeat
an extra beat or an early beat of the ventricles
114
electrocardiogram
a trace that records the electrical activity of the heart
115
fibrillation
uncoordinated contraction of the atria and ventricles
116
myogenic muscle
muscle that can initiate its own contraction
117
purkyne tissue
consists of specially adapted muscle fibres that conduct the wave of excitation from the AVN down the septum to the ventricles
118
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
119
tachycardia
a rapid heart rhythm
120
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
121
dissociation
releasing oxygen from oxyhaemoglobin
122
fetal haemoglobin
the type of Hb usually found only in the fetus
123
carbonic anyhydrase
the enzyme that catalyses the combination of carbon dioxide and water
124
chloride shift
the movement of chloride ions into the erythrocytes to balance the charge as hydrogencarbonate ions leave the cell
125
bohr effect
the effect that extra carbon dioxide has on the Hb, explaining the release of more oxygen
126
haemoglobinic acid
the compound formed by the buffering action of Hb as it combines with excess hydrogen ions
127
dicotyledonous plants
plants with two seed leaves and a branching pattern of veins in the leaf
128
meristem
a layer of dividing cells, here it is called the pericycle
129
phloem
transports dissolved assimilates
130
vascular tissue
consists of cells specialised for transporting fluids by mass flow
131
xylem
transports water and minerals
132
companion cells
the cells that help to load sucrose into the sieve tubes
133
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
134
xylem vessels
the tubes which carry water up the plant
135
plasmodesmata
gaps in the cell wall containing cytoplasm that connects two cells
136
potometer
a device that can measure the rate of water uptake, as a leafy stem transpires
137
transpiration
the loss of water vapour from the aerial parts of a plant, mostly through the stomata in the leaves
138
adhesion
the attraction between water molecules and the walls of the xylem vessel
139
cohesion
the attraction between water molecules caused by hydrogen bonds
140
hydrophyte
a plant adapted to living in water or where the ground is very wet
141
xerophyte
a plant adapted to living in dry conditions
142
assimilates
substances that have become part of the plant
143
sink
a part of the plant where certain materials are removed from the transport system
144
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
145
translocation
the transport of assimilates throughout a plant
146
callose
a large polysaccharide deposit that blocks old phloem sieve tubes
147
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
148
clonal selection
selection of a specific B or T cell that is specific to the antigen
149
cytokines
hormone-like molecules used in cell signalling to stimulate the immune response
150
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
151
opsonins
proteins that bind to the antigen on a pathogen and then allow phagocytes to bind
152
antibodies
specific proteins released by plasma cells that can attach to pathogenic antigens
153
B memory cells
cells that remain in the blood for a long time, providing long-term immunity
154
clonal expansion
an increase in the number of cells by mitotic cell division
155
interleukins
signalling molecules that are used to communicate between different white blood cells
156
plasma cells
derived from B lymphocytes, these are cells that manufacture antibodies
157
T helper cells
cells that release signalling molecules to stimulate the immune response
158
T killer cells
cells that attack and destroy our own body cells that are infected by a pathogen
159
T memory cells
cells that remain in the blood for a long time, providing long-term immunity
160
T regulator cells
cells that are involved with inhibiting or ending the immune response
161
agglutinins
antibodies that cause pathogens to stick together
162
anti-toxins
antibodies that render toxins harmless
163
opsonins
antibodies that make it easer for phagocytes to engulf the pathogen
164
active immunity
where the immune system is activated and manufactures its own antibodies
165
artificial immunity
immunity that is achieved as a result of medical intervention
166
natural immunity
immunity achieved through normal life processes
167
passive immunity
immunity achieved when antibodies are passed to the individual through breast feeding or injection
168
vaccination
a way of stimulating an immune response so that immunity is achieved
169
antibiotic
a chemical which prevents the growth of microorganisms
170
personalised medicine
the development of designer medicines for individuals
171
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
172
biodiversity
a measure of variation found in the living world
173
habitat
where an organism lives
174
species
a group of organisms that can freely interbreed to produce fertile offspring
175
allele
a version of a gene
176
locus
the position of a gene on a chromosome
177
polymorphic gene locus
a locus that has more than two alleles
178
species evenness
a measure of how evenly represented the species are
179
species richness
a measure of how many different species are present
180
monoculture
a crop consisting of one strain of one species
181
keystone species
one that has a disproportionate effect upon its environment relative to its abundance
182
soil depletion
the loss of soil fertility caused by removal of minerals by continuous cropping
183
conservation in situ
carrying out active management to maintain the biodiversity in a natural environment
184
conservation ex situ
conservation outside the normal habitat of the species
185
CITES
the Convention on International Trade in Endangered Species
186
countryside stewardship scheme
a scheme to encourage farmers to manage parts of their land in a way that promotes conservation
187
phylogeny
the study of the evolutionary relationships between organisms
188
interspecific variation
the differences between species
189
intraspecific variation
the variation between members of the same species
190
correlation coefficient
a measure of how closely two sets of data are correlated - a value of 1 means perfect correlation
191
standard deviation
a measure of the spread around a mean
192
students t-test
a test used to compare two means
193
cell signalling
the way in which cells communicate with each other
194
effector
a cell, tissue or organ that brings about a response
195
homeostasis
maintaining a constant internal environment despite changes in external and internal factors
196
negative feedback
the mechanism that reverses a change, bringing the system back to the optimum
197
positive feedback
the mechanism that increases a change, taking the system further away from the optimum
198
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
199
ectotherm
an organism that relies on external sources of heart to maintain body temperature
200
endotherm
an organism that uses heat from metabolic reactions to maintain body temperature
201
excretion
the removal of metabolic waste from the body
202
metabolic waste
a substance that is produced in excess by the metabolic processes in the cells; it may become toxic
203
ornithine cycle
a series of biochemical reactions that convert ammonia to urea
204
nephron
the functional unit of the kidney
205
ultrafiltration
filtration of the blood at a molecular level under pressure
206
antidiuretic hormone (ADH)
a hormone that controls the permeability of the collecting duct walls
207
osmoreceptors
a sensory receptor that detects changes in water potential
208
glomerular filtration rate (GFR)
the rate at which fluid enters the nephrons
209
monoclonal antibodies
antibodies made from one type of cell - they are specific to one complementary molecule
210
renal dialysis
a mechanism used to artificially regulate the concentrations of solutes in the blood
211
pacinian corpuscle
a pressure sensor found in the skin
212
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
213
transducer
a cell that converts one form of energy into another - in this case to an electrical impulse
214
motor neurones
neurones that carry an action potential from the cns to the effector
215
myelinated neurone
has an individual later of myelin around it
216
non-myelinated neurone
has no individual layer of myelin
217
relay neurones
join sensory neurones to motor neurones
218
sensory neurones
neurones that carry an action potential from the sensory receptor to the CNS
219
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
220
positive feedback
a mechanism that increases a change taking the system further away from the optimum
221
resting potential
the potential difference across the membrane while the neurone is at rest
