Vocabulary Flashcards
a helical structure formed by a polypeptide chain, held in place by hydrogen bonds; an example of secondary structure in a protein
alpha-helix
the energy that must be provided to make a reaction take place; enzymes reduce the ____ required for a substrate to change into a product
activation energy
immunity gained when an antigen enters the body, an immune response ovvurs and antibodies are produced by plasma cells
active immunity
an area on an enzyme molecule where the substrate can bind
active site
the movement of molecules or ions through transport proteins across a cell membrane, against their concentration gradient, using energy form ATP
active transport
nitrogen-containing purine base found in DNA and RNA
adenine (A)
one of the products from hydrolysis of ATP
adenosine diphosphate (ADP)
a hormone secreted by the adrenal glands in times of stress or excitement
adrenaline
plant tissue containing air spaces
aerenchyma
a particular variety of a gene
allele
a polymer of alpha-glucose monomers linked by both 1, 4 and 1, 6 lindages, forming a branched chain; a constituent of starch
amylopectin
a polymer of apha-glucose monomers linked by 1, 4 linkages, forming a curving chain; a constituent of starch
amylose
a substance produced by a living organism that is capable of killing or inhibiting the growth of a microorganism
antibiotic
a glycoprotein (immunoglobulin) made by plasma cells derived from B-lymphocytes, secreted in response to an antigen; the variable region of the antobody molecule is complementary in shape to its spectitic antigen
antibody
sequence of three unpaired bases on a tRNA molecule that binds with a codon on mRNA
anticodon
a substance that is foreign to the body and stimulates an immune response
antigen
the non-living system of interconnected cell walls extending throughout a plant, used a s a transport pathway for the movement of water and mineral ions
apolastic pathway
small blood vessel that carries blood from arteries to capillaries; determine how much blood flows through capillaries
arteriole
a blood vessel that carries blood away from the heart; it has a relatively thich wall and contains large amounts of elastic fibres
artery
immunity gained either by vaccination (active) or by injecting antibodies (passive)
artificial immunity
the universal energy currency of cells
adenosine triphosphate (ATP)
the enzyme catalysing the phosphorylation of ADP to ATP
ATP synthase
a patch of tissue in the septum of the heart through which the wave of electrical excition is passed from the atria to the Purkyne tissue
atrioventricular node
a type of disease in whcih there is a mistaken immune response to a self antigen leading to the production of antibodies and the destruction of body tissues; myasthenia gravis is an example
autoimmune disease
all the chromosomes except the X and Y (sex) chromosome
autosomes
an enzyme made by antibiotic-resistant bacteria that breaks down penicillin molecules
beta-lactamase
a loose, sheet-like structure formed by hydrogen bonding between parallel polypeptide chains; an example of secondary structure in a protein
beta-pleated sheet
a type of lymphocyte that gives rise to plasma cells and secretes antibodies
B-lymphocyte
a test for the presence of reducing sugars; the unknown substance is heated with _____, and a change from a clear blue soluion to the production of a yellow red or brown precipitate indicates he presence of reducing sugars such as glucose
Benedict’s test
a test for the presence of amine groups and thus for the presence of proteins; ____ is added to the unknown substance, and a change from pale blue to purple indicates the presence of proteins
biuret test
the decrease in affinity of haemoglobin for exygen that occurs when carbon dioxide is present
Bohr effect
a disease in whci the airways in the lungs become inflamed and congested with mucus;___ often associated with smoking
bronchitis (chronic)
the apparatus in which the energy value of a compound can be measured by burning it in oxygen
calorimeter
a disease, often but not always treatbale, that results from a breakdown in the usual control mechanisms that regulate cell division; certain cells divide uncontrollably and form tumours, from which cells may bread away and form secondary tumours in other arease of the body (metastasis)
cancer
the smallest type of blood vessel, whose function is facilitate exchange of substances between the blood and the tissues; capillary walls are made up of a single layer of squamous epithelium, and their internal diameter is only a little larger than that of a red blood cell
capillary
a substance that can cause cancer
carcinogen
the sequence of events taking place during one heart beat
cardiac cycle
the muscle tissue that makes up most of the heart; striated
cardiac muscle
degeneratice diseases of the heart and circulatory system e.g. coronary heart disease or stroke
cardiovascular diesease
someone who is infected with a pathogen bust does not show any symptoms of the disease; people like his can be sources of infection that are hard to trave
carrier
a type of membrane protein which changes shape oto allow the passage into or out of the cell of specific ions or molecules by facilitated diffusion or active transport
carrier protein
the basic unit of all living organisms; it is srrounded by a cell surface membrane (alsoknown as the pasma membrane) and contains cytoplasm and organelles
cell
the sequence of events that takes place from one cell division until the next; it is made up of interphase, mitosis and cytokinesis
cell cycle
the molecular mechanisms by which cells detect and respond to external stimuli, including communication between cells
cell signalling
a very thin membrane (about 7nm diameter) surrounding all cells; it is partially permeable and controls the exchange of materials between the cell and its environmnt
cell surface membrane
a wall surrounding prokaryote, plant and fungal cells; contains a strengthening material which protects the cell from mechanical damage, supports it and prevents it from bursting by osmosis if the cell is surroudned by a solution with a higher water potential
cell wall
one of two small, cylindrical structures, made from microtubules, found just outside the nucleus in animal cells, in a region known as the centrosome; they are also found at the bases of cilia and flagella
centriole
a membrane protein of fixed shape which has a water-filled pore through whcih selected hydrophilic ions or molecules can pass; aid facilitated diffusion
channel protein
a green pigment responsible for light capture in photosynthesis in algae and plants
chlorophyll
the photosynthetic orgelle in eukaryotes
chloroplast
a small, lipid-related molecule with a hydrophilic head and a hydrophobic tail which is an essential constituent of membranes, particularly in animal cells, conferring fluidity, flexibility and stability to the membrane
cholesterol
one of two identical parts of a chromosome, held together by a centromere, formed during interphase by the replication of the DNA strand
chromatid
the loosely coiled form of chromosomes during interphase of the cell cycle; made of DNA and proteins and is visible as loosely distributed patches or fibres within the nucleus when stained
chromatin
a structure made of DNA and histones, found in the nucleus of a eukaryotic cell; the term bacterial _____ is now commenly used for the circular strand of DNA present in a prokaryotic cell
chromosome
a random and unpredictable change in the structure or number of chromosomes in a cell
chromosome mutation
a disease of the lungs characterised by bronchitis and emphysema
chronic obstructive pulmonary disease (COPD)
sequence of three bases on an mRNA molecule that codes for a specific amino acid or for a stop signal
codon
a modified form of parenchyma in which the corners of the cells have extra cellulose thickening, providing extra support, as in the midrib of leaves and at the corners of square stems; in three dimensions the tissue occurs in strands (as in celery petioles)
collenchyma
a cell with an unthickened cellulose wall and dense cytoplasm that is found in close association with a phloem sieve element to which it is directly linked via many plasmodesmata; ____ and the sieve element form a functional unit
companion cell
when a substance reduces the rate of activity of an enzyme by competing with the substrate molecules fo rthe enzyme’s active site; increasing the concentration of the substrate reduces the degree of inhibition
competitive inhibition
the hydrogen bonding of A with T or Uand of C with G in nucleic acids
complementary base pairing
a chemical reaction involving the joining together of two molecules by removal of a water molecule
condensation reaction
an experiment in which the factor whose effect if being investigated (the independent variable is absent); it is used as a standard of comparison
control experiment
variables (factors) that are kept constant in an experiment; only the independent variable should be changed
controlled variables / standardised variables
a disease of heart caused by damage to the coronary arteries
coronary heart disease
a fold of the inner membrane of the mitochondrial envelope on which are found stalked particles of ATP synthase and electron transport chains associated with aerobic respiration
crista, plural: cristae
the contents of a cell excluding the nucleus
cytoplasm
nitrogen-containing pyrimidine base found in DNA and RNA
cytosine (C)
a pentose (5C) sugar found in DNA
deoxyribose
in an experiment, the variable that changes as a result of changing the independent variable
dependent variable
the net movement of molecules or ions from a region of higher concentration to a region of lower concentration down a gradient, as a result of the random movements of particles
diffusion
one that possesses two complete sets of chromosomes; 2n
diploid cell
a sugar molecule consisting of two monosaccharides joined together by a glycosidic bond
disaccharide
an enzyme that catalyses the linkage of nucleotides during the formation of a DNA molecule
DNA ligase
a circulatory system in which the blood travels twice through the heart on one complete circuit of the body; the pathway from heart to lungs and bck to the heart is known as the pulmonary ciculation, and that from heart to the rest of the body and back to the heart as the systemic circulation
double circulation
a disease in which alveoli are destroyed, giving large air spaces and decreased surface area for gaseous exchange; it is often associated with chronic bronchitis
emphysema
the bulk movement of liquids (pinocytosis) or solids (phagocytosis) into a cell, by the infolding of the cell surface membrane to form vesicles containing the substance; an active process requiring ATP
endocytosis
a network of flattened sacs running through the cytoplasm of eukaryotic cells; molecules, particularly proteins, can be transported through the cell inside the sacs separate from the rest of the cytoplasm;is continuous with the outer membrane of the nuclear envelope
endoplasmic reticulum (ER)
a tissue that lines the inside of a structure, such as the inner surface of a blood vessel
endothelium
a protein produced by a living organism that acts as a catalyst in a specific reaction by reducing activation energy
enzyme
a tissue that covers the outside of a structure
epithelium
a cell containing a nucleus and other membrane-bound organelles
eukaryotic cell
the bulk movement of liquids or solids out of a cell, by the fusion of vesicles containing the substance with the cell surfave membrane; an active process requiring ATP
excytosis
the diffusion of a substance through transport proteins in a cell membrane; the proteins procide hydrophilic areas that allow the molecules or ions to pass through the membrane which would otherwise be less permeable to them
facilitated diffusion
a protein whose molecules have a relatively long, thin sructure that is generally insoluble and metabolically inactive, and whose function is usually structural, e.g. keratin and collagen
fibrous protein
the currently accepted basic model of membrane structure, proposed by Singer and Nicolson in 1972, in which protein molecules are free to move about in a fluid bilayer of phospholipid molecules
fluid mosaic model
a haploid cell specialised for fertilisation
gamete
gthe movement of gases between an organism and its environment, e.g. the intake of oxygen and the loss of carbon dioxide;often takes place across a specialised surfave such as the alveoli of the lungs
gas exchange
a length of DNA that codes for a particular protein or polypeptide
gene
a change in the base sequence in part of a DNA molecule
gene mutation
cells that can divide to form gametes
germ cells
a protein which forms the basic unit of a group of proteins that bind oxygen, namely myoglobin and different forms of haemoglobin; has a characteristic tertiary structure; exists in several closely similar forms such as alpha-, beta-, gamma-_____
globin
a protein whose molecules are folded into a relatively spherical shape, and which is often water-soluble and metabolically active, e.g. insulin and haemoglobin
globular protein
a polysaccharide made of many glucose molecules linked together, that acts as a glucose store in liver and muscle cells
glycogen
a coc link between two monosaccharide molecules, formed by a condensation reaction
glycosidic bond
an organelle found in eukaryotic cells; consists of a stack of flattened sacs, constantly forming at one end and breading up into ___ vesicles at the other end; chemically modifies the molecules it transports; e.g. sugars may be added to proteins to make glycoproteins
Golfi body/apparatus/complex
a stack of circular thylakoids in a chloroplast
granum, plural: grana
nitrogen-containing purine base found in DNA and RNA
guanine (G)
a sausage-shaped epidermal cell found with another, in a pair bounding a stoma and controlling its opening or closure
guard cell
the red pigment found in red blood cells, whose molecules contain four iron atoms within a globular protein made up of four polypeptides, and that combines reversibly with oxygen
haemoglobin
one that possesses one complete set of chromosomes; N
haploid cell
a pair of chromosomes in a diploid cell that have the same structure as each other, with the same genes (but not necessarily the same alleles of those genes) at the same loci, and that pair together to form a bivalent during the first division of meiosis
homologous chromosomes
a substance secreted by an endocrine gland, that is carried in blood plasma to another part of the body where it has an effect
hormone
a relatively weak bond formed by the attraction between a group with a small positive charge on a hydrogne atom and another group carrying a small negative chare, e/g/ between OH groups
hydrogen bond
a reaction in which a complex molecule is bronken down to simpler ones, involving the addition fo water
hydrolysis
enzymes that have been fixed to a surfave or within a bead of agar gel
immobilised enzymes
the complex series of responses of the body to the entry of a foreign antigen; involves the activity of lymphocytes and phagocytes
immune response
the body’s defence system
immune system
protection against infectiour diseases, gained either actively or passively
immunity
an antibody
immunoglobulin
the ability of the immune system to respond quickly to antigens that it recogises as having entered the body before
immunological memory
the variable (factor) that is deliberately changed in an experiment
independent variable
a moel for enzyme action; the substrate is a complementary shape the the active site of the enzyme, but not an exact fit - the enzyme or sometimes substrate can change shape slightly to ensure a perfect fit
induced fit hypothesis
a disease caused by an organism such a bacterium or virus
infection disease
the range of values into which the middle 50% of a set of data falls
interquartile range
atoms of the same element with differenet atomic mass number
isotopes
a photograph or diagram of a set of chromosomes from an individual; the chromosomes are normally arranged in their homologous pairs in order of size; sex chromosomes may be shown separately
karyogram
a protein structure found at the centromere of a chromatid to which microtubules attach during cell division
kinetochore
cancer of the stem cells that give rise to white blood cells
leukaemia
the one factor, of many affecting a process, that is nearest its lowest value and hence is rate-limiting
limiting factor
a model for enzyme action; the substrate is a complementary shape to the active site of the enzyme, and fits exactly into the site
lock and key hypothesis
the position at which a particular gene is found on a particular chromosome; the same gene is always found at the same ____
locus
an almost colourless fluid, very similar in composition to blood plasma but with fewer plasma proteins, that is present in lymph vessels
lymph
a type of white blood cell that is involved in the immune response; unlike phagocytes they become active only in the presence of a particular antigen that ‘matches’ their specific receptors or antibodies
lymphocyte
a spherical organelle found in eukaryotic cells; contains digestive (hydrolytic) enzymes and has a variety of destructive functions, such as removal of old cell organelles
lysosome
a large biological molecule such as a protein, polysaccharide or nucleic acid
macromolecule
phagocytic cell found in tissues throughout the body; they act as antigen-presenting cells (APCs)
macrophage
the number of times greater that an image is than the actual object; = image size/actual (real) size of the object
magnification
the middle value of all the values in a set of data showing a normal distribution
median
lymphocytes which develop during an immune response and retain the ability to respond quickly when an antigen enters the body on a second or any subsequent occasion
memory cells
the internal tissue of a leaf blade with chloroplasts for photosynthesis and consisting of an upper layer of palisade ____ (the main photosynthetic tissue) and a lower layer of spongy ___ with large air spaces for gas exchange
mesophyll
a single-stranded RNA molecule that carries the genetic code from DNA to a ribosome
messenger RNA (mRNA)
the substrate concentration at which an enzyme works at half its maximum rate (1/2Vmax), used as a measure of the efficiency of an enzyme; the lower the value of __, the more efficient the enzyme
Michaelis-Menten constant (Km)
tiny tubes made of a protein called tubulin and found in most eukaryotic cells; have a large variety of functions, including cell support and determining cell shape; the ‘spindle’ on which chromosomes separate during nuclear division is made of ____
microtubules
the organelle in eukaryotes in which aerobic respiration takes place
mitochondiron, plural: mitochondria
the division of a nucleus into two so that the two daughter cells have exactly the same number and type of chromosomes as the parent cell
mitosis
the value that occurs most frequently in a set of data showing a normal distribution
mode (modal class)
many identical antibodies, made by hybridoma cells formed by the fusion of a plasma cell and a cancer cell
monoclonal antibodies
a relatively simple molecule which is used as a basic building block for hte synthesis of a polymer, usually by condensation reactions; common examples of molecules used as ___ are monosaccharides, amino acids and nucleotides
monomer
a substance that can cause mutation
mutagen
an unpreductable change in the structure of DNA, or in the structure and number of chromosomes
mutation
immunity gained by being infected (active) or by receiving antibodies from the mother across the placenta or in breast milk (passive)
natural immunity
a phagocytic white blood cell
neutrophil
a chemical found in tabacco smake that can bind with acetylcholine receptors on the postsynaptic membrane of cholinergic synapses
nicotine
when a substance reduces the rate of activity of an enzyme, but increasing the concentration of the substrate does not reduce the degree of inhibition; many ___ors bind to areas of the enzyme molecule other than the active site itself
non-competitive inhibition
any disease not caused by a pathogen
non-infectious disease
any substance or cell that is recognised by the immune system as being foreign and will stimulate an immune response
non-self
a pattern shown by a set of data that are distributed symmetrically on both sides of the mean value
normal distribution
the two membranes, situated closely togethe, that surround the nuvleus; the envelope is perforated with nuclear pores
nuclear envelope
pores found in the nuclear envelope which control the exchange of materials, e.g. mRNA, between the nucleus and the cytoplasm
nuclear pores
a small structure, one or more of which is found inside the nucleus; the nucleolus is usually visible as a densely stained body; its function is to manufacture ribosomes using the information in its own DNA
nucleolus
a bead-like structure made of eight histone molecules, around which DNA is wrapped; the fundamental subunits of chromatin
nucleosome
a molecule consisting of a nitogen-containing base, a pentose sugar and a phosphate group
nucleotide
a relatively large organelle found is eukaryotic cells but absent from prokaryotic cells; the nuvleus contains the cell’s DNA and therefor controls the activities of the cell
nucleus
a hypothesis that assumes there is no relationship between two variables, or that there is no significant difference between two samples
null hypothesis
a functionally and structurally distinct part of a cell, e.g. a ribosome or mitochondrion
organelle
a compound containing carbon and hydrogen
organic molecule
the net movement of water molecules from a region of higher water potential to a region of lower water potential, through a partially permeable membrane, as a result of their random motion (diffusion)
osmosis
a basic plant tissue typically used as packing tissue between more specialised strucutes; it is metabolically active and may have a variety of functions such as food storage, support and transport via symplast and apoplast pathways
parenchyma
immunity gained without an immune response; antibodies are injuected (artificial) or pass from mother to child across the placenta or in breast milk (natural)
passive immunity
an organism that causes infectious disease
pathogen
a C-N link between two amino acid molecules, formed by a condensation reaction
peptide bond
a substance, also known as murein, whose molecules are made of amino acid chains to which sugars are attached; bacterial cell walls contain peptioglycans; they make the wall more rigid, preventing the cell from bursting by osmosis when it is surrounded by a solution with a higher water potential
peptidoglycan
a type of cell that ingests and destroys pathogens or damaged body cells by the process of phagocytosis; some ___ are WBC
phagocyte
tissue containing sieve tubes and other types of cell, responsible for he translocation of assimilates such as sucrose through a plant
phloem
a substance whose molecules are made up of glycerol molecule, two fatty acids and a phosphate group; a bilayer of phopholipids forms the basic structure of all cell membranes
phospholipid
the transfer of a phosphate group to an organic compound
phosphorylation
a small, circular piece of DNA in a bacterium (not its main ‘chromosome’; plasmids often contain genes that confer resistance to antibiotics)
plamid
a pore-like structure found in plant cell walls; ___ of neighbouring plant cells line up to form tube-like pores through the cell walls allowing the controlled passage of materials from one cell to the other; the pores contain DR and are lined with the cell surface membrane
plasmodesma, plural: plasmodesmata
a giant melecule made from many similar repeating subunits joined together in a chain; the subunits are much smaller and simpler molecules known as monomers; may also be referred to as macromolecules; e.g. polysaccharides, proteins and nucleic acids
polymer
a chain of nucleotides
polynucelotide
a long chain of amino acids formed by condensation reactions between the individual amino acids; proteins are mad of one or more ____ chains
polypeptide
a polymer whose subunits are monosaccharids joined togther by glycosidic bonds
polysaccharide
a pieve of apparatus used to measure the rate of uptake of water by a plant
potometer
the sequence of aminiacids in a polypeptide or protein
primary structure
a length of DNA that has a complementary base sequence to another pieve of DNA that you are trying to detect
probe
a cell that does not contain a nucleus or any other membrane-bound organelles; e.g. bacteria and archeans
prokaryotic cell
a length of DNA that controls the expression of a gene
promoter
a non-protein component that is attached to a protein to form a complex molecule; it aids the protein in its function; e.g. hearm group
prosthetic group
the living contents of a plant cell, including the cell surface membrane, but excluding the cell wall
protoplast
an area of tissue in the septum of the heart that conducts the wave of excitation from the atria to the base of the ventricles
Purkyne tissue
the 3D arrangement of 2 or more polypeptides, or of a polypeptide and a non-protein component
quaternary structure
a cell which is sensitive to a change in the environment and that may generate an action potential as a result of a stimulus
receptor cell
the ability to distinguish between two objects very close together; the higher the ____ of an image, the greater the detail that can be seen
resolution
enzymatic release of energy from organic compounds in living cells
respiration
a pentose sugar found in RNA
ribose
a tiny organelle found in large numbers in all cells prokaryotic ___ are smaller (70s, 20nm diameter)than eukaryotic ___ (80s, 25nm diameter); made of protien and ribosomal RNA and consist of two subunits; sites of protein synthesis in cels
ribosome
the structure of a protein molecule resulting from the regular coiling or folding of the chain of amino acids, e.g. an alpha-helix or beta-pleated sheet
secondary structure
refers to substances produced by the body that the immune system does not recognise as foreign, so do not stimulate an immune response
self
the method by whcih a DNA molecule is copied to form two identical molecule, each containing one strand from the original molecule an one newly synthesised strand
semi-conservative replication
the pair of chromosomes that determine the sex of an individual; in humans they are the X and Y chromosomes
sex chromosomes
a gene that is carried on an X chromosome but not on a Y chromosome
sex-linked gene
reproduction involving the fusion of gametes (fertilisation) to produce a zygote
sexual reproduction
a genetic disease caused by a faulty gene coding for haemoglobin, in which haemoglobin tends to precipitate when oxygen concentrations are low
sickle cell anaemia
a person who is heterozygous for the sickle cell allel is said to have _____; there are normally no symptoms, except occasionally in very severe conditions of oxygen shortage
sickle cell trait
a cell found in phloem tissue, with non-thickened cellulose walls, very little cytoplasm, no nucleus and end walls perforated to form sieve plates, through which sap containing sucrose is transported
sieve element / sieve tube element
tubes formed by sieve elements lined up end to end
sieve tube
a mutation in which the change in the DNA has no discernible effect on an organism
silent mutation
a patch of muscle in the wall of the gith atrium of the heart whose intrinsic rate of rhythmic contraction is faster than that of the the rest of the cardiac muscle, and from whcih waves of excitation spread to the rest of the heart to initiate its contraction during the cardiac cycle
sinoatrial node
type of muscle tissue found in walls of lood vessels (exvept capillaries), trachea, bronchi and bronchioles, alimentary canal and ureter; the muscel cells are not striated
smooth muscle
a membrane protein(s) that moves Na ions out of a cell and K ions into, using ATP
sodium-potassium pump
cells that are not involved in gamete formation
somatic cells
a measure of how widely a set of data is spread out on either isde of the mean
standard deviation
variables (factors) that are kept constant in an experiment; only the independent variable should be changed
standardised variables
a measure of how likely it is that a mean calculated from a sample represents the true mean for the whole population
standard error
a relatively unspecialised cell that retains the ability to divide an nlimited number of times
stem cell
a pore in the epidermis of a leaf, bounded by two guard cells and needed for efficient gas examge
stoma, plural: stomata
damage the the brain caused by bursting or blockage of an artery
stroke
the matrix of a chloroplast in which the light independent reactions of photosynthesis occur
stoma, plural: stomata
the living system of interconnected protoplasts extending throughout a plant, used as transport pathway for the movement of water and solutes; individual protoplasts are connected via plasmodesmata
symplast
a lymphocyte that does not secrete antibodies; __ helper ___ stimulate the immune system to respond during an infection and killer ____ destroy human cells that are infected with pathogens such as bacteira and viruses
T-lymphocyte
repetitive sequences of DNA at the end of chromosomes that protect genes from the chromosome shortening that happens at each cell division
telomeres
the compact structure of a protein molecule resulting from the 3D coiling of the already-folded chain of amino acids 2°
tertiary structure
a flattened, membrane-bound, fluid-filled sac, which is the site of the light-dependent reactions of photosynthesis in a chloroplast
thylakoid
nitrogen-containing pyrimidine base found in DNA
thymine (T)
the almost colourless fluid that fills the spaces between body cells; tissue fluid forms from the fluid that leaks from blood capillarie, and most of it eventually collects into lymph vessels where it forms lymph
tissue fluid
the partially permeable membrane that surrounds plant vacuoles
tissue fluid
the partially permeable membrane that surrounds plant vacuoles
tonoplast
production of an mRNA molecule on DNA
transcription
a folded, single-stranded RNA molecule that carries an amino acid to a ribosome for protein synthesis
transfer RNA (tRNA)
production of a polypeptide at a ribosome from the code on mRNA
translation
the transport of assimilates such as sucrose through a plant, in phloem tissue; requires the input of metabolic energy
translocation
the transfer of a pathogen from one person to another
transmission
the loss of water vapour from a plant to its environment, by diffusion down a water potential gradient; most transpiration takes place through the stmata in the leaves
transpiration
a lipid whose molecules are made up of glycerol molecule and three fatty acids
triglyceride
a statistical procedure used to determine whether the means of two samples differ significantly
t-test
nitrogen-containing pyrimidine base found in RNA
uracil (U)
the theoretical maximum rate of an enzyme-controlled reaction, obtained when all the active sites are occupied
Vmax
givin a vaccine containing antigens for a disease, either by injection or by mouth; confers artificial active immunity
vaccination
an organelle found in eukaryotic cells; a large permanent central vacuole is a typical feature of plant cells, where it has a variety of functions, including storage of biochemicals such as salts, sugars and waste products; temporary ____, such as phagocytic ____/vesicles, may form in animal cells
vacuole
a blood vessel that carries blood back towards the heart; it has relatively thin walls and contains valves
vein
very small (20-300nm) infectious particle which can replicate only inside living cells and consists essentially of a simple basic structure of a genetic code of DNA or RNA surrounded by a protein coat
virus
a channel protein through a cell membrane that opens or closes in response to changes in electrical potential across the membrane
voltage-gated channel
a measure of the tendency of water to move from one place to another; water moves from a solution with higher ___ to one with lower ____; decreased by the addition of solute, increased by the application of pressure; symbol is ψ or ψw
water potential
a plant adapted to survive in conditions where water is in short supply
xerophyte
a dead, empty tube with lignified walls, through which water is transported in plants; it is formed by xylem vessel elements lined up end to end
xylem vessel
a dead, lignified cell found in xylem specialised for transporting water and support; the ends of the cells break down and join with neighbouring elements to form longtubes called xylem vessels
xylem vessel element
a cell formed by the fusion of two gametes; nornally the gametes are haploid and ___ is diploid
zygote
