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200 Cards in this Set
- Front
- Back
Stimulus |
any change in the environment that causes a response
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Response
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a change in behaviour or physiology as a result of a change in the environment (stimulus)
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Ectotherm
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an organism that relies on external sources of heat to regulate its body temperature
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Endotherm
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an organism that can use internal sources of heat, such as heat generated from metabolism in the liver, to maintain its body temperature |
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Polarised membrane
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a membrane that has a potential difference across it. this is the resting potential
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Depolarisation
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the loss of polarisation across the membrane. refers to the period when sodium ions are entering the cell, making the inside less negative with respect to the outside |
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Generator potential
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a small depolarisation caused by sodium ions entering the cell.
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Action potential
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an action potential is achieved when the membrane is depolarised to a value of about +40mV. it is an all-or-nothing response. in the events leading up to an action potential, the membrane depolarises and reaches a threshold level, then lots of sodium ions enter the axon and an action potential is reached. |
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Resting potential
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the potential difference or voltage difference across the neurone cell membrane while the neurone's at rest. it's about -60mV inside the cell compared with the outside. other cells may also maintain a resting potential that might change under certain circumstances
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Voltage-gated channels
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channels in the cell membrane that allow the passage of charged particles or ions. they have a mechanism called a gate which can open and close the channel. in these channels the gates respond to changes in the potential difference across the membrane
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Threshold potential
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a potential difference across the membrane of about -50mV. if the depolarisation of the membrane doesn't reach the threshold potential then no action potential's created. if the depolarisation reaches the threshold potential then an action potential's created
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Action potential
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a depolarisation of the cell membrane so that the inside's more positive than the outside, with a potential difference across the membrane of +40mV. this can be transmitted along the axon or dendron plasma membrane
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Local currents
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the movement of ions along the neurone. the flow of ions is caused by an increase in concentration at 1 point, which causes diffusion away from the region of higher concentration
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Saltatory conduction
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means 'jumping conduction'. refers to the way the action potential appears to jump from 1 node of Ranvier to the next
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Neurotransmitter
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a transmitter substance; a chemical that diffuses across the cleft of the synapse to transmit a signal to the postsynaptic neurone
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Cholinergic synapse
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a synapse that uses acetylcholine as its transmitter substance (neurotransmitter)
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Synaptic knob
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a swelling at the end of the presynaptic neurone
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acetylcholinesterase
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an enzyme in the synaptic cleft. it breaks down the transmitter substance acetylcholine
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All or nothing
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a neurone either conducts an action potential or it doesn't. all action potentials are of the same magnitude, +40mV
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Summation
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several small potential changes can combine to produce 1 larger change in potential difference across the membran
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Hormones
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molecules that are released by an endocrine gland directly into the blood. they act as messengers, carrying a signal from the endocrine gland to a specific target organ or tissue
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Endocrine gland
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a gland that secretes hormones directly into the blood. endocrine glands have no ducts
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exocrine gland
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a gland that secretes molecules into a duct that carries the molecules to where they are used
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Target cells
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cells that possess a specific receptor on their plasma (cell surface) membrane. the shape of the receptor is complementary to the shape of the hormone molecule. many similar cells together form a tissue
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Adenyl cyclase
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an enzyme associated with the receptor for many hormones, including adrenaline. found on the inside of the cell surface membrane
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First messenger
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the hormone that transmits a signal around the body
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Second transmitter
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cAMP, which transmits a signal inside the cell
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Pancreatic duct
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a tube that collects all the secretions from the exocrine gland in the pancreas and carries the fluid to the small intestine
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Islets of Langerhans
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small patches of tissue in the pancreas that have an endocrine function
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alpha (α) and beta (β) cells
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found in the islets of Langerhans; α secrete the hormone glucagon and β cells secrete the hormone insulin
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insulin
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the hormone, released from the pancreas, that causes blood glucose levels to fall
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glucagon
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the hormone that causes blood glucose levels to rise
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hepatocytes
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liver cells. they are specialised to perform a range of metabolic functions
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diabetes mellitus
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a disease in which blood glucose concentrations cannot be controlled effectively
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hyperglycaemia
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the state in which the blood glucose concentration is too high (hyper=above, glyc=glucose, anaemia=blood)
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hypoglycaemia
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the state in which the blood glucose concentration is too low (hypo=under)
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genetically engineered bacteria
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bacteria in which the DNA has been altered. in our case, a gene coding for human insulin has been inserted into the DNA of the bacteria
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stem cells
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unspecialised cells that have the potential to develop into any type of cell
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cell metabolism
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the result of all the chemical reactions taking place in the cytoplasm
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myogenic muscle tissue
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muscle tissue that can initiate its own contractions
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pacemaker
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a region of tissue in the right atrium wall that can generate an impulse and initiates the contraction of the chambers
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medulla oblongata
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a region at the base of the brain. coordinates the unconscious functions of the body such as breathing rate and heart rate
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accelerator nerve and vagus nerve
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nerves that run from the medulla oblongata to the heart
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cardiovascular centre
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a specific region of the medulla oblongata that receives sensory inputs about levels of physical activity, blood carbon dioxide concentration and blood pressure. it sends nerve impulses to the SAN in the heart to alter the frequency of excitation waves
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excretion
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the removal of metabolic waste from the body
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metabolic waste
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waste substances that may be toxic or are produced in excess by the reactions inside the cell
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deamination
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the removal of the amine group from an amino acid to produce ammonia
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hepatic portal vein
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an unusual blood vessel that has capillaries at both ends- it carries blood from the digestive system to the liver
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kupffer cells
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primary function appears to be the breakdown and recycling of old red blood cells
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bilirubin
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one of the waste products from the breakdown for haemoglobin
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urea
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an excretory product formed from the breakdown of excess amino acids
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ornithine cycle
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the process in which ammonia is converted to urea. it occurs partly in the cytosol and partly in the mitochondria, as ATP is used
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detoxification
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the conversion of toxic molecules to less toxic or non-toxic molecules
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nephron
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the functional unit of the kidney. it's a microscopic tubule that receives fluid from the blood capillaries in the cortex and converts this to urine, which drains into the ureter
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glomerulus
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a fine network of capillaries that increases the local blood pressure to squeeze fluid out into the blood. it's surrounded by a cup- or funnel-shaped capsule which collects the fluid and leads into the nephron
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selective reabsorption
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useful substances are reabsorbed from the nephron into the bloodstream while other excretory substances remain in the nephron
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afferent vessels
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bring blood into the organ
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efferent vessels
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carry blood away from the organ. in a glomerulus the efferent vessel is an arteriole- which is muscular and can constrict to raise the blood pressure in the glomerulus. in most organs a venule carries blood away
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ultrafiltration
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filtration at a molecular level- as in the glomerulus where large molecules and cells are left in the blood and smaller molecules pass into the Bowman's capsule
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podocytes
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specialised cells that make up the lining of the bowman's capsule
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microvilli
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microscopic folds of the cell surface membrane that increase the surface area of the cell
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co-transporter proteins
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proteins in the cell surface membrane that allow the facilitated diffusion of simple ions to be accompanied by transport of a larger molecule such as glucose
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sodium-potassium pump
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special proteins in the cell surface membrane that actively transport sodium and potassium ions against their concentration gradients
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hairpin countercurrent multiplier
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the arrangement of a tubule in a sharp hairpin so that 1 part of the tubule passes close to another part of the tubule with the fluid flowing in opposite directions. this allows exchange between the contents and can be used to create a very high concentration of solutes
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osmoregulation
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the control and regulation of the water potential of the blood and body fluids. in humans the kidney controls the water potential of the blood
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distal convoluted tubule
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the coiled portion of the nephron between the loop of henle and the collecting duct
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antidiuretic hormone (ADH)
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a hormone released from the pituitary gland and acts on the collecting ducts in the kidneys to increase their reabsorption of water
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osmoreceptors
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receptor cells that monitor the water potential of the blood. if the blood has a low water potential then water is moved out of the osmoreceptor cells by osmosis, causing the to shrink. this causes stimulations of the neurosecretory cells
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hypothalamus
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a part of the pain that contains neurosecretory cells and various receptors that monitor the blood
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neurosecretory cells
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specialised cells that act like nerve cells but release a hormone into the blood. ADH is manufactured in the cell body and passes down the axon to be stored in the terminal bulb. if an action potential passes down the axon then ADH is released from the terminal bulb
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posterior pituitary gland
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the hind part of the pituitary gland, which releases ADH
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half-life
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the time taken for a substance's concentration to drop to half its original value
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dialysis
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use of a partially permeable membrane to filter the blood
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dialysis membrane
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a partially permeable membrane that seperates the dialysis fluid from the patients blood in a dialysis machine
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dialysis fluid
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a complex solution that matches the composition of body fluids
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haemodialysis
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blood is taken from a vein and passed through a dialysis machine so that exchange can occur across an artificial partially permeable membrane.
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peritoneal dialysis
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dialysis fluid is pumped into the body cavity so that exchange can occur across the peritoneal membrane
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human chorionic gonadotrophin (hCG)
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a hormone released by human embryos; its presence in the mother's urine confirms pregnancy
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monoclonal antibodies
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identical antibodies because they have been produced by cells that are clones of 1 original cell
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anabolic steroids
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drugs that mimic the action of steroid hormones that increase muscle growth
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gas chromatography
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a technique used to separate substances in a gaseous state
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chromatogram
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a chart produced when substances are separated by movement of a solvent along a permeable material such as paper or gel
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autotrophs
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organisms that use light or chemical energy and inorganic molecules (carbon dioxide and water) to synthesise complex organic molecules
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heterotrophs
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organisms that ingest and digest complex molecules, releasing the chemical potential energy stored in them
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photosynthetic pigments
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molecules that absorb light energy. each pigment absorbs a range of wavelengths in the visible region and has its own distinct peak of absorption. other wavelengths are reflected
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photophosphorylation
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making ATP from ADP and inorganic phosphate in the presence of light
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electron carriers
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molecules that transfer electrons
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electron acceptors
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chemicals that accept electrons from another compound. they're reduced while acting as oxidising agents
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light-independent stage
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the stage of photosynthesis where carbon dioxide's fixed and used to build complex organic molecules
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limiting factor (metabolic processes)
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the factor that's present at the lowest or least favourable value
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photosynthometer
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used to measure the rate of photosynthesis by collecting and measuring the volume of oxygen produced in a certain time
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cotyledons
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where the seeds of dicotyledonous plants store their food. sometimes appear in the soil after germination and act as the first leaves, as in cress.
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energy
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the ability to do work
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ATP
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a phosphorylated nucleotide and the universal energy currency
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anabolic reactions
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biochemical reactions where large molecules are synthesised from smaller ones
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catabolic reactions
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larger molecules are hydrolysed to produce smaller molecules
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oxidation
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loss of electrons
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reduction
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gain of electrons
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glycolysis
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a metabolic pathway where each glucose molecule's broken down to 2 molecules of pyruvate. occurs in the cytoplasm of all living cells and is common to anaerobic (without oxygen) and aerobic (with oxygen) respiration
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hexose sugars
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sugars with 6 carbon atoms in each molecule
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hydrolysis
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breaking down large molecules to smaller molecules by the addition of water
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triose sugars
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sugars with 3 carbon atoms in each molecule
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mitochondria
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organelles found in eukaryotic cells. the sites of the link reaction, krebs cycle and oxidative phosphorylation- the aerobic stages of respiration
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link reaction
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converts pyruvate to acetate. NAD is reduced. occurs in the mitochondrial matrix
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krebs cycle
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oxidises acetate to carbon dioxide. NAD and FAD are reduced. ATP is made by substrate-level phosphorylation. occurs in the mitochondrial matrix
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oxidative phosphorylation
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the formation of ATP by adding a phosphate group to ADP in the presence of oxygen, the final electron acceptor
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chemiosmosis
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the diffusion of ions through a partially permeable membrane. relates specifically to the flow of hydrogen ions (protons) across a membrane, which is coupled to the generation of ATP during respiration. in eukaryotic cells the membrane is the inner mitochondrial membrane and in prokaryotes it is the cell surface membrane, which may be invaginated to increase surface area
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anaerobic respiration
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the release of energy from substrates, such as glucose, in the absence of oxygen
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respiratory substrate
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an organic substrate that can be used for respiration
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1 mole
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the gram molecular mass of a substance. 180g glucose is 1 mole (mol) of glucose
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gene
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a length of DNA that codes for 1 (or more) polypeptides
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polypeptide
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a polymer consisting of a chain of amino acid residues joined by peptide bonds
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genome
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the entire DNA sequence of that organism. the human genome consists of about 3 billion nucleotide base pairs
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protein
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a very large polypeptide- usually 100 or more amino acids. some proteins consist of 1 polypeptide chain and some consist of more than 1 chain
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transcription
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the creation of a single-stranded mRNA copy of the DNA coding strand
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translation
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the assembly of polypeptides (proteins) at ribosomes
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mutation
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a change in the amount, or arrangement, of the genetic material in a cell
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chromosome mutation
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mutation involving changes to parts of or whole chromosomes
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DNA mutation
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change to a gene due to changes in nucleotide base sequences
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allele
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an alternative version of a gene. it's still at the same locus on the chromosome and codes for the same polypeptide, but the alteration to the DNA base sequence may alter the protein's structure
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operon
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a length of DNA, made up of structural genes and control sites. the structural genes code for proteins such as enzymes. the control sites are the operator region and a promoter region
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operator and promoter
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both genes as they are lengths of DNA. do not code for polypeptides
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repressor protein
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binds to the operator region, and RNA polymerase binds to the promoter region to transcribe the structural genes
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homeobox genes
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control the development of the body plan of an organism, including the polarity (head and tail ends) and positioning of the organs
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phagocytosis
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the endocytosis of large solid molecules into a cell
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allele
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a version of a gene. a gen's a length of DNA that codes for 1 or more polypeptides. an allele of the gene has a difference in the DNA base sequence that is expressed as (translates into) a slightly different polypeptide
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locus
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the position of a gene on a chromosome
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crossing over
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when lengths of DNA are swapped from 1 chromatid to another
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maternal chromosomes
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the set of chromosomes in an individual's cells that were contributed by the egg
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paternal chromosomes
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the set of chromosomes in an individual's cells that were contributed by the sperm
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chromosome mutation
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a random change to the structure of a chromosome
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inversion chromosomal mutation
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a section of chromosome turns through 180 degrees
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deletion chromosomal mutation
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a part of the chromosome is lost
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translocational chromosomal mutation
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a piece of 1 chromosome becomes attached to another
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non-disjunctional chromosomal mutation
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homologous chromosomes fail to separate properly at meiosis 1 or chromatids fail to separate at meiosis 2; if this happens to a whole set of chromosomes, polyploidy results.
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codominance
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when both alleles contribute to a phenotype
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epistasis
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the interaction of different gene loci so that 1 gene locus masks or suppresses the expression of another gene locus
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population
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a group of individuals of the same species that can interbreed. populations are dynamic- they can expand or contract due to changes in birth or death rates or migration
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gene pool
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the set of genetic information carried by a population
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selection pressure
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an environmental factor that confers greater chances of survival to reproductive age on some members of the population
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biological species concept
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a group of similar organisms that can interbreed and produce fertile offspring
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phylogenetic species concept
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a group of organisms that have similar morphology (shape), physiology (biochemistry), embryology (stages of development) and behaviour, and occupy the same ecological 'niche'
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monophyletic
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a group that includes an ancestral organism and all its descendent species
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paraphyletic
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a group that includes the most recent ancestor but not all its descendents. it is a monophyletic group with 1 or more clades excluded. for example, the grouping of reptiles is paraphyletic as it excludes birds, which are descendents of reptiles. the group of prokaryotes is paraphyletic as it comprises bacteria (eubacteria) and archaea (archaebacteria) but excludes the eukaryotes
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vegetative propagation
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the production of structures in an organism that can grow into new individual organisms. these offspring contain the same genetic information as the parent and so are clones of the parent.
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tissue culture
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the separation of cells of any tissue type and their growth in or on a nutrient medium. in plants, the undifferentiated callus tissue is grown in nutrient medium containing plant hormones that stimulate development of the complete plant
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cloned animal
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an animal that has been produced using the same genetic information as another animal. such an animal has the same genotype as the donor organism
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biotechnology
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technology based on biology and involves the exploitation of living organisms or biological processes, to improve agriculture, animal husbandry, food sciences, medicine and industry
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culture
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a growth of microorganisms. may be a single species (a pure culture) or a mixture of species (a mixed culture). microorganisms can be cultured in a liquid such as nutrient broth, or on a solid surface such as nutrient agar gel
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aseptic technique
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any measure taken at any point in a biotechnological process to ensure that unwanted microorganisms do not contaminate the culture that's being grown or the products that are extracted
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asepsis
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the absence of unwanted microorganisms
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immobilisation of enzymes
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any technique where enzyme molecules are held, separated from the reaction mixture. substrate molecules can bind to the enzyme molecules and the products formed go back into the reaction mixture leaving the enzyme in place.
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genomics
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the study of the whole set of genetic information in the form of the DNA base sequences that occur in the cells of organisms of a particular species. the sequenced genomes of organisms are placed on public access databases
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electrophoresis
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similar to chromatography. separation of different lengths of DNA fragments, in a mixture, is achieved because, as the negatively charged fragments move towards the positive electrode, shorter fragments pass through the gel more easily and so move further down in a fixed time.
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primers
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short, single-stranded sequences of DNA, around 10-20 bases in length. they are needed, in sequencing reactions and polymerase chain reactions, to bind to a section of DNA because the DNA polymerase enzymes can't bind directly to single-stranded DNA fragments
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sticky end
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formed when DNA is cut out using a restriction enzyme. it's a short run of unpaired, exposed bases seen at the end of the cut section. complementary sticky ends can anneal (bases pair together) as part of the process of recombining DNA fragments
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transgenic
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an organism containing DNA that has been added to its cells as a result of genetic engineering
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replica plating
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the process of growing bacteria on an agar plate, then transferring a replica of that growth to other plates, usually containing different growth promoters or inhibitors. analysis of growth patterns on the replica plates gives information about the genetic properties of the growing bacteria
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golden rice (TM)
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said to be BIOFORTIFIED because it contains higher than normal concentrations of a particular nutrient, in this case beta-carotene
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biofortified
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when a foodstuff contains higher than normal concentrations of a particular nutrient
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GMO (genetically modified organism)
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an organism that has undergone genetic engineering
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transgenic
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an organism that has received an allele of a gene from another organism, often a different species
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liposomes
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small spheres of lipid bilayer containing a functioning allele. they can pass through the lipid bilayer of cells and therefore act as vectors to carry the allele into the cell.
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xenotransplantation
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transplantation of cell tissues or organs between animals of different species
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allotransplantation
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transplantation between animals of the same species
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habitat
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the place where an organism lives
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population
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all the organisms of 1 species that live in the same place at the same time, and can breed together
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community
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all the populations of different species that live in the same place at the same time, and can interact with each other
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trophic level
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the level at which an organism feeds in a food change
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productivity
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the rate at which energy passes through each trophic level in a food chain
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primary productivity
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the total amount of energy fixed by photosynthesis. it is the net flux of carbon from the atmosphere to plants, per unit time. it is a rate and may be measured in terms of energy per unit time
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net primary productivity
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the rate at which carbohydrate accumulates in the tissue of plants of an exosystem and is measured in dry organic mass.
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net primary productivity
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primary productivity - respiratory heat loss
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net primary productivity
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the amount of energy available to heterotrophs in the ecosystem. it is a fundamental ecological variable and is an important factor in determining the amount of biomass that a particular ecosystem can support
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succession
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a directional change in a community of organisms over time
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carrying capacity
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the maximum population size that can be maintained over a period of time in a particular habitat
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limiting factor
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the factor whose magnitude limits the rate of the process. it is often the factor in shortest supply
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competition
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when resources (like food or water) are not present in adequate amounts to satisfy the needs of all the individuals who rely on those resources, competition occurs
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coppicing
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cutting a tree trunk close to the ground to encourage growth
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conservation
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the maintenance of biodiversity, including diversity between species, genetic diversity with species, and maintenance of a variety of habitats and ecosystems
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tropism
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a directional growth with response in which the direction of the response is determined by the direction of the external stimulus
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apical dominance
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the growing apical bud at the tip of the shoots inhibits growth of lateral buds further down the shoot
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cerebrum
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the largest and most recognisable part of the brain. it is responsible for the elements of the nervous system, that are associated with being 'human', including thought, imagination and reasoning
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cerebellum
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controls the coordination of movement and posture
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hypothalamus
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controls the autonomic nervous system and the endocrine gland
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medulla oblongata
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controls the action of smooth muscle in the gut wall, and controls breathing movements and heart rate
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central nervous system (CNS)
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consists of the brain and spinal cord
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peripheral nervous system
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all of the sensory and motor neurones that are outside the CNS- connecting the receptors and effectors to the CNS
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neuromuscular junction
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a specialised synapse which occurs at the end of a motor neurone where it meets the muscle fibre. release of acetylcholine (neurotransmitter), following depolarisation at the neuromuscular junction, stimulates contraction of muscle fibre. the end of the motor neurone's often referred to as an end plate or motor end plate
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sarcomere
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the smallest contractile unit of a muscle
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cross-bridge
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the name given to the attachment formed by a myosin head binding to a binding site on an actin filament
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'fight or flight' response
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the full range of coordinated responses of animals to situations of perceived danger. the combined nervous and hormonal response has dramatic effects on the whole organism, making it ready for actions that lead to confrontation of the danger or escape from it
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stressor
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a stimulus that causes the stress response. causes wear and tear on the body's physical or mental resources
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innate behaviour
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any animal response that occurs without the need for learning. it is an inherited response, similar in all members of the same species and is always performed in the same way in response to the same stimulus
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learned behaviour
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animal responses that change or adapt with experience. there is a range of learned behaviours identified, from simply learning not to respond to a repeated stimulation, to the ability to consider a problem and formulate a solution
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hierarchy
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where individuals have a place in the order of importance within the group. often shown by individuals higher up in the hierarchy receiving more food, or having rights of access to mate with other individuals
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social behavior
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organisms of a particular species living together in groups with relatively defined roles for each member of the group
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DRD4
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1 of the 5 genes that code for dopamine receptor molecules. dopamine can bind to each of these receptor molecules but they cause differing effects because they lead to different cellular responses
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psychosis
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a mental health condition, characterised by an impaired grasp on reality, diminished impulse control and disorder of perception (such as hallucinations)
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longitudinal study
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an investigation in which the same individuals are studied repeatedly over a long period of time in order to gather relevant data about progression of the factors under investigation
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