Year 13 Mrs Winters Key Terms Flashcards
Actin
Thin filaments in proteins which bind with myosin in muscle contraction
Actinomyosin bridge
Formation when myosin head binds to actin
Action potential
When an axon membrane is depolarised and stretch mediated sodium ion channels open diffusing sodium ions across the membrane
All or nothing principle
Threshold intensity generates an action potential. Action potential always the same size. Strong stimuli creates more frequent action potentials.
Antagonistic
Opposed
Atrioventricular node
Mass of conducting cells in atrioventricular junction of heart
Responsible for passing waves of electical activity onto bundle of his during heart beat
Bundle of his
Group of muscle fibres responsible for conduction the waves of electrical activity between ventricles and bottom of heart
Chemoreceptors
Monitor carbon dioxide in blood located in aorta and carotid arteries. Allow body to know if heart rate needs to increase or decrease.
Cholinergic synapse.
A junction between two neurones which uses acetylcholine as it’s neurotransmitter
Cones
Receptors which give colour vision. They absorb high light intensity, bright light. They have low sensitivity so if not enough light they will not work. They give high acuity
Acuity
Resolution
Depolarisation
Process which must happen to produce an action potential. Where the axon charge is more positive on inside than outside
Fast muscle fibres
Used for short bursts of activity. Quick to fatigue. Fast contraction causing more force. Fewer blood vessels and mitochondria. Low conc of myoglobin. High conc of glycolysis enzymes and atp hydrolyse
Generator potential
A local change in resting potential from a stimulus which may result in an action potential occurring
Moron neurone
Transfers electrical impulse from relay neurone to effector
Myelinated neurone.
Axons which have myelin on around membrane. Allowing for Saltatory conduction- jumping from node of ranveir
Myofibril
Tightly packed proteins bundled together in muscle
Myosin
A quaternary protein that has a coiled structure of two proteins intertwined on tail and then a head with a short and long chain
Myoglobin
Stores oxygen in muscle
Neuromuscular junction
Junction between a motor neurone and an effector muscle
Non myelinated neorun
Neurone with no myelin around it’s membrane preventing impulse from jumping between each node of ranvier. Causes impulse speed to be much slower
Pacinian corpuscle
A mechanoreceptor which responds to pressure causing a distortion in membrane of naked axon causing sodium ions to diffuse through stretch mediated sodium ion channels. Creating an action potential
Phosphcreatin
Molecule used to phosphrilate ADP to ATP in muscle contraction
Purkyne tissue
Carries wave of electrical activity from bundle of his to muscular walls in ventricles causing them to contract allowing heat beat
Receptor
Chemical structures which respond to stimulus
Refractory period
Time delay between the conduction of one action potential and the next. Ensures no overlapping of impulses and that no impulse can travel backwards.
Rods
Receptors which give black and white vision. Work in low light intensities. Have high sensitivity meaning don’t need much energy to form and image. Results in low acuity
Saltatory conduction
Occurs in myelinated neurones. Allowing impulse to jump to the next node of ranvier Enabling impulse to travel more rapidly.
Slow muscle fibres
Used for endurance. Slow to fatigue and have slow contractions so produce less force. More blood vessels needed to supply oxygen. Lots of mitochondria and myoglobin. Lower conc of glycolysis enzymes and atp hydrolyase
Sino atrial node
Small mass of tissue in right atrium similar to a pacemaker and sets the rhythm of the heart by transferring waves of electrical activity to AVN.
Acetylcholine
Released onto the SAN to decrease heart rate. Also the neurotransmitter that crosses synapse to transfer an impulse. Broken down into acytlie and choline
Noradrenaline
Chemical released onto SAN to increase heart rate
Iodopsin
Photo receptive pigment which is broken down in cone cells
Rhodopsin
Photo receptive pigment which is broken down in rod cells
Spatial summation
Sum of lots of synapses firing at the same time
Stretch-mediated sodium ion channels
Protein channels that stretch when pressure is exerted and change permeability of sodium ions. Found in pacinnian corpuscle
Synapse
Gap between pre synaptic knob and pro synaptic knob
Tropomyosim
A protein of muscle which cover myosin binding sites on actin regulating interaction in muscle contraction
Troponin
Where calcium ions bind on muscle protein causing tropomyosin to change shape and reveal actin binding sites
Cell elongation
Result of having enough water and sunlight for plants
Choice chamber
A container whit different compartments, in which you can create different environmental conditions
Tactic response (taxis)
A directional movement in response to a stimulus. The direction of the stimulus affects the response.
Kinesis response
Non directional movement in response to a stimulus. The intensity of stimulus affects response
Example of taxis and kinesis response
Taxis- woodlice shows tactic response to light as they move away from light source to keep them concealed from predators
Kinesis- woodlice show to humidity. In high humidity they move slower and turn less often as to stay where they are as to prevent water loss
Gravitropism
Growth of plant in response to gravity
Indoeaceitc acid
Important auxin that’s produced in tips of shoots and roots in plants. Moved around the plant to control tropisms. Causes plant to grow in that area
Phototropism
Growth of a plant in response to light
Photropism in shoots
Grows towards light -positively phototropism
Phototropism in roots
Grows away from light - negatively phototropism
Grvitopism in shoots
Negatively gravotropic so grow away from gravity
Gravitropism in roots
Positively gravitropism so grow s downwards
Acetate
Formed when pyruvate is oxidised in link reaction. Binds with co enzyme A to form acetyl coA
ATP synthase
Enzyme embedded in inner mitochondria membrane which synthesises ADP and Pi into ATP
Electron chain transfer
The movement of electrons across carrier proteins and H+ ions diffusing into inter membrane space
Chemiosmotic theory
Process of ATP production driven by the movement of H+ ions across a membrane
FAD
Molecule which is reduced to form FADH. Requires less energy to reduce than NAD
Glucose phosphate
Molecule formed in first stage of glycolysis after glucose has been phosphorylated creating that and one ADP
Glycolysis
First stage in respiration which take glucose and forms 2 molecules of pyruvate and a net gain of 2 ATP
Krebs cycle
Produces coenzyme a, acetate, 2x CO2, 1 ATP, 3x NAD, 1 FAD
Mitochondria
Has folded inner membrane called cristae, which provides large surface are for max respiration.
NAD
Molecule which is reduced to form NADH which is used in oxidative phosphorylation
Phosphorylation
Metabolic process of adding an inorganic phosphate to an organic molecule
Protons
H+ ions
Pyruvate
A 3 carbon molecule formed by oxidation of triose phosphate in glycolysis
Substrate level phosphorylation
The enzyme-catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate
Triose phosphate
Molecule formed when glucose phosphate is phosphorylated again in glycolysis
Alcoholic fermentation in plants
Pyruvate is decarboxylated and NADH is reduced to NAD to form ethanol
Lactate fermentation
Pyruvate reduced by oxidation of NADH to form lactate
Anaerobic respiration
Where pyruvate is converted to ethanol or lactate in respiration without oxygen