Module 5 Flashcards
Absicisic acid (ABA)
Plant hormone that stimulates stomatal cloning, maintains see dormancy and triggers cold protective responses
Abscission
Shedding of leaves in plants
Acetylcholine
A type of neurotransmitter used for communication between neurones
Actin
Type of protein filament found in myofibrils. Forms thin filaments consisting of two long twisted chains
Actin-myosin binding site
Site of actin which normally blocked by tropmyosin. During muscle contraction, becomes exposed, allowing a myosin head to attach
Actin-myosin cross-bridge
Cross bridge formed when a myosin head attaches to the myosin binding site on an actin filament
Adenylyl cyclase
An enzyme which catalyses the conversion of ATP to cAMP
Adrenal glands
Glands at top of kidneys and produce adrenaline and steroid hormones
Adrenaline
Hormone which is secreted under stressful conditions. Serves as primary messanger and actives adenylyl cyclase
Afferent arteriole
Larger diameter arterioles which carries blood to glomerulus for ultrafiltration
Alkaloids
Group of nitrogenous compounds found in plants. Bitter tasting and affect metabolism of animals/insects which take them in
All or nothing principle
Principle which describes how any generator potential which reaches or exceeds threshold potential will produce an action potential
Alpha cells
Found in pancreas which secrete glucagon into blood to raise glucose conc
Anisotropic bands
Darker bands in a myofibril which consist of overlapping actin and myosin filaments
Anabolic steroids
Class of performance enhancing drugs which are structurally similar testosterone and used illegally by atheletes
Anterior pituitary gland
Region of pituitary gland which produces and secretes hormones
Antidiuretic hormones (ADH)
A hormone released from the posterior pituitary gland that increases the reabsorption of water in the kidney tubules
Aquaporin
A membrane channel used for selective transport of water in and out of cell
Autonomic nervous system
A branch of nervous system that carries nerve impulses to muscles and glands. Controls involuntary activities and two divisions: sympathetic and parasympathetic
Auxins
Class of plant hormones which control elongation, produce tropsims, prevent abscission, maintain apical dominance
Axon
Extension from a nerve cell which carries impulses away from the cell body
Beta cells
Found in pancreas and secrete insulin into blood to lower glucose conc
Bile canaliculi
Vessels which collect bile produced by hepatocytes
Cardiac muscle
Myogenic muscle in walls of heart
CNS
Brain and spinal cord
Cerebrum
Largest region of brain, consisting of two hemispheres- recieving sensory info from receptors and sends info via motor neurons to effectors
Cerebellum
Region of the brain that controls muscle coordination and non-voluntary movement
Cholinergetic synapse
Synaose which uses the neurotransmitter acetylcholine
Creatine phosphate
Compound stored in muscles which serves as phosphate reserve enabling ATP regeneration
Cyclic AMP (cAMP)
Second messenger involved in action of adrenaline that activates protein kinase
Dendron
Extension from a nerve cells which carries impulses towards the cell body
Depolarisation
Rapid influx of sodium ions into cell which causes it to lose its negative charge and the membrane potential to increase
Ectotherm
Organism which is dependent on its environment to maintain its body temp
Effector
Organ, tissue or cell which produces a response to a stimulus
Efferent arteriole
Smaller diameter arteriole which carries blood away from the glomerulus after ultrafiltration
Endocrine signalling
Type of signalling that uses hormones secretes by endocrine cells into blood which produces effect on receptors
Endotherm
Organism which can regulate its own body temp without relying on external heat sources
Ethene
Plant hormones which stimulates the ripening of fruit and promotes abscission in deciduous trees
EPSP
Impulse which stimulates an action potential in the postsynaptic neuron
Excretion
Removing metabolic waste from an organism
Flight or fight
Physiological reaction of body in response to a potentially dangerous situ
Geotropism
Plants growth response to gravity
Gibberellins
Plant hormones which control stem elongation, trigger growth of pollen tube during fertilisation and stimulate mobilisation of food storage reserves during seed germination
Glomerular filtration rate
Method of measuring kidney function which asseses amount of blood plasma filtered per unit of time and produces value above 90mL/min in healthy adults
Glomerulus
Bundle of blood vessels at beginning of a kidney nephron where ultrafiltration occurs
Haemodialysis
Type of dialysis used where patients blood fed into a dialysis machine and passed across an artificial membrane to remove waste
Hepatic artery
Main artery which supplies the liver tissue with oxygenated blood from the heart
Hepatic portal vein
Main vein which carries blood rich in nutrients from the small intestine and pancreas to the liver
Hepatic vein
Main vein which takes deoxygenated blood away from the liver back to the heart
Homeostasis
Maintaining constant internal environment around an optimum despite external change
Hormones
Cell signalling molecules produced by endocrine glands and released into blood. They travel to target cells and bind to specific receptors , initiating response. Long lasting effects
Hyperpolarisation
Drop in membrane potential below the resting potential after repolarisation due to open potassium ion channels
Hypothalamus
Region of brain which serves as control centre for the autonomic nervous system. Responsible for hormone production, regulation of water poten of body fluids
IPSP
An impulse which inhibits the next neurone from generating an action potential
Islet of Langerhans
Region of pancreas which contains a and b cells
Isotropic bands
Lighter bands in a myofibril, consisting of non-overlapping actin and myosin filaments
Kupffer cell
Specialised type of macrophage which is located within the sinusoids of the liver and removes pathogens and dead cells
Loop of henle
A large hairpin shaped loop found in kidney tubule used to regulate the water and salt conc of blood
Neurotransmitters
Chemicals are used for communication between neurones and their target cells. Stored in synaptic vesicles in presynaptic neurone and released into synaptic cleft
Medulla oblongata
Region of brain regulating autonomic activities such as ventilation, heart rate and peristalsis.
Metabolic waste
Productss produced in metabolic reactions which have no benefit to organism
Monoclonal antibodies
Antibodies which have been produced by plasma cells that are identical clones of the same parent cell
Motor neurone
Neurone which carries nerve impulses from CNS to effector
Myelination
Formation of myelin sheath around nerve cells by Schwann cells
Myofibrils
Tiny contractile muscle fibres which group together. Numerous myofibril bundles constitute muscles. Contain two protein filaments: Actin, myosin
Negative feedback
Product of a process which counteracts change to maintain an equilibrium
Neuromuscular junction
Excitatory synapse formed between a motor neurone and a muscle fibre that uses acetylcholine
Nodes of ranvier
Unmyelinated sections of nerve cells which allow for the propagation of an action potential due to their many ion channels
Osmoreceptors
Type of receptor found in the hypothalamus which can detect the water conc of blood plasma to maintain an appropriate water balance in the body
Pacinian corpuscle
Type of sensor receptor which detects changes in pressure on the skin
Pancreas
Organ which has exocrine and endocrine functions and is involved in digestion and homeostatic control of blood glucose conc levels
Paracrine signalling
Type of signalling between adjacent cells
Parasympathetic NS
Branch of autonomic NS which is active under normal, resting conditions- inhibiting effectors, slowing down activity
Peritoneal dialysis
Type of dialysis which dialysis fluid is placed inside the abdomen and waste subsances are passed across the peritoneal membrane from the blood
Pheromones
Cell signalling molecule produced by an organism which affects the social behaviour of other members of the same species
Photoperodism
Plants growth response to seasonal changes in the length of daylight
Pituitary gland
Small, hormones producing gland located at base of brain. In two regions: anterior and posterior
Positive feedback
Process which causes an increase in change away from the normal
Posterior pituitary gland
Region of p gland that stores and secretes hormones produced by hypothalamus
Posttsynaptic neurone
Neurone after synapse which contains specific receptor proteins on its membrane, complementary to the neurotransmitter
Presynaptic neurone
Neurone before the synapse which releases neurotransmitters from synaptic vesicles into cleft
Receptors
Specialised structure which detects specific type of stimulus
Reflex
Rapid, automatic response to a sensory stimulus by the body. Serves as protective mechanism
Reflex arc
Pathway of neurones involved in reflex actions
Resting potential
Potential difference across cell membrane of a neurone at rest typically between -60- and -70mV
Saltatory conduction
Setting up of localised circuits between nodes of Ranvier which allows for rapid propagation of action potential
Schwann cells
Cells which form myelin sheath around nerve cells in the peripheral ns
Second messanger model
Mechanism which a hormone has an effect in cell by triggering production of second messanger such as cAMP
Selective reabsorption
Selective uptake of useful substances along the kiney nephron using membrane transport proteins
Sensory neurone
Neurone which carries nerve impulses from receptors to CNS
Sinusoid
Type of vessel found in the liver which is formed from convergence of the hepatic artery and hepatic portal vein
Skeletal muscle
Voluntary muscle responsible for movement. Makes up most of the body muscle and attached to the skeleton by tendons
Smooth muscle
Involuntary muscle under control of autonomic NS. Found in walls of blood vessels, digestive tract and organs
Somatic NS
Branch of NS which carries impulses to skeletal muscles- controls voluntary
Summation
Combination of impulses which stimulate the generation of an action potwnrial in the postsynaptic neuron
Sympathetic NS
Branch of autonomic NS which is active under stressful conditions. Stimulates effectors, speeding up activity
Synapse
Junction between two nerve cells or nerve cell and effector
Synaptic vesicles
Located in presynaptic neurone and store neurotransmitters. Upon fusion with presynaptic membrane, contents released into synaptic cleft
Ornithine cycle
Cycle of reactions responsible for producing urea from ammonia for detoxification and excretion
Type 1
Autoimmune disorder in which beta cells destroyed and pancreas fails to produce sufficient insulin characterised by uncontrolled high blood g levels
Type 2
Where body fails to produce enough insulin or pancreas no longer reacts to insulin
Ultrafiltration
Removal of small substances from blood through pressure created by structure of kidney nephron
Acetyl Coenzyme a
Two carbon molecule formed in oxidative decarboxylation where an acetyl group is bound by coenzyme A. Oxidised in Krebs cycle
ATP
Universal energy carrier found in all living cells
Aerobic respiration
Form of cellular respiration that takes place in prescence of o2 and produces co2, water and atp
Alcoholic fermentation
Takes place in plant root cells and yeast cells producing ethanol and co2
ATP synthase
Enzyme found in cellular membranes that phosphorylates ADP to form ATP as protons flow through it
Chemiosmotic theory
Synthesis of ATP through movement of protons down their conc gradient across a semi permeable membrane, catalysed by ATP synthase
Chlorophyll
Photosynthetic pigment found in thylakoids of chloroplasts that absorb light energy. A and B
Chloroplast
Organelle found in plants and algae which is the site of photosynthesis
Citrate
6 carbon molecule formed in first stage of Krebs cycle from reaction of acetyl coenzyme A and oxaloacetate
Coenzyme A
Coenzyme which binds an acetyl group to form acetyl coenzyme A during oxidative decarboxylation of aerobic respiration
Coenzymes
Molecules which help enzymes carry out their function e.g. NAD, FAD
Cristae
Folds of inner mitochondrial membrane which provides large SA for oxidative phosphorylation
Cyclic photophosphorylation
Formation of ATP including only Photosystem 1
Decarboxylation
Removal of CO2 molecule
Dehydrogenation
Removal of hydrogen atom
Electron acceptor
O2 acts as final electron acceptor in ETC
Electron carrier
Proteins which accept and release electrons e.g. NADP, NADP
Electron transport chain
Series of electron carrier proteins which transfer electrons in chain of oxidation-reduction reactions
FAD
Coenzyme that becomes reduced when takes up hydrogen atoms during krebs cycle, forming reduced FAD
Fermentation
Anaerobic resp which does not involve an ETC
GP
3 carbon molecule reduced by reduced NADP in light-independant stage of photosynthesis o form two molecules of TP.
Glycolysis
An anaerobic process that takes place in the cytosol of the cell and breaks
down glucose into two molecules of pyruvate. Two molecules of ATP and two molecules of
reduced NAD are also formed.
Grana
Stacks of thylakoids connected by intergranal lamellae
Hexose bisphosphate
The compound formed from the phosphorylation of glucose in
glycolysis. It splits into two molecules of triose phosphate.
Inner mitochondrial membrane
The mitochondrial membrane that segregates the matrix
from the intermembrane space. It is the site of the electron transport chain.
Intermembrane space
The small space between the inner and outer mitochondrial
membranes. The electron transport chain results in a high proton concentration here.
Krebs cycle
A series of oxidation-reduction reactions in the matrix of the mitochondria in
which acetyl coenzyme A is oxidised, generating reduced NAD, reduced FAD, ATP and
carbon dioxide.
Lactate dehydrogenase
Enzyme which catalyses the conversion of pyruvate to lactate
Lamellae
Membranous channels that connect adjacent grana in a chloroplast.
Light-dependant reaction
The first stage of photosynthesis that uses light energy to
produce ATP, reduced NADP and oxygen. It takes place in the thylakoids of the chloroplast.
Light-harvesting system
A collection of protein and chlorophyll molecules found in the
thylakoid membranes of chloroplasts that absorbs light energy of varying wavelengths and
transfers it to the reaction centre. It is also known as an antennae complex.
Light independant reaction
The second stage of photosynthesis, also known as the
Calvin cycle, in which the products of the light-dependent stage and carbon dioxide are used
to build organic molecules. It does not require light energy and takes place in the stroma.
Limiting factor
Variable which limits rate of a particular reaction
Matrix
Fluid filled space within inner membrane of the mitochondria which contains mitochondrial DNA and enzymes required for aerobic respiration
Mitochondrian
Organelle in eukaryotic cells which is site of aerobic resp
NAD
A coenzyme that becomes reduced when it takes up hydrogen atoms during aerobic
respiration, forming reduced NAD
NADP
A coenzyme that becomes reduced when it takes up hydrogen atoms during the
light-dependent stage of photosynthesis, forming reduced NADP.
Non-cyclic photophosphorylation
The formation of ATP and reduced NADP involving
both photosystems I and II.
Outer mitochondrial membrane
The membrane segregating the contents of the
mitochondrion from the rest of the cell. It creates optimal conditions for aerobic respiration.
Oxaloacetate
A four-carbon molecule that combines with acetyl coenzyme A to produce
six-carbon citrate in the first stage of the Krebs cycle. It is eventually regenerated, allowing
the cycle to continue.
Oxidative decarboxylation
The first stage of aerobic respiration (also known as the ‘link
reaction’) that takes place in the mitochondrial matrix and converts pyruvate into acetyl
coenzyme A and carbon dioxide. Reduced NAD is also formed. Overall:
Pyruvate + NAD + CoA ⟶ acetyl CoA + reduced NAD + CO2
Oxidative phosphorylation
The synthesis of ATP from reduced coenzymes and oxygen in
the electron transport chain of aerobic respiration.
Photolysis
Splitting of molecule of water in prescense of light that occurs during the light-dependent stage of photosynthesis
H2O ⟶ 2H+
+ 2e-
+ ½O2
Photophosphorylation
The harnessing of light energy in photosynthesis to phosphorylate
ADP, forming ATP.
Photosynthesis
A complex metabolic pathway that synthesises organic molecules in the
presence of light. It consists of three main stages: capturing of light energy, light-dependent
reaction, light-independent reaction. Overall:
6CO2
+ 6H2O ⟶ C6H12O6
+ 6O2
Photosynthetic pigments
Molecules present in chloroplasts that absorb certain
wavelengths of light e.g. chlorophyll a, chlorophyll b, xanthophylls and carotenoids.
Photosystem
Protein complex consisting of a light harvesting system and reaction centre, involved in absorption of light and transfer of elecrons in photosyntheiss
Pyruvate
A three-carbon molecule produced in glycolysis. In the link reaction of aerobic
respiration, it is oxidised to acetate. During fermentation, it is converted to lactate (animals)
or ethanol and carbon dioxide (plants and microorganisms).
Respiration
A set of metabolic reactions that take place in organisms and break down
respiratory substances, such as glucose, into smaller inorganic molecules, like water and
carbon dioxide. This is linked to the synthesis of ATP.
Respiratory quotient
The ratio of carbon dioxide produced to oxygen consumed
during respiration. Calculated using:
Co2 produced/ o2 consumed
Respiratory substrate
An organic molecule that can be broken down via the respiratory
pathways to produce ATP.
Respirometer
A device used to determine respiration rate in living organisms by measuring
the change in volume of oxygen or carbon dioxide.
RuBP
A five-carbon compound that reacts with carbon dioxide in
the light-independent stage of photosynthesis, forming two molecules of GP.
RuBisCo
An enzyme that catalyses the reaction of
RuBP and carbon dioxide in the light-independent stage of photosynthesis.
Thylakoids
A series of flattened membrane-bound compartments in chloroplasts. They are
stacked to form grana and contain the chlorophyll and other molecules needed for the
light-dependent reaction
