Module 5 - Communication, Homeostasis & Energy Flashcards
(196 cards)
1
Q
Abscisic Acid (ABA)
A
Plant hormone that stimulates stomatal cloning, maintains seed dormancy & triggers cold protective responses
2
Q
Abscission
A
The shedding of leaves in plants
3
Q
Acetylcholine
A
Type of neurotransmitter that is used for communication between neurones
4
Q
Actin
A
Type of protein filament found in myofibrils, forms thin filaments consisting of 2 long twisted chains
5
Q
Actin-myosin binding site
A
A site on actin that is normally blocked by tropomyosin, during it becomes exposed, allowing myosin head to attach
6
Q
Actin-myosin cross-bridge
A
Cross-bridge forms when a myosin head attaches to the myosin binding site on an actin filament
7
Q
Adenylyl cyclase
A
Enzyme that catalyses the conversion of ATP to cAMP
8
Q
Adrenal glands
A
Glands which are located on top of kidneys & produce adrenaline & steroid hormones
9
Q
Adrenaline
A
Hormone that is secreted by adrenal glands under stressful conditions, serves as ‘primary messenger’ activating adenylyl cyclase
10
Q
Afferent arteriole
A
Larger diameter arteriole which carries blood to glomerulus for ultrafiltration
11
Q
Alkaloids
A
Group of nitrogenous compounds found in plants, are bitter-tasting & affect metabolism of animals/insects that take them in
12
Q
All-or-nothing principle
A
Any generator potential that reaches/exceeds the threshold potential will produce an action potential of equal magnitude
13
Q
Alpha cells (α cells)
A
Cells found in pancreas which secrete glucagon into the blood to raise glucose concentration
14
Q
Anisotropic (A) bands
A
Darker bands in myofibril, consist of overlapping actin & myosin filaments
15
Q
Anabolic steroid
A
Class of PED that are structurally similar to testosterone & used illegally by athletes to promote muscle growth
16
Q
Anterior pituitary gland
A
Region of pituitary gland that produces & secretes hormones
17
Q
Antidiuretic hormone (ADH)
A
Hormone released from posterior pituitary gland that increases reabsorption of water in kidney tubules
18
Q
Aquaporin
A
Membrane channel used for selective transport of water in & out of the cell
19
Q
Autonomic nervous system
A
Branch of nervous system that carries nerve impulses to muscles & glands, controls involuntary activities & have 2 divisions:
sympathetic
parasympathetic
20
Q
Auxins
A
Class of plant hormones that control cell elongation, produce tropisms, prevent abscission, maintain apical dominance & stimulate production of ethene
21
Q
Axon
A
Extension of nerve cell that carries impulses away from cell body
22
Q
Beta (β) cells
A
Cells found in pancreas which secrete insulin into blood to lower glucose concentration
23
Q
Bile Canaliculi
A
Vessels which collect the bile produced by hepatocytes
24
Q
Blinking reflex
A
Involuntary blinking of eyelid when an object is held close to eye, last reflex to be lost
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Cardiac muscle
Myogenic muscle found in walls of the heart
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Central Nervous System (CNS)
Brain & spinal cord
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Cerebellum
Region of brain that controls muscle coordination & non-voluntary movement e.g. balance & posture
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Cerebrum
Largest region of brain, consists of 2 hemispheres, receives sensory information from receptors & sends information via motor neurones to effectors, responsible for all involuntary responses
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Cholinergic synapse
Synapse which uses acetylcholine as its neurotransmitter
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Creatine phosphate
Compound stored in muscles, serves as phosphate reserve enabling ATP regeneration
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Cutting
Small section of the root/stem of an adult plant
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Cyclic AMP (cAMP)
'Secondary messenger' involved in action of adrenaline that activates protein kinase
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Dendron
Extension from nerve cell that carries impulses towards cell body
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Depolarisation
Rapid influx of Na+ into cell, causes it to lose its negative charge & membrane potential increases
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Ectotherm
Type of organisms which is dependent on its environment to maintain its body temp
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Effector
Organ/tissue/cell that produces a response to stimulus
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Efferent arteriole
Smaller diameter arteriole which carries blood away from the glomerulus after ultrafiltration
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Endocrine signalling
Type of signalling that uses hormones secreted by endocrine cells into blood which produce an effect on receptors
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Endotherm
Type of organisms which can regulate its own body temp without relying on external heat sources
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Ethene
Plant hormone that stimulates ripening of fruit & promotes abscission in deciduous trees
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Excitatory postsynaptic potential (EPSP)
Impulse which stimulates an action potential in postsynaptic neurone
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Excretion
Process of removing metabolic waste from an organism
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Fight or Flight response
Physiological reaction of body in response to potentially dangerous situation
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Geotropism
Plant's growth response to gravity
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Gibberellins
Plant hormone that controls stem elongation, trigger growth of pollen tube during fertilisation & stimulate mobilisation of food storage reserves during seed germination
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Glomerular filtrate rate (GFR)
Method of measuring kidney function which assesses the amount of blood plasma filtered per unit of time & produces values which should be above 90mL/min in healthy adults
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Glomerulus
Bundle of blood vessels at beginning of kidney nephron where ultrafiltration takes place
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Haemodialysis
Type of dialysis used where a patient's blood is fed into dialysis machine & passed across an artificial membrane to remove waste
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Hepatic artery
Main artery which supplies liver tissue with oxygenated blood from heart
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Hepatic Vein
Main vein which takes deoxy blood from liver back to heart
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Homeostasis
Maintaining a constant internal environment around an optimum despite external change
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Hormonal Weed killers
Hormones (synthetic dicot auxin) that alter plant metabolism promoting rapid growth that's unsustainable
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Hormones
Cell signalling molecules produced by endocrine glands & releases into blood. Travel to target cells & bind to specific receptors, initiating response, effects of hormones are usually long-lasting
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Hyperpolarisation
Drop in membrane potential below resting potential after repolarisation due to open K+ ion channels
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Hypothalamus
Region of the brain that serves as the control centre for the autonomic nervous system. It is responsible for production of hormones, regulation of the H2O potential of body fluids & the control of behavioural patterns
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H-zone
Lighter region in the centre of each A band
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Inhibitory postsynaptic potential (IPSP)
Impulse which inhibits next neurone from generating an action potential
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Islet of Langerhans
Regions of the pancreas which contain α & β cells
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Isotropic (I) bands
Lighter bands in a myofibril, consists of non-overlapping actin & myosin filaments
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Knee-jerk reflex
Type of spinal reflex commonly tested by doctors, involves sudden involuntary movement of the lower leg when the patella is tapped
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Kupffer cells
Specialised type of macrophage which is located within sinusoids of the liver & removes pathogens & dead cells
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Loop of Henle
Large hairpin shaped loop found in the kidney tubule, used to regulate the water & salt concentration of the blood
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Negative tropism
Growth of a plant away from a stimulus
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Neurotransmitters
Chemicals that are used for communication between neurones & their target cells. Neurotransmitters are stored in synaptic vesicles in presynaptic neurone & released into the synaptic cleft
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Medulla oblongta
Region of the brain that regulates autonomic activities e.g. ventilation & HR, made up of regulatory centres of the autonomic nervous system
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Metabolic waste
Products produced in metabolic reactions which have no benefit to the organism
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Mimosa pudica
Plant that exhibits rapid leaf-folding & collapse in response to tough, serves as a protective mechanism against larger herbivores & small insects
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Monoclonal antibodies
Antibodies which have been produced by plasma cells that are identical clones of the same parent cell
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Motor neurone
Carries nerve impulse from CNS to effectors
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Myelintion
Formation of a myelin sheath around nerve cells by Schwann cells
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Myofibrils
Tiny contractile muscle fibres which group together, numerous myofibril bundles constitute muscles, myofibrils consist of 2 protein filaments: actin & myosin
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Myogenic
Describes cardiac muscle tissue that initiates its own contraction without outside stimulation from nervous impulses
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Myosin
Type of protein filament found in myofibrils, forms thick filaments, consisting of long tails with bulbous heads, positioned to the side
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Negative feedback
Product of a process that counteracts change to maintain an equilibrium around a normal level
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Neuromuscular junction
Excitatory synapse formed between a motor neurone & a muscle fibre that uses the neurotransmitter acetylcholine
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Nodes of Ranvier
Unmyelinated sections of nerve cells which allow for the propagation of an action potential due to many ion channels
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Osmoreceptor
Type of receptor found in hypothalamus which can detect the water concentration of blood plasma to maintain an appropriate water balance in the body
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Pacinian Corpuscle
Type of sensory receptor which detect changes in pressure on the skin
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Pancreas
Organ which has both exocrine & endocrine functions and is involved in both digestion & homeostatic control of blood glucose levels
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Paracrine signalling
Type of signalling which occurs between adjacent cells
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Parasympathetic nervous system
Branch of autonomic nervous system that is active under normal, resting condition, it inhibits effectors, slowing down activity
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Peripheral nervous system (PNS)
Pairs of nerves that originate from the CNS & carry nerve impulses into & out of CNS, it is divided into the sensory nervous system & motor nervous system
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Peritoneal dialysis
Type of dialysis where dialysis fluid is placed inside the abdomen & waste substances are passed across the peritoneal membrane from the blood
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Pheromones
Cell-signalling molecules produced by an organism that affects the social behaviour of the other members of the same species
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Photoperiodism
Plant's growth response to seasonal changes in the length of daylight
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Phototropism
Plant's growth response to light
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Pituitary gland
Small, hormone-producing gland located at the base of the brain, it is divided into 2 regions, anterior pituitary & posterior pituitary
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Positive feedback
Process which causes an increase in changes away from the normal
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Positive tropism
The growth of a plant towards a stimulus
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Posterior pituitary gland
Region of the pituitary gland that stores & secretes hormones produced by hypothalamus
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Postsynaptic neurone
Neurone after the synapse which contains specific receptor proteins on its membrane, complementary to the neurotransmitter
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Presynaptic neurone
Neurone before the synapse which releases neurotransmitters from synaptic vesicles into the synaptic cleft
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Receptor
Specialised structure that detects a specific type of stimulus
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Reflex
Rapid, automatic response to a sensory stimulus by the body, it serves as a protective mechanism
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Reflex arc
Pathway of neurones involved in a reflex action: stimulus→ receptor→ sensory neurone→ relay neurone→ motor neurone→ effector→ response
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Relay neurone
Neurone located in the spinal cord that links the sensory neurone to the motor neurone
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Resting potential
The potential difference across the cell membrane of a neurone at rest which is typically between -60 & -70 mV
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Rooting powder
Hormone powder applied to cuttings that increases root formation & chance of successful propagation
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Saltatory conduction
Setting up localised circuits between nodes of Ranvier which allows for the rapid propagation of an action potential
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Sacromere
repeating unit of striations between adjacent Z-lines
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Sarcoplasm
Cytoplasm shared by muscle fibres, consists of a high concerntration of mitochondria & endoplasmic reticulum
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Schwann cells
Cells that form myelin sheath around nerve cells in the peeripheral nervous system
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Secondary messenger model
Mechanism by which a hormone has an effect inside a cell by triggering the production of a secondary messenger
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Selective reabsorption
Selective reuptake of useful substances along the kidney nephron using membrane transport proteins
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Sensory Neurone
Neurone that carries nerve impulses from the receptors from CNS
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Sinusoid
Type of vessel found in the liver which is formed from the convergence of heptic artery & hepatic portal vein
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Skeletal Muscle
Voluntary muscle responsible for movement, makes up majority of body muscle & is attached to skeleton by tendons
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Sliding filament theory
Mechanism by which a muscle contracts, during contraction, myosin filaments pull actin filaments to the centre of the sacromere, the actin filaments slide along the myosin filaments. The sarcomere is shortened & the muscle length is reduced
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Smooth muscle
Involuntary muscle under control of autonomic nervous system, its found in walls of blood vessels, digestive tract & organs
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Somatice nervous system
Branch of nervous system that carries impulses to the skeletal muscles, conttrols voluntary activities
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Synapse
Junction between 2 nerve cells/nerve cell & an effector
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Synaptic vesicles
Secretory vesicles located in the presynaptic neurone that store neurotransmitters, upon fusion with the presynaptic membrane, contents are released intot he synaptic cleft
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Tannins
Phenols produced by many plants, serve as chemical defece agaisnt herbivory, thier bitter taste deters animals from eating them & they are toxic to insects
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The Ornithine cycle
Cycle of reactions responsible for producing urea from ammonia for detoxification & excretion
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Tropism
Growth response of a plant to a directional stimulus
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Type 1 diabetes
Autoimmune disorder in which the beta cells are destroyed & pancreas fails to produce sufficient insulin which is characterised by uncontrolled high blood glucose levels
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Type 2 diabetes
Type of diabetes where the body fails to produce enough insulin/when the pancreas no longer reacts to insulin which can be caused by poor diet & lack of exercise
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Ultrafiltration
Removal of small substances from the blood through the pressure created by the structure of the kidney nephron
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Z-line
Line in the centre of each I band
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Acetyl coenzyme A
2-carbon molecule formed in oxidative decarboxylation when an acetyl group is bound by coenzyme A, it is oxidised in the Krebs cycle
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Adenosine triphosphate (ATP)
Universal energy carrier found in all living cells
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Aerobic respiration
Form of cellular respiration that takes place in presence of O2 & produces CO2, H2O & ATP:
C6H12O6 + 6O2→6CO2 + 6H2O
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Alcoholic fermentation
Type of fermentation that takes place in plant root cells & yeast cells, produces ethanol & CO2
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Anaerobic respiration
Form of cellular respiration that takes place in absence of O2, produces less ATP
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ATP synthase
Enzyme found embedded in cellular membranes that phosphorylates ADP→ATP as protons flow through it
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Calvin cycle
Products of light-dependent stage & CO2 are used to build inorganic molecules
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Chemiosmotic theory
Synthesis of ATP through the movement of protons down their concentration gradient across a semipermeable membrane, catalysed by ATP synthase
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Chlorophyll
Photosynthetic pigment located in thylakoids of chloroplasts that absorb light energy, are 2 main types, chlorophyll a & b
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Chloroplast
Organelle found in plants & algae that is site of photosynthesis
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Citrate
6-carbon molecule formed in 1st stage of Krebs cycle from reaction of acetyl coenzyme A & oxaloacetate
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Coenzyme A
Coenzyme that binds an acetyl group to form acetyl coenzyme A during oxidative decarboxylation of aerobic respiration
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Coenzymes
Molecules that help enzymes carry out their function e.g. NAD, FAD, coenzyme A, NADP
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Cristae
Folds of the inner mitochondrial membrane that provide large surface area for oxidative phosphorylation
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Cyclic photophosphorylation
Formation of ATP involving photosystem I only
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Decarboxylation
Removal of CO2 molecule
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Dehydrogenation
Removal of H atoms
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Electron acceptor
Oxygen acts as final electron acceptor in electron transport chain;
1/2O2 + 2e- +2H+→H2O
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Electron carriers
Protein molecules that accept & release electrons e.g. NAD, NADP
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Electron transport chain
Series of electron carrier proteins that transfer electrons in a chain of oxidation-reduction reactions
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FAD
Coenzyme that becomes reduced when it takes up H+ during Krebs cycle, forming reduced FAD
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Fermentation
Type of anaerobic respiration that doesn't involve and electron transport chain
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Glycerate 3-phosphate (GP)
3-carbon molecule that is reduced by reducing NADP in light independent stage of photosynthesis to form 2 molecules of TP, requires ATP
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Glycolysis
Anaerobic process that takes place in cytosol of cells & breaks down glucose into 2 molecules of pyruvate, 2 molecules of ATP & reduced NAD are formed
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Grana
Stacks of thylakoids connected by intergranal lamellae
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Hexose bisphosphate
Compound formed from phosphorylation of glucose in glycolysis, splits into 2 molecules of triose phosphate
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Inner mitochondrial membrane
Mitochondrial membrane that segregates matrix from the intermembrane space, site of electron transport chain
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Intermembrane space
Small space between inner & outer mitochondrial membranes
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Krebs cycle
Series of oxidation-reduction reactions in matric of mitochondria, acetyl coenzyme A is oxidised, generating reduced NAD, reduced FAD, ATP & CO2
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Lactate dehydrogenase
Enzyme that catalyses conversion of pyruvate to lactate
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Lactate fermentation
Type of fermentation that takes place in animal cells & produces lactate
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Lamellae
Membranous channels that connect adjacent grana in chloroplast
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Light-dependent reaction
1st stage of photosynthesis that uses light energy to produce ATP, reduced NAD & O2, takes place in thylakoids of chloroplasts
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Light-harvesting system
Collection of protein & chlorophyll molecules found in thylakoid membranes of chloroplast that absorb light energy of varying wavelengths & transfer it to reaction centre, also known as antennae complex
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Light-independent Reaction
2nd stage of photosynthesis, Calvin cycle, products of light-dependent stage & CO2 are used to build organic molecules, doesn't require light energy & takes place in stroma
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Limiting factor
Variable that limits rate of a particular reaction
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Link reaction
1st stage of aerobic respiration, takes place in mitochondrial matrix & converts pyruvate to acetyl coenzyme A & CO2, reduced NAD is also formed
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Matrix
Fluid-filled space within inner membrane of mitochondria which contains mitochondrial DNA & enzymes required for aerobic respiration
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Mitochondrion
Organelle found in eukaryotic cells that is the site of aerobic respiration
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NAD
Coenzyme that becomes reduced when it takes up H atoms during aerobic respiration, forming reduced NAD
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NADP
Coenzyme that becomes reduced when it takes up H atoms during light-dependent stage of photosynthesis, forming reduced NADP
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Non-cyclic photophosphorylation
Formation of ATP & reduced NADP involving both photosystems I & II
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Outer mitochondrial membrane
Membrane segregating the contents of the mitochondrion from the rest of the cell, creates optimal conditions for aerobic respiration
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Oxaloacetate
4-Carbon molecule that combines with acetyl CoA to produce 6-Carbon citrate in 1st stage of Krebs cycle, eventually regenerated, allowing cycle to continue
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Oxidative decarboxylation
Link Reaction- in mitochondrial matrix & converts pyruvate into acetyl CoA & CO2, reduced NAD is formed:
Pyruvate + NAD +CoA→Acetyl CoA + reduced NAD + CO2
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Oxidative phosphorylation
Synthesis of ATP from reduced Co & O2 in electron transport chain of aerobic respiration
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Photolysis
Splitting of a molecule of H2O in presence of light that occurs during the light-dependent stage of photosynthesis, produces protons, electrons & O2:
H2O → 2H+ + 2E- + 1/2O2
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Photophosphorylation
Harnessing of light energy in photosynthesis to phosphorylate ADP → ATP
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Photosynthesis
Complex metabolic pathway that synthesises organic molecules in presence of light, consists of 3 main stages:
capturing light
light-dependent reaction
light-independent reaction
6CO2 + 6H2O→C6H12O6 + 6O2
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Photosynthetic pigments
Molecules present in chloroplasts that absorb certain wavelengths of light e.g. chlorophyll a & b
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Photosystem
Protein complex consisting of a light-harvesting system & reaction centre, its involved in absorption of light & transfer of electrons in photosynthesis
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Pyruvate
3-C molecule produced in glycolysis, in the link reaction its oxidised to acetate, in fermentation its converted to lactate/ethanol & CO2
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Reaction centre
Region of a photosystem where energy is funnelled & photosynthetic reactions take place, contains 2 chlorophyll a molecules
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Respiration
Set of metabolic reactions that take place in organisms & break down respiratory substances, into smaller inorganic molecules, linked to synthesis of ATP
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Respiratory quotient (RQ)
Ratio of CO2 produced to O2 consumed during respiration
RQ=CO2 produced / CO2 consumed
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Respiratory substrate
Organic molecule that can be broken down via respiratory pathway to produce ATP
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Respirometer
Device used to determine respiration rate in living organisms by measuring change in volume of O2/CO2
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Retention value (Rf)
Rf=Distance travelled by component / Distance travelled by solvent
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Ribulose bisphosphate (RuBP)
5-C compound that reacts with CO2 in light independent stage of photosynthesis, forming 2 molecules of GP
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Ribulose bisphosphate carboxylase (RuBisCO)
Enzyme that catalyses the reaction of RuBP & CO2 in the light-independent stage of photosynthesis
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Stroma
Fluid interior of chloroplasts that contains the enzymes required for the light-independent reaction
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Substrate level phosphorylation
Synthesis of ATP by the transfer of a phosphate group from a phosphorylated intermediate to ADP
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Thin-layer chromatography (TLC)
Technique used to separate photosynthetic pigments by their rate of movement when carried by a solvent, across an inert surface. Differences in rate arise due to varying solubilities in the mobile phase & interactions with the stationary phase
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Thylakoids
Series of flattened membrane-bound compartments in chloroplasts, they are stacked to form grana & contain the chlorophyll & other molecules needed for light-dependent reaction
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Triose phosphate (TP)
3-C compound formed in glycolysis & light-independent stage of photosynthesis, may serve as a starting material for the formation of organic molecules/ be used to regenerate RuBP
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Why do multicellular organisms need communication systems?
To respond when their internal & external environment changes
To coordinate organ function
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What is cell signalling?
Communication between cells: electrical signals carried by neurones/chemical signals as hormones
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What is homeostasis?
Internal environment is maintained within set limits around an optimum
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Negative feedback
Self-regulating mechanisms return internal environment to optimum when there is a fluctuation
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Outline behavioural methods endotherms use to regulate their body temp
-Basking in the sun
-Pressing against warm surfaces
-Digging burrows
-Hibernation/aestivation
-Panting
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How does the autonomic nervous system enable endotherms to thermoregulate
Negative feedback:
-Peripheral thermoreceptors detect changes in skin temp
-Thermoreceptors in hypothalamus detect changes in blood temp
-Hypothalamus sends impulses to effectors in skin & muscles
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Role of skin in thermoregulation
Vasodilation/constriction of arterioles supplying skin capillaries controls heat loss to skin surface
Hair erector muscles contract & follicles protrude to trap air for insulation
Evaporation of sweat cools skin surface
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Gross structure of mammalian liver
-Liver lobules (cylinders of hepatocytes arranged in rows & connected at centre) connected to
-Hepatic vein, deoxygenated blood away from liver & attached to→hepatic portal vein, contains products of digestion & hepatic artery, supplies oxygenated blood via Sinusoid capillaries
-Bile duct, transports bile to gall bladder for storage
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Functions of mammalian liver
-Site of gluconeogenesis, glycolysis, glycogenesis
-Stores glycogen
-Deaminates excess amino acids, forming ammonia & organic acid, acids can be respired/converted into glycogen, ammonia is detoxified by addition of CO2 in ornithine cycle
-Detoxifies chemicals, converts alcohol→ethanal then acetic acid
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Gross structure of mammalian kidney
Fibrous capsule-protects kidney
Cortex-outer region, consists of Bowman's capsules, convoluted tubules, blood vessels
Medulla-inner region, consists of collecting ducts, loop of Henle, blood vessels
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