WJEC AS Biology Unit 2 Revision Mindmaps

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so they are more suited to the environment POPULATION 1 Simpson's Biodiversity Index: O N(N-1) SPECIES NUMBER OF INDIVIDUALS 4 {n(n-1) FOX DEER BEETLE SPARROW WORM RABBIT 300 * 299 35,138 = 2.55 2 88 31 163 12 N = 300 POPULATION 2 Biodiversity: O The number of species and individuals within the species in a given area o Spatial - varies over the planet O Coral reefs/rainforests have the most biodiversity O Varies due to succession (community of organisms changes its habitat); natural selection; human influence (deforestation; pollution) O Benefits: raw materials; medicines; food n(n-1) 4x3 =12 2x1=2 88×87 = 7656 31 x 30 = 930 163x162=26406 12 * 11 = 132 En(n-1)=35,138 Chapter 1 Species: o Organisms with similar characteristics that can successfully interbreed and produce fertile offspring o Sexual dimorphism: peacocks & peahens Polymorphism: Transect: O Presence of a number of different alleles for a gene, giving more than 1 phenotype Adaptive Radiation: o Single species adapts to fill available niches Assessing Relatedness: Quadrat: Randomly placed; ensures reliability; DNA sequences: sequences undergo changes until they are completely different: more similar DNA bases, more closely related o DNA hybridisation: DNA extracted from 2 organisms, mixed, complimentary bases hybridise together; more hybridisation, more closely related Amino acid sequences: more similar the amino acid sequences, more closely related O Quadrat placed evenly along a transect (non-mobile organisms) O Mark, Release, Recapture: Mobile organisms; mark in a non- harming/threatening way; wait a periodo of time; recapture; identify those marked Immunology: mix antigens of one with antibodies of another, they coagulate; more coagulation, more closely related Adaptations for Gas Exchange Surfaces: o Very thin: ensures a short diffusion pathway Large surface area: increases the area for gas exchange to take place O o Maintained concentration gradient: good supply to maximise diffusion Moist: allows gases to diffuse more+easily O Amoeba Single cell; large SA:V Multicellular; small short diffusion pathway; fast to meet O₂ demands BLOOD VESSELS LAMELLAE GILL ARCH Flatworm SA:V; flattened body to reduce diffusion pathway Gills: FILAMENTS MUSCLE CELL O SPIRACLE. O AIR SAC o Many folds (large SA) Thin o Supported by gill arch Water forced over filaments by ventilating system EXOSKELETON Insects: TRACHEA Earthworm Multicellular; small SA:V; circulatory system; mucus for moist skin TRACHEOLES KLO Covered in chitin to reduce water loss so cannot have an external exchange o Spiracles on thorax and abdomen o Spiracles lead to trachea lead to tracheoles O O O Tracheoles enter muscles directly for diffusion o During flight, O₂ in need, fluid decreases (shorten pathway), body contracts for ventilation Chapter 2 O O O Parallel Flow 486 200 ↓ SS 28 o Cartilaginous fish Inspiration in Fish: o Mouth opens O Operculum closes o Mouth floor lowers Volume increases o Pressure decreases O Water flows in 50 Gills Blood travels in the same direction to water Less efficient 50 Have to keep mouth open for ventilation 100 O ↓ 954 O O Countercurrent Flow O Water Expiration in Fish: 22 Blood travels in opposite direction to water o More efficient O Mouth closes Gills O Bony fish Can close mouth due to ventilation system Operculum opens O Mouth floor raises O Volume decreases O Pressure increases Water is forced out over the gills UPPER EPIDERMIS SPONGY MESOPHYLL- O O O STOMATA OPEN Opening of Stomata: o In light, chloroplasts photosynthesis, produce ATP ATP for active transport of o K* into guard cells Starch converted to malate Malate and K+ lower the Yo of guard cells; water drawn in (osmosis) Guard cell inner walls swell, bend, open stomatal pore O GUARD CELLS d STOMATA CLOSED O -WAXY CUTICLE O o Waxy Cuticle: transparent; reduces water loss To Upper Epidermis: transparent O Palisade Mesophyll: packed with chloroplasts O Vascular Bundle: xylem; phloem; o Spongey Mesophyll: surrounded by air spaces for diffusion Stomata: allow exchange of gases; surrounded by guard cells Lower Epidermis: site of stomata and guard cells PALISADE MESOPHYLL -XYLEM O O Closing of Stomata: O In darkness, chloroplasts don't photosynthesis, no ATP K not pumped into guard cells Starch stops converting to malate Y of guard cells increases; water moves out (osmosis) Guard cell inner walls become flaccid, flatten, closes stomatal pore Chapter 2 O RED BLOOD CELL ALVEOLAR WALL O BRONCHIOLE- RIGHT BRONCHUS HIGH 80 THIN FILM OF MOISTURE Inspiration: O Intercostal muscles contract O Ribcage moves out and up O External pleural membrane moves out Pressure in pleural cavity decreases O Inner pleural membrane moves out (alveoli expand) Volume increases/pressure decreases O Air goes in TRACHEA DIAPHRAGM o Cartilage: allows some movement of trachea; keeps airways open/flexible; expands/contracts CO INTERCOSTAL MUSCLES Expiration: ALVEOLI Alveoli Adaptations: Large SA; good blood supply (next to capillaries); short -CAPILLARY diffusion pathways; moist; steep concentration gradient O Intercostal muscles relax O Ribcage moves in and down O External pleural membrane moves in O Pressure in pleural cavity increases O Inner pleural membrane moves in (alveoli relax) O Volume decreases/pressure increases O Air goes out VASCULAR HOD BUNDLE Xylem: WATER AND MINERAL IONS STEM ellele D eellee eléve -XYLEM PHLOEM -SCLERENCHYMA يمتعو LEAF LIGNIN XYLEM PHLOEM Tracheid's: NO END CELL WALLS O O Vessels: ROOT O PHLOEM Roles: transport H₂O & o dissolved minerals; provide mechanical strength and support XYLEM Stem: O Vascular bundles are in a ring at the edge Gives flexible support and resists bending O Root: o o o Xylem is central and star shaped Phloem is between groups of xylem cells Arrangement resists vertical stresses and anchors plant in spoil Leaves: O Flowering plants (except mosses) Mosses have no tissues; can't SIEVE TUBE ELEMENT transport water; can't grow tall o Only in angiosperms o Lignin builds up in cell walls, contents die, empty space left Water climbs straight up to the plant Lignin stains red so easily identifiable Vascular tissue in midrib/network of veins Capillarity: xylem acts like capillaries; H₂O creeps O Flexible strength and resistance to up the tubes pulling more H₂0; short distances tearing Chapter 3 PLASMODESMATA SIEVE END PLATE Water Uptake by Roots: O Root hair cells (large SA; thin surface) o Epidermal cells (water moves into the cytoplasm through osmosis) Sclerenchyma: O Vascular bundles; structural support; dead cells Cohesion tension: H₂0 moves against gravity; H₂O evaporates from leaves; creates tension pulling H₂O most accepted Root pressure: pushes H₂0 already in xylem further; weak pressure; not just this in big plants Phloem: -COMPANION CELL O O Transport sucrose and amino acids from the source (where it is made) to sink (where it is needed) Sieve tubes: living cells; no organelles meaning they cannot survive on their own so are attached to a companion cell o Companion cells: contains a nucleus and mitochondria They are connected by plasmodesmata for communication O Apoplast: Cell wall to cell wall o H₂O moves through cellulose fibres due O O to cohesion O Symplast: Fastest route - no resistance EPIDERMIS APOPLAST PATHWAY Vacuolar: o Cytoplasm to cytoplasm Through plasmodesmata O Continual pathway across the root cortex O Vacuole to vacuole O Slowest CORTEX ENDODERMIS 1000 have route - to pass through each membrane CASPARIAN STRIP SYMPIAST PATHWAY XYLEM o H₂O supportive (don't need lignin) o Xylem poorly evolved (surrounded by H₂O) o Limited waxy cuticle (no water loss) O Stomata on surface o Large air spaces (buoyancy) Casparian Strip (endodermis): impermeable strip of suberin; blocks movement of water through apoplast, continuing through symplast Xerophytes: water is scarce Hydrophyte: lots of water o Waxy cuticle (waterproof) O Curled leaf (reduces transpiration o Sunken Stomata (reduces gradient & transpiration) Hairs (locks vapour) o E.g. cacti Transpiration: O o Loss of water through stomata by evaporation o Temperature: rise in temp increases rate of transpiration o Humidity: more humid the surrounding area, lower rate of transpiration O Air Speed: less wind; lower rate of transpiration o Light intensity: more light, higher rate of transpiration (stomata open. water lost) Chapter 3 Limitations of Mass Flow: Mesophyte: adequate water Translocation (phloem): O Ringing experiments: outer bark tissue removed in ring; above ring: lots of sucrose; below ring: no sucrose; translocated in phloem O Radioactive tracers: photosynthesis in isotope; stem section placed in photographic film; shows that phloem translocates sucrose o Aphid experiments: aphid stylet put in sieve tube; sap exudes in pressure; aphid removed; stylet remains in phloem; sucrose is there o Aphids & Radioactive tracers: plant photosynthesises in ¹4 CO₂ O Translocation 10,000 times faster than diffusion Doesn't allow enough pressure to be developed to transfer material to top of large trees Sucrose and amino acids move at different rates in different directions O O Most land plants in temperate o regions Slows when respiratory poisons added suggesting an active process Mass Flow Hypothesis: O Passive mass flow of sugars from phloem (high concentration) to sink areas such as growing tissues (low concentration) Circulatory Systems: Open: blood pumped with little control over flow direction; blood not SMALL LUMEN- contained in blood vessels O THICK MUSCULAR WALL WITH ELASTIC FIBRES CAPILLARY VERY SMALL LUMEN PULMONARY ARTERY Closed: blood pumped in vessels with controlled direction; organs bathed in tissue fluid Single: blood passes through the heart one in each circulation Double: blood passes through the heart twice in each circulation: pulmonary (lung) circulation, THIN POROUS WALLS then systemic (body) circulation Capillaries: connect arteries and veins; small pores enable the exchange of substances; walls one cell thick, reducing diffusion pathway Insects: open circulatory system; dorsal tube shaped heart; no respiratory pigment; tracheal gas exchange system Earthworms: closed circulatory system; 5 pseudo hearts; haemoglobin carries respiratory gases in blood Fish: closed, single circulatory system; blood pumped and oxygenated in gills and to tissues; slower flow ATRIOVENTRICULAR Mammals: closed, double circulation VALVE system; high blood pressure to body delivers oxygen; low pressure to lungs forcing tissue fluid into reducing alveoli efficiency ARTERY RIGHT ATRIUM VENA CAVA AORTA RIGHT VENTRICLE LEFT ATRIUM Arteries: carries blood from heart to organs; high pressure environment so thick muscular wall of elastic tissue; inner lining LEFT VENTRICLE allows arteries to expand to THIN LAYER OF MUSCLE withstand pressure; small lumen AND ELASTIC FIBRES ensures maintained high pressure PULMONARY VEIN SEMI-LUNAR VALVE LARGE LUMEN- Apex: pointed area of the heart Chapter 3 Aorta: carries OXY blood from left ventricle to body Pulmonary Artery: takes DEOXY blood to lungs from ventricle Pulmonary Vein: OXY blood from lungs Semilunar Valves: prevents backflow into ventricles between heartbeats Superior Vena Cava: head to heart Inferior Vena Cava: body to heart Right/Left Atrioventricular Valves: prevents backflow when ventricles contract Atria: contracts to pump blood into ventricle (R - DEOXY, L - OXY) Right Ventricle: thin for low pressure Left Ventricle: thick for high pressure Septum: separates sides of the heart VALVES TO PREVENT THE BACKFLOW OF BLOOD Veins: carry blood from organs to the heart; blood flows at lower pressure; larger lumen and thinner walls containing elastic tissue; valves prevent backflow . ATRIAL SYSTOLE ↑ PRESSURE IN ATRIA ATRIOVENTRICULAR VALVES OPEN BLOOD FLOWS INTO VENTRICIES VENTRICULAR SYSTOLE ↑ PRESSURE IN VENTRICIES ATRIOVENTRICULAR VALVES CLOSE SEMI-LUNAR VALVES OPEN BLOOD FLOWS INTO ARTERIES DIASTOLE SEMI-LUNAR VALVES CLOSE •PRESSURE IN VENTRICIES AND ATRIA •BLOOD FLOWS INTO ATRIA HIGH HYDROSTATIC PRESSURE O TISSUE FLUID LYMPH Tissue Fluid Formation (link between blood and cells): Atrial end of capillary: hydrostatic pressure > osmotic pressure H₂O/small soluble molecules forced through capillary walls Proteins/cells to large to be forced out Blood pressure falls as it moves in capillary Venous end of capillary: osmotic pressure > hydrostatic pressure Most H₂O moves back into capillaries; remainder of tissue fluid returned to blood O 0 0 0 0 0 0 BLOOD O SINO-AIRIAL NODE- (SAN) ATRIOVENTRICULAR NODE (AUN) O PURKYNE LOW Y O -BUNDLE OF HIS 100- % saturation of haemoglobin 80 60 40 Tissues 20 CO₂ myoglobin. Plasma Red blood cell CO₂ Įc.a. HCO3+H* + O₂ + HHb+HbO₂2 foetal haemoglobin normal haemoglobin 10 12 Initiating the Heartbeat: Myogenic: heart beats without external stimulus O2 Dissociation: 14 partial pressure of oxygen (Kpa) The Chloride Shift: Myoglobin: shifts left; high 02 affinity; O2 muscle store 4. HCO3 diffuses out of RBC; Ct diffuses into RBC 5. H binds to oxyhaemoglobin 1. CO₂ diffuses into RBC 2. CO₂ + H₂O -> carbonic acid (catalyst: carbonic anhydrase) 6. 02 is released from haemoglobin 3. Carbonic acid dissociates 7. 02 diffuses from RBC into into H+ HCO3 plasma PRESSURE (mmHg) O Impulse travels up Purkinje fibres; ventricles contract bottom up; all blood pumped out SAN acts as pacemaker; sends waves of excitation across atria (contract simultaneously) Connective tissue prevents wave passing to ventricles Wave passes to AVN; there's a delay for atria to complete contraction AVN transmits impulse down Bundle of His to apex 120- 100- 80- 60- 40- 20- 0. P WAVE SEMI-LUNAR VALVES OPEN AORTIC PRESSURE VENTRICULAR PRESSURE AV VALVES CLOSE R T WAVE QRS COMPLEX Foetal haemoglobin: slightly left; higher O2 affinity at all partial pressures (take O₂ from mother) SYSTOLE SEMI-LUNAR VALVES CLOSE AV VALVES OPEN ATRIAL PRESSURE DIASTOLE the heart: Pressure changes in Electrocardiograms (ECGs): P wave: atria contacting / atrial systole QRS wave: ventricles contact / ventricular systole T wave: ventricles relax / ventricular diastole Autotrophic: Make own food using simple inorganic substances (CO₂) Phototrophic: Plants; light as energy source; photosynthesis Chemoautotrophic: Energy from chemical reactions Heterotrophic: Depend on others for food (fungi/bacteria) Saprotrophic: Extra-cellular digestion of dead matter Parasitic: Obtain organic compounds from a host Holozoic: Unicellular: Holozoic O Large SA:V O Use of diffusion O Molecules taken in by endocytosis O "OESOPHAGUS "LIVER "GALL BLADDER "MOUTH "PANCREAS a "SMALL INTESTINE APPENDIX "SALIVARY GLANDS STOMACH "BILE DUCT "LARGE INTESTINE fo"RECTUM ANUS Buccal Cavity: mechanical digestion, amylase digests starch and glycogen into maltose Oesophagus: peristaltic movements force food bolus down, mucus acts as a lubricant Multicellular: O 2 layers of cells Tentacles around mouth to sting and paralyse food O Extra-cellular digestion Ingestion: taking in food through the mouth Digestion: breaking large insoluble molecules into smaller soluble ones Endopeptidases: O Hydrolyse peptide bonds in specific amino acids to form shorter polypeptide chains Chapter 4 Liver: produces bile (emulsify lipids to increase SA for lipases); slightly neutralises stomach acid for pancreatic enzymes Gall Bladder: stores bile before going to duodenum via the bile duct Duodenum: digestion on epithelial cells Stomach: gastric glands produce gastric juice; oxyntic cells produce HCl, lowering pH Maltose + Maltase -> a glucose to 2; peptic cells produce pepsinogen; goblet cells produce mucus to protect stomach lining Sucrose+ Sucrase -> Fructose Lactose+Lactase -> Glucose + Galactose Peristalsis: Obtain nutrients with ingestion, Pancreas: produces amylase, transported to Polypeptides digested by endopeptidases digestion, egestion duodenum and exopeptidases O Muscles contracting and relaxing to force food down Absorption: taking in nutrients into the blood Egestion: getting rid of waste Exopeptidases: Hydrolyses peptide bonds on the ends of peptides (amine group or carboxyl group) lleum: amino acids actively transported to villi; facilitated diffusion into capillaries; monosaccharides move into epithelial cells (co-transport); fatty acids/glycerol diffuse into cells and reassemble into triglycerides Colon: absorption of water and minerals Rectum: storage as faeces Anus: egestion Pancreatic Secretion Enzymes Trypsinogen Endopeptidases Amylase Lipase Sodium Hydrogen Carbonate Layers of the Gut: Serosa: tough outer layer of Rumen connective tissue Muscle: longitudinal muscle contracts to shorten gut; circular muscle contracts to reduce diameter Submucosa: contains blood and lymph vessels to remove digested food Function Inactive enzymes converted to trypsin by enterokinase Hydrolyse proteins and polypeptides into peptides Digests starch into maltose Hydrolyses lipids into fatty acids and glycerol Raises pH, neutralises stomach acid for pH for pancreatic enzymes Omasum Hoyo 1.Grass mixes with saliva, Mucosa: inner layer secreting mucus (lubrication); secrets digestive juices; absorbs products chewed and Epithelium: layers of cells in swallowed contact with food Abosmasum Chapter 4 Reticulum 2.Cud rumen; cellulose digesting bacteria (symbiotic) produces cellulase; ferments into organic acids Herbivore: O Incisors on lower jaw; horny pad on top O Diastema separates front and side teeth (area of the tongue) Jaw works in sideways grinding motion so teeth can interlock o Sharp incisors to cut, crush, tear o Large pointed canines for tearing and seizing Molars cut and crush Greater vertical movement Parasites: an organism that obtains nutrients from a host organism Tape Worm: Ectoparasite (lice): Body made up of proglottid sections, scolex, suckers 9 (sticks to gut wall) 3.Cud then enters reticulum; cud is then regurgitated to be rechewed O Carnivore: O O Must survive hostile conditions (around digestive juices; withstand peristalsis; pH changes; host's immune system) Hermaphrodite: male and female reproduction 4 rechewed cud is swallowed, enters the omasum; water is absorbed Transferred to host by direct contact Feeds on blood Able to stick to the hair to remain attached to the host 5-food moves to the abomasum for protein digestion 6 Products of digestion are absorbed into the blood in the small intestine