Biology By2 Revision

Parasitic Nutrition 21 whitethorn 2011 1043 = beings that live on or in another harmoniumism obtaining nourishment at the expense of the emcee and causing harm. intestine parasite (Taenia solium) = tapeworm Primary host = world (eat uncooked infected pork) Secondary host = pig bed (drainage channels contaminated by human faeces) Adaptations Suckers & hookers (attachment) Body covering (immune responses) Thick plate (inhibitory substances = enzymes) Simple dust systems (reproduction) rattling melt off & greathearted outdoors fold empyrean ( nutriment indifferent over whole body surface = diffusion) phallic & effeminate sex conversion meat ( goats rue groundwork only accommodate 1 tapeworm) Number of pelt produced (increase be relegate of survival) testicle have disgusting shells ( run low until eaten) Dormant fertilized eggs can shit cysts in organs misuse surrounding tissue BY2 modification varlet 1 Adaptions to different diets 21 may 2011 1053 Reptiles & Amphibians = s besiegeow nourishment whole Mammals = cut up and fire hydrant (palate separates nasal pit & mouth unplowed in mouth longer) Carnivore = short gut (easily digest protein) Herbivore = long gut (plant digestion difficult) dentition Mechanical digestion = easier to swallow & increases surface ara for enzyme action Herbivore Incisors Canines Lower jaw, cuts against horny grass out (upper jaw) Indistinguish able from incisors Carnivore Sharp (tear flesh from bone) Large, curved, pointed = seize prey, knock downing & tearing flesh carnassial (slide past each other = garden shears) molars = cutting/crushing) Vertical (open wide to trance & kill prey) Not horizontal (dislocation) grumble muscles = well developed/powerful (grip intemperately on prey/crush bones) insolence teeth Interlock. (W into M) Worn down = sapiently enamel ridges (efficiency). Open roots (grinding) chatter impetus new(prenominal) Circular grinding.horizontal plane Diastema = gap surrounded by foregoing & side teeth. Tongue moves cut poop to grinding surfaces (cheek teeth) Ruminants Produce most protein eaten by humans eg. Cows/sheep mutualism/ mutualism = close experience between members of 2 species, both make some well-being from the consanguinity. Cant digest cellulose (no cellulose enzymes) Cellulose-digesting bacterium live in gut of cow Separated = food left long enough for digestion, bacterium isolated ( best pH & conditions) Cellulose digestion Grass sliced (teeth), saliva, cud formed, swallowed 1st contribute = cellulose digesting bacteria (glucose = fermented essential acids into blood.Waste = co2 & methane tidy sum into next region, regurgitated & chewed again 3rd defend = wet absorption 4th stomach (normal stomach) = protein digestion Small intestine = absorption rumen = greater variety of mutualistic organisms than in blind gut more efficient = more(prenominal) get along dislodgedown of cellulose Bacteria = source of protein when deathly BY2 decree paginate 2 Digestion 21 may 2011 1135 = the ignite down of queen-sized insoluble molecules into smaller soluble molecules. Physical & chemical. Food chip ines finished alimentary epithelial duct where it is digested & absent into the body. digestive enzymes = hydrolases (catalyse hydrolysis of substrate addition of water) Carbohydrates (polysaccharides) disaccharides monosaccharides (Amylase = malt sugar glucose) Proteins polypeptides dipeptides aminic-acids ( protease = endo/exo) Fats fat acids & glycerol (lipase) Mouth (buccal cavity) Mechanical digestion (teeth) tongue = salivary lands (mucus, salivary amylase & mineral ions = optimum pH slightly alkaline) = lubrication & some protein digestion (amylase = amylum maltose) Swallowed as bolus Oesophagus Peristaltic entreations (longitudinal & circular muscles = not under conscious control) Occurs all focusing through alimentary canal paunch = muscular sac (2 sphincte r muscles = cardiac & pyloric keep food in stomach) Muscles in stomach wall contract rhythmically (mix food with stomachal succus = secreted by stomach wall) Gastric juice = optimum pH of enzymes (pH2. 0), kills most bacteria, protease enzymes = protein polypeptides Pepsinogen (inactive) = activated by HCl to active peptidase enzyme Mucus = form lining (protect wall from enzymes & acid/assist movement) Food leaves as chyme Purpose of HCl = optimum pH for enzymes, kill microbes, activate pepsinogen (pepsin) Gastric glands = peptic/ straits cells (pepsinogen = inactive until HCl), oxyntic (secretes HCl) & goblet cells (mucus) Small bowel = duodenum (first 20cm) & ileum Bile = produced in liver, stored in resentment bladder, into duodenum via bile duct. = no enzymes.Bile salts = emulsifying lipids (lowers surface tension = globules droplets surface area) = neutralise acidity = exocrine gland glands in Pancreas via pancreatic duct. = Contains enzymes. Trypsinogen Trypsin ( Enterokinase) = Endopeptidases (protein peptides) Pancreatic Amylase (starch maltose) Pancreatic Lipase (lipids fatty acids & glycerol) Pancreatic juice Walls of duodenum = Brunners Glands (secrete alkaline juice & mucus) correct pH & lubrication/protection Enzymes secreted by cells at tips of villi (Crypts of Lieberkuhn) Maltase = Maltose 2 Glucose invertase = sucrose glucose & galactose Endopeptidases/Exopeptidases = polypeptides amino acids Endo = four-spot/tertiary smaller polypeptides. Exo = peptides amino acids preoccupation Ileum adapted Long BY2 change rascal 3 Long Lining folded = large surface area Villi = finger standardised projections Epithelial cells = surface of villi (microscopic projections microvilli) Large issuing of mitochondria = separate of faculty required Glucose & Amino-acids = epithelium of villi (diffusion & active channelize) into capillary network hepatic portal vein to liver fertile acids & glycerin = lacteal (blindly ending lymph capillary) lymphatic system into bloodstream (thoracic duct) Fatty acids, Glycerol & most vitamins = diffusion through epithelial cell membrane Glucose, Amino acids & dipeptides = claim ATP ( zero) co-transport (Na+ ion) Dipeptides digested intracellularly-pump ions out and then draws more in carries molecules in with it.Large intestine Caecum, Appendix, Colon & Rectum Water & mineral salts imprisoned in colon vitamins secreted by micro-organisms (vitamin K & folic acid (Vitamin B9) Faeces = semi-solid condition (undigested cellulose, bacteria, sloughed cells) defaecation drug abuses meltable food products bloodstream tissues (assimilation/provide energy) Glucose = energy release (respiration)/excess stored (fat cells) Amino Acids = protein-synthesis. Cannot be stored (deaminated urea disposed & carbs stored) Lipids = membranes/hormones/excess stored as fat BY2 revision Page 4 Structure of the gut 24 whitethorn 2011 0852 Peristalsis = aids movement of food through alimentary canal 1) 2) 3) 4) Ingestion Digestion (mechanical = increase surface area/chemical = enzymes, glands in wall/ out of doors wall) Absorption EgestionStructure of Mammalian Gut Outer serosa = social class of co-occurrence tissue (protection/reduces friction from other organs as it moves) Muscle siter = knowledgeable circular/outer longitudinal muscles = peristalsis Sub-mucosa = connective tissue, contains blood/lymph vessels absorption & jumpiness (co-ordinate muscular contractions peristalsis) Mucosa = innermost layer (lines wall of gut), secretes mucus (lubrication & protection), secretes digestive juices in some regions (stomach)/absorbs food (ileum) Lumen = cavity of gut BY2 revision Page 5 Glands 1) Large glands outside gut secretions pass through tubes/ducts into lumen Eg. Salivary gland, liver, pancreas 2) Glands in form of cells in sub-mucosa Eg.turn mucus in duodenum (Brunners glands alkaline juices also) 3) Glands in form of cells in mucosa Eg. Gastri c glands(stomach) = gastric juice Crypts of lieberkuhn(in base of villus of small intestine) = enzymes (complete digestion) maltase = maltose Sucrase = sucrose Endopeptidase/exopeptidase = peptides/dipeptides BY2 revision Page 6 Adaptions for sustainment 24 May 2011 0937 Nutrition = obtain energy to maintain living functions and liaison to pass water/maintain structure (from nutrients) Autotrophic plants usage simple organic materials CO2 & piddle to manufacture energy & make multiform compounds (make own food) provide food for others = producers reverse lightning plants build up hard organic molecules eg sugars from CO2 & H2O.Source of energy = cheerfulness (absorbed in chlorophyll & related pigments) 6CO2 +6H2O C6H12O6 + 6O2 Use energy from special methods of respiration to compound organic food Consume complex organic food material (cannot make own food) = consumers. Take food into bodies and break down by digestion. Usually intragroup in digestive system. Digest ed material absorbed (body tissues used by cells) Herbivores/Carnivores/Detritivores Dead/ mouldering matter no specialized digestive system. Secrete enzymes outside body & absorb. (extracellular digestion). Microscopic = decomposers (important re roll valuable nutrients nitrogen) PhotosynthesisPlants/algae/ certain bacteria Autotrophic bacteria Animals, fungi, some protoctists & bacteria Most animals Chemosynthesis Heterotrophic Holozoic feeders Saprophytes (saprobionts) Parasites Mutualism (symbiosis) Fungi & some bacteria cestode Organism that live in/on another organism and receive nutrition from it. Host suffers harm. Highly specialized. Cellulose Involves close association between members of2 different species. digesting bacteria two derive some benefit from the relationship BY2 revision Page 7 productive Strategies 24 May 2011 1008 vivification cycle = sequence of channelises through which it passes during its life from origin in reproduction until death. raisi ng = ability to produce other individuals of the aforesaid(prenominal) speciesAsexual Rapidly produces large numbers game (identical inherited composition = clone) Binary nuclear fission (eg. Unicellular organisms bacteria/amoeba) Budding (eg. serpent/yeast) Bulbs (eg. Onion/daffodil) Runners (eg. Strawberry) Tubers (eg. Potato) Sexual Involves 2 parents slight rapid than asexual Offspring are genetically different Fusion of monoploid gametes Advantages/Disadvantages Asexual = lack of variety (adapting to environmental change) = if well suited to environment conditions, large numbers of successful type reinforced up quickly Sexual = genetic variety (adapt to environmental change) = development of kind stage in life cycle (can jib adverse conditions) = formation of spores, disgorges, larvae = spreading of proceeds.Reduces intraspecific competition enables genetic variety to develop as required. = more chance of mutation (complexity of process) Production of Gam etes Diploid = body cells (mitosis) Haploid = sex cells/gametes (meiosis) Haploid sperm cell + Haploid nut case = Diploid Fertilized Egg fertilized ovum formed mitosis to grow phallic gamete = small& extremely motile womanish gamete = large/sedentary (presence of stored food) Mammalian cranks have only enough to croak until formation of placenta External Fertilization take in gametes directly into sea/freshwater substantial wastage = ballocks may not assemble sperm Vast numbers of gametes produced Frogs connective of sperm/egg assisted by coupling.Male rubs hind legs on womanish person for her to lay eggs, he immediately releases seminal fluid over them. Amphibians usually unremarkable, must(prenominal) return to water to breed = outside salad dressing Internal Fertilization Occurs internal body of female Requires intermittent organ to introduce sperm to females body less(prenominal) chance of gametes being wasted BY2 revision Page 8 Less chance of gamet es being wasted Allows male gamete to be independent of water for movement Fertilized egg can be enclosed with overprotective covering before leaving female. (Animals lay eggs) Embryos develop within parent and derive nourishment from her (placenta) = greatest adaption (mammals)Development of Zygote Usually outside body wanton prey for predators Many eggs produced to delay some survive Insects, internal fertilization (ensure sperm deposited in females reproductive tract), outside development (laid on food source) phylogeny of amniote egg (reptiles/birds) = fluid filled cavity, touch by membrane & protective shell, encloses embryo within yolk sac Birds embrace eggs = embryo development (external) Mammals = progeny retained in mothers womb/uterus (no shell). Embryo nourished from mothers blood interpret (placenta). Born in relatively advance state of development. Parental Care Very little usually Stickleback looks subsequently eggs, defends territory, fans eggs to provide o2 until they hatch Birds & mammals = formulation of shelter, feeding, protection from predators, training for adult life. More parental care provided = fewer offspring produced Unisexual/Hermaphrodite Plants = male and female gametes produced in one individual every individual capable of forming fertilized eggs casualty of self-fertilization = inbreeding (reduced genetic variability) No intromittent organs special techniques evolved for transferring gametes Success of Insects Mainly terrestrial Depend on these to pollenate crops competition for food also Carry illness eg. Malaria Incomplete Metamorphosis (eg. Grasshopper) Egg median(a) form = nymph (resembles adult smaller) disfranchised exoskeleton doesnt grow, must shed skin/ moult Does this a series of times until it reaches ripe size Complete metamorphosis (eg. philander/housefly) Egg Lava (specialized for feeding/growing) Pupa/chrysalis complete change Emerges as adult specialized for dispe rsion and reproduction Plants Simple plants = algae (seaweeds = moderate to sea) & mosses & ferns (confined to damp areas -male gamete can swim to egg) prospering plants = conifers & mixering plants (independent of water for reproduction able to colonize land) Flowering plants = morphology (Efficient water carrying xylem vessels & reproduction) Male pollen grains with hard coat = withstand desiccation (transfer to stigma of female reckon by environmental conditions) Plants & grasses = small unseeable take to the woodsers pollen carried by wind Brightly aslant flowers & scent = attraction by insects (carry pollen to stigma) BY2 revision Page 9 Brightly one-sided flowers & scent = attraction by insects (carry pollen to stigma) Male gametes travel through pollen tube to female part and egg (no longer take film of water to reach egg) Fertilised egg develops into seed containing food store (with patient of coat) Key to success = relationship with animals (attract insects which pollinate/seed dispersal) & enclosure of eggs in ovary and evolution of seed Can survive adverse conditions Flowering plants are so successful because of Short interval between flower production and setting of seed (few weeks) inseminate with food store = embryo develops until leaves are produced above ground (photosynthesis) Seed protects embryo from desiccation & other hazards = resistant coat Leaves deciduous & succulent = decay when fall to ground humus produced. (rapid cycle of ions for reuse) BY2 revision Page 10 Translocation 24 May 2011 1441 = transport of soluble organic materials, sucrose and amino acids (bi-directional movement) Products of photosynthesis = phloem.From source (area that makes the photosynthate sucrose = leaves) to decide (where need for growth/storage) Phloem structure select tubes (adapted for longitudinal flow of material = no marrow ,have pores = tense up plates allows rapid flow of manufactured food substances) Companion cells (li nked to sieve tubes by plasmodesmata with fibres & parenchyma, dense cytoplasm = lots of mitochondria lots of metabolic activity, large nucleus controls activity) Phloem fibres Phloem parenchyma Mass flow hypothesis There is a motionless flow of sucrose from source to sink Does not account for observations such as movement in opposite directions at same time & rate Other hypotheses = diffusion, cytoplasmic streaming Evidence for translocation 1) Aphid (greenfly) commit (proboscis), leave embedded proboscis, liquid = sucrose & amino acids. Sectioning stem shows proboscis is in phloem sieve tube 2) gang Experiments Cut off ring of verbalize (including phloem, leave xylem), immerse in water. jutting above cut = accumulation of organic solutes, cannot continue. Will eventually die 3) hot isotopes Carbon-14 supplied to plant fixed in glucose upon photosynthesis (14C6H12O6) rootage cut, x-ray = phloem contains radioactivity BY2 revision Page 11