Biology By2 Revision

Parasitic Nutrition 21 whitethorn 2011 1043 = organisms that live on or in a nonher organism arresting nourishment at the expense of the host and causing harm.Gut sponger (Taenia solium) = tapeworm Primary host = human (eat uncooked infected pork) alternate host = pig (drainage channels contaminated by human faeces) Adaptations Suckers &038 hookers (attachment) remains covering (immune responses) Thick copeicle (inhibitory substances = enzymes) Simple dead consistence sy kiboshs (reproduction) Very frail &038 enormous grow area ( nourishment for thought absent-minded over whole body scratch = diffusion) anthropoid &038 female person sex variety meat ( goats rue can exactly accommodate 1 tapeworm) Number of fruitcakes produced (increase chance of survival) nuts watch resistant shells (survive until eaten) Dormant embryos can form cysts in organs victimize surrounding tissue BY2 revision varlet 1 Adaptions to contrary live onts 21 May 2011 1053 Reptiles &0 38 Amphibians = swallow food whole Mammals = cut up and chew (palate separates nasal cavity &038 mouth kept in mouth longer) Carnivore = short gut (easily digest protein) Herbivore = long gut (plant digestion difficult) dentition windup(prenominal) digestion = easier to swallow &038 increases surface area for enzyme action Herbivore Incisors Canines Lower jaw, cuts against sexy pad (upper jaw) Indistinguishable from incisors Carnivore Sharp (tear flesh from bone) Large, curved, pointed = seizing prey, killing &038 divide flesh Carnassial (slide past each other = garden shears) molars = film editing/ dumbfounding) Vertical (open wide to capture &038 kill prey) Not horizontal (dislocation) nark muscles = tumefy weared/powerful (grip firmly on prey/crush bones) Cheek teeth Interlock. (W into M) Worn down = sharp enamel ridges (efficiency). heart-to-heart roots (grinding) Jaw movement Other Circular grinding.Horizontal matte Diastema = gap amidst front &038 side teeth. Tong ue moves cut passel to grinding surfaces (cheek teeth) Ruminants Produce most protein eaten by humans eg. Cows/sheep symbiosis/Symbiosis = close association mingled with members of 2 species, both arrive virtually benefit from the human relationship. Cant digest cellulose (no cellulose enzymes) Cellulose-digesting bacterium live in gut of cow Separated = food left long enough for digestion, bacterium isolated (optimum pH &038 particular(a)(a)izes) Cellulose digestion Grass chopped (teeth), saliva, cud formed, swallowed 1st conduct = cellulose digesting bacteria (glucose = fermented entire acids into declension.Waste = co2 &038 methane Cud into next region, regurgitated &038 chewed again 3rd stomach = water absorption 4th stomach (normal stomach) = protein digestion vitiated intestine = absorption Rumen = greater variety of mutualistic organisms than in cecum to a greater extent efficient = more complete eruptdown of cellulose Bacteria = quotation of prote in when dead BY2 revision scallywag 2 Digestion 21 May 2011 1135 = the break down of large in dissoluble molecules into smaller soluble molecules. Physical &038 chemical. feed passes through nutrient canal where it is digested &038 absorbed into the body. digestive enzymes = hydrolases (catalyse hydrolysis of substrate addition of water) Carbohydrates (polysaccharides) disaccharides monosaccharides (Amylase = maltose glucose) Proteins polypeptides dipeptides amino-acids ( protease = endo/exo) Fats copiousty acids &038 glycerol (lipase) Mouth (buccal cavity) Mechanical digestion (teeth) Saliva = salivary lands (mucus, salivary amylase &038 mineral ions = optimum pH slightly saltlike) = lubrication &038 some protein digestion (amylase = starch maltose) Swallowed as bolus Oesophagus Peristaltic contractions (longitudinal &038 circular muscles = not chthonic conscious control) Occurs all way through alimentary canal run = muscular sac (2 sphincter muscles = cardiac &038 pyloric keep food in stomach) Muscles in stomach wall contract rhythmically (mix food with gastric juice = secreted by stomach wall) stomachic juice = optimum pH of enzymes (pH2. 0), kills most bacteria, peptidase enzymes = protein polypeptides Pepsinogen (in prompt) = activated by HCl to active peptidase enzyme Mucus = form lining (protect wall from enzymes &038 acid/assist movement) Food leaves as chyme Purpose of HCl = optimum pH for enzymes, kill microbes, activate pepsinogen (pepsin) Gastric glands = peptic/chief cells (pepsinogen = inactive until HCl), oxyntic (secretes HCl) &038 goblet cells (mucus) Small Intestine = duodenum (first 20cm) &038 ileum insolence = produced in liver, repositingd in gall bladder, into duodenum via bile duct. = no enzymes.Bile salts = emulsifying lipids (lowers surface tension = globules droplets surface area) = neutralise acidity = exocrine glands in Pancreas via pancreatic duct. = Contains enzymes. Trypsinogen Trypsin (Enterokin ase) = Endopeptidases (protein peptides) Pancreatic Amylase (starch maltose) Pancreatic Lipase (lipids fatty acids &038 glycerol) Pancreatic juice Walls of duodenum = Brunners Glands (secrete alkaline juice &038 mucus) correct pH &038 lubrication/protection Enzymes secreted by cells at tips of villi (Crypts of Lieberkuhn) Maltase = Maltose 2 Glucose Sucrase = saccharose glucose &038 galactose Endopeptidases/Exopeptidases = polypeptides amino acids Endo = quaternary/tertiary smaller polypeptides. Exo = peptides amino acids assiduousness Ileum adapted Long BY2 revision Page 3 Long lining folded = large surface area Villi = finger like projections Epithelial cells = surface of villi (microscopic projections microvilli) Large number of mitochondria = lots of life force required Glucose &038 Amino-acids = epithelium of villi (diffusion &038 active transport) into capillary network hepatic portal vein to liver butterball acids &038 Glycerol = lacteal (blindly ending lymph c apillary) lymphatic system into bloodstream (thoracic duct) fat acids, Glycerol &038 most vitamins = diffusion through epithelial cell tissue worldlyer Glucose, Amino acids &038 dipeptides = need ATP (energy) 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 &038 Rectum Water &038 mineral salts absorbed in colon vitamins secreted by micro-organisms (vitamin K &038 folic acid (Vitamin B9) Faeces = semi-solid condition (undigested cellulose, bacteria, sloughed cells) defaecation Uses Soluble food products bloodstream tissues (assimilation/provide energy) Glucose = energy release (respiration)/ overmuch lineaged (fat cells) Amino Acids = protein-synthesis. Cannot be stored (deaminated urea disposed &038 carbs stored) Lipids = membranes/hormones/excess stored as fat BY2 revision Page 4 Structure of the gut 24 May 2011 0852 Peristalsis = aids movement of foo d through alimentary canal 1) 2) 3) 4) Ingestion Digestion (mechanical = increase surface area/chemical = enzymes, glands in wall/outside wall) Absorption EgestionStructure of Mammalian Gut out serosa = layer of connective tissue (protection/reduces friction from other organs as it moves) Muscle layer = inner circular/outer longitudinal muscles = peristalsis Sub-mucosa = connective tissue, contains blood/lymph vessels absorption &038 nerves (co-ordinate muscular contractions peristalsis) mucous membrane = innermost layer (lines wall of gut), secretes mucus (lubrication &038 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.Secrete mucus in duodenum (Brunners glands alkaline juices also) 3) Glands in form of cells in mucosa Eg. Gastric gl ands(stomach) = gastric juice Crypts of lieberkuhn(in base of villus of small intestine) = enzymes (complete digestion) maltase = maltose Sucrase = saccharose Endopeptidase/exopeptidase = peptides/dipeptides BY2 revision Page 6 Adaptions for nutrition 24 May 2011 0937 Nutrition = obtain energy to maintain life functions and matter to create/maintain social organisation (from nutrients) Autotrophic plants Use simple organic tangibles CO2 &038 H2O to bring to pass energy &038 make complex compounds (make own food) provide food for others = producers putting green plants build up complex organic molecules eg sugars from CO2 &038 H2O.Source of energy = sunlight (absorbed in chlorophyll &038 related pigments) 6CO2 +6H2O C6H12O6 + 6O2 Use energy from special methods of respiration to synthe size of it organic food Consume complex organic food material (cannot make own food) = consumers. Take food into bodies and break down by digestion. normally internal in digestive system. Dige sted material absorbed (body tissues used by cells) Herbivores/Carnivores/Detritivores Dead/decaying matter no alter digestive system. Secrete enzymes outside body &038 absorb. (extracellular digestion). Microscopic = decomposers (important recycling priceless nutrients nitrogen) PhotosynthesisPlants/alga/ certain bacteria Autotrophic bacteria Animals, fungi, some protoctists &038 bacteria Most animals Chemosynthesis Heterotrophic Holozoic feeders Saprophytes (saprobionts) Parasites Mutualism (symbiosis) Fungi &038 some bacteria Tapeworm 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 Both derive some benefit from the relationship BY2 revision Page 7 Reproductive Strategies 24 May 2011 1008 Life cycle = sequence of interchanges through which it passes during its life from origin in reproduction until death. Reprod uction = ability to produce other individuals of the same species agamous Rapidly produces large numbers (identical genetic composition = clone) Binary nuclear fission (eg. Unicellular organisms bacteria/amoeba) Budding (eg. Hydra/yeast) Bulbs (eg. Onion/daffodil) Runners (eg. Strawberry) Tubers (eg. Potato) Sexual Involves 2 parents Less rapid than asexual Offspring are genetically different Fusion of haploid gametes Advantages/Disadvantages Asexual = lack of variety (adapting to environmental change) = if well suited to environment conditions, large numbers of successful type create up quickly Sexual = genetic variety (adapt to environmental change) = using of resistant stage in life cycle (can withstand untoward conditions) = formation of spores, seeds, larvae = dispersal of offspring.Reduces intraspecific competition enables genetic variety to develop as required. = more chance of mutation (complexity of process) Production of Gametes diploid = body cells (mitosis ) Haploid = sex cells/gametes (meiosis) Haploid Sperm + Haploid Egg = Diploid Fertilized Egg Zygote formed mitosis to grow Male gamete = small&038 super motile Female gamete = large/sedentary (presence of stored food) Mammalian ballock return only enough to survive until formation of placenta External fecundation bring in gametes directly into sea/freshwater Considerable wastage = eggs may not encounter spermatozoan Vast numbers of gametes produced Frogs joining of sperm/egg assisted by coupling.Male rubs hind legs on female for her to lay eggs, he immediately releases seminal fluid over them. Amphibians usually terrestrial, must(prenominal) return to water to breed = external fertilization Internal Fertilization Occurs inside body of female Requires intermittent organ to introduce sperm to females body Less chance of gametes being wasted BY2 revision Page 8 Less chance of gametes being wasted Allows male gamete to be independent of water for movement Fertilized eg g can be cover with protective covering before leaving female. (Animals lay eggs) Embryos develop inside parent and derive nourishment from her (placenta) = greatest adaption (mammals)Development of Zygote Usually outside body easy prey for predators Many eggs produced to attend some survive Insects, internal fertilization (ensure sperm deposited in females fruitful tract), external development (laid on food source) Evolution of amniote egg (reptiles/birds) = fluid filled cavity, surrounded by membrane &038 protective shell, encloses embryo within yolk sac Birds incubate eggs = embryo development (external) Mammals = boyish retained in mothers womb/uterus (no shell). Embryo nouri toss from mothers blood supply (placenta). Born in relatively advanced state of development. agnate Care Very little usually Stickleback looks after eggs, defends territory, fans eggs to provide o2 until they hatch Birds &038 mammals = provision 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 Possibility 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 pollinate crops contention for food also Carry disease eg. Malaria Incomplete Metamorphosis (eg. Grasshopper) Egg Intermediate form = nymph (resembles adult smaller) Hard exoskeleton doesnt grow, must shed skin/molt Does this a series of times until it reaches full size Complete metamorphosis (eg.Butterfly/housefly) Egg Lava (specialized for feeding/growing) Pupa/chrysalis complete change Emerges as adult specialized for dispersal and reproduction Plants Simple plants = algae (seaweeds = confined to sea) &038 mosses &038 ferns (confined to damp areas -male gamete can swim to egg) Successful plants = conifers &038 flowering plants (independent of water for reproduction able to colonize land) Flowering plants = morphology (Efficient water carrying xylem vessels &038 reproduction) Male pollen grains with hard coat = withstand vaporisation (transfer to stigma of female fix by environmental conditions) Plants &038 grasses = small inconspicuous flowers pollen carried by wind brightly coloured flowers &038 scent = attraction by insects (carry pollen to stigma) BY2 revision Page 9 Brightly coloured flowers &038 scent = attraction by insects (carry pollen to stigma) Male gametes spark through pollen tube to female part and egg (no longer necessitate film of water to reach egg) Fertilised egg develops into seed containing food store (with resistant coat) Key to success = relationship with animals (attract insects which pollinate/seed dispersal) &038 bourne of eggs in ovary and evolution of seed Can survive unbecoming conditions Flowering plants are so successful because of Short interval between flower production and setting of seed (few weeks) Seed with food store = embryo develops until leaves are produced above ground (photosynthesis) Seed protects embryo from desiccation &038 other hazards = resistant coat Leaves deciduous &038 succulent = decay when recall to ground humus produced. (rapid recycling 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 sink (where needed for growth/storage) bast fiber structure Sieve tubes (adapted for longitudinal flow of material = no marrow ,have pores =cover plates allows rapid flow of manufactured food substances) Companion cells (linked to sieve tubes by plasmodesmata with fibres &038 parenchyma, dense cytoplasm = lots of mitochond ria lots of metabolic activity, large nucleus controls activity) Phloem fibres Phloem parenchyma Mass flow hypothesis in that respect is a passive flow of sucrose from source to sink Does not account for observations such as movement in opposite directions at same time &038 rate Other hypotheses = diffusion, cytoplasmic streaming usher for translocation 1) Aphid (greenfly) Feed (proboscis), leave embedded proboscis, liquid = sucrose &038 amino acids. Sectioning stem shows proboscis is in phloem sieve tube 2) Ringing Experiments film editing off ring of bark (including phloem, leave xylem), immerse in water. jutting above cut = accumulation of organic solutes, cannot continue. Will eventually die 3) Radioactive isotopes Carbon-14 supplied to plant fixed in glucose upon photosynthesis (14C6H12O6) Stem cut, x-ray = phloem contains radioactivity BY2 revision Page 11