Gcse Biology Revision

• Animalia:Multi-Cellular,Hetrotrophic-Feeders,No cell walls.
• Plantae:Multi-Cellular,Cell walls made: Cellulose,Autrophic feeders: Chlorophyll
• Fungi:Muli-Cellular,No Chorophyll,Cell walls; Cellulose.
• Protoctista:Mostly unicellular:(Few:Mulitcellular,Complex Cell structure with nucleaus.
• Prokokayrates:Unicelluar:Simple Cell Sturucture; no nucleaus
• Virus particles-doesnt show any life process:Growing/Feeding.

• Phylum Chordata:Animals:Backbone:Length; body.
• Scientists: Place vertaebrates; groups:Oxygen-abortion methods-lungs,gills,skin.
• Reproduction-Internal; external fertilisation.
• Oviparous-Lay eggs
• Vivaporous-Give Birth

Limitation species produce fertile offsprings:Some organisims do not  reproduce sexually; some hybrids: fertile.

• Bionominal system useful:Organisims ; same names:Diffrent.
• Hybridisation in ducks produces ducks:Contionous range; characteristics. 

• Contionous Variation-Numerical Value
• Discontinous Variation: fixed set of values.

Reasons of Variety

Organisism ;previously adapted characteristics.Enables them to survive ;extreme enviroments:Deep-sea hydrothermal vents;Polar regions.

Causes of Variation:

• Genetic Variation-Different characteristics result: Mutation/ Reproduction.
• Enviromental Variation-Characteristics caused by:  Organisims Enviroment.

Darwin's theory of evolution  by natural evolution:

• Variation
• Over-Production
• Gradual Change
• Survival

Speciaion occurs because of geographical isolation

Structure of nucleaus: chromosones:Where genes: Located.

Genes exist in different forms called alleles.

Dominant allele: Allele that will always have an effect.

Recessive gene:Will have an effect if other gene: Recessive.

Homozygous:Same alleles.

Heterozygous:Different alleles

Phenotype:Physical characteristics.Set ;alleles cause.

Genotype:Alleles: Certain charateristics.

1/4 chance of inheriting diseases in families.

Sickle cell disease:Tired,Short of breath

Cystic Fibrosis:Weight loss.Difficult to breath.

• Maintainance of stable internal enviroment.
• Control of body temprature:Theremogulotion.
• Body temprature:37:Chemical reactions work best, in body.
• Osmoregulotion:Controls water. Controls concentration of some materials. E.G Glucose in Blood.
• Role of Dermis: Sweat Glands,Blood Vessels,Nerve Endings,Hair-Erector Muscles,Sabecous Glands,
• Role of Hypathalamus: Regulates Body Temprature.
• Hypathalamus: Blood flow reduced to skin: Narrowing blood vessels, close to surface: Body is cold.
• Vasolidation:blood vessels supply blood to  skin can swell;dilate. Allows warm blood to flow near surface of  skin, where heat is be lost to  air.
• Vasoconstriction:blood vessels supply warm blood to skin becomes: narrow; constrict. Reduces flow of warm blood near surface of  skin;reduces heat loss.
• Negative Feedback:Changes in body happens in one direction; mechanisims in body work to change in opposite way.

Structure of nucleaus contains chromosones:Where genes are located.

Genes exist in different forms called alleles.

Dominant allele: Allele that will always have an effect

Recessive gene:Will have an effect if other gene is recessive.

Homozygous:Same alleles.

Heterozygous:Different alleles

Phenotype:Physical characteristics.Set of alleles cause.

Genotype:Alleles for certain charateristics.

1/4 chance of inheriting diseases in families

• Central Nervous System:Brain;Spinal Cord.
• Central Nervous System:Linked to sense organs by nerves.
• Dendrites:Recieve impulses from receptor cells for other neurones.
• Impulse:Passed along axon,to ending;passed across to other neurones
• Brain:Process electrical signals;sends:impulses to other organs.

• Role of mylin Sheath:heath helps insulate neuronefrom surrounding tissue;allows impulses:Carried faster,
• Fatty layer around axon
• Neurotransmitters:Impulses transmitted across gaps in synapses.
• Reflex arc:Sensory neurones directly control motor neurones.
• Reflexes:Protects body.

• Hormones:Located endorine glands.
• Transported; blood  target organs.
• Blood glucse organs:Regulated ; insulin;excess blood coverted ; glycogen : air.
• When glucose gets above certain concentration:Pancreas releases hormone:Insulin
• Liver takes glucose out  blood;converts glycogen.

• Diabetes:Caused: Lack insulin
• Insulin:Needs to injected; fat layer beneath skin.
• Insulin spreads into blood vessels;carried around body blood.
• Type 2 diabetes:Caused:Person resistant insulin
• Type 2 diabetes:Controlled:Changing person's diet;increasing amount excerise.

• In roots auxins cause cell:stop elogating;causes: phototropism.
• Phototropism:Growth towards direction; gravity.

• Selective weed-killers:Artificial auxins used: selective weed killer.
• Selective weed killer:Makes Plants; broad leaves;grows out; control;dies.
• Farmers kill plants;without affecting crops.
• Rooting powder:Synthetic auxins;used: Rooting powder.
• Plant cutting;dipped: Root powder plants develop roots quickly.
• Seedless Fruit:Flowers sprayed: Plant hormones;cause fruits to develop; not seeds.
• Fruits sprayed: Gibberllins;increase size.
• Fruit Ripening:Plant hormones naturally control ripeneing: Fruits.

• Drug:Chemical Substance:Narcotics,hallocinagen:Controls nervous system.
• Morphine:Painkiller.
• Pain-Killers:Block nervous impulses.
• Lsd:Hallocinages:Distort sense perception:Sight,Hearing,Feeling.
• Caffeine:Stimulants.
• Stimulants:Increase speed  reactions;neurotransmission:Synapses.
• Alcholol:Slow down brain activity.

• Nicotine:Addictive part tobacco; difficult give up.
• Tar:Contains Carcinogens;causes cancer:developes:lung of mouth.

Harmful affects of alcohol abuse:

Short Term-Blurred Visions,blowering inhabitants,slowing  reactions.

Long term-Liver Cirrhosis;Brain Damage.

• Hospitals,not give all patients,liver transplants,until proven; alcohol:Six months.
• Heart Transplant:Clinically Obese.
• Hospitals not perform heart transplants until ,stick;diet.

• Pathgens spread:Cholcera bacterium  water,Salmonella,bacterium,food,influenza virus(sneezin,airborne)athelete's foot,Hiv,bodily fluids.
• Animal Vectors:House-fly,dysentry bactrium,malerian protzoan:Anopheles Mosquito.

• How human body;effective against attacks pathogens.
• Phyical Barries-Skin,Cilla,Mucus.
• Hydrochloric acid-Stomach,Lynsomes-Tears.
• Plants produce chemicals:ani-bactrial effects;defend theselves;used: Humans.
• Anti-Biotics-Prevent pathogen getting into wound
• Anti-Biotics affect bacteria-Penicillin-AniBacterials.
• Anti-Fungals-Treat Fugal Infections
• Anti-Biotics-Affect Bacteria Nystatin:Anti-Fungals.

• Interdependence:Dynamic; living things.
• Some energy transferred;less useful,limits energy.
• Shape:Pyramid;Biomass:Determined;energy transferred;each level.

• Parasites:Feeding relationship;two organisms live together,feeding off host.
• Examples:Fleas,Headlies,Tapeworms,Mistletoe.
• Mutualists:Organisisms benefit off each other.
• Example:Cleaner-Fish,Nitrogen-Fixing Bacteria,

• Method to Eutrophocation:
• Fertiliser:Added,Heavy Rain:Washes: Fertliser off
• Nitrates,Phospahates:Dissolve:Soil-Water
• Nitrates;Phosphates;taken up by plants;washed:Steam/River.
• High Nitrate phosphates concentrations:Water:Enlarge plants;Algae;Grows rapidly.
• Surafce plants:Block Sunlight ;plants in water die,stops producing oxgen:Photosynthesis
• Bacteria:Breaks down dead macterials increase:Numbers;use up:More oxyen;water
• Oxgen Water Concentration:Water Decreases.

• Pollution Indicators:Scienticts : Assess pollution level
• Examples:Polluted Water Indicator:Blood-Worm,Sludge-Worm,
• Clean Water-Indicator:Stone-Fly,Fresh-Water Shrimps.
• Air Quality Indicator:Lichen Species,Black Foot Fungus,Roses.
• Recycling:Reduces demand:Recources;Problem:Waste disposal:Plastics,Paper,Metals.

• Photosynthesis:Plants:Remove carbon-dioxide,from atmosphere,
• Carbon Compounds pass along:Food chain.
• Respiration:Organisisms release carbon-dioxide into atmosphere.
• Combustion Fossil Fuels:Release Carbon-Dioxide into atmosphere.

• Nitrogen gas: Air;cannot be used: Animals;Plants.
• Nitrogen-FIxing Bacteria-Lives-Root Noudles/Soil:Fixes Nitrogen Gas.
• Action of Lightening:Converts Nitrogen gas:Nitrates.
• Decomposers:Breaks down:Animals;Plants.