Biology Igcse

Biology Revision summer 2012
1-Characteristics of living organisms
Nutrition- taking in of nutrients which are organic substances and mineral ions , containing raw materials or energy for growth and tissue repair , absorbing and assimilating them .
Excretion- the removal from organisms of toxic material, the waste products of metabolism and substances in excess of requirement .
Respiration- the chemical reactions that break down the
Sensitivity- The ability to detect or sense changes in the environment (stimuli) and to make responses.
Reproduction- The processes that make more of the same kind of organism.
Growth- A permanent increase in size and dry mass by an increase in the cell number, size or both.
Movement- An action by an organism causing a change of position or place.

MRS GREN

2-Classification System
Key words: Binomial, Genus, species, Vertebrate, Fish, Amphibian, Reptile, Bird, Mammal, Virus, Bacteria, Fungi. The five main classes of vertebrates need to be classified by visible, external characteristics only. Fish Amphibians Reptiles Mammals Birds The main features of the adaption to the environment of viruses, bacteria and fungi. Main features include the following but are not limited to them. The name of the bacteria should be italic when typed or underlined when hand written.

| Main Features | Virus | Protein coat. DNA or RNA single stranded genetic material. Spikes. Non-Living. No cell membrane. Capsomere. Multiplication by replication. Relies on living cells. No metabolic pathways. Vulnerable outside of the host. | Bacteria | Bacilli (bacillus .sing), Cocci (coccus sing) and Sprilli (sprillum sing.). 1-2µm in length. Cytoplasm. Glycogen. Slime coat. Cell wall. Cell membrane. Plasmids. DNA (not in nucleus). Flagella. Living. Reproduce by binary fission. Feeding is saprotrophic or parasitical (dead or living organic material) | Fungi | Hyphae. Mycelium. Nucleus. Vacuole. Cytoplasm. Glycogen Granule. Hyphal wall. Asexual reproduction by spores(most fungi) or budding (yeast). Feeding is saprotrophic or parasitical (dead or living material). Decomposers. Cellulase. | http://room114.wikispaces.com/file/view/VirusFlu.JPG/40381400/VirusFlu.JPG http://www.backyardnature.net/f/rhizopus.gif http://dbscience1.wikispaces.com/file/view/jasonbacteria.jpg/58526032/jasonbacteria.jpg Binomial naming system: When writing the binomial name, the first letter of the genus should be in upper case and the first letter of the species should be in lower case. The binomial names are Latin words.

For Example;
Lubricous terrestrius

Genus Species

3- Adaption of organisms
Key words - Monocotyledons, dicotyledons, Arthropods, Insects, Crustaceans, arachnids, Myriapod, Annelids, Nematodes, Molluscs.

Monocots: Dicots: http://t3.gstatic.com/images?q=tbn:ANd9GcQXExBPqTDJajBeDIjbVVjYTBWIRR3DvO5Ed7X6_IWpoJVlKYFB5whttp://www.google.com/url?source=imglanding&ct=img&q=http://homepage.smc.edu/hodson_kent/plant_growth/Angiosperms/ID/Monocot.jpg&sa=X&ei=F4a6T9vGAsWUswbOh-DUBw&ved=0CAwQ8wc&usg=AFQjCNEIRfyQzySHjo5OphmoNZMah7Lagw Arthropods: Any of numerous invertebrate animals of the phylum Arthropoda, including the insects, crustaceans, arachnids, and myriapods, that are characterized by a chitinous exoskeleton and a segmented body to which jointed appendages are articulated in pairs.

Insects: http://t2.gstatic.com/images?q=tbn:ANd9GcRfxs7x-PehPgiRFmyjP1VaabGvsXdNtJzVFfppnVPeuIONFXaQ1A Arachnids: http://www.google.com/url?source=imglanding&ct=img&q=http://nz.merial.com/disease_information/dairy/imagefolder/ecto_draw1.gif&sa=X&ei=SYi6T6DZIIzOswa4yqytCA&ved=0CAsQ8wc&usg=AFQjCNHF34RXCvuZoxSG4SgPGc7_W7Tyzg Crustaceans: http://www.google.com/url?source=imglanding&ct=img&q=http://www.kentuckyawake.org/files/external%20anatomy/Crustacean.png&sa=X&ei=voe6T7XZBszLswaJu_TmBw&ved=0CAsQ8wc&usg=AFQjCNHm3fuqKVHPcWvKJjTWlvwQ-3snTg Myriapods:

http://www.google.com/url?source=imglanding&ct=img&q=http://www.cals.ncsu.edu/course/ent425/text02/centipede02.gif&sa=X&ei=7oi6T_n2KYritQaY8tjyBw&ved=0CAwQ8wc&usg=AFQjCNFBHQDKbYFTWgcTI4p5WjgkWfmUvw

Annelids http://www.google.com/url?source=imglanding&ct=img&q=http://www.southtexascollege.edu/nilsson/4_GB_Lecture_figs_f/4_GB_23_AnimaliaInvert_Fig_f/Annelid.GIF&sa=X&ei=aom6T_3vNJHOsgbPsqmVCA&ved=0CAsQ8wc&usg=AFQjCNFsHSNwXP1T7VO7_6uVDuKZB6bCAg Nematodes http://t2.gstatic.com/images?q=tbn:ANd9GcQ7icfHn-QiWjfsHVTejokmS9JHb7K0sY9CwIh7jawe51YeEVY Molluscs

C:\Users\sharon cain\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\P4IQGTA6\MC900391446[1].wmfC:\Users\sharon cain\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\QHEVFI61\MC900446200[1].wmf

4-Simple Keys
Dichotomous keys: http://www.google.com/url?source=imglanding&ct=img&q=http://www.lucidcentral.com/portals/1/images/general/dichotomous.gif&sa=X&ei=Ooq6T8_UC4PQtAaEuPizCA&ved=0CA0Q8wc&usg=AFQjCNFz_NO_GQt3TZBV_t2eSVzt1xa_Qw 5-Cell structure and organisation
Key words: Vesicle, cytoplasm, Vacuole, Glycogen, Cell membrane, Cytoplasm, Nucleus, Chloroplast, Starch, Cell Wall, Heterotroph, Autotroph, Turgor.
Animal cell : http://www.google.com/url?source=imglanding&ct=img&q=http://4.bp.blogspot.com/_7lmDZdRw2x8/TPg6zBI27PI/AAAAAAAAAOM/7QENWimUWVc/s1600/basic+animal+cell.jpg&sa=X&ei=F4u6T8PmGMzSsgaT3_WdCA&ved=0CBAQ8wc&usg=AFQjCNGwAzFP_YFLfX02ijCWlVCjcqmm_Q Plant cells: http://www.google.com/url?source=imglanding&ct=img&q=http://www.valdosta.edu/~tjyoung/cell2.gif&sa=X&ei=T4u6T4CINIrAswaAvpm7CA&ved=0CBEQ8wc&usg=AFQjCNFS0mQCetXtNqHTt6cYkpIhHKzq8w Cells water content varies the shape: http://www.google.com/url?source=imglanding&ct=img&q=http://www.islay.argyll-bute.sch.uk/courses/Biology%20Website%20files/int2/graphics/cells/plantosmosis.gif&sa=X&ei=vYu6T6asJ8botQbHsbTpBw&ved=0CAwQ8wc&usg=AFQjCNHPqQG3Y4xFo3xF_5nWKEgiElPmHA

6-Levels of organisation:
Key words: Tissue, Organ, Organ System, Ciliated Cell, Root Hair Cell, Xylem Vessel, Muscle Cell, Red Blood Cell. Ciliated cell: http://www.google.com/url?source=imglanding&ct=img&q=http://www.ivy-rose.co.uk/HumanBody-Images/Respiratory/nares.gif&sa=X&ei=9NG7T8CVFOWc0QWgpMnlBw&ved=0CAwQ8wc&usg=AFQjCNE9fS54M_IZ2EsJiEdYp0onP932YA

Root hair cell: http://www.google.com/url?source=imglanding&ct=img&q=http://www.skinnerscience.com/Biology/gcse%20unit3%20revision%20notes_files/image018.jpg&sa=X&ei=QdK7T534KcmX0QWmrtWfAQ&ved=0CAwQ8wc&usg=AFQjCNEdcN5IYenGWOuEqgfbDnRNuw0XSg Xylem vessels: http://www.google.com/url?source=imglanding&ct=img&q=http://leavingbio.net/FLOWERING%20PLANTS_files/image049.gif&sa=X&ei=oNK7T_GeLMeZ0QXli-HjBw&ved=0CAwQ8wc&usg=AFQjCNGlHyGrii5y-nAbEwZkOBtUftKeGQ Muscle cells contraction: http://www.google.com/url?source=imglanding&ct=img&q=http://www.vitamin-b12-deficiency.org/wp-content/uploads/2011/08/100085.jpg&sa=X&ei=79O7T5TfC-L80QXbrPHEAg&ved=0CBEQ8wc&usg=AFQjCNGvblXg-5Io-0gf0SvQMMsTEaMj5A Red blood cells – transport : http://t1.gstatic.com/images?q=tbn:ANd9GcQHN9f0f4EAv6lGGCH9gz-nsjTuMX0zfThaTH4wdCed__TU-I51MQ Tissue: A group of cells with similar structures working together to perform a shared function.
Organ: A structure made up of a group of tissues working together to perform a specific function.
Organ System: A group of organs with related functions working together to perform body functions.

7 – Size of Specimens
Key word: magnification.
Magnification = measured length / actual length, or actual length = measured length / magnification.

8 – Diffusion
Key words: diffusion, solute, solvent, solution, concentration gradient, equilibrium.
Diffusion: The net movement of molecules from a region of their higher concentration to a region of their lower concentration down a concentration gradient.
Diffusion – gases (lungs or plant leaves), solutes (digestion or synapses) and of water as a solvent (transport of CO2 or sugar)
Solute: dissolved in the solvent.
Solvent: dissolves the solute.
Solution: Solute + solvent.
9 – Osmosis
Key words: osmosis, semi permeable membrane, water potential, equilibrium.
Osmosis: the diffusion of water molecules from a region of their higher concentration to a region of their lower concentration through a semi permeable membrane as a result of their random movement.

http://www.google.com/url?source=imglanding&ct=img&q=http://www.bbc.co.uk/bang/images/446x251/osmosis.jpg&sa=X&ei=HNi7T429Ccis0QX5-9DhBw&ved=0CAsQ8wc&usg=AFQjCNFncXidDU-kLGK5QPTspHY2gI006w

When osmosis occurs a cell becomes flaccid.
A turgid cell is full of water.

10 – Active Transport
Key words: active transport, concentration gradient, ions, ATP.
Active transport: the movement of ions in or out of a cell through the cell membrane from a region of their lower concentration to a region of their higher concentration gradient using energy released during respiration.
The importance of active transport is apparent as an energy consuming process by which substances are transported against a concentration gradient e.g ion uptake by root hair cells and uptake of glucose by epithelial cells or of villi.
ATP: provides energy for cells to perform functions.
ATP is provided by respiration.

11 – Enzymes
Key words: catalyst, enzyme, denature, lock and key, pectinase, antibiotic, penicillium, active site, optimum, protease, amylase, lipase, fermenter.
Catalyst: a substance that speeds up a chemical reaction and remains chemically unchanged after the reaction.
Enzyme: a protein that functions as a biological catalyst.
Enzymes are simple molecules and are not alive so cannot be killed. http://www.google.com/url?source=imglanding&ct=img&q=http://www.bbc.co.uk/schools/gcsebitesize/science/images/gcsechem_18part2.gif&sa=X&ei=SNu7T7DJEOXb0QXbg_ncBw&ved=0CAwQ8wc&usg=AFQjCNE6NnoIqZejIEXg1U6v-0f4QjQfywhttp://www.google.com/url?source=imglanding&ct=img&q=http://www.bbc.co.uk/schools/gcsebitesize/science/images/gcsechem_18part1.gif&sa=X&ei=X9u7T_D9BdOk0AXgzpyfCA&ved=0CAwQ8wc&usg=AFQjCNFE-Utn54wNO6xe0DQFxyyAm2dfUg http://t1.gstatic.com/images?q=tbn:ANd9GcRvcFqKFb_TJKDUIMYAvwpfJHemOGftSQ2kFu4OG5Nl1M0ORjs0Enzymes are specific to what they do. This is known as the lock and key method. http://www.google.com/url?source=imglanding&ct=img&q=http://www.chem4kids.com/files/art/bio_enzyme2.gif&sa=X&ei=rt27T4mPMKjL0QWckanVBw&ved=0CAwQ8wc&usg=AFQjCNEiRM2V6XvLfmCSNkl0bTvcQWvjpQ Uses of Enzymes: Germination of seeds (amylase) Biological washing products (protease, amylase and lipase) Food industry (pectinase and fruit juice)
Micro-organisms and fermenters are used in the manufacturing of penicillin. The fungus penicillium is used to produce penicillin.
12-Nutrition and nutrients
Key words: nutrition, nutrient, absorption, assimilation, hydrolysis, condensation, amino acids, starch, carbohydrates, fat, protein, glycogen, fatty acids, glycerol, oil, organic molecule.
Nutrition: taking in of nutrients which are organic substances and mineral ions, containing raw materials or energy for growth and tissue repair, absorbing and assimilating them.
Organic molecule: Molecules containing carbon and hydrogen.
Carbohydrates: contain Carbon, Oxygen and HydrogenFats: contain Carbon, Oxygen and HydrogenProtein: Carbon, Hydrogen, Oxygen and Nitrogen make up all proteins, they are in all amino acids.
The monomers of organic compounds join together by a chemical reaction know as dehydration synthesis to make polymers. The reverse reaction of breaking up polymers is accomplished by another chemical reaction known as hydrolysis. The following animations illustrate these reactions.

Condensation Synthesis and Hydration synthesis:
Carbohydrate Metabolism
Dehydration Synthesis and Hydrolysis are Reversible Glucose + Fructose http://nhscience.lonestar.edu/biol/dehydrat/reverse.gifSucrose + H2Ohttp://nhscience.lonestar.edu/biol/dehydrat/glucose.gif
Generalized Reaction of Dehydration Synthesis and Hydrolysis http://nhscience.lonestar.edu/biol/dehydrat/synthesi.gif Condensation is a chemical process by which 2 molecules are joined together to make a larger, more complex, molecule, with the loss of water.
It is the basis for the synthesis of all the important biological macromolecules (carbohydrates, proteins, lipids, nucleic acids) from their simpler sub-units. http://t3.gstatic.com/images?q=tbn:ANd9GcRtTQggS8FB-1b7uR-0eAvtWLe1sPWMgFAr7gtX6_wfKmtauRbH Simple sugars and glycogenStarch http://t1.gstatic.com/images?q=tbn:ANd9GcQ8WKmWSzDSIX9WdQD-1YH-moFiBxkL2g2YQaBNz8jY4emYPyFkbg Amino acids Proteins http://www.google.com/url?source=imglanding&ct=img&q=http://www.answersingenesis.org/assets/images/articles/tj/v18/i2/abiogenesis-proteins.jpg&sa=X&ei=0OO7T9qgBuer0QW-o4ToBw&ved=0CAwQ8wc&usg=AFQjCNFpndhxk59fn2lNDgH1Qo5Eg-mStw Fatty acids and glycerol fats and oils http://t3.gstatic.com/images?q=tbn:ANd9GcS_fyoHozd0F1jfwdoYdtIy4knIJXKnwGKYeEDcdh6yjpmdJRuo Food tests:
Starch - Iodine
Glucose - Benedict’s
Protein – Biurets
Fats - Ethanol

http://faculty.ntcc.edu/mhearron/BenedictsTest.jpg http://faculty.ntcc.edu/mhearron/IodineTest.jpg

http://faculty.ntcc.edu/mhearron/BiuretTest.jpg http://www.google.com/url?source=imglanding&ct=img&q=http://www.bioclix.org/images/fat-test.gif&sa=X&ei=Fea7T_WWBcin0AWOuKyfBQ&ved=0CAwQ8wc&usg=AFQjCNGqrL3i0iy_2xdXU27vmjIAtvknug

13-Nutrients
Key words: deficiency, Kwashiorkor, scurvy, rickets, balanced diet, vitamin, mineral salts, fibre.
Carbohydrate – bread, pasta.
Fats – McDonalds, butter, cream.
Proteins – fish, meat.
Vitamins C and D – orange, sun.
Mineral salts – calcium, iron.
Fibre (roughage) – cereal.
Water – a tap.

Scurvy – lack of vitamin C and D.
Rickets – lack of calcium and vitamins.
Anaemia – lack of iron.
Kwashiorkor – protein.

The food colouring Tartrazine is linked to hyperactivity in children.

14-Micro-organisms and the food industry
Key words: whey, curd, pasteurisation, Incubation, Homogenisation, Rennin, Chymosin, Fermentation.
Yogurt- micro-organisms are used in lactose fermentation to create yogurt.
Beer/ bread- Fermentation of yeast.