Y9 Biology Revision Notes

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the cell, contains chromosomes. Ligaments - structure that connects the bones of the skeleton together. Cytoplasm - Jelly like substance where most chemical reactions happen. Experimental tools for assessing ecosystems - Quadrats and transects Enzymes - chemically break down the food on its journey through the digestive system. Mitochondria - Carries out aerobic respiration using sugar and oxygen to release energy. Red blood cells - LSA in bi concave shape, has protein called haemoglobin to transport oxygen, no nucleus to have more space for oxygen. Stationary - not moving LSA - large surface area Facts: Mesophyll can photosynthesize. Bacteria and fungi are decomposers. Muscular tissue - contracts to bring about force and motion. Epithelial tissue lines the outer surface of organs and blood vessels. If the temperature is above 45 enzymes denature(not work anymore). Xylem vessels collect water from the root cortex and transport it up the plant's stem. Burning fossil fuels & deforestation increases the atmospheric concentration of CO2. Human skin and the waxy covering of some plants are examples of epidermal tissues. Transects can be used to investigate the effect of a factor on the distribution of a species. The waxy cuticle is the waterproof top layer of the leaf, it prevents water from escaping from the uppermost surface. Young cells differentiating means they acquire different subcellular structures to become specialised. Factors affecting seed dispersal - plant height, seed weight, weather Factors affecting diffusion - High temp & gradient(makes ROD faster), membrane surface area. Outer ear: Pinna - funnels sound into ear Ear canal - 2cm passage from pinna to ear drum Ear drum- a thin flap of skin that vibrates with sound Parts of the ossicles: Hammer - in contact with the eardrum Anvil in contact with the hammer Stirrup transmits sound to the cochlea Inner ear: Cochlea - hairs around it, filled with fluid, the fluid moves, it vibrates the hairs, turns sound waves into electrical signals Auditory nerve - send signals The eye - Retina, Lens, Cornea, Optic nerve, Iris, Pupil Why biodiversity is important: Ecosystem stability, environmental benefits, many medicines come from plants (more plants more medicines to find/make). How to investigate the effect of light intensity on the rate of photosynthesis: By using an aquatic plant like pondweed. To do this, change the distance between the lamp and the pondweed and count the number of bubbles produced per unit of time (e.g. five per minute). In this experiment, light intensity is the independent variable and the number of bubbles is the dependent variable. Phloem tubes: Made up of specialised cells called sieve elements, which are connected end-to-end to form a long tube-like structure. These cells have perforated walls with tiny holes called sieve plates, which allow the movement of fluids and substances when a plant produces sugars Stationary - not moving LSA - large surface area through photosynthesis in its leaves, these sugars are converted into a liquid called sap. The sap moves through the phloem tubes a process called translocation. Carl Woes' 3 domain system: Archaea - primitive bacteria Bacteria - true bacteria Eukaryota - organisms possessing complex sub-cellular structures (protists, fungi, plants and animals). Carl Linnaeus' traditional classification system: Kingdom, Phylum, Class, Order, Family, Genus, Species. (in descending order of size) The discovery of genes as the mechanism of inheritance and variation (i.e. that characteristic are passed on to offspring in their genes) provides further evidence for the theory of evolution. Pictures or smt total survey area area sampled estimated population size = number of individuals counted x- Area of 10 quadrats = 10 x quadrat length (m) × quadrat height (m) Natural Selection Different individuals within a biological population display genetic variation Individuals with genes that make them better adapted to the environment will have a greater chance of survival Individuals with the best chances of survival are the most likely to breed successfully (because they survive) The characteristics that make an individual more likely to survive are more likely to be passed on to the next generation Carbon Cycle Stationary - not moving LSA - large surface area Carbon is removed from the atmosphere by producers (e.g. algae) who use it in photosynthesis. By consuming plant matter, animals obtain carbon compounds. Carbon is returned into the atmosphere (as carbon dioxide) because of the respiration that happens in plant and animal cells. When animals and plants die, decomposers return the carbon locked in their bodies back to the atmosphere via decay. Combustion of fossil fuels is another source of carbon entry into the atmosphere. Convex lens Also called a converging lens Stamen. Lenses Aids people who are long-sighted Anther Filament Concave lens Sepal Also called a diverging lens Aids people who are short-sighted Stigma Style Ovule Ovary Petal Carpel