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1、精品文档，仅供学习与交流，如有侵权请联系网站删除IGCSE Biology 2012http:/www.s-cool.co.uk/gcse/biologyhttp:/ of living things1 List and describe the characteristics of living organisms.Assimilation is a much better word than nutrition (because plants taking in and using CO2 and H2O is not nutrition but is assimilation). The
2、 word assimilation in biology means taking in substances from the surrounding environment and building them into your own structures.Sensitivity leads to a response.Respiration is one of the biochemical reactions of cell metabolism.So we can produce an alternate list.GrowthAssimilation (replaces nut
3、rition)Metabolism (includes respiration)ExcretionResponse (sensitivity)ReproductionGAMER2AssimilationTaking in inorganic and organic chemicals from the surrounding environment, and using them for cell construction and cell metabolism.MetabolismAll the chemical reactions that occur in a cell and resu
4、lt in what we call life.ExcretionRemoval of the waste products of metabolism from a cell.SensitivityUsing the sense organs to notice change.ResponseReacting to external change from the environment.ReproductionProducing new cells from pre-existing cells.To be a living thing something must exhibit all
5、 of GAMER2 and be made of cells.Cell structure and organisation1 State that living organisms are made of cells. Everything, from bacteria to plants to insects to animals are all made of one (unicellular) or more cells (multicellular)Cell TheoryLiving organisms are composed of cells.Cells are the sma
6、llest unit of life.Cells come from pre-existing cells.2 Identify and describe the structure of a plant cell (palisade cell) and an animal cell (liver cell), as seen under a light microscope. 3 Relate the structures seen under the light microscope in the plant cell and in the animal cell to their fun
7、ctions.(a) cell surface membrane, which controls what enters and leaves the cellThe cell membrane allows diffusion of simple substances without control (passive transport), e.g. movement of oxygen into the cell, carbon dioxide out of the cells and ions into or out of the cells. Additionally the memb
8、rane proteins can control movement of substances into or out of the cell and against a concentration gradient (if needed). The cell uses ATP energy to do this (active transport)(b) nucleus, which contains DNA which is inherited, and which controls the activities of the cell Nuclear DNA contained wit
9、hin the cell carries the messages of life (genes).Genes tell the cell how to build specific proteins needed for all the functions of a cell.(c) chloroplasts, in which photosynthesis takes placeChloroplasts are membrane bound organelles found in green plants. Each chloroplast contains a green pigment
10、 protein molecule called chlorophyll, which is capable of using the energy from sunlight to produce glucose during photosynthesis.(d) cell wall, provides support to the cell so it can maintain its shape. It also help to prevent damage to the cell membrane.The cell wall has large spaces in it allowin
11、g anything to pass easily, it is fully permeable.4 Describe the differences in structure between typical animal and plant cells. Animal CellsPlant cellsNo cell wallCell wallNo vacuoleMay have a vacuole, but not alwaysNo chloroplastsChloroplasts in photosynthesizing cellsHeterotrophic must take in or
12、ganic molecules from the surrounding environmentAutotrophic can make their ownOrganic molecules from inorganicMolecules using photosynthesis.Use the organic molecules- Glucose- Lipids- Amino acids- Nucleic acidsUse the inorganic molecules- Water- Carbon dioxide- Nitrates- PhosphatesRely on plants fo
13、r foodSelf sufficient5 Calculate magnification and size of biological specimens using millimetres as units.Magnification = Drawing or image size for the specimen biological(mm)Actual size of the biological specimen (mm) How big is a cell?http:/ in and out of cells1 Define diffusion as the net moveme
14、nt of molecules from a region of their higher concentration to a region of their lower concentration down a concentration gradient, as a result of their random movement.Diffusion, Brownian motionhttp:/highered.mcgraw- CO2, and small ions can diffuse in or out of cells.2 Describe the importance of diffusion of gases and solutes and of water as a solvent.ing organisms Water (H2O) is not an organic compound but it is essential for life on Earth. Cell membranes are shaped into hollow spheres because of the polar nature of water and the way it interacts with lipid molecules that
