Hsc Biology Module 1

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1 of 22 HSC Biology Module 1 - Maintaining A Balance Focus 1: Most organisms are active in a limited temperature range. Identify the role of enzymes in metabolism, Describe their chemical composition and use a simple model to describe their specificity on substrates. Enzymes: • Biological catalysts. - Provide a site for the reaction to take place. - Reduce the amount of energy required to initiate a reaction. - Influence the rate at which forward & reverse reactions reach equilibrium. - Not consumed in the reaction. - Required in minute amounts only. • Structure & composition. - 3D protein structure. - Constructed of AAs. - 20 different AAs make up proteins & enzymes in organisms. - Have an active site. - Specific to substrate. - Site where reaction takes place. - May be: - Elongated (straight chained polypeptide). - Spherical (coiled polypeptide). - Many enzymes require the assistance of other chemicals. - Not made of proteins. - Coenzymes. - Organic molecules (vitamins). - Cofactors. - Metallic ions (Fe2+, Ca2+, Mg2+, Zn2+, Cu2+, K+). 2 of 22 • Location. - Intracellular (used within the cells that produce them. - eg. photosynthesis enzymes. - Extracellular (act outside cells that produce them. - eg. digestive…show more content…
Transpiration: - Heat within the plant is used to evaporate water off the surface of cells. - Water mainly exits through the stomata. Convection: - Air around plant becomes heated. - Heated air is less dense, rises away from plant. Takes heat with it. Leaf shape: - Thinnest where 2 surfaces come together, lose most heat from this section. Heat shock proteins: - Produce these @ 400C. Protect enzymes & other proteins from denaturing. Leaf orientation: - Drooping leaves to minimise surface exposure to sun (parallel to light rays). Structure: - Trunks used to store water. - Deciduous (drop leaves in summer). - No stomata, less surface area to lose water / absorb heat. Leaf

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