f212 Biological Molecules 5.0 / 5 based on 1 ratingTeacher recommended ? BiologyBiological moleculesASOCR Created by: ashleighholmes23Created on: 31-05-16 16:09 Carbohydrates All monosaccharides are reducing sugars Cn(H2O)n Alpha glucose (plants & animals can break down) - starch & glycogen Beta glucose (plants & animals cannot break down) - cellulose Structural isomers = different shaped forms of the same molecule Disaccharides formed by 2 monosaccharides joining together to form a disaccharide Glucose + glucose = maltose New covalent bond - glycosidic bond formed Glucose molecules contain a large number of bonds that can be broken to form simpler molecules Breaking down of glucose in respiration releases energy This energy can be used to make ATP In living organisms glucose is broken down in many steps by enzymes 1 of 10 Monosaccharides Glucose Small, sweet, soluble & crystalline Energy via respiration Deoxyribose (5C) Information molecule 2 of 10 Disaccharides Maltose Glucose + glucose = maltose Further condensation reactions - amylose - coil into spring - insoluble Sugar obtained when starch broken down in hydrolysis reaction Split glucose during respiration 3 of 10 Polysaccharides Starch Long, straight chain amylose Branched amylopectin (1,4 glycosidic bond - helical and 1,6 glycosidic bond - branched) Chloropasts in membrane bound starch grains Energy-storage carbohydrate in PLANTS. Starch - glucose - ATP Cellulose Large molecules Many beta-glucose molecules Insoluble in water Very strong Structural Plant cell walls Cross-linked by H bonds- microfibrils & macrofibrils 4 of 10 Proteins from amino acids Function Structural Enzymes Hormones Antibodies Membrane carriers & pores - active transport & facilitated diffusion Primary structure Specific sequence of amino acids that make up the protein Secondary structure Coiling & pleating of parts of the polypeptide molecule Tertiary structure Overall 3D structure of the final polypeptide or protein molecule Hydrophobic, hydrophilic interactions, disulfide bonds & ionic interactions 5 of 10 Haemoglobin Quaternary structure 4 polypeptide subunits: 2 alpha & 2 beta chains 4 subunits form one haemoglobin molecule which is water-soluble globular protein Haemoglobin's function is to carry oxygen from the lungs to the tissues Binds oxygen in the lungs & releases it in the tissues Haem group (prosthetic group) contains Fe2+ ion An oxygen molecule can bind to iron in haem group One complete haemoglobin molecule can bind up to 4 oxygen molecules 6 of 10 Collagen Quaternary structure Fibrous protein Insoluble in water 3 polypeptide chains wound around each other Each of the 3 chains is itself- made up of 1000 amino acids Hydrogen bonds form between the chains - structure strength Each collagen molecule forms covalent bonds - cross-links with other colagen molecules. Cross-links are staggered along the collagen molecules - adding strength Collagen fibril Collagen fibre Approximately 35% molecule's primary structure os glycine Collagen's functions: Walls of arteries preventing blood that is being pumped from the heart at high pressure from bursting walls Tendons form strong connection that allows muscles to pull bones for movement 7 of 10 Lipids Triglyceride Glycerol 3 fatty acids Compact energy store Insoluble in water - no effect on water potential Stored as at Thermal insulation Protective properties Phospholipid Phosphate head - hydrophilic Glycerol 2 fatty acids - hydrophobic Perfect for cell membranes Phosphate group may have carbohydrate attached - glycolipids involved in cell signalling 8 of 10 Polysaccharides Glycogen Alpha glucose subunits Large branched molecule Different from amylopectin 1,4 glucose chain shorter & branched more More compact than starch Energy-storage carbohydrate in ANIMALS. Glycogen granule in animal cells 9 of 10 Lipids Cholesterol 4-C based ring structures joined together Forms small, thin molecule that fits into lipid bilayer Strength & stability Steroid hormones Excess cholesterol: bile (cholesterol sticks together forming lumps - gallstones) & blood (deposited in innter lining of blood vessel - atherosclerosis - circulatory problems) 10 of 10
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