Course review
Review each learning objective in this topic, then open its concept explanation or question set.
Learning objective
• Carbon forms four strong covalent bonds with C, H, O, N, S, and P • Carbon skeletons form chains, branches, rings, and single or double bonds • Functional groups give carbon compounds distinctive chemical properties
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Learning objective
• Condensation links monomers with covalent bonds and releases water • Polysaccharides, polypeptides, and nucleic acids are polymers made this way • Glycosidic, peptide, and phosphodiester bonds are key examples
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Learning objective
• Hydrolysis breaks covalent bonds in polymers using water • Water provides -H and -OH groups to form monomers • Amylases, proteases, and nucleases catalyse hydrolysis of major biomolecules
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Learning objective
• Pentoses such as ribose and hexoses such as glucose are monosaccharides • Glucose is soluble, transportable, chemically stable, and a direct respiratory substrate • Alpha- and beta-glucose differ at carbon 1 and form different polysaccharides
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Learning objective
• Starch stores energy in plants as amylose and amylopectin • Glycogen stores energy in animals and fungi and is more highly branched • Insolubility, compactness, and easy hydrolysis make both effective glucose stores
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Learning objective
• Cellulose is made from beta-glucose joined by 1,4 glycosidic bonds • Alternating glucose orientation makes straight, unbranched chains • Hydrogen bonds form fibrils and fibres that strengthen plant cell walls
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Learning objective
• Glycoproteins and glycolipids form the external glycocalyx of membranes • Cell-surface carbohydrates enable self/non-self recognition, adhesion, and signalling • ABO blood group antigens show how surface sugars affect immune compatibility
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Learning objective
• Lipids are hydrophobic, sparingly soluble in water, and soluble in non-polar solvents • Fats, oils, waxes, phospholipids, and steroids are lipid examples • Lipids are not true polymers because they are not built from repeating identical monomers
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Learning objective
• Condensation forms ester bonds between glycerol and fatty acids • Triglycerides contain glycerol plus three fatty acids • Phospholipids contain glycerol, two fatty acids, and an ionized phosphate group
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Learning objective
• Saturated fatty acids have no carbon-carbon double bonds • Monounsaturated and polyunsaturated fatty acids have one or multiple double bonds • Double bonds create kinks, lower melting points, and affect membrane and storage properties
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Learning objective
• Triglycerides in adipose tissue store concentrated long-term energy • Insoluble fat stores avoid osmotic effects and can provide insulation, protection, and buoyancy • Fat oxidation releases more energy and metabolic water than carbohydrate of the same mass
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Learning objective
• Phospholipids are amphipathic with hydrophilic phosphate heads and hydrophobic tails • In water they form monolayers or bilayers with tails away from water • Bilayers are stable barriers and the basic structure of cell membranes
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Learning objective
• Steroids are mostly non-polar lipids with four fused carbon rings • Non-polar steroids pass through the hydrophobic core of phospholipid bilayers • Oestradiol and testosterone are cholesterol-derived steroid hormone examples
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