sbi4u - biochemistry macromolecules carbohydrates & lipids
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SBI4U - Biochemistry
Macromolecules
Carbohydrates & Lipids
Organic Chemistry
• originally the chemistry of compounds produced by living organisms
• in general organic compounds contain carbon and hydrogen, and usually other elements such as nitrogen, sulfur and oxygen
Electronegativity
Homework, p.18 #9,8
• In a bond between nitrogen and hydrogen (N-H), which atom will the electrons be closer to? Explain your reasoning.
• How do polar covalent bonds and non-polar covalent bonds differ?
Homework, p.18 #10
• Oxygen plays a major role in biological molecules. Explain how oxygen plays a role in polarity, bond shape, (and redox reactions).
Polar vs. Non-Polar
• molecular polarity is determined by:– polarity of bonds within molecule– symmetry of molecular structure
• polarity of molecules or functional groups determines characteristics such as solubility
Homework, p.18 #6,7
• How can the atomic composition and shape of a molecule affect its polarity?
• What effect to the polarity, size, and shape of molecule have on the physical properties of the molecule?
• How do these factors affect intermolecular forces?
Homework, p.24 #1,5
• Water is a polar molecule. Explain how the polarity of water accounts for its lattice structure.
• How does polarity influence water’s role as a solvent?
H-bonding
Homework, p.18 #11
• In what ways do hydrogen bonds produce attractive forces between molecules? Include a labelled diagram to illustrate your answer.
• How do hydrogen bonds influence the physical properties of water?
Functional Groups
• specific clusters of atoms attached to the carbon backbone
• functional groups react in characteristic ways, giving chemical properties to macromolecules, and are involved in most reactions in living organisms
Functional Groups
Homework, p.28 #4
• Explain how functional groups influence solubility and the forces of attraction between molecules.
Macromolecules
• macromolecules are large molecules that are often composed of repeating sub-units
• some of the biologically important macromolecules are:– carbohydrates -lipids– proteins -nucleic acids
Carbohydrates
• carbohydrates are the most important energy source
• animals cannot synthesize carbohydrates; they must be consumed in plant material
Structure of Carbohydrates
• carbohydrates are made up of either single sugar molecules, or chains of many single sugar molecules– monosaccharides– disaccharides– oligosaccharides– polysaccharides
Monosaccharides
• single sugars in straight chain or ring form
• C:H:O usually in 1:2:1 ratio (glucose is C6H12O6)
• examples: fructose, galactose, ribose, deoxyribose
Monosaccharides
• some monosaccharides are isomers, e.g., glucose, fructose, and galactose
Disaccharides
• sugar molecules made from 2 single sugars
• formed by a dehydration synthesis (condensation) reaction
• See animation: http://www.youtube.com/watch?v=UyDnnD3fMaU
Find the sugars…
Polysaccharides
• oligosaccharides are shorter-chain sugars with 3-10 single sugars
• longer chain carbohydrates are called polysaccharides
• examples: starch, cellulose, glycogen, chitin
Polysaccharides
Lipids
• 4 groups:– fats & oils– phospholipids– steroids– waxes
• Functions:– energy storage– insulation– absorption of vitamins– raw materials
Triglycerides
• most common type of fat
• glycerol + 3 fatty acid molecules
• saturated and unsaturated fatty acid chains
• See animation: http://www.youtube.com/watch?v=3xF_LK9pnL0
Phospholipids
• key component of cell membranes
• 1 glycerol + 2 fatty acid chains + 1 phosphate group
• phosphate end is polar and water-soluble, fatty acid end is non-polar
Phospholipids
Steroids (Sterols)
• carbon-based multiple-ring structure
• used to make hormones such as estrogen and testosterone
Waxes
• long-chain fatty acids linked to alcohols/carbon rings
• suitable as water-proof coating for plant leaves, animal feathers, etc.
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