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1. Identify monosaccharides, disaccharides, oligosaccharides and polysaccharides.
Monosaccharide: building blocks/monomers
Disaccharide: 2 linked monosaccharides
Oligosaccharide: 3-10 linked monosaccharides
Polysaccharide: Many linked monosaccharides
8. Describe the stereochemistry of monosaccharides.
Use L forms of amino acids
Use D forms of monosaccharides
Most monosaccharides have more than 1 chiral carbon (4 stereoisomers)
Classifying when theres more than 1 chiral carbon:
Depends on orientation of chiral carbon farthest from carbonyl group (2nd carbon from bottom)
13. Describe condensation reactions of monosaccharides.
Linking monosaccharides together, removing water, to form disaccharides
How to describe linkages
List the 2 monosaccharides that are linked
Determine the carbons involved
Indicate alpha or beta if either of these were used:
C1 of a pyranose (hexagon) ring
C2 of a furanose (pentagon) ring
Alpha or beta (# → #) (Numbers always in numerical order)
Can be both alpha & beta or beta & beta or alpha & alpha if we use 3 o'clock carbons in both
1. Identify the importance of lipids in biology.
Many structures give you many functions (like proteins)
They aren’t based on sequence or order like proteins are
6. Identify the structure, properties and functions of triglycerides.
Function: Fuel for energy production
Most abundant lipid in food & body
Long-term energy reserve, stored in fat globules in adipose cells
2. Identify the importance of carbohydrates in biology.
Primary fuel source in our diet
Provides energy upon combustion
Reservoir of stored chemical energy
Supply carbon for building other molecules
Provide supporting structures (in plants especially)
9. Identify important monosaccharides.
Dextrose (D-glucose)
Levulose (D-fructose)
D-galactose (diastereomer of D-glucose)
D-ribose & D-deoxyribose
14. Identify important disaccharides.
Small structures; no light scattering
Different disaccharides have different monosaccharide components & linkages
Glycosidic bond: In disacchairdes, links a monosaccharide to another monosaccharide
“Oxygen bridge”
Lactose:
Sucrose:
Maltose:
Isomaltose:
Mannobiose:
2. Identify several physical properties of lipids.
Water-insoluble
Soluble in nonpolar solvents (cyclohexane)
Most like hydrocarbons (lot of carbons)
Waxy, greasy, oily, less dense than water
Made up of fatty acids (building blocks)
7. Distinguish fats from oils.
Not pure substances (mixture of triglycerides obtained from animals/plants)
Fats:
Source: Animals
Predominant type of fatty acid: Saturated
State at room temp: Solid
Oils:
Source: Fish
Predominant type of fatty acid: Unsaturated
State at room temp: Liquid
3. Identify functional groups found in carbohydrates.
Aldehydes or Ketones
Alcohol (hydroxyl group)
10. Identify physical properties of monosaccharides.
Small structures
Very polar (carboxyls)
Very high boiling/melting points
Solid at room temp
Soluble in water
Sweet
15. Identify important polysaccharides.
Scatter light; form colloids; large structures
Different polysaccharides have different monosaccharide components, length, branching
Starch: Storage polysaccharide in plants (energy)
Soluble in water (from thousands of hydroxyl groups)
Amylose: 1000-2000 D-glucose connected alpha (1→4)
Curl up to form helices supported by hydrogen bonds
Amylopectin: 100k-1M D-glucose linked alpha (1→4) and alpha (1→6)
Branched structure from the 1→6 linkage
Looks like a branched alkane
Glycogen: Storage polysaccharide in animals (energy)
D-glucose linked alpha (1→4) and alpha (1→6)
Excess dietary glucose is stored in liver/muscle cells
Stored until needed (in-b/w meals)
Similar to amylopectin but more branched; similar function in animals as starch provides for plants (energy storage)
Cellulose: Structural polysaccharide in plants (infrastructure)
D-glucose beta (1→4)
Cell walls; wood, stems, leaves
Stack into sheet-like structures
Extensive hydrogen bonding
Very strong
Can’t be digested (fiber)
3. Identify the structure, properties and functions of fatty acids.
Structure: Unbranched carboxylic acid w/ many carbons, can have double bonds
Saturated: Don’t have carbon-carbon double bonds
Solid
Hard to melt
Unsaturated: Have carbon-carbon double bonds
Liquid
Easy to melt
Naming: (# of carbons:# of double bonds)
Properties: Amphipathic (hydrophilic & hydrophobic part in one structure)
Nonpolar tail: Hydrocarbon part
Hydrophobic
Should have an even number of carbon atoms
Polar head: Carboxyl group
Hydrophilic
Functions: Polar head is attracted to water, but the hydrocarbon is not
Form micelles (picture)
Polar heads on outside, tails on inside (hiding from water) → Similar to tertiary structure w/ nonpolar components on inside
8. Describe the hydrogenation of triglycerides.
React alkenes w/ hydrogen gas to make alkanes
Remove double bond from carbons
Add 2 hydrogens to the newly made single bonds
Leave extra double bonds as is if not enough hydrogen
Double bonds are eventually broken, but not by adding hydrogen → turn into trans double bonds rather than cis
4. Classify carbohydrates (aldose, ketose, triose, tetrose, pentose, hexose, simple, complex)
Categories:
Aldose: Has an aldehyde
Glyceraldehyde
Ketose: Has a ketone
Dihydroxyacetone
Triose: 3 carbons
Tetrose: 4 carbons
Pentose: 5 carbons
Hexose: 6 carbons
Simple: Monosaccharides and disaccharides
Complex: Polysaccharides
11. Describe the formation and significance of sugar alcohols.
Derivatives of monosaccharides
Hydrogenation
Still taste sweet but aren't absorbed well–passes through body
Turns an aldehyde or ketone into a primary or secondary alcohol
Not a carb anymore
16. Describe chemical tests that characterize carbohydrates.
Iodine (I2) Test: Iodine molecules fit inside starch helices
Complexes turn blue = Positive for starch
Water insoluble (b/c of hydroxyl bonds being used up for the sheet structure)
4. Distinguish saponifiable lipids from nonsaponifiable lipids.
Saponifiable lipids: Structures assembled from building blocks
Can be disassembled (hydrolysis)
Structures w/ linked pieces, built by dehydration-condensation reactions
Contain several building blocks (a “backbone” w/ more pieces attached at key sites)
Building blocks are connected by ester, amide, phosphodester, or glycosidic linkages
Simple: Have an alcohol backbone + fatty acid(s)
Waxes: Long-chain alcohol backbone
Alcohol w/ long attachment site to OH
Esters (O=COC) made from a long-chain alcohol & long-chain fatty acid (lot of carbons)
Nonpolar
Triglycerides: Glycerol backbone
Glycerol + 3 fatty acids make ester linkage
Simple: 3 of the same fatty acids
Mixed: Mixture of fatty acids attached to glycerol
Nonpolar
Saturated: Don’t have carbon-carbon double bonds (solid)
Not as healthy for you
Unsaturated: Have carbon-carbon double bonds (liquid)
Complex: Contain the same as simple + additional pieces
Phosphoglycerides: Glycerol backbone, 2 fatty acids, phosphoric acid, aminoalcohol (3 attachment points to backbone)
Ester & Phosphodiester linkages
Lecithins: Subclass of aminoalcohols (choline)
Cephalins: Subclass of aminoalcohols (serine, ethanolamine)
Amphipathic (hydrophilic & hydrophobic part)
Hydrophilic: Phosphoric acid, amino alcohol
Hydrophobic: 2 fatty acids
Sphingolipids: Sphingosine backbone
Amphipathic
Hydrophilic: Phosphoric acid & choline, or carb
Hydrophobic: non-polar tails (fatty acid, sphingosine)
Sphingomyelins: Sphingosine, fatty acid, phosphoric acid, choline (2 attachment points to backbone)
Amide linkage to fatty acid
Phosphodiester linkage to phosphoric acid & choline
Big extension
Glycolipids
Sphingosine, fatty acid, carbohydrate
Amide linkage to fatty acid
Glycosidic linkage to carbohydrate
Nonsaponifiable lipids: Stand-alone structures
Don’t contain linked pieces
Eicosanoids:
Steroids: Class of lipids w/ common 17-carbon fused-ring structure
Cholesterol
Most abundant steroid in humans
8 chiral carbons
Synthesized in the liver
Amphipathic
Bile Salts: Polyatomic ions containing the fused ring steroid structure
Amphipathic
Hydrophobic: Hydrocarbons
Hydrophilic: Hydroxyl groups, terminal charged end
Aid in digestion by breaking triglycerides into smaller fat droplets (emulsify)
Hormones
Chemical messengers that contain the steroid ring structure
Synthesized in 1 part of body, sent away, act on target cell
All made from cholesterol
9. Describe the hydrolysis of triglycerides.
Separates triglycerides into their glycerol & fatty acid components
Water provides H & O for the building block components
Use strong acid catalysts (H+) at high temps (laboratory)
Lipase enzyme catalysts are used insead of strong acid catalysts (biologically)
5. Describe carbohydrate nomenclature.
End in -ose
Aldo/keto + tri/tetr/pent/hex + ose
12. Describe the formation of cyclic monosaccharides.
Aldohexoses react with themselves to form hexagon-shaped pyranoses labeled alpha or beta
Alcohol oxygen makes a bond with aldehyde carbon
The hydroxyl group of alcohol is cut
The double bond of aldehyde is cut
Alcohol hydrogen moves to aldehyde oxygen
Alpha/beta pairs are a diastereomer pair (anomers)
C-1 Carbon in pyranoses is called anomeric carbon (3 o'clock on clock face)
Ketohexoses react with themselves to form pentagon-shaped furanoses labeled alpha or beta
C-2 carbon is called anomeric carbon (3 o'clock)
17. Describe the hydrolysis of carbohydrates.
Opposite reaction to dehydration condensation
Steals water to make monosaccharides (as supposed to releasing water to make disaccharides)
Lab: Needs strong acid catalyst at high temps
Biological: Needs specific enzymes w/ absolute specificity
Needed for digestion
5. Identify the structure, properties and function of waxes.
Function: Prevents dehydration (repels water) & flotation device
10. Identify the structure, properties and functions of phosphoglycerides and sphingolipids.
Function:
Phosphoglycerides:
Lecithins: Targeted drug delivery of nonpolar medicines
Cephalins: In platelets, involved in blood clotting
Sphingolipids:
Sphingomyelins: Major components of myelin sheath
Glycolipids: Cell membranes