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Chapter 5A: Carbohydrates and Lipids - Coggle Diagram
Chapter 5A: Carbohydrates and Lipids
Macromolecules 3: Sugar-based (Carbohydrates, Polysaccharides)
Functions
build/attach, construct bigger things: CELLULOSE holds structure in plants
Storage: STARCH (plants), GLYCOGEN (animals)
MONOSACCHARIDES (-ose denotes sugars), C:H:O ratio 1:2:1
things to know
Carbon chains: 6 carbon's = HEXOSES
5-carbon example is a ribose (backbone of nucleotide)
Many HYDROXYL groups (polar, hydrophilic)
ex. glucose syrup is very soluble in water
when linear
C=O bond at end (ALDOSE)
C=O bond at position 2 (KETOSE)
monosaccharides to know: glucose, galactose, fructose
Monosaccharides in a pair are DISACCHARIDES
glucose + fructose = sucrose
galactose + glucose = lactose
In cells, monosaccharides are present as RINGS
numbering starts at the position closest to the DOUBLE BOND
Hexoses can be linked end to end by GLYCOSIDIC BONDS
CONDENSATION REACTION: loss of a water molecule (take out a hydroxyl from one monosaccharide and H from the OH of another monosacharride)
forms a C-O-C bond
examples of polysaccharides
cellulose joins a bunch of glucose together (linen)
starch (glucose)
glycogen (glucose chains are branched)
pectin: mixture of monosaccharides
Macromolecules 4: Hydrophobic (hydrocarbon chains, lipids)
Important features
favor separation from water
compact (highly concentrated) storage of energy
Carbohydrates vs. hydrocarbons
carbohydrates are polar: have HYDROXYLS
hydrocarbons are nonpolar: made up of ONLY carbons and hydrogens
Water does not mix easily with hydrocarbons (lipids, hydrophobic amino acids)
in water, it's favorable to MINIMIZE the surface area of hydrophobic molecules by CLUMPING them together (example: oil clumps in water)
driving force for this clumping is water
Fatty acids are composed of repeated C2H4 elements (HYDROCARBON CHAIN) and carboxyl at the end
SATURATED: NO C=C double bonds
UNSATURATED: has C=C double bonds
C=C double bonds make chain STIFF
presence of double bonds influences FLUIDITY of fats, oils, and membranes
presence of cis double bonds in UNSATURATED FATTY ACIDS interferes with the tight packaging (LIQUID at room temperature)
SATURATED FATTY ACIDS packed very closely together into crystalline arrays, stabilized by hydrophobic interaction (SOLID at room temperature)
Lipids: 2-3 fatty acids linked through a glycerol
glycerol: 3-carbon molecule with OH attached to each carbon
Triacylglycerol: 3 fatty acids w/ a glycerol
in triaglycerol, a CONDENSATION reaction occurs between each glycerol and carboxyl group
Phosphatidylcholine: choline head + phosphate group + glycerol backbone + 2 fatty acid tails
Van der waals forces help lipids COME TOGETHER TIGHTLY in water (non-covalent bonding)
SYNCHRONY of charge fluctuations can hold large molecules together
individual interactions are WEAK, but add them together to generate stronger interactions (larger molecules)
van der waals are strongest when molecules are VERY CLOSE (unsaturated fatty acids drive chains FURTHER apart making forces weak)
Why does the chain at the C=C double bond BEND?
cis fatty acids: when H's are on the same side, they REPEL each other (bend)
trans: when H's are on the opposite side, they DON'T BEND
