B1.1 Carbohydrates and lipids Flashcards
B1.1.1 - Chemical properties of a carbon atom allowing for the formation of diverse compounds upon whic life is based
Forms stable molecules through up to 4 strong covalent bonds, allowing complex structures.
B1.1.2 - Production of macromolecules by
condensation reactions - (CR)
CR - The chemical process that links another monomer onto the end of the polymer.
Two molecules link together, releasing a smaller molecule. For polysaccharides, polypeptides and nucleic acids, it is water.
B1.1.2 - Production of macromolecules by
condensation reactions - glucose
Glucose molecules are linked up with glycosidic bonds, C–O–C linkages.
The -OH on C1 of a glucose links to -OH on C4 at the end of the growing chain (1→4).
To branch, C1 of a glucose is linked to a C6.
B1.1.3 - Digestion of polymers into monomers by hydrolysis reactions
Uses a molecule of water to break a disaccharide into its two monosaccharides.
B1.1.4 - Form and function of monosaccharides - structure
3-7 carbons.
Pent. + hex. = 1 oxygen, 5-6 carbon in a ring.
B1.1.4 - Form and function of monosaccharides - properties and uses of glucose
Glucose is soluble and a relatively small,
so it is easily transported.
Glucose yields energy when it is oxidized. It can be used as a substrate for respiration.
B1.1.4 - Form and function of monosaccharides - glucose anomers
Beta glucose = -OH group attached above the ring.
Alpha glucose = -OH group linked below the ring.
B1.1.5 - Polysaccharides as energy storage
compounds
Starch (plants) and glycogen (animals) are energy stores. Both are made of α-glucose, which can be used a substrate in aerobic and anaerobic cell respiration.
B1.1.5 - Polysaccharides as energy storage
compounds - starch
Amylose is an unbranched chain of α-glucose linked by 1→4 glycosidic bonds. Bond angles make the chain helical.
Amylopectin has some 1→6 glycosidic bonds making the molecule branched.
B1.1.5 - Polysaccharides as energy storage
compounds - glycogen
Structure: α-glucose molecules linked by 1→4 glycosidic bonds, with 1→6 branching. It is more branched than amylopectin.
Large size reduces solubility, minimizing its impact on osmotic concentration. Branched structure ensures compactness despite mass. These things make it ideal for storing glucose.
B1.1.6 - Structure of cellulose related to its function as a structural polysaccharide in plants - structure
Cellulose is a polymer of β-glucose. All the links in cellulose are 1→4 glycosidic bonds .
To allow a condensation reaction to occur, each β-glucose added to the chain has to be inverted in relation to the previous one.
B1.1.6 - Structure of cellulose related to its function as a structural polysaccharide in plants - structure benefit
Regularly spaced -OH groups enable lots of H-bonding, forming strong microfibrils that make up cell walls. Their high tensile strength, due to covalent bonds, many molecules, and cross-links, prevents cells bursting under high osmotic pressure.
B1.1.8 - Hydrophobic properties of lipids
Lipids dissolve in non-polar solvents and are only sparingly soluble in aqueous solvents.
B1.1.8 - Hydrophobic properties of lipids - oils and fats
Oils: melting point below 20°C, solidify at low temperatures.
Fats: melting point between 20-37°C, solid at room temp and liquid at body temp.
B1.1.9 - Formation of triglycerides by condensation reactions
Combining three fatty acids with one glycerol in a condensation reaction.
Linkage = ester bond.
The reaction is between the –COOH group on a fatty acid and an -OH on the glycerol.
The reaction removes hydrophilic groups, making triglycerides hydrophobic.
B1.1.9 - Formation of phospholipids by condensation reactions
Two fatty acids linked to glycerol, and a phosphate group.
Phosphate = hydrophilic, so phospholipids are part hydrophilic and part hydrophobic.
B1.1.10 - fatty acid chain structure
An unbranched hydrocarbon chain. At one end of the chain is a -COOH group, at the other is a methyl group (–CH3). Most have 14-20 carbons.
B1.1.10 - Difference between saturated and unsaturated
Saturated = only single bonds, maximizing hydrogen atoms.
Unsaturated = one or more double bonds.
B1.1.10 - Difference between monounsaturated and polyunsaturated
Monounsaturated = one double bond.
Polyunsaturated = multiple double bonds.
B1.1.10 - Cis-fatty acids
Have hydrogen atoms on the same side of the double-bonded carbon atoms.
This causes a kink in the hydrocarbon chain, making the triglyceride less compact, resulting in a low melting point (liquid room temp - oils).
B1.1.10 - Trans-fatty acids
Have hydrogen atoms on opposite sides of the double bond, resulting in straight chains and a higher melting point (solid room temp).
B1.1.11 Triglycerides stored in adipose tissues - properties for energy storage
Very chemically stable, so energy is not lost over time.
Naturally forms droplets in the cytoplasm which don’t have osmotic effects on the cell.
Releases twice as much energy per gram as carbohydrates allowing energy storage in half the body mass.
B1.1.11 Triglycerides stored in adipose tissues - properties for (thermal) insulation + other
Poor heat conductor = thermal insulator in animals that need to conserve body heat.
Liquid at body temperature = acts as a shock absorber—e.g. around the kidneys.
B1.1.11 Triglycerides in adipose tissues for energy storage and thermal insulation - sea lions
Insulation is crucial in cold habitats, where body temp is higher than enviroment.
Sea lions struggle w/ overheating on land when breeding. Blubber hinders heat dissipation, and air is warmer than the ocean.
B1.1.12 Formation of phospholipid bilayers
as a consequence of the hydrophobic and
hydrophilic regions
Phosphate heads = attracted to water, hydrocarbon tails = attracted to each other more. So [] arranges into phospolipid bilayers.
B1.1.13 Ability of non-polar steroids to pass
through the phospholipid bilayer
Steroids are mostly hydrocarbon = hydrophobic. Allows passage through p-bilayers and enter or leave cells.
