IB SL Bio Carbs and Lipids

Monosaccharide

Single sugar unit; the monomer of carbohydrates

Condensation reaction

Reaction that links monosaccharides together; produces water.

Glycosidic bond

Bond formed between two monosaccharides.

Hydrolysis

Reaction that breaks polysaccharides into monomers; requires water.

Alpha vs beta glucose

OH on carbon-1 points down in α-glucose, up in β-glucose.

Maltose formation

Glucose + glucose 

Lactose formation

Glucose + Galactose

Sucrose formation

Glucose + fructose

Starch is made of…

Alpha-glucose

Cellulose is made of…

Beta-glucose

Amylose linkages

1–4 glycosidic linkages.

Amylopectin linkages

1–4 and 1–6 glycosidic linkages (branched).

Cellulose linkages

1–4 glycosidic linkages of β-glucose

Why cellulose is strong?

Straight chains form hydrogen bonds → microfibrils.

Glycogen linkages

1–4 and frequent 1–6 glycosidic linkages.

Why glycogen is a good energy store?

Highly branched → rapid release of glucose.

Polysaccharide definition

Polymer of many monosaccharides.

Energy comparison of Lipids and Carbs?

Lipids store more energy per gram than carbohydrates.

Triglyceride structure

Glycerol + three fatty acids.

Ester bond?

Bond between glycerol and fatty acids.

Triglyceride formation?

Condensation reaction releasing 3 water molecules.

Saturated fatty acid

No double bonds; straight chain; maximum hydrogen.

Unsaturated fatty acid

At least one double bond; bent chain.

Cis vs trans fatty acids?

Cis: Hs same side (bent); Trans: Hs opposite sides (straighter).

Fatty acids linked to heart disease

Trans fats and saturated fats.

Unsaturated fats at room temp

Bent chains prevent tight packing → liquid.

Why lipids store more energy

More C–H bonds → more energy released during oxidation.

BMI purpose?

Used to estimate body fatness (not diagnostic).

BMI formula?

BMI = mass (kg) / height² (m²).

Phospholipid vs triglyceride

Phospholipid has 2 fatty acids + phosphate group; triglyceride has 3 fatty acids.