B1.1: Carbohydrates and Lipids

Macromolecules

Large biological molecules neccessary for life (Proteins, Lipids, Carbohydrates, Nucleic Acids)

Macromolecules bonding

Condensation reaction

Macromolecules breaking down

Hydrolysis

Smallest form of carbohydrate

Monosaccharide

Monosaccharide formula

C_nH_2nO_n, where n = number of carbons

Disaccharides

Two monosaccharides bonded together

Polysaccharides

Long chains of monosaccharides bonded together

Monomers of triglycerides

Glycerol and fatty acids

Lipid type depends on

Fatty acids

Per g of substance:

Lipids store about 2x the amount of energy compared to carbohydrates

Why is life on Earth carbon-based?

The four main macromolecules that build up living organisms contain carbon

3 main monosaccharides

Glucose, fructose, galactose

OH functional group

Hydroxyl (alcohol)

NH₂ functional group

Amino/Amine

COOH functional group

Carboxyl

P functional group

Phosphate

Peptide bond

New covalent bond is created between two amino acids, breaking covalent bonds within each individual molecule and producing a water molecule. Catalysed by enzyme.

What indicates the shape of a monosaccharide?

The number following c in the formula. Ie. Ribose = C₅H₁₀O₅ , thus ribose is pentose.

Properties of glucose

• Molecular stability (covalent bonds)

• Highly soluble in water (polarity)

• Therefore easily transportable

• High energy yield from oxidation

What does (1-4) and (1-6) refer to in glycosidic linkages?

Carbon numbers of the two carbons joined together by the bond.

A starch with only (1-4) linkages will have what shape?

Linear helix

What does the addition of (1-6) linkages create?

Branches

Which polysaccharide consists of only 1-4 linkages?

Amylose

Which polysaccharide is known for having 1-6 linkages?

Amylopectin and glycogen

Starch

Polymer of glucose containing amylose and amylopectin

Excess glucose is stored as

Glycogen

What does alpha and beta refer to in a monosaccharide?

Orientation of the hydrogen and hydroxyl group

Alpha orientation

Hydrogen on top

Beta orientation

Hydroxyl on top

Difference between bonds in cellulose and amylose

Cellulose uses beta 1-4 linkages whereas amylose uses alpha 1-4 linkages

Glycoproteins and blood transfusion

Glycoproteins facilitate cell-to-cell recognition, on red blood cells they form the antigens that decide blood type (A, B, AB, O)

Type O can give blood to

Any blood type, as neither A or B glycoproteins (antigens) are present

Types of lipids

Fat, oil, wax, steroid (changes form depending on temperature)

How are triglycerides formed?

1 glyceride + 3 fatty acids

How are phospolipids formed?

1 glyceride + 2 fatty acids + 1 inorganic phosphate

How do phosphates/fatty acids bind to glycerol?

Glycerol is a 3-carbon molecule with each carbon bonded to a hydroxyl group. Every fatty acid has a terminal carboxyl group. This facilitates a condesation reaction, removing the hydroxyl group entirely and allowing the remaining oxygen molecule in the fatty acid to bond to the carbon in the glycerol.

Saturated fatty acids

Higher melting point, more rigid and linear structure, fats at room temp, all carbons have single bonds meaning that all available carbons are bonded to hydrogen

Monounsaturated fatty acids

Lower melting point, oil form at room temperature, one double bond between two carbons.

Polyunsaturated fatty acids

Also oil at room temp, low melting point, multiple double bonds between carbons.

Adipose tissue

Cells that store fat (triglycerides) for long-term energy storage - e.g blubber in whales and seals. Typically found next to skin, used for thermal insulation

Steroid hormones

Chemical messengers. Lipid-based and therefore insoluble, pass through membrane easily to direct transcription.

Why are starch and glycogen good energy stores?

• Their coiled, branched structure makes them compact

• They are relatively insoluble so they don’t draw extra water by osmosis

• Glucose can be easily added or removed according to neccessity

Triglycerides

Fats and oils