Macromolecules

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Lipids

General term for compounds which are not soluble in water.

Lipids are soluble in hydrophobic solvents.

Remember: “stores the most energy”

Examples: 1. Fats

2. Phospholipids

3. Oils

4. Waxes

5. Steroid hormones

6. Triglycerides

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Lipids

Six functions of lipids:

1. Long term energy storage

2. Protection against heat loss (insulation)

3. Protection against physical shock

4. Protection against water loss

5. Chemical messengers (hormones)

6. Major component of membranes (phospholipids)

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Lipids

Triglycerides: composed of 1 glycerol and 3 fatty acids.

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Fatty Acids

There are two kinds of fatty acids you may see these on food labels:

1. Saturated fatty acids: no double bonds (bad)

2. Unsaturated fatty acids: double bonds (good)

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Proteins

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Proteins (Polypeptides)

Amino acids (20 different kinds of aa) bonded together by peptide bonds (polypeptides).

Six functions of proteins:

1. Storage: albumin (egg white)

2. Transport: hemoglobin

3. Regulatory: hormones

4. Movement: muscles

5. Structural: membranes, hair, nails

6. Enzymes: cellular reactions

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Proteins (Polypeptides)

Four levels of protein structure:

A. Primary Structure

B. Secondary Structure

C. Tertiary Structure

D. Quaternary Structure

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Primary Structure

Amino acids bonded together by peptide bonds (straight chains)

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Secondary Structure

3-dimensional folding arrangement of a primary structure into coils and pleats held together by hydrogen bonds.

Two examples:

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Tertiary Structure

Secondary structures bent and folded into a more complex 3-D arrangement of linked polypeptides

Bonds: H-bonds, ionic, disulfide bridges (S-S)

Call a “subunit”.

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Quaternary Structure

Composed of 2 or more “subunits”

Globular in shape

Form in Aqueous environments