The Building blocks of life

Macromolecules

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Organic Compounds• Compounds that contain CARBON

are called organic.

• Macromolecules are large organic molecules.

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LIFE ON EARTH IS CARBON-BASED

• Carbon is a component of almost all biological molecules.

• Carbon has 4 electrons in outer shell.

• Carbon can form covalent bonds with as many as 4 other atoms (elements).

• Usually with C, H, O or N.

• Example: CH4(methane)

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Macromolecules

• Large organic molecules.• Also called POLYMERS.• Made up of smaller “building blocks”

called MONOMERS.• Examples:

1. Carbohydrates2. Lipids3. Proteins4. Nucleic acids (DNA and RNA)

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Question:How Are

Macromolecules Formed?

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Answer: Dehydration Synthesis

• Also called “condensation reaction”

• Forms polymers by combining monomers by “removing water”.

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HO H

HO HO HH

H2O

Question:How are

Macromolecules separated or digested?

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Answer: Hydrolysis

• Separates monomers by “adding water”

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HO HO HH

HO H

H2O

CarbohydratesFunction: main energy resources.

In plants called cellulose gives structural support to the cell

wall.

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Carbohydrates

• Small sugar molecules to large sugar molecules.

• Examples:A. monosaccharideB. disaccharideC. polysaccharide

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Carbohydrates

Disaccharide: two sugar unit

Examples: –Sucrose (glucose+fructose)

–Lactose (glucose+galactose)

–Maltose (glucose+glucose)

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glucoseglucose

CarbohydratesPolysaccharide: many sugar units

Examples: starch (bread, potatoes)

glycogen (beef muscle)

cellulose (lettuce, corn)

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glucoseglucose

glucoseglucose

glucoseglucose

glucoseglucose

cellulose

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. Phospholipids3. Oils4. Waxes5. Steroid hormones6. Triglycerides

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Lipids

Six functions of lipids:1. Long term energy storage2. Protection against heat loss (insulation).In plant leaves called wax3. Protection against physical shock4. Protection against water loss5. 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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H

H-C----O

H-C----O

H-C----O

H

glycerol

O

C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3

fatty acids

O

C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3

O

C-CH2-CH2-CH2-CH

=CH-CH2-CH2-CH2-CH2-CH3

Fatty AcidsThere are two kinds of fatty acids:

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

2. Unsaturated fatty acids: double bonds (good)

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O

C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3saturated

O

C-CH2-CH2-CH2-CH

=CH-CH2-CH2-CH2-CH2-CH3

unsaturated

ProteinsAmino acids (20 different kinds)bonded together by peptide bonds(polypeptides).

Proteins (Polypeptides)

• Six functions of proteins:1. Storage: albumin (egg white)2. Transport: hemoglobin3. Regulatory: hormones4. Movement: muscles5. Structural: membranes, hair, nails6. Enzymes: cellular reactions

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Proteins (Polypeptides)

Four levels of protein structure based on the variable groups contained in the different amino acids :A. Primary StructureB. 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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aa1 aa2 aa3 aa4 aa5 aa6

Peptide Bonds

Amino Acids (aa)

Secondary Structure

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

• Two examples:

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Alpha Helix

Beta Pleated Sheet

Hydrogen Bonds

Quaternary Structure• Composed of 2 or more “subunits”• Globular in shape• Form in Aqueous environments• Example: enzymes (hemoglobin)

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subunits

Nucleic Acidsstore and transmit genetic

information.

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Nucleic acids

• Two types:a. Deoxyribonucleic acid (DNA-

double helix)b. Ribonucleic acid (RNA-single

strand)• Nucleic acids are composed of long

chains of nucleotides linked by dehydration synthesis.

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Nucleic acids• Nucleotides include:

phosphate grouppentose sugar (5-carbon)nitrogenous bases:

adenine (A)thymine (T) DNA onlyuracil (U) RNA onlycytosine (C)guanine (G)

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Nucleotide

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O

O=P-O

O

Phosphate

Group

NNitrogenous base

(A, G, C, or T)

CH2

O

C1C4

C3 C2

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Sugar

(deoxyribose)

DNA - double helix

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P

P

P

O

O

O

1

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4

5

5

3

3

5

P

P

PO

O

O

1

2 3

4

5

5

3

5

3

G C

T A