Molecules of Life

Condensation Reaction (2)

Joins two monomers together (forms a chemical bond)

Releases one water molecule

Hydrolosis Reaction (2)

Breaks a chemical bond between monomers

Uses a water molecule to split them apart

Monosaccharide (3)

Simple sugar / single sugar unit

CnH2nOn

Glucose, fructose, galactose

Glycosidic bond

Bond formed between two monosaccharides by a condensation reaction

Starch (4)

Polysaccharide of α-glucose

Helical (helix shape)

1,4 and 1,6 glycosidic bonds

Energy storage

Cellulose (4)

Polysaccharide of β-glucose

Straight chains

Only 1,4 bonds but H-bonds form microfibrils

Structural support

Triglyceride (3)

Glycerol + 3 fatty acids

Joined by ester bonds

Hydrophobic

Phospholid (3)

Glycerol + 2 Fatty acids + Phosphate group

Phosphate head = hydrophilic (water-loving)

Fatty acid tails = hydrophobic

Saturated (3)

No double carbon bonds

Saturated with hydrogen

Solid at room temperature

Unsaturated (3)

At least one double carbon bond

Causes kink in a chain

Liquid at room temperature

Amino acid structure (3)

Central carbon

-NH2, -COOH

-H and variable R-group

Peptide bond (2)

Formed by condensation between amino acid and carboxyl groups

Links amino acids to polypeptides

Nucleotide structure

Pentose sugar + Nitrogenous base + Phosphate group

DNA (3)

Deoxyribose sugar

Bases A,T,C,G

Double stranded

RNA (3)

Ribose sugar

Baes A,U,C,G

Single stranded

ATP: Structure

Adenine + ribose + 3 phosphate groups

ATP: Function (2)

Immediate energy source

Hydrolysis releases energy quickly in small usable amounts

Carbon (3)

Has 4 valence electrons so forms 4 stable covalent bonds

Builds chains, branches and rings

Huge variety of organic molecules

Hydroxyl (3)

-OH

Polar

Makes molecules soluble in water

Carboxyl (3

-COOH

Acts as an acid

Releases H+ ions

Phosphate (3)

-PO4³⁻

Releases energy when bonds break

Found ATP/nucleotides

Methyl (3)

-CH3

Non-polar

Affects solubility

Protein structure: Primary

Sequence of amino acids joined by peptide bonds

Protein structure: Secondary (2)

Folding into α-helix / β-pleated sheet

Held by hydrogen bonds

Protein structure: Tertiary (4)

Final 3D functional shape

Held by H-bonds

Ionic bonds

Disulfide bridges

When are polypetides functional?

Only when folded into correct 3D structure

Carbohydrate breakdown (3)

Hydrolysis

Breaks glycosidic bonds using water

eg. Polysaccharide → disaccharide → monosaccharide

Lipids (3)

General: Non-polar so hydrophobic so insoluble in water

Saturated: Only C-C single bonds and no double bonds

Unsaturated: At least one C=C double bonds so creates kink in chain

Nucleic acids basics (3)

DNA and RNA

Store and transfer genetic information

Monomer: Nucleotide

What is the bond between nucleotides called?

Phosphodiester bond

ATP (3)

Adenosine triphosphate

Adenine + ribose sugar + 3 phosphate groups

Immediate energy currency of the cell

How does ATP release energy?

Hydrolysis removes 1 phosphate to form ADP + Pi + Energy