microbiology lecture chapter 2

Atoms

Neutrons, electrons, protons.

Isotopes:

Same element different neuron number.

Chemical bonds:

Ionic=transfer of electrons (NaCl)

Covalent=sharing electrons (H2O, organic molecules)

Hydrogen=weak attraction (DNA base pairs, water)

Water properties:

polar, hydrogen bonding, universal solvent, temp buffer.

pH scale:

pH scale: acidic (H⁺), basic (OH⁻), neutral = 7.

Importance in biology:

enzymes & proteins sensitive to pH changes.

Carbohydrates:

monosaccharides (glucose), polysaccharides (starch, glycogen, peptidoglycan).

Lipids:

Fats = glycerol + fatty acids.

Phospholipids = membranes (polar head, nonpolar tail).

Steroids = cholesterol, hormones.

Proteins:

amino acids → peptide bonds → structures (primary → quaternary).
Enzymes, transport, movement, toxins.

Denaturation:

heat, pH, or chemicals disrupt structure.

Nucleic acids:

DNA (A-T, C-G), DNA has deoxyribose. RNA (A-U, C-G), RNA has ribose. DNA is double-stranded, RNA is single-stranded.
ATP = adenine + ribose + 3 phosphates (energy).

Pathogen Highlight:

• Clostridium perfringens

  • Gram-positive, spore-forming bacillus, anaerobe.

  • Causes gas gangrene, diarrhea.

  • Produces exotoxins.

  • Treatment = IV penicillin G.