Medical Microbiology - Chapter 3 - Basic Chemistry

Medical Microbiology - Chapter 3 - Basic Chemistry

I. Basic Chemistry

A. Atoms - all matter composed of atoms

1. nucleus - protons, neutrons

2. electrons orbit nucleus

B. Elements - contain only 1 kind of atom

1. Periodic Table - arranged according to reactivity

2. Elements in living matter

a. 20

b. 4 make up 97% of all living matter; rest called trace elements

C. Molecules - 2 or more atoms bonded together

D. Compounds

1. 2 or more atoms joined together in a definite proportion by weight
2. properties of reactants different than product

3. formula represents cpds.

4. 2 types of cpds.: inorganic and organic

E. Solutions - where one substance is dissolved into another

1. Solute - substance dissolved

2. solvent - substance that does the dissolving

3. soluble - substance can be dissolved

4. insoluble - substance can't be dissolved

5. Water is universal solvent - polar

6. Tincture - where a substance is dissolved into alcohol

II. Acids, Bases, and Salts

A. Acid

- substance that ionizes in water into positively charged Hydronium ions (H3O+)

B. Base

- substance that ionizes in water into negatively charged Hydroxide (OH-) ions

C. Neutralization and Salts

1. acid + base → salt + water - called neutralization

2. example: HCL + NaOH → NaCL + H2O

ions of acid and ions of base join to form water and salt

III. Indicators - special chemicals used to test for H+ ion concentration in solutions

- examples of indicators:Blue litmus paper - blue in base; red in acid

Bromthymol Blue - blue in base; yellow in acid

Phenolphthalein - pink in base; colorless in acid

IV. pH of Living Organisms - not too acid or too base

A. pH - measure of acidity

B. pH scale - 7 neutral

0-6.9 - acid

7.1-14 - base

-tears 7.3, blood 7.4, urine 5-7.5

C. Biochemical reactions

1. must occur at given pH

2. deviation could be disastrous and/or fatal

D. Buffers

1. maintain pH balance

2. either donate or accept H+ ions

V. Types of compounds

A. Inorganic

1. don't have carbon

2. exceptions: CO2 and CaCO3

B. Organic

1. large and complex

2. have C, H, O, and usually N and P

3. hydrocarbons - consisting only of carbons and hydrogens

VI. Carbohydrates

A. contain C, H, and O in ration of 1:2:1

B. Monosaccharides

1. simple sugar - can't be broken down any further

2. 3 monosaccharrides

a. glucose - C6H12O6

b. fructose (fruits and honey)

c. galactose (flaxseed, agar, milk)

3. isomers - same molecular formula but different structure

4. Glucose used by living organisms to produce energy - ATP (adenosine triphosphate)

a. oxidation: glucose + oxygen → ATP

b. oxidation - any reaction that involves oxygen or any reaction that causes an atom to

lose electrons

C. Disaccharides

1. 2 sugars bonded together

2. bonding occurs by dehydration synthesis

3. examples:sucrose (table sugar) - glucose + fructose

lactose (milk sugar) - glucose + galactose

maltose (malt sugar) - glucose + glucose

4. bonds broken by hydrolysis

D. Polysaccharides

1. huge polymer

2. examples:starch - storage form of glucose in plants

cellulose - found in cell wall - very strong and rigid

glycogen - (animal starch) storage form of glucose in liver/muscles of animals

chitin - exoskeleton of invertebrates

VII. Lipids

A. Characteristics of Lipids

1. ratio of hydrogen to oxygen - lots of hydrogen, less oxygen

2. fats, oils, waxes

3. gram for gram, fat produces more energy than sugar (carbs)

4. 3 categories of lipids: simple, compound, derived

5. general structure: 1 glycerol molecule + 3 fatty acid molecules

6. formed by dehydration synthesis

B. Simple - C, H, and O

1. fats and oils

2. ex.: butter, margarine, bees wax, lanolin, oils - corn, safflower, olive, peanut

3. 2 types of simple lipids

a. saturated

-all C bonds are single covalent bonds - b/c bonds are saturated with H

-fatty acid tails straight - pack tightly together

-solid at room temperature (b/c of single covalent bonds between the carbons)

- bad for you - raise cholesterol levels in blood

b. unsaturated

-in some of C bonds, 2 H bonds replaced with double bonds between C atoms (C-C)

-causes bump in fatty acid tails - tails can't pack tightly

-more double bonds you have, more unsaturated it is (polyunsaturated)

-liquid at room temperature

-good for you - lowers cholesterol levels in blood; easier to digest

C. Compound - C, H, O, N, and P

1. amount remains constant in organism

2. phospholipids in cell membrane

3. glycolipids in brain and nerve cells

D. Derived - C, H, O

1. steroids found in male and female hormones

2. Vitamin D

3. cholesterol

4. fat soluble vitamins: A, D, E, and K

5. called lipids because soluble in fat solvents

VIII. Proteins - C, H, O, N, and S

-most diverse and essential organic cpd. in all living organisms

-made of amino acids bonded together

A. Amino acids

1. 20 total

2. basic structure

a. central carbon - C

b. amino group - NH2

c. carboxyl group - COOH

d. radical (R) group - what makes every amino acid different

B. peptide bond

1. bond between amino acids

2. 300-1'000's amino acids bonded together to form protein; bond between C of one

amino acid and N of other amino acid

3. polypeptide

C. 4 structural levels of protein

1. primary

-structure - straight chain

2. secondary

a fibrous proteins - strong/stable

b. structure-alpha helix

- beta pleated sheets

c. examples: hair, nails

3. tertiary

a. structure - globular protein - one protein folds forming globs of amino acids

b. examples - enzymes

4. quaternary

a. structure - 2 or more globular proteins bonded together

b. examples - hemoglobin

D. Enzymes

1. all enzymes are proteins

2. organic catalyst - speed up chemical reaction but itself remains unchanged

3. causes chemical reaction to occur at right time

4. composition of enzymes

a. protein or part protein molecule + nonprotein

b. apoenzyme - protein part

c. coenzyme - nonprotein part (ex.: Ca, Fe, Mg, Cu, vitamins C and B-complex)

5. highly specific

6. enzyme-substrate complex

a. active site on enzyme

b. substrate - substance enzyme reacts with

IX. Nucleic Acids

A. C, H, O, N, and P

B. 2 types

1. DNA

2. RNA

C. Chromosomes and Genes - genes on chromosomes

D. Structure

1. made of smaller subunits - nucleotides

2. nucleotides

a. 5 C sugar - deoxyribose or ribose

b. phosphate group

c. N2 base

-purines: adenine and guanine

-pyrimidines: cytosine, thymine, and uracil

-bonding specific: A-T (U); C-G

E. DNA - deoxyribonucleic acid

1. location - nucleus, mitochondria, cell membrane, chloroplasts

2. structure

a. double stranded (double helix0

b. 5 C sugar - deoxyribose

c. phosphate group

d. four N2 bases: A-T and C-G

3. function - carries genetic information

F. RNA - ribonucleic

1. location - nucleus, cytoplasm, ribosomes

2. structure

a. single stranded

b. 5 C sugar - ribose

c. four N2 bases: A-U and C-G

3. function - essential for protein synthesis

4. 3 types

a. mRNA

b. tRNA

c. rRNA