Chapter 2 Microbiology

smallest unit of matter

contains a nucleus and an electron cloud

composed of subatomic particles

join together to form molecules

attractions between cations (electron donor) and anions (electron acceptor)

positively charged ion

negatively charged ion

involves sharing electrons

weak polar bonds based on partial electrical attractions

breaks down chemical bonds

AB→ A + B

“water loosening or breaking”

ABCDE + H2O→ABC -- H + HO -- DE

breakdown of complex molecules withing body cells that produces energy

--CD → C + D + energy

Forms chemical bonds

A + B → AB

• formations of a water molecule

• ABC-- H + OH -- DE → ABCDE + H20

synthesis of new molecules within body cells that uses energy

-- C + D + energy → CD

involves decomposition of first, then synthesis

-- AB + CD → AD + CB

occurs simultaneously in both directions

• AB <-> A + B

• @ equilibrium the amount of chemicals does not change even though the reactions are still occurring

• Reversible reactions seek equilibrium

protein catalysts that lower the activation energy of reactions

not changed or used up in a reaction

amount of energy needed to get a reaction started

chemical reactions in cells cannot start without help

produce more energy than they use

generates body heat

use more energy than they produce

uses body heat

mixture of 2 or more substances

medium (liquid, air)

atoms, ions, or molecules which are dispersed (or dissolved) in solvent

water’s ability to dissolve a solute in a solvent to make a solution

ionic bonds broken in water due to polarity of water

sheath of water molecules around an ion in solution

water loving

molecules that interact readily with water molecules

ions, polar molecules

extremely reactive in solution

concentration of hydrogen ions (H+) in solution

the amount of solute in a solvent (mg/mL)

balance of H+ and OH-

-pH of human blood -- from 7.35 to 7.45

pH lower than 7.0

high H+ concentration

pH higher than 7.0

low H+ concentration

inverse relationship with [H+]

ranged from 0-14

a solute that dissociates in solution & releases H+

proton donor

strong acids dissociates completely in solution (HCI)

HCI → H+ Cl-

a solute that removes hydrogen ions from a solution

proton acceptor

strong bases dissociate completely in solution (NaOH)

NaOH → Na+ OH-

fail to dissociate completely (carbonic acid → bicarbonate)

H2CO3 → H+ + HCO3

help balance the pH

solution that dissociate into cations and anions (except hydrogen ions and hydroxide ions)

NaCl → Na+ + Cl-

stabilize pH by removing or replacing H+

neutralizes either a strong acid or strong base

sodium bicarbonate is very important in humans

buffers carbonic acid

a basic compound that neutralizes acid and forms a salt

tums, rolaids

molecules not based on carbon or hydrogen

oxygen, water, inorganic acids, bases and salts, carbon dioxide

usually small and structurally simple

molecules based on carbon or hydrogen

carbohydrates, proteins, lipids, nucleic acids

an arrangement of atoms in an organic molecule that is responsible for most of the chemical properties of that molecule

contain H, C and usually O

covalently bonded

contain functional groups that determine chemistry

polymers consisting of many small repeating molecules called monomers

monomers join by dehydration synthesis reactions

contain C, H, O in a 1:2:1 ratio

simple sugars with 3 to 7 carbon atoms

two simple sugars condensed by dehydration synthesis

many monosaccharides condensed by dehydration synthesis

hydrolysis breaks disaccharides → monosaccharides

(picture)

(picture)

• carbon: hydrogen ration is 1:2

• contain much less O than carbs

• nonpolar & insoluble in water

• hydrophobic molecules: fats, oils, waxes

  • need transporter in blood

• fatty acids, eicosanoids, glycerides, steroids, phospholipids, glycolipids

• primary components of cell membranes

• fats or triglycerides

• contain glycerol and fatty acids

• formed by dehydration synthesis

• broken by hydrolysis

• chains of hydrocarbons

with hydrogen (no double bonds)

( one or more double bonds between carbons)

contains C, H, and O & P, N, or S

phospholipids that make up membranes

• water loving

  • interacts with water

  • ions and polar molecules

• water fearing

• does not interact with water

• nonpolar molecules, fats, oils

• four carbon rings with OH- group attached to one ring

• part of membranes; keeps membranes fluid

• most abundant and important organic molecules

• contains C, H, O, N

• 20 amino acids - building blocks

• amino acid structure

  • central carbon atom

  • hydrogen atom

  • amino group (--NH2)

  • carboxylic acid group (--COOH)

  • variable side chain or R group

• exist in either of two stereoisomers: D or L

• L- forms are most often found in nature

requires dehydration synthesis between amino group and carboxylic group producing a peptide bond

• support- structural proteins

• movement- contractile proteins

• transport- transport (carrier) proteins

• buffering- regulation of pH

• metabolic regulation- enzymes

• coordination and control- hormones

• defense- antibodies

• conjugated proteins- consists of amino acids combined with other organic molecules

  • glycoproteins

  • nucleoproteins

  • lipoproteins

the sequence of amino acids along a polypeptide

hydrogen bonds form spirals or pleats

secondary structure folds into a unique shape

final protein shape - several tertiary structures together

change in structure

due to temp, pH changes

protein becomes nonfunctional

extended sheets or strands

soluble spheres with active functions

protein function based on shape

shape based on sequence of amino acids

proteins can undergo this

occurs when proteins encounter hostile environments such as temperature and pH

causes proteins to lose their shapes and functions

• large organic molecules found in nucleus

  • store & process information at molecular level

• determines inherited characteristics

• directs protein synthesis

• controls enzyme production

• controls metabolism

controls and performs intermediate steps in protein synthesis

building blocks of DNA, RNA

3 molecular parts:

1. sugar (deoxyribose or ribose)

2. phosphate groups

3. nitrogenous base

   (A, G, T, C, or U)

double stranded

• bases form hydrogen bonds to hold together

• twisting double- helix

• purines pair with pyrimidines

• adenine (A) to thymine (T)

• cytosine (C) to guanine (G)

usually single stranded

• uracil (U) replaces thymine; binds to adenine

• messenger RNA (mRNA), transfer RNA (tRNA), ribosomal RNA (rRNA)

nucleotides can be used to store energy

two phosphate groups; di- = 2

3 phosphate groups; tri- = 3