Microbial Metabolism & Growth
Basic Organic Chem Review Four Basic Types of Macromolecules A) Proteins (Made up of Amino Acids) B) Nucleic Acids (Made up of NucleoEdes) C) Carbohydrates (Mainly Carbon, Hydrogen, and Oxygen in a 1:2:1 raeo) D) Lipids (Mainly Carbon & Hydrogen)
A. Proteins consist of long, complex chains of amino acids (20 kinds) the most abundant organic components of microbes function as structural materials as well as destruction of the proteins in an organism usually results in death
Protein structure: amino acids AMINO ACIDS are the building blocks of proteins a specific amino acid
Protein structure: amino acids NOTE: All amino acids look alike except for the highlighted poreons. This is important in building many different proteins.
Peptide bonding of amino acids Proteins are built by linking amino acids end to end. Each link is a.
Protein structure: Primary
Protein structure: Secondary
Protein structure: 3 dimensional The 3 dimensional shape of a protein dictates its function. If the 3 dimensional shape is altered, the protein is destroyed.
Protein structure: Quaternary (Hemoglobin)
Protein Altered 3- D shape = destroyed protein
B. Nucleic Acids Two types function in all living things: ( deoxyribonucleic acid ) acts as the genetic material of the chromosome ( ribonucleic acid ) functions in the construction of proteins Both DNA and RNA are composed of repeating units called nucleotides As with proteins, the nucleic acids cannot be altered without disrupting the organism or killing it.
C. Carbohydrates 1. general formula = (CH 2 O) n 2. sugars, starches, cellulose, etc 3. have a vital function as energy sources in cells 4. also found in several cellular structures such as cell walls and bacterial capsules 5. monosaccharides are the simplest carbohydrates, the building blocks e.g., fructose C 6 H 12 O 6
Carbohydrates 6. disaccharides are double sugars (2 monosaccharides bonded together) e.g. (table sugar) is one glucose and one fructose C 12 H 22 O 11 : one H 2 O lost when bond forms DehydraEon Synthesis (PuVng together) Hydrolysis (breaking apart) glucose fructose NOTE: 2 monosaccharides linked together.
Macromolecules (How to Make Them) CH 2 OH CH 2 OH CH 2 OH CH 2 OH H O H H O H H O H O H H H H H OH H OH H OH H O OH H HO OH HO OH HO OH H 2 O H OH H OH H OH H OH Dehydration Synthesis Hydrolysis
C. Carbohydrates 7. complex sugars are called polysaccharides or complex carbohydrates (e.g. starch, cellulose ) long chains of sugars: sugar sugar sugar sugar sugar sugar sugar
D. Lipids Broad group of organic compounds that dissolve in oily solvents (e.g. acetone, or benzene) and alcohol but generally do not dissolve in water Mostly composed of carbon and hydrogen
D. Lipids 1. Best known lipids are fats serve living organisms as important energy sources consist of glycerol and up to three long-chain fatty acids 2. Modified fats called phospholipids glycerine are the major components of membranes 3. Other types of lipids include waxes and steroids fawy acid
Fatty Acids + Glycerol
Fats
Other important lipids you should know! Phospholipids Steroids such as cholesterol
I. MICROBIAL PHYSIOLOGY : the sum of all biochemical processes taking place in a living cell. Two phases: : constructive metabolism; the synthesis reactions; small molecules bonded into larger molecules; energy is used up : destructive metabolism; decomposition reactions; large molecules split into smaller molecules; energy is released
A. the enzymes present in an organism determine the nature of its physiology enzymes are biological catalysts (catalysts are agents that speed up chemical reactions) Enzymes are reusable protein molecules that brings about a chemical change while remaining unchanged itself
= the amount of energy required to do the reaction
net energy released from splitting of lactose Without enzyme lactose glucose + galactose activation energy without enzyme With enzyme Activation Energy = the amount of energy required to do the reaction lactose glucose + galactose activation energy with enzyme net energy released
Enzymes = what the enzymes works on = what is made
Enzymes Active Site Allosteric Site Competitive Inhibitor Noncompetitive inhibitor
Action of enzyme inhibitors Examples of inhibitors: 1. CompeEEve=sulfa drug (sulfanilamide) 2. NoncompeEEve=Certain poisons, such as cyanide and fluoride (enzyme poison in bacteria)
Factors influencing enzyme action: a. Terms: optimum: the environmental state where the enzyme works the fastest. maximum: The maximum environmental limit where the enzyme works at all. minimum: The minimum environmental limit where the enzyme works at all. e.g. temperature: every enzyme has its optimum temperature (where it works fastest). Curve is unusual:
enzyme activity vs temperature
Measurement of acid/base balance Logarithmic scale 0-6.9 = acid 7.1-14 = basic (alkaline) 7 = neutral (like pure water) ph
enzyme activity vs ph every enzyme has its optimum ph (where it works fastest). Bell curve
Naming of enzymes names end with -ase name of substrate + ase e.g. sucrose is digested by sucrase kind of reaction + ase e.g. an enzyme that causes oxidation is called oxidase
Types of Enzymes based on location endoenzymes: remain inside of the cell (work internally) enzymes of cellular metabolism vulnerable enzymes exoenzymes: released to the exterior of the cell (work externally) digestive enzymes and enzymes of virulence
Constitutive vs Induced Enzymes enzymes: always present necessary for life of cell enzymes: produced only when substrates are present e.g. digestive enzymes provide efficiency and adaptability
B. Energy and ATP Energy released from catabolism of foods is stored in a compound called ATP (adenosine triphosphate) a molecule of ATP acts like a portable battery it s instant energy for a cell to use ATP molecules are used everywhere in a cell to meet energy needs. (When the supply is exhausted, the cell dies)
ADP + Phosphate + Energy = ATP captures heat releases heat
ATP Although ATP molecules are used everywhere in the cell to meet energy needs, they are not suitable for storing energy. The molecules are large and bulky, and surplus takes up too much space in a cell. Therefore, cells synthesize or obtain small molecules such as glucose or lipids for energy storage. When needed, these energy storage molecules can be converted to ATP! glucose is a principle source of energy for ATP production.
C. Pathways of Energy Production Most of a cell s energy is produced from carbohydrate catabolism Glucose is the most commonly used carbohydrate: C 6 H 12 O 6 + 6 O 2 + 38 ADP + 38 P 6 CO 2 + 6 H 2 O + 38 ATP
To produce energy (ATP) from glucose, microbes use 2 general processes: 1. respiration in which glucose is completely broken down 2. fermentation in which glucose is partially broken down Both processes usually start with the same first step (glycolysis), but follow different subsequent pathways
Glycolysis the first stage in the breakdown of glucose glucose (energy source ) series of controlled reaceons releasing a liwle ATP 2 pyruvic acid
Overview of Respiration & Fermentation glycolysis respiraeon pathways fermentaeon pathways Aerobic= CO 2 + H 2 O + 38 ATP an organic end- product (like alcohol or lacec acid) with low ATP yield
Classification of organisms by oxygen use (study table 6.1) 1. obligate aerobes: (= strictly aerobic): must have oxygen to grow (go dormant without oxygen) 2. microaerophiles: grow best at low oxygen levels (less than atmospheric) 3. facultative anaerobes: use oxygen if it s present, but can also grow anaerobically (capable of growing at any oxygen level, but greater growth with oxygen present) 4. aerotolerant anaerobes: never use oxygen, but not inhibited by it 5. obligate anaerobes: grow only in absence of oxygen (inhibited by oxygen) Good Essay QuesEon!
Growth at different oxygen levels
E. Growth at different temperatures Each species has different temperature requirements minimum growth temperature: lowest temperature at which growth will occur (very slow growth at this temp) below the minimum, most microorganisms go dormant, but do not die optimum growth temperature: temp at which most rapid growth occurs maximum growth temperature: highest temp at which growth occurs above this temp, enzymes are denatured and death might occur NOTE: Growth parallels rate of enzyme activity.
Growth speed vs temperature Growth Speed
F. Classification by temperature requirements (= cryophiles): cold-loving organisms; have optimum growth temp below 25 C mesophiles (meso = middle): have optimum of 25-40 C : heat-loving organisms; have optimum > 40 C : hyperthermophiles growth range = 70-105 o C; optimum > 90 o C Good Essay QuesEon Also!
Growth versus temperature
Does size of pan (with same volume) matter?
Growth speed G. ph and microbial growth every organism has its minimum, optimum, and maximum growth ph microorganisms often change the ph of their environment usually create acidity sometimes create alkalinity
Thus, the requirements for bacterial growth include: Physical aspects Temperature ph Osmotic pressure Chemical aspects Carbon, nitrogen, sulfur, phosphorus, trace elements, oxygen, and organic growth factors
H. Bacterial fission (cell division) less complex than mitosis (division of eucaryotic cells) only one chromosome Binary fission (see figure 6.12)
Remember... When we talk about microbial growth, we are really referring to the number of cells, not the size of the cells. Microbes that are growing are increasing in number, accumulating into clumps of hundreds, colonies ( can be seen with naked eye ) of hundreds of thousands, or populations of billions.
How do we measure microbial Plate counts and serial dilutions growth? We ll do as part of the microbiology of water and milk lab See figure 6.16 Filtration We ll do as part of the microbiology of water lab See figure 6.18 Direct Microscopic Count See figure 6.20 Turbidity Using the spectrophotometer See figure 6.21 Dry weight
I. Population dynamics potential populations: huge doubling time of 20-30 minutes for many microorganisms from 1 cell to over a million in 10 hours (with 30 minute generation) See figure 6.13 & 6.14 populations are self-limiting depletion of food supply accumulation of toxic metabolic wastes
population growth curve maximum staeonary phase (aging populaeon) lag phase: slow growth logarithmic (log) phase: rapid growth death phase: rapid decline survivor phase Eme