Micro Lecture Exam II

• 1. Nutritional
• 2. Temperature
• 3. Gas (O₂)

• 1. Photoautotroph- photosynthesize
• 2. Chemoautotroph- oxidize chemical compounds

• microbes that photosynthesize (derive energy from light and transform it into chemical energy that could be used in cell metabolism)
• ex: Green sulfur bacteria, cyanobacteria

• microbes that oxidize chemical compounds
• neither sunlight nor organic nutrients
• oxidize inorganic compounds such as hydrogen gas, Hydrogen sulfide, iron, sulfur to obtain the necessary  energy to produce their own organic compounds)
• ex: 1. Methanogens 2. vent bacteria

• derive both carbon and energy from organic compound (aerobic respiration)
• ex: 1. Saprobes 2. Parasites

Optimal- the small intermediate between the minimum and maximum which promotes the fastest rate of growth and metabolism

• optimum temp of 15^oC, it is an obligate in respect to the cold and cannot grow above 20^oC
• -20^o to 15^o C

• gtow at intermediate temperatures (include most pathogens)
• 10^o to 50^o C

• grow at temperatures higher than 45^oC
• 45^o to 80^o C

• grow slowly at a lower temperature, but have an optimum temp above 20^o C
• concern- they can grow in refrigerated food and cause food borne illness
• ex: 1. Staphylococcus aureus 2. Listeria monocytogenes

• can survice short exposure to high temperatures, but are normally mesophiles
• can be contaminants of heated and pasteurized foods
• ex: 1. Bacillus 2. Clostridium

• spore forming anaerobe that commonly inhabits soil and water and occasionally, the intestianal tract of animals
• factors in food processing that lead to botulism dependent on several factors
• concern-- spores present on vegetables or meat at the time of gathering and are difficult to remove by washing alone

• 1. Obligate aerobe- requires O₂
• 2. Obligate anaerobe- O₂ kills them
• 3. Facultative anaerobe- can grow with or without O₂
• 4. Aerotolerant anaerobe- resists O₂
• 5. Microaerophiles- 4-6% O₂
• 6. Capnophiles- 3-10% O₂

• build up of singlet oxygen and the oxidation of membrane lipids and other molecules can damage and destroy a cell
• Superoxide ion, peroxide, and hydroxyl radicals are other metabolic by products of oxygen

• during abdominal surgery
• traumatic injuries to include gas gangrene and tetanus

• in soil and gastrointestinal tracts of animals
• spores usually enter body through accidental puncture wounds, burns, the umbilicus, frostbite, and crushed body parts

requires special media, methods of incubation, and handling chambers that exclude oxygen

• produces toxins that kill surrounding tissues, providing the bacterium with more nutrients and increasing the size of the anaerobic environment necessary for Clostrium to grow
• pain, gas gangrene (blackening of the infect muscle, skin and production of bubbles that may break out with a frothy brownish fluid)
• shock, kidney failure, and death can follow often withing a week of infection

• 1. Neisseria
• 2. Brucella
• 3. Streptococcus pneumoniae
• (3-10% CO₂ incubation)

• 1. soil
• 2. water or
• 3. human body
• (small amounts of O₂) (not exposed to the atmosphere)

• not harmed by O2--> alternative mechanisms for breaking down peroxidde and superoxide
• ex: 1. Lactobacilli 2. Streptococci
• use manganese ions or peroxidases to do this

• 1. Anabolism
• 2. Carabolism

• building complex organic molecules from simpler ones
• 

breakdown of complex organic molecules into simpler ones

• protein compounds
• catalysts (speed up chemical reactions)
• only lower energy of activation (do not create reactions)
• substrate specific
• coded by a specific gene
• affected by pH and temperature
• shape determines function
• provide active sites for substrates
• many enzymes need cofactors or coenzymes to work effectively

• cofactors- inorganic ions (Mg, Fe)
• many enzymes need cofactors to work effectively

• EA ( enzyme active site) can be blocked by the presence of inhibitors
• drug affecting inhibitors (Sulfa drugs):
•  kill bacteria by working as competitive inhibitors of EA in the synthesis of folic acid from para-amino-benzoic acid (PABA)

substance resembles normal substrate competes w/substrate for active site

• concentration of product at the end of a pathway blocks the action of a key enzyme
• 

• stop further synthesis of an enzyme somewhere along its pathway
• any process where it keeps an enzyme to be made
• as the level of the end product of a pathway has been built to excess, the genetic apparatus responsible for replacing these enzymes is automatically repressed
• 
• 

• Process that allow the enzyme to be made
• enzymes appear when suitable substrates are present
• induced by a substrate (a carbohydrate-note lactose)

Glycolysis occurs in the CYTOPLASM both prokaryotes and eukaryotes

• Krebs Cycle- cytoplasm of prokaryotes
•                    mitochondria of eukaryotes

• ETC- cell membrane of prokaryotes
•         mitochondrial membrane of eukaryotes

• 1. Aerobic respiration
• 2. Anarobic respiration
• 3. Fermentation

• 3 main cathabolic pathways:
• 1. Glycolysis, 2. KC 3. ETC
• uses O₂ as the main electron acceptor at the end of the ETC
• main energy pathway of strict aerobes and facilitative anaerobes

the lack of cytochromes, catalase, and peroxidases in anaerobes may limit their ability to process free oxygen and contributes to its toxic effect on them

• in organisms that can utilize and O2 containing salt as the final electron acceptor in the ETC
• ex: nitrate, nitrite, sulfates, or carbonates)
• used by:
• 1. Strict Anaerobess
• 2. Facultative Anaerobes
• 3. Microaerophiles
• 4. Aerotolerant anaerobes

• incomplete oxidation of glucose and other carbohydrates (limited ATP production)
• main products of fermentation:
• 1. Ethanol (alcoholic fermentation)
• 2. Organic acids ( mixed acidic fermentation) lactic, propionic, butyric, formic, acetic acids
• Anaerobic fermentation:
• 1. Souring milk (Streptococcus, Lactobacillus)