Describe the bacterial growth curve. During which period would you measure generation time?
LAG: Little or no cell division, intense metabolic activity, gearing up for next action. LOG: High activity and growth/division. During this time, generations are measured. STATIONARY: Growth=Death rate, decline due to exhaustion of nutrients. DEATH: Growth rate is less than the death rate.
Compare aerobic respiration and fermentation.
Both start in the cytoplasm with glycolysis and yeild 2 ATP. Then, in respiration, the process moves on to acetyl-coA formation, the Krebs cycle and electron transport. Final ATP is 36. For fermentation, the process ends at glycolysis, ending with only 2 ATP.
List characteristics of an ideal disinfectant (8).
Kills germs (antimicrobial), works at normal temperatures, liquid (soluble), works rapidly, stable, nontoxic to pets and humans, homogeneous (same stuff throughout), noncorroding.
List four mechanisms by which microbial control may work.
1. Damage cell wall 2. Alter membrane permiability 3. Alter proteins or nucleic acid 4. Inhibit enzyme action
List groups of chemicals used to control microbes (specific examples).
PHENOLS: damages plasma membrane and denatures protein. ALCOHOLS: Dissolves lipids, dehydrates, and denatures proteins. HALOGEN (Iodine): Combines with proteins and oxidizes. HEAVY METALS (Silver, Copper, Zinc): Denatures -SH bond and high affinity for all proteins.
Utilitarian clothing. Hair tied back. Clear and cleaned workspaces. No eating, drinking or smoking. No objects in mouth. Microscopes should not be plugged in at the same time as the burners. Culture spills should be mopped up immediately. Infectious or used materials should be disposed of properly. Do not move through lab with loop or pipette containing microbes. Label all materials with name, date, specimen and medium used.
Respiration that requires oxygen.
Process by which cells release energy in the absence of oxygen.
Flickr Creative Commons Images
Some images used in this set are licensed under the Creative Commons through Flickr.com. Click to see the original works with their full license.