Population
True of False: The log phase of the population curve contains the largest population (greatest # of individuals).
False
The term for media with a specific, reproducible recipe.
What is a ‘chemically defined’ media?
True or False - Disinfectants are used on skin and kill all living organisms.
False! Disinfectants target pathogens and are for use on nonliving surfaces such as tables or floors.
Name the two RNA nucleotides that are single rings (pyrimidines) that pair with the purines.
Bonus: - Name the purines, those double rings, too!
What are the pyrimidines, Uracil and Cytosine?
What are the purines, Guanine and Adenine?
U-A and C-G
Identify the parameters for an autoclave to sterilize.
15 minutes at 121 degrees Celsius and 15 psi
Provide the population equation, and define all terms.
Use this example to identify a numerical value with each term: Claire made egg salad at 9 am, and introduced 35 cells of S. aureus into her meal. She left the egg salad on the counter until her lunch at noon. How many cells were in her egg salad?
Nf = Ni (2)g , Example: 35 (2)6 cfu = 2240 cfu
Nf = Final Population
Ni = Initial Population, Example: 35
(2) = Binary Fission constant
g = # of generations, Example: 6
Describe how a differential media allows one to differentiate between organisms.
Use motility media to explain your reasoning.
Differential media allows for a visual change to occur which enables an observer to differentiate between organisms based on that visual change. For example, motility media allows use to see migration of motile bacteria, allowing the observer to differentiate between motile and nonmotile species.
Define degerming and provide three examples.
Is degerming physical, chemcial or mechanical control?
Degerming is the removal of microbes from a specific environment, such as hand washing, air filatration, and membrane filtration. Degerming is a mechanical control method.
Translation occurs in which 3 stages.
What is 1) initiation, 2) elongation, and 3) termination?
The pore size for a filter to sterilize (remove bacteria and larger organisms).
What is 0.22 microns or 0.22um?
This phase of the population growth curve includes the fastest growth rates.
What is the log phase?
This term describes carbon dioxide loving organisms.
What is a capnophile?
What does MOA stand for? Provide the MOAs for aldehydes, and surfactants.
MOA stands for 'Mechanism of Action' for the control method.
Aldehydes control microbial growth by alkylating CHO functional group (CHO becomes CH3), denaturing proteins and inactivating nucleic acids.
Surfactants are amphiphilic agents that control microbes by emulsifying the plasma membrane.
The genetic information housed in DNA is expressed by the synthesis of proteins through RNA in these two processes. Identify each process, and location of the processes, and final product.
What is...
1) Transcription, which occurs in the nucleus of eukaryotes and the nucleiod region of prokaryotes, produces mRNA and
2) Translation, which occurs in the cytoplasm at the ribosomes, produces proteins.
Provide the MOA and an example for heavy metals as a chemical method of control.
The mechanism of action (MOA) of heavy metals is the deactivation or 3D alteration of proteins by blocking the binding sites, rendering them nonfunctional.
Examples include silver-containing creams, and copper-containing instruments.
This type of symbiosis occurs when one organism benefits from the relationship while another organism is neither harmed nor benefited. Provide an example.
What is commensalism? Examples: An orchid (the commensal) and the tree it grows on, or yeast (the commensal) and the human who’s skin it grows on.
This type of media encourages growth of some organisms by the addition of nutrients without inhibiting others. Provide an example.
What is ‘enriched’ media?
Examples include blood agar, chocolate agar, or Tryptic Soy Agar (TSA).
What does a fungicide do? What does a bacteriostatic do?
Fungicides kill fungi.
Bacteriostatic substances inhibit bacterial growth.
Nucleotides, the building blocks of nucleic acids, contain three components. List those three components and identify which two components make up the backbone of DNA.
What are 1) a phosphate group, 2) a 5- carbon sugar, and 3) a nitrogenous ring base such as adenine, cytosine, guanine, thymine, and uracil.
The backbone is made up of a phosphate group and a 5-carbon sugar.
The phosphate group is attached to the 5' side and a -OH group is attached to the 3' side.
Compare the parameters for batch and flash pasteurization. Identify if these processes are a form of sanitation or sterilization.
Both processes are forms or sanitation, aimed at killing pathogenic organisms - not all life.
Both process utilize thermal input
Batch pasteurization is slower and cooler - 30 minutes at 63 degrees C
Flash pasteurization is much faster and a bit hotter - 15 seconds at 72 degrees C
Identify the population stages at which the following occurs:
1) germination of endospores,
2) sporulation of endospores begins, and
3) complete sporulation of endospores and release from vegetative cell.
1) Lag phase
2) Stationary phase
3) Near death phase
A saprobe or saprophyte (a special type of heterotroph) acquire their nutrients from this specific source. Provide an example.
What is dead or decaying matter? Fungi are an example.
List the two organisms/infectious particles most susceptible to control methods.
List the three organisms/infectious particles most resistant to control methods.
Think about possible reasons for why...
The two organisms/infectious particles most susceptible to control methods are enveloped viruses and gram-positive bacteria.
The three organisms/infectious particles most resistant to control methods are Mycobacteria, bacterial endospores, and prions.
Identify the enzymes needed for DNA replication and their role. Which one(s) interact with the lagging strand only.
Topoisomerase: Relaxes DNA and keeps DNA from supercoiling in front of replication fork
Helicase: Unzips DNA at replication fork
Primase: Adds RNA primer at replication starting point
DNA Polymerase: Adds complementary DNA nucleotides to build new strands of DNA, starting at the RNA primer
Ligase: Links the Okazaki fragments in the lagging strand
Ligase:
Explain the term ‘Antiparallel’ with regards to parent DNA orientation and how antiparallel arrangement impacts replication.
One strand of DNA (the leading strand) runs 5’ to 3’ and can be replicated continuously, while the corresponding strand (the lagging strand) runs 3’ to 5’ and must be replicated in segments (Okazaki segments) and ligated together.