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Index
»
Microbiology
»
Chapter 1
»
Level 1
level: Level 1
Questions and Answers List
level questions: Level 1
Question
Answer
Bacteriophages: Immediate or delayed Virusu: Immediate or delayed
cell destruction
any cleansing technique that mechanically removes microbes and debris a soap or detergent used to sanitize
skin decontamination/sanitation:
an organism that bears a mutation
mutant strain
- parent cell enlarges - chromosomes are duplicated - cell envelope pulls together in the center of the cell to form a septum -cell divides into two daughter cells
Binary fission and the results
makes a copy of the DNA Primer: applies primer
DNA processes in detail: replication
creates RNA from DNA genes
Transcription:
creates protein to rna
Translation:
(Air with a low moisture that has been heated by flame or something electric) lack of water increases stability of some,If there's no water around, some proteins become stronger and need more heat and time to break down.
Compare dry heat
Hot water,boiling water) operates at lower temperature and shorter exposure times than dry heat, Killing microbes mostly happens by causing their proteins to clump together and become unusable, which stops their growth permanently.
compare moist heat
The is the first stage in the growth of a population of cells. During this phase, the population appears to not be growing because the newly added cells need time to adjust and grow larger before they can start dividing and growing at their maximum rate. The population is so sparse that it may not be easily detectable by sampling.
LAG phase
is a period when the number of cells in a population increases rapidly and continuously. During this phase, the growth curve increases geometrically, which means that the number of cells doubles at a consistent rate. The log phase will continue as long as the cells have enough nutrients to consume and the environment is suitable for their growth.
EXPONENTIAL GROWTH(log phase)
During the growth phase, the population of cells enters a survival mode where they stop growing or grow very slowly. The number of new cells being produced is equal to the number of cells dying.
STATIONARY
In the the limiting factors intensify, and the cells start dying at an exponential rate. The curve on the graph of cell growth dips downward, indicating a decrease in the number of cells
In the DEATH phase,
are small changes that affect only one base on a gene. They can involve the addition, deletion, or substitution of a single base.
(Point mutations)
are mutations that cause cell dysfunction or death.
(Lethal mutations)
Is a type of mutation that results in a change in the genetic code, causing a different amino acid to be placed in the proteins
(Missense mutation
is another type of mutation that changes a normal codon into a stop codon, which does not code for an amino acid.
Nonsense mutation
is a random change in the DNA that happens when errors occur during DNA replication.
Spontaneous mutation
on the other hand, result from exposure to known mutagens such as chemicals, radiation, or other environmental factors.
Induced mutations,
are neither harmful nor beneficial to the organism.
Neutral mutations
occur when a gene that has undergone a mutation reverses back to its original base composition.
Back mutations
are a type of point mutation that does not change the amino acid sequence of the protein, even though the base sequence has been altered. This occurs because the genetic code is redundant.
Silent mutations
existing Dna change
Mutations
a microorganism that exhibits a natural nonmutated charsiaterics ,the trait present in the hignest numbers in a population
wild type
an organism that bears a mutation
mutant strain
occurs when one or more bases are inserted or deleted from a newly synthesized DNA strand, nearly always results in a non fuctional protien
fameshift worst mutation
there is a lower concentration of solutes outside the cell compared to inside. Water will move into the cell to balance the concentration, causing the cell to swell or even burst.(LYSIS)
hypotonic
the concentration of solutes is the same inside and outside the cell. There is no net movement of water, so the cell stays the same size.
isotonic
there is a higher concentration of solutes outside the cell compared to inside. Water will move out of the cell to balance the concentration, causing the cell to shrink or even die.(PLASMOLYSIS)
hypertonic
removes/destroys all viable microorganisms including viruses (usually used for medical instruments)
). Sterilization
destroys vegetative pathogens but not bacterial endospores Can only be used on inanimate objects cause its too harsh for human tissue
Disinfection
reduces number of microbes on the skin (scrubbing of the skin or immersing it in chemicals) Mechanically removes potential pathogens on the outer layer of the skin
antisepsis/germation:
any cleansing technique that mechanically removes microbes and debris a soap or detergent used to sanitize
skin decontamination/sanitation:
protein shell on outside
Understand the structure of viruses : Capsid
genetic material that is DNA or RNA
Nucleic acid
capsid+nucleic acid together
Nucleocapsid
envelope present
Enveloped virus
envelope absent (only have a nucleocapsid)
Naked virus:
1. Adsorption (ALL) 2. Penetration (PEOPLE) 3. Uncoating (UNDER) 4. Synthesis (SIXTEEN) 5. Assembly (ARE) 6. Release from the host cell (REBELLIOUS)
Know the steps of viral replication
Temperature PH level
Understand the various environmental requirements and how to apply them
new DNA has entered the cell from outside
Recombination:
comes from living bacteria
Conjugation:
takes DNA that's freely floating (usually from dead bacteria)
Transformation
bacteriophage transfers DNA
Transduction:
is used on living tissue reduction of the number of microbes on the skin
antisepsis
is used on inanimate objects destroy vegetative pathogens but not bacterial endospores
disinfection
eliminates all microbial life
sterilization
reduces the number of microorganisms to a safe level.
sanitization
parasitize all bacteria species which can make them more pathogenic
Bacteriophages
Bacteriophages: Precise attachment of special tail fibers to cell wall Virus:Attachment of capsid or envelope to cell wall receptors
adsorption
Bacteriophages- injection of nucleic acid through cell wall; no uncoating of nucleic acid viruses- Whole virus is engulfed and uncoated, nucleic acid is released
penetration
Bacteriophages: -occurs in cytoplasm Virus : occurs in cytoplasm & nucleus
synthesis and assembly
bacteriophages: lysogeny Viruses : Latency, cancer, chronic infection
viral persistence
Bacterophages : Cell lysis when viral enzymes weaken it Virus: Some cells lyse, other bud
release from host cell
Bacteriophages: Immediate or delayed Virusu: Immediate or delayed
cell destruction
unzips the helix
Helicase(REPLICATION)
: adds bases to new DNA chain (can only add from 5’-3’)
DNA polymerase 3(REPLICATION)
removes primer, closes gaps, repairs mistake Ligase: final binding in DNA during synthesis and repair
DNA polymerase 1: REPLICATION