lecture notes Flashcards
What is binary fission?
The basis of population growth
doubling - elongate - complete separation
what is mitosis?
Cell growth (only occurs in eukaryotes, plant and animal cells)
What are split cells known as?
Daughter cells
The time required for a complete fission cycle
generation of doubling time
What does each new fission cycle increase by?
A factor of 2
what is the average generation time?
30 to 60 minutes, some 10 to 12 min
psychrophiles
cold-loving
mesophiles
middle loving
thermophiles
heat loving
acidophiles
Grow in acidic environments 0.1-5.4
neutrophiles
Grow at neutral pH 5.4-8.5
alkaphile
grow at alkaline pH 7-12 or higher
what pH level do most bacteria prefer?
neutral 6.5-7.5
What are the chemical requirements for growth?
ATP for cellular processes
CARBON for the production of macromolecules
OXYGEN for metabolism
NITROGEN for amino acid synthesis
SULFUR for vitamins, amino acids, structural stability of proteins
Requires O2
Obligate aerobes
Grows with or without O2
Facultative anaerobes
Does not require O2
Obligate anaerobes
Nutritional material prepared for microbial growth in a lab
-must be sterile
-appropriate nutrients
-Incubated at proper temperature
Culture Medium
Introduced to medium (broth or solid)
Inoculum
The act of cultivating microorganisms, creating an environment for microbial growth
Culture
Adding additional nutrients for growth
Enriched medium
Selects one specific type of organism to grow while inhibiting most others
Specific medium
Allows for differentiation when a color change has occurred based on a pH change
Differential medium
Stages in the microbial growth curve
- Lag phase
- Exponential growth phase
- Stationary phase
- Rapidly declining phase
- Death
Cells recognize conditions
lag phase
Cells begin to double, more cells growing than dying
Exponential growth phase
Equal amount of cells growing and dying
Stationary phase
Cells begin to die
Rapidly declining phase
Most cellular activity stops
Death
Bactericidal
Kills microbes
Bacteriostatic
Stops the growth of certain microbes
What is the purpose of bactericidal and bacteriostatic antimicrobials?
Their effectiveness comes from an ability to interact with essential cellular components on the microbe and make them nonfunctional
3 Common cleaning agents
- Anti-bacterial hand soap
- Hand sanitizer
- Betadine
What percent of alcohol is best?
70%
How to calculate the magnification of a microscope
It is determined by multiplying the magnifying power of the eyepiece by the magnifying power of the objective lens
ex) value of eye piece: 10x Value of lens: 4x
Total magnifying power= 10 x 4 = 40x
