Micro I Exam 2

increase in cell number

immediate consequence of cell division

cell division for most prokaryotic organisms

simple transverse division

asexual form of reproduction

binary fission process

doubling time

the time it takes a cell to do one binary fission
   starting from having just divided
   ending at having just completed the next
    division

vary depending on organism and environment

range from 20 minutes for a fast growing bacterium under ideal conditions, to hours and days for less than ideal conditions of for slowly growing bacteria

no bacterial cell is exactly the same as another

changes in genetic make up of a cell can be caused by

external influences on variations in genetic makeup

internal influences on variations in genetic makeup

alteration in the DNA sequence causing a change in form

(usually lethal)

intermicrobial transfer

- a donor cell dies and releases DNA into the medium

- this DNA breaks into many small fragments

- a recipient cell will pick up a fragment of this DNA and incorporate the genetic information into its own DNA

a sexual form of reproduction

2 cells unite by a sex pilus

DNA slowly transfers from one cell to the other

as this process is occurring, the pilus breaks allowing only a portion of the DNA to be transferred

this fragment of DNA then recombines with the DNA of the recipient cell causing chanages

an indirect transfer of DNA by a virus

a virus carries a fragment of DNA from the cell where it was formed and enters a new cell

the virus takes over the controls of this cell and the genetic material is incorporated into the DNA of the new cell

as the cells continue to divide the mass of cells become visible to the human eye

a visible mass of vegetative bacterial cells

the environment must provide them with many specific substances and conditions

conditions affecting bacterial growth

food requirements

organisms that require only inorganic substances for growth

they are self-sufficient and able to produce their own nutrients

they are free-living and do not associate with a living host or cause disease

heterotrophic bacteria

organisms that require one or more organic compounds for growth

all pathogenic organisms are

they require dead organic matter for nutrition

they require living organic matter for nutrition

they must have a living host

prefer living organic matter but can survive minimally with dead organic matter

prefer dead organic matter but can survive minimally with living organic matter

to prefer the condition NOT named

oxygen requirements

must have free atmospheric oxygen as found in the air in order to survive

they require the absence of free atmospheric oxygen

these acquire oxygen for metabolism by breaking down food sources that contain oxygen

require only small amounts of oxygen

they may not grow better but can survive in the presence of free atmospheric oxygen

they prefer the absence of of free atmospheric oxygen but can survive in its presence

prefer the presence of free atmospheric oxygen but can survive without it

require an increased level of carbon dioxide

as for any cell, the presence of water is a requirement for survival

water acts as the solvent to carry nutrients into & wastes out of the cell

provides for the hydrolysis of nutrients

water provides 75-80% of the total cell weight

the absence of water will lead to dehydration and death of the cell

all bacteria have a temperature range that is required for growth but it varies from one organism to another

temperature requirements
although the ranges may vary, all bacteria will have the following requirements

the lowest temperature at which a particular organism will grow

the highest temperature at which a particular organism will grow

the temperature at which an organism prefers to grow and will grow the fastest

classification of bacteria in relation to temperature range

prefer cold temperatures
   between 0^o-15^oC

prefer midrange temperatures
   between 25^o-45^oC

most human pathogens are found in this group

prefer high or hot temperatures
   anything above 45^oC

these will not cause disease because human body temp is too low for them to survive

bacteria grow at a wide range of pH values

human pathogens grow best in a neutral or slightly alkaline environment
  between 6-8 pH

making the pH of the body the perfect environment

exception to Hydrogen Ion Concentration (pH)
Lactobacillus prefers a pH of 5 or less

exception to Hydrogen Ion Concentration (pH)
Vibrio prefers a pH of 9 or above

all light is harmful to the growth of bacteria

the most harmful is ultraviolet(UV) light

as it passes through the cell it alters the structure of the DNA

causes mutations to occur that are lethal to the cell

causes changes in their size, volume, and viability

a cell that is present in a hypertonic environment

there is a greater amount of solute outside the cell than inside

this draws water out of the cell causing the cell to shrink

the shrinkage of cells

a cell that is present in a hypotonic environment

there is a greater amount of solute inside this cell than outside

this draws water into the cell causing swelling to the point of bursting

the swelling of cells to bursting

a cell that is present in an isotonic environment

there are equal amounts of solute inside & outside the cell

moisture still moves in & out of the cell, but at an equal rate

the fact that interrelationships exist between biological organisms requires that we examine how these relationships effect the growth and survival of bacteria

bacterial associations
there are several types of relationships to be considered

the relationship in which two organisms grow well together and cannot survive without each other

the relationship in which two organisms grow well together but can survive alone

they do better together but the relationship is not required

means "to eat at the same table"

the relationship in which two organisms are growing together but there is a benefit to one organism while there is no effect to the other

the second organism is neither benefitted nor harmed

the relationship between two organisms in which one organism is harmed by the presence of the other

is often due to to the production of a substance by one bacteria that inhibits the growth of kills the other organism

the substance formed can be referred to as an antibiotic

the relationship between two organisms in which one organism acts as a host for the other

the parasite gains nutrition, protection, & livelihood from the host

usually at the expense of the host

organic catalysts

cause the physiological chemical reactions that occur in living cells to be started or to be carried to completion

they are protein by nature

the name always ends with -ase

the substance upon which an enzyme will act

the organic compounds present in the cell

every organic compound has a specific type of enzyme that will react with it

every enzyme is very specific as to what ____ it will react with

carbohydrase reacts upon

protease reacts upon

lipase reacts upon

nuclease reacts upon