MICROBIOLOGY MIDTERM EXAM QUESTIONS AND
ANSWERS
Define Micro- - Answers - Less than 1mm and cannot see with the naked eye
Need a microscope to see
Microbes, microorganisms, germs, bugs
What are the 5 groups of microorganisms studied? - Answers - Bacteria--most famous
Virus--2nd
Fungus--3rd
Protozoa--some but few
Algae--not a human pathogen
What generates 1/2 of the O2 that we breathe and would make life impossible without?
- Answers - Microbes
What is the smallest simplest single-celled organism? - Answers - Bacteria
What is not a cell, can't live by itself and needs to invade a cell? - Answers - Virus
What are the two different classification of fungus? - Answers - Molds and yeast--micro
Mushrooms--Macro
What is a mostly single-celled organism that is Animal like? - Answers - Protozoa
What are parasites? - Answers - Different organisms that range from worms, insects
and protozoa that need a host to survive
What are the different applied microbiology fields of study - Answers - Immunology
Epidemiology--control spread of disease
Food Micro--relationship between bacteria, food and drink
Agriculture Micro--relationship between bacteria and crop
Industrial Micro--microbes to produce vitamins, AA, Enzymes, etc.
Eukaryotic cells are... - Answers - more complete
Prokaryotic cells are... - Answers - all micro organisms and lack a nucleus
Characteristics of microorganisms - Answers - Small size
Unicellular simplicity
High Growth rate
Adaptability
,microscope - Answers - instrument used for enlargement of small objects
simple microscope - Answers - single lens and a few working parts. not strong
compound microscope - Answers - 2 magnifying lenses, a visible light sours, a
condenser which collects light to direct toward the object
magnification - Answers - capacity of an optical system to enlarge small objects
ocular lens - Answers - one we look through. 10X
objective lens - Answers - 4 different, 4X, 10X, 40X, 100X
What is resoltion? - Answers - Capacity of optical systems to distinguish or separate 2
adjacent objects/points from each other. represents clarity of image
Types of microscope? - Answers - Light--visible light, bright field, dark field, phase
contrast, diff interference
Ultraviolet--florescence
Electron--scanning, transmission
what type of microscope do we use in the lab? - Answers - bright field light microscope
how does a microscope work? - Answers - light source is on the bottom. The light
travels from the lamp, hits the condenser lents which collects light and points it toward
the object. the light passes through the objective lens and the real image of the object
forms behind the ocular lens. the image we see is the virtual image after it asses
through the ocular lens and is at the total magnification
Highest magnification for all light microscopes? - Answers - 2,000X and 200 nm
resolution
eubacteria - Answers - the common bacteria of the 2 types. (-) WITH cell walls, (+)
WITH cell walls, and no cell wall (mycoplasm)
archebacteria - Answers - less common type of bacteria. do not produce peptidoglycan
and can live in extreme environments
appendages - Answers - attached to bacteria on one side, the other side is "free"
motility appendages - Answers - flagella and axial filaments
flagella - Answers - for motility and self propulsion. found mostly in gram negative
bacteria. provide a smooth forward movement
, structure of flagella - Answers - made of protein with 3 distinct parts: filament, hook,
basal body (inside and has 4 rings and a rod that rotate)
axial filament - Answers - wrap around the cell and cause spiral like movements. has
only two parts: a long thin microfibril inserted into a hook.
attachment appendages - Answers - fimbriae and pili
fimbriae - Answers - short appendages that allow bacteria to attach to bacteria
pili - Answers - long appendages are found in gram negative bacteria and are useful
when mating
cell envelope - Answers - the bacterial surface (glycocalyx), the cell wall, cell membrane
glycocalyx/bacterial surface - Answers - this layer is a coating to protect the cell. two
types
slime layer - Answers - type of glycocalyx that protects bacteria from loss of water and
nutrients and loosely bound to the bacteria
capsule - Answers - thick, gummy consistency. It is tightly bound to the bacteria and is
not easily washed off
cell wall - Answers - the layer beneath the glycocalyx and provides the cell with
structure. It determines the shape of the bacterium from bursting or collapsing from
changes in pressure. ESSENTIAL for bacterial survival
peptidogylcan - Answers - provides the protective quality of the cell wall. rigid. compose
of long glycol chains. forms a meshwork.
gram positive cell wall - Answers - purple. thick sheet with peptidoglycan and tightly
bound polysaccharides. has a lot of peptidoglycan which binds to the purple die
gram negative cell wall - Answers - pink. small amounts of peptidoglycan and there is a
large space between the peptidoglycan and the outer membrane
Gram Staining - Answers - 1. crystal violet (both will turn purple. gram + will have more
precipitin on cell wall bc more peptidoglycan)
2. grams iodine (not a stain. binding agent)
3. alcohol (washes color off gram -. too much is bound to gram + to wash off)
4. safranin (red/pink, gram negative will take up this stain)
Why doesn't the outer membrane associated with gram negative bacteria prevent the
alcohol from washing off the crystal violet? - Answers - The outer layer is made of lipids,
ANSWERS
Define Micro- - Answers - Less than 1mm and cannot see with the naked eye
Need a microscope to see
Microbes, microorganisms, germs, bugs
What are the 5 groups of microorganisms studied? - Answers - Bacteria--most famous
Virus--2nd
Fungus--3rd
Protozoa--some but few
Algae--not a human pathogen
What generates 1/2 of the O2 that we breathe and would make life impossible without?
- Answers - Microbes
What is the smallest simplest single-celled organism? - Answers - Bacteria
What is not a cell, can't live by itself and needs to invade a cell? - Answers - Virus
What are the two different classification of fungus? - Answers - Molds and yeast--micro
Mushrooms--Macro
What is a mostly single-celled organism that is Animal like? - Answers - Protozoa
What are parasites? - Answers - Different organisms that range from worms, insects
and protozoa that need a host to survive
What are the different applied microbiology fields of study - Answers - Immunology
Epidemiology--control spread of disease
Food Micro--relationship between bacteria, food and drink
Agriculture Micro--relationship between bacteria and crop
Industrial Micro--microbes to produce vitamins, AA, Enzymes, etc.
Eukaryotic cells are... - Answers - more complete
Prokaryotic cells are... - Answers - all micro organisms and lack a nucleus
Characteristics of microorganisms - Answers - Small size
Unicellular simplicity
High Growth rate
Adaptability
,microscope - Answers - instrument used for enlargement of small objects
simple microscope - Answers - single lens and a few working parts. not strong
compound microscope - Answers - 2 magnifying lenses, a visible light sours, a
condenser which collects light to direct toward the object
magnification - Answers - capacity of an optical system to enlarge small objects
ocular lens - Answers - one we look through. 10X
objective lens - Answers - 4 different, 4X, 10X, 40X, 100X
What is resoltion? - Answers - Capacity of optical systems to distinguish or separate 2
adjacent objects/points from each other. represents clarity of image
Types of microscope? - Answers - Light--visible light, bright field, dark field, phase
contrast, diff interference
Ultraviolet--florescence
Electron--scanning, transmission
what type of microscope do we use in the lab? - Answers - bright field light microscope
how does a microscope work? - Answers - light source is on the bottom. The light
travels from the lamp, hits the condenser lents which collects light and points it toward
the object. the light passes through the objective lens and the real image of the object
forms behind the ocular lens. the image we see is the virtual image after it asses
through the ocular lens and is at the total magnification
Highest magnification for all light microscopes? - Answers - 2,000X and 200 nm
resolution
eubacteria - Answers - the common bacteria of the 2 types. (-) WITH cell walls, (+)
WITH cell walls, and no cell wall (mycoplasm)
archebacteria - Answers - less common type of bacteria. do not produce peptidoglycan
and can live in extreme environments
appendages - Answers - attached to bacteria on one side, the other side is "free"
motility appendages - Answers - flagella and axial filaments
flagella - Answers - for motility and self propulsion. found mostly in gram negative
bacteria. provide a smooth forward movement
, structure of flagella - Answers - made of protein with 3 distinct parts: filament, hook,
basal body (inside and has 4 rings and a rod that rotate)
axial filament - Answers - wrap around the cell and cause spiral like movements. has
only two parts: a long thin microfibril inserted into a hook.
attachment appendages - Answers - fimbriae and pili
fimbriae - Answers - short appendages that allow bacteria to attach to bacteria
pili - Answers - long appendages are found in gram negative bacteria and are useful
when mating
cell envelope - Answers - the bacterial surface (glycocalyx), the cell wall, cell membrane
glycocalyx/bacterial surface - Answers - this layer is a coating to protect the cell. two
types
slime layer - Answers - type of glycocalyx that protects bacteria from loss of water and
nutrients and loosely bound to the bacteria
capsule - Answers - thick, gummy consistency. It is tightly bound to the bacteria and is
not easily washed off
cell wall - Answers - the layer beneath the glycocalyx and provides the cell with
structure. It determines the shape of the bacterium from bursting or collapsing from
changes in pressure. ESSENTIAL for bacterial survival
peptidogylcan - Answers - provides the protective quality of the cell wall. rigid. compose
of long glycol chains. forms a meshwork.
gram positive cell wall - Answers - purple. thick sheet with peptidoglycan and tightly
bound polysaccharides. has a lot of peptidoglycan which binds to the purple die
gram negative cell wall - Answers - pink. small amounts of peptidoglycan and there is a
large space between the peptidoglycan and the outer membrane
Gram Staining - Answers - 1. crystal violet (both will turn purple. gram + will have more
precipitin on cell wall bc more peptidoglycan)
2. grams iodine (not a stain. binding agent)
3. alcohol (washes color off gram -. too much is bound to gram + to wash off)
4. safranin (red/pink, gram negative will take up this stain)
Why doesn't the outer membrane associated with gram negative bacteria prevent the
alcohol from washing off the crystal violet? - Answers - The outer layer is made of lipids,
