BIO 225 - Midterm Laboratory Practical (MTC Lema) Exam Questions and Answers Already
Passed
microbiology - Answers study of organisms too small to e seem w the naked eye
microscope used in lab: - Answers compound, bright-field microscope
specimens is viewed by using two sets of lens, ocular and objectives (compound), against a
light background (bright field)
ocular - Answers the part you look through, provides a small amount of magnification, usually
10x
objective - Answers lenses closest to specimens, preform bulk of magnification and often found
as 10x, 40x, and 100x
rubber rim - Answers part of the revolving nosepiece that you grasp and turn in order to put
another objective in place - do not grab and turn objects themselves
head - Answers part of the ocular, part may be rotated but should be positioned as seen in
picture
arm - Answers part to grasp when lifting microscope
condenser - Answers this housing contains a series of lenses that gather and direct light onto
the specimen - may be moved up and down by turning a condenser adjustment knob; normally
this is positioned all the way up
diaphragm lever - Answers on the condenser housing is a lever, this lever opens and closes a
diaphragm (hole)that regulates how much light leaves the condenser and hits the specimens -
lever slides left to right to open/close the hole; needs to be adjusted based on magnification
(higher the magnification more it needs to be opened)
on/off switch - Answers a rocker switch. The "o" refers to the off position. The "i" refers to the
on position.
dimmer - Answers light intensity knob - turning it one way or the other increases/decreases
intensity of light; typically to max intensity
focusing knob - Answers The fat inner part is the coarse focus (only used with 10x objective),
the thin outer part is the fine focus. It may be used with all other magnifications. It is the only
adjustment used at the higher magnifications.
total magnification - Answers ocular lens x objective lens
10x x 40x = 400x
, resolution - Answers Rp = (wavelength x 0.5) / numerical aperture
Rp = (wavelength) / (2 x numerical aperture)
Rp = resolving power - Answers The number is how far apart two objects may be and still be
seen as two objects. It is measured by nanometers and teh smaller the RP the better. The limit
of resolution using visible light appears to be approximately 0.2um
wavelength - Answers the distance between the tops of two adjacent light waves in nanometers
- different wave lengths as seen in different colors:
white light: 550 nm; green light: 450 nm; blue light: 425 nm
numerical aperture - Answers the width of the come of light that may enter lens
- measurement of hoe far light can scatter and still enter lens
- property of lens and typically written as values below:
0.25 for 10x; 0.65 for 40x; 1.35 for 100x
two factors that affect resolution - Answers
Whitaker's 5 kingdom system - Answers 5 kingdoms: Monera, Protista, Fungi, Plantae and
Animalia
5 kingdom classifications: cell structure, body organisation, mode of nutrition and reproduction,
and phylogenetic relationships. ... They reproduce both asexually and sexually.
oil affects resolution because - Answers the purpose of the oil is to decrease the amount of
light refraction (bending), thereby increasing the amount of light that enters the lens effectively
increasing resolution
bacterial shapes - Answers coccus - round like a sphere and is usually easy to recognize
bacillus - rod shaped but depending upon genetics or growth conditions, they may look
somewhat coccoid or coccobacillus
spiral:
- vibrio - bent like a comma; causes cholera
- spirillum - bent like a rigid corkscrew; causes rat bite fever
- spirochete - bent like a spaghetti strand; causes syphilis
Passed
microbiology - Answers study of organisms too small to e seem w the naked eye
microscope used in lab: - Answers compound, bright-field microscope
specimens is viewed by using two sets of lens, ocular and objectives (compound), against a
light background (bright field)
ocular - Answers the part you look through, provides a small amount of magnification, usually
10x
objective - Answers lenses closest to specimens, preform bulk of magnification and often found
as 10x, 40x, and 100x
rubber rim - Answers part of the revolving nosepiece that you grasp and turn in order to put
another objective in place - do not grab and turn objects themselves
head - Answers part of the ocular, part may be rotated but should be positioned as seen in
picture
arm - Answers part to grasp when lifting microscope
condenser - Answers this housing contains a series of lenses that gather and direct light onto
the specimen - may be moved up and down by turning a condenser adjustment knob; normally
this is positioned all the way up
diaphragm lever - Answers on the condenser housing is a lever, this lever opens and closes a
diaphragm (hole)that regulates how much light leaves the condenser and hits the specimens -
lever slides left to right to open/close the hole; needs to be adjusted based on magnification
(higher the magnification more it needs to be opened)
on/off switch - Answers a rocker switch. The "o" refers to the off position. The "i" refers to the
on position.
dimmer - Answers light intensity knob - turning it one way or the other increases/decreases
intensity of light; typically to max intensity
focusing knob - Answers The fat inner part is the coarse focus (only used with 10x objective),
the thin outer part is the fine focus. It may be used with all other magnifications. It is the only
adjustment used at the higher magnifications.
total magnification - Answers ocular lens x objective lens
10x x 40x = 400x
, resolution - Answers Rp = (wavelength x 0.5) / numerical aperture
Rp = (wavelength) / (2 x numerical aperture)
Rp = resolving power - Answers The number is how far apart two objects may be and still be
seen as two objects. It is measured by nanometers and teh smaller the RP the better. The limit
of resolution using visible light appears to be approximately 0.2um
wavelength - Answers the distance between the tops of two adjacent light waves in nanometers
- different wave lengths as seen in different colors:
white light: 550 nm; green light: 450 nm; blue light: 425 nm
numerical aperture - Answers the width of the come of light that may enter lens
- measurement of hoe far light can scatter and still enter lens
- property of lens and typically written as values below:
0.25 for 10x; 0.65 for 40x; 1.35 for 100x
two factors that affect resolution - Answers
Whitaker's 5 kingdom system - Answers 5 kingdoms: Monera, Protista, Fungi, Plantae and
Animalia
5 kingdom classifications: cell structure, body organisation, mode of nutrition and reproduction,
and phylogenetic relationships. ... They reproduce both asexually and sexually.
oil affects resolution because - Answers the purpose of the oil is to decrease the amount of
light refraction (bending), thereby increasing the amount of light that enters the lens effectively
increasing resolution
bacterial shapes - Answers coccus - round like a sphere and is usually easy to recognize
bacillus - rod shaped but depending upon genetics or growth conditions, they may look
somewhat coccoid or coccobacillus
spiral:
- vibrio - bent like a comma; causes cholera
- spirillum - bent like a rigid corkscrew; causes rat bite fever
- spirochete - bent like a spaghetti strand; causes syphilis
