MIMG 101 MIDTERM STUDY GUIDE
EXAM AND ACTUAL ANSWERS 2026-
2027 UPDATED.
robert hooke - Answer first description of microorganisms
leeuwenhoek - Answer first person to see bacteria
louis pasteur - Answer did not believe in spontaneous generation, heat experiment and seal
experiment, organisms still grow
robert koch - Answer linked cause and effect in an infectious disease
Koch's Postulates - Answer 1. The suspected pathogen must be present in all cases of the
disease and absent from healthy animals.
2. The suspected pathogen must be grown in pure culture.
3. Cells from a pure culture of the suspected pathogen must cause disease in a healthy animal.
4. The suspected pathogen must be reisolated and shown to be the same as the original.
common features to ALL cells - Answer dna/rna, plasma membrane, cytoplasm, ribosomes
magnification vs resolution - Answer Magnification enlarges, resolution distinguishes objects
5 types of compound light microscopes - Answer bright field, phase contrast, differential
interface contrast, dark field, fluorescence
bright field - Answer microscope detects light scattered by cells, stained/pigmented scatter
light better
phase contrast - Answer difference between diffracted and undiffracted light is amplified,
difference accentuated, living/unpigmented cells, best for internal structures
dark field - Answer light directed toward cell from sides, only scattered reaches lens, best for
small organisms & flagella
differential interface contrast - Answer provides 3D image, polarized light through prism
generates two beams, beams pass through cells, enter objective lens, recombine
,fluorescence microscopy - Answer visualize specimens that fluoresce, emit light of one color
when another color is shined (autofluorescence, fluorescent proteins, immunofluorescence
assay)
fluorescent proteins - Answer subcellular localization, fuse GFP into a gene of interest
immunofluorescence - Answer 1. add unlabeled primary antibody
2. wash away unbound antibody
3. add fluoro secondary antibody
electron microscopy (+ 2 types) - Answer use electrons instead of visible light (transmission
EM and scanning EM)
transmission EM - Answer 0.2nm, needs very thinly sectioned samples stained with special
stains, best for internal structures in cells
scanning EM - Answer better for 3D images, surface and external structures, coated with
heavy metal (gold)
simple stain - Answer dyes that have an affinity for specific cellular materials (methylene
blue, crystal violet, safranin bind to negative charge)
gram positive bacteria - Answer thick peptidoglycan, stain purple
gram negative bacteria - Answer periplasm, stain pink
gram staining procedure - Answer 1. flood heat fixed smear with crystal violent (CV)
2. add iodine solution (iodine and CV aggregate into a complex)
3. decolorize with alcohol (CV stauys in G+)
4. counterstain with safranin
spherical shape - Answer cocci
rods shape - Answer bacilli
curved shape - Answer spirilla
, comma shaped - Answer vibrio
rigid and corkscrew shaped - Answer spirochetes
string like shaped - Answer filamentous
bacteria in pairs - Answer diplo
grape like clusters - Answer staphylo
chain like clusters - Answer strepto
in groups of 4 - Answer tetrad
in groups of 8 - Answer sarcinae
different temperature classifications - Answer psychrophile, mesophile, thermophile,
hyperthermophile
traits of psychrophiles (extreme cold) - Answer unsat fat in their membranes to keep fluidity,
shorter fatty acid chain length, cold-active enzymes, more alpha helices than beta sheets in
enzymes allows more flexibility, produce cryoprotectants to prevent ice crystals, produce cold
shock proteins as chaperone
traits of thermophiles and hyperthermophiles (extreme heat) - Answer ionic bonding
between basic/acidic AAs, heat protecting solutes, long chains in membrane, saturated fatty
acids, makes it more hydrophobic + increase melting pt
classifications based on pH - Answer neutrophile (5.5.-8), acidophile (<5.5), alkaliphile (>8)
cytoplasmic pH needs to be kept between? - Answer 5-9
strategies for acidophiles - Answer rigid membrane w low proton permeability, efficient
proton pump, cytoplasm sequesters protons, ramp up DNA and protein repairs
EXAM AND ACTUAL ANSWERS 2026-
2027 UPDATED.
robert hooke - Answer first description of microorganisms
leeuwenhoek - Answer first person to see bacteria
louis pasteur - Answer did not believe in spontaneous generation, heat experiment and seal
experiment, organisms still grow
robert koch - Answer linked cause and effect in an infectious disease
Koch's Postulates - Answer 1. The suspected pathogen must be present in all cases of the
disease and absent from healthy animals.
2. The suspected pathogen must be grown in pure culture.
3. Cells from a pure culture of the suspected pathogen must cause disease in a healthy animal.
4. The suspected pathogen must be reisolated and shown to be the same as the original.
common features to ALL cells - Answer dna/rna, plasma membrane, cytoplasm, ribosomes
magnification vs resolution - Answer Magnification enlarges, resolution distinguishes objects
5 types of compound light microscopes - Answer bright field, phase contrast, differential
interface contrast, dark field, fluorescence
bright field - Answer microscope detects light scattered by cells, stained/pigmented scatter
light better
phase contrast - Answer difference between diffracted and undiffracted light is amplified,
difference accentuated, living/unpigmented cells, best for internal structures
dark field - Answer light directed toward cell from sides, only scattered reaches lens, best for
small organisms & flagella
differential interface contrast - Answer provides 3D image, polarized light through prism
generates two beams, beams pass through cells, enter objective lens, recombine
,fluorescence microscopy - Answer visualize specimens that fluoresce, emit light of one color
when another color is shined (autofluorescence, fluorescent proteins, immunofluorescence
assay)
fluorescent proteins - Answer subcellular localization, fuse GFP into a gene of interest
immunofluorescence - Answer 1. add unlabeled primary antibody
2. wash away unbound antibody
3. add fluoro secondary antibody
electron microscopy (+ 2 types) - Answer use electrons instead of visible light (transmission
EM and scanning EM)
transmission EM - Answer 0.2nm, needs very thinly sectioned samples stained with special
stains, best for internal structures in cells
scanning EM - Answer better for 3D images, surface and external structures, coated with
heavy metal (gold)
simple stain - Answer dyes that have an affinity for specific cellular materials (methylene
blue, crystal violet, safranin bind to negative charge)
gram positive bacteria - Answer thick peptidoglycan, stain purple
gram negative bacteria - Answer periplasm, stain pink
gram staining procedure - Answer 1. flood heat fixed smear with crystal violent (CV)
2. add iodine solution (iodine and CV aggregate into a complex)
3. decolorize with alcohol (CV stauys in G+)
4. counterstain with safranin
spherical shape - Answer cocci
rods shape - Answer bacilli
curved shape - Answer spirilla
, comma shaped - Answer vibrio
rigid and corkscrew shaped - Answer spirochetes
string like shaped - Answer filamentous
bacteria in pairs - Answer diplo
grape like clusters - Answer staphylo
chain like clusters - Answer strepto
in groups of 4 - Answer tetrad
in groups of 8 - Answer sarcinae
different temperature classifications - Answer psychrophile, mesophile, thermophile,
hyperthermophile
traits of psychrophiles (extreme cold) - Answer unsat fat in their membranes to keep fluidity,
shorter fatty acid chain length, cold-active enzymes, more alpha helices than beta sheets in
enzymes allows more flexibility, produce cryoprotectants to prevent ice crystals, produce cold
shock proteins as chaperone
traits of thermophiles and hyperthermophiles (extreme heat) - Answer ionic bonding
between basic/acidic AAs, heat protecting solutes, long chains in membrane, saturated fatty
acids, makes it more hydrophobic + increase melting pt
classifications based on pH - Answer neutrophile (5.5.-8), acidophile (<5.5), alkaliphile (>8)
cytoplasmic pH needs to be kept between? - Answer 5-9
strategies for acidophiles - Answer rigid membrane w low proton permeability, efficient
proton pump, cytoplasm sequesters protons, ramp up DNA and protein repairs
