BMSC 210 Midterm 1 Review | 100% Correct
Answers | Verified | Latest 2024 Version
Describe Koch's postulates and the significance of his experiment - ✔✔Koch's postulates: with the use of
anthrax provided a basis for Germ Theory.
the experiment: extract blood from diseased individual
grow culture
put culture into healthy individual, develop disease
extract this blood, culture it to show same results
Describe the importance of Louis Pasteur and the significance of his swan-neck flask experiment -
✔✔Disproved spontaneous generation (miasma)
the swan-neck made contamination- and growth- visible
Why are viruses not considered living? - ✔✔they do not perform metabolism and they are parasitic
(cannot grow on own), also missing cytoplasm
How do light microscopes work? What light microscopes did we learn about? - ✔✔Use of light to make
observation, can see live specimen
Brightfield: absorb and scatter light, use gram staining (due to lack of pigment), can observe motility
Darkfield: specimen deflect and scatter light
Phase-Contrast: very detailed, high contrast
Differential Interference Contrast: #D w/ use of 2 light beams
Fluorescence: use of fluorochromes, UV light, and excitation (confocal: 3D fluorescence)
How do electron microscopes work? What types have we learned about? - ✔✔Use of electrons and
magnets, higher mag/res, but specimen must be dead
TEM: go through specimen, can see inside
SEM: electrons bounce off
, explain how gram staining works? - ✔✔1) stain with crystal violet (cells purple)
2) add iodine (cells purple)
3) de-colorize with alcohol (G- lose colour)
4) counter-stain with safranin (G- stay purple, G+ pink)
What is the cell envelope? What is it composed of? - ✔✔Cell envelope: layers around the cytoplasm
-Cytoplasmic membrane: selectively permeable barrier
-Cell Wall: prevent osmotic lysis and maintain shape
Bacteria: made of peptidoglycan (lysozyme-sensitive)
G+: thick, presence of techoic and lipotechoic acid, interbridge
G-: thin so presence of outer membrane, presence of lipopolysaccharide (LPS)
-S-Layer: outermost layer, protein mesh
Bacteria: protection/adhesion
archaea: act as cell wall (keep shape, prevent osmotic lysis)
-Capsule & Slime Layer: sticky polysaccharide coat
capsule: tight, strong attachment
slime layer: loose
what is the difference between Bacteria and Archaea cell walls? - ✔✔cell walls of bacteria are made of
peptidoglycan which is lysozyme-sensitive; archaea are lysozyme insensitive
what are acid fast bacteria? - ✔✔G+ w/ wax coat
differentiate between G+ and G- bacteria - ✔✔G+: have thick peptidoglycan wall and interbridge
presence of techoic and lipotechoic acid
G-: have outer membrane
presence of LPS
Answers | Verified | Latest 2024 Version
Describe Koch's postulates and the significance of his experiment - ✔✔Koch's postulates: with the use of
anthrax provided a basis for Germ Theory.
the experiment: extract blood from diseased individual
grow culture
put culture into healthy individual, develop disease
extract this blood, culture it to show same results
Describe the importance of Louis Pasteur and the significance of his swan-neck flask experiment -
✔✔Disproved spontaneous generation (miasma)
the swan-neck made contamination- and growth- visible
Why are viruses not considered living? - ✔✔they do not perform metabolism and they are parasitic
(cannot grow on own), also missing cytoplasm
How do light microscopes work? What light microscopes did we learn about? - ✔✔Use of light to make
observation, can see live specimen
Brightfield: absorb and scatter light, use gram staining (due to lack of pigment), can observe motility
Darkfield: specimen deflect and scatter light
Phase-Contrast: very detailed, high contrast
Differential Interference Contrast: #D w/ use of 2 light beams
Fluorescence: use of fluorochromes, UV light, and excitation (confocal: 3D fluorescence)
How do electron microscopes work? What types have we learned about? - ✔✔Use of electrons and
magnets, higher mag/res, but specimen must be dead
TEM: go through specimen, can see inside
SEM: electrons bounce off
, explain how gram staining works? - ✔✔1) stain with crystal violet (cells purple)
2) add iodine (cells purple)
3) de-colorize with alcohol (G- lose colour)
4) counter-stain with safranin (G- stay purple, G+ pink)
What is the cell envelope? What is it composed of? - ✔✔Cell envelope: layers around the cytoplasm
-Cytoplasmic membrane: selectively permeable barrier
-Cell Wall: prevent osmotic lysis and maintain shape
Bacteria: made of peptidoglycan (lysozyme-sensitive)
G+: thick, presence of techoic and lipotechoic acid, interbridge
G-: thin so presence of outer membrane, presence of lipopolysaccharide (LPS)
-S-Layer: outermost layer, protein mesh
Bacteria: protection/adhesion
archaea: act as cell wall (keep shape, prevent osmotic lysis)
-Capsule & Slime Layer: sticky polysaccharide coat
capsule: tight, strong attachment
slime layer: loose
what is the difference between Bacteria and Archaea cell walls? - ✔✔cell walls of bacteria are made of
peptidoglycan which is lysozyme-sensitive; archaea are lysozyme insensitive
what are acid fast bacteria? - ✔✔G+ w/ wax coat
differentiate between G+ and G- bacteria - ✔✔G+: have thick peptidoglycan wall and interbridge
presence of techoic and lipotechoic acid
G-: have outer membrane
presence of LPS
