MIC 102 EVALUATION EXAM 2025/2026 QUESTIONS AND
ANSWERS GRADED A+
✔✔Microscope Basics - ✔✔Magnification: apparent enlargement of the specimen
Resolution: shortest distance between two objects that can still be distinguished as two
separate objects
✔✔Light Microscopy - ✔✔modern light microscopes that can achieves 2000x
magnification, 1000x fairly easily
limited ability to visualize bacterial components or distinguish between bacteria without
something extra
-extremely versatile
✔✔Phase-Contrasts (Light Microscopy) - ✔✔Use refraction + interference by structures
to create high contrast high resolution images without staining
-useful for viewing lives specimens and structures such as endospores and organelle
✔✔Fluorescence (Light Microscopy) - ✔✔-Use of fluorochromes that emit light of
specific wavelengths when excited by light of a different wavelength
-can be an external dye, attached to a molecule such as an antibody or DNA probe
-Can be engineered into genes and viewed in living cells
-Use to identify pathogens, find particular species, distinguish living from dead cells, find
locations of specific molecules
✔✔Electron Microscopy - ✔✔uses electrons instead of light, the shorter wavelength of
electrons gives greater resolution
magnifies up to ~500,000 X
-can't use on living material
✔✔Scanning Electron Microscope (SEM) - ✔✔A microscope that uses an electron
beam to scan the surface of a sample, coated with metal atoms, to study details of its
topography.
-To see surface
-Can use false colored?
✔✔Transmission Electron Microscope (TEM) - ✔✔A microscope that uses an electron
beam to study the internal structure of thinly sectioned specimens.
,-To see internal structures, smallest specimens
✔✔Scanning Probe Microscopy (SPM) - ✔✔-does not use light or electrons, uses
probes
100,000,000x magnification
can be used to observe individual atoms on surfaces
✔✔Where does life come from? - ✔✔Spontaneous generation
-life arose from nonliving matter
Modern Cell Theory
- Endosymbiosis Theory Prof Lynn Margulis
✔✔Endosymbiosis Theory - ✔✔Mitochondria and chloroplasts, organelles found in
many types of organisms, have their origins in bacteria.
✔✔Prokaryotic cell shapes and arrangements - ✔✔large variety
✔✔Prokaryotic Cell Structures: External - ✔✔Flagella
Pili/Fimbriae
Glycocalyx: Capsule, S-layer
✔✔Prokaryotic Cell Structures: Envelope - ✔✔LPS (only 1 group)
Lipoprotein
Cell wall
Cell membrane
✔✔Prokaryotic Cell Structures: Internal - ✔✔Cytoplasm
Cytoskeleton
Nucleoid/chromosome
Ribosome
Inclusions
Endospore (only 1 group)
✔✔Archaea vs. Bacteria Cell Membrane - ✔✔Archaea -> Ether Linkage
Bacteria -> Ester Linkage
✔✔What cannot pass through a phospholipid bilayer? - ✔✔large, polar molecules
cannot pass (glucose, amino acids and water)
✔✔Isotonic Solution - ✔✔No net movement of water particles
Cell membrane is attached to cell wall
, ✔✔Hypertonic Solution - ✔✔Water particles move out of the cell. Cell membrane
shrinks and detaches from a cell wall
Water moves from high concentration to low concentration
20% solute concentration placed into 40% solute concentration
placed into higher concentration
✔✔Hypotonic Solution - ✔✔Water particles move into the cell. Cell wall counteracts
osmotic pressure to prevent swelling and lysis
20% solute concentration placed into 10% solute concentration
placed into lower concentration
✔✔Why are cell walls important and how does penicillin interact with it? - ✔✔Cell
protects against osmotic stress
Penicillin inhibits bacterial cell wall synthesis and result in bacteria lysis
✔✔What is the main component of bacterial cell walls? - ✔✔Peptidoglycan (or murein)
✔✔Gram Positive Cell Wall - ✔✔Has Lipoteichoic acid
Less complex than Gram negative
Peptidoglycan (cell wall) -> plasma membrane
Dyes purple
✔✔Peptidoglycan features - ✔✔alternating NAM and NAG
NAM cross linked to adjacent strands with peptide bonds
this cross-linking aids in protection, shape
cleaved by Lysozymes
also an antibiotic target
✔✔Peptidoglycan Staining Steps - ✔✔1. Crystal Violet dye
2. Iodine -> adhere to cell wall
3. Alcohol -> wash
4. Safranin -> dye adhere to gram negative
✔✔Gram Negative Cell Wall - ✔✔-Thin peptidoglycan layer
-More complex than Gram positive
ANSWERS GRADED A+
✔✔Microscope Basics - ✔✔Magnification: apparent enlargement of the specimen
Resolution: shortest distance between two objects that can still be distinguished as two
separate objects
✔✔Light Microscopy - ✔✔modern light microscopes that can achieves 2000x
magnification, 1000x fairly easily
limited ability to visualize bacterial components or distinguish between bacteria without
something extra
-extremely versatile
✔✔Phase-Contrasts (Light Microscopy) - ✔✔Use refraction + interference by structures
to create high contrast high resolution images without staining
-useful for viewing lives specimens and structures such as endospores and organelle
✔✔Fluorescence (Light Microscopy) - ✔✔-Use of fluorochromes that emit light of
specific wavelengths when excited by light of a different wavelength
-can be an external dye, attached to a molecule such as an antibody or DNA probe
-Can be engineered into genes and viewed in living cells
-Use to identify pathogens, find particular species, distinguish living from dead cells, find
locations of specific molecules
✔✔Electron Microscopy - ✔✔uses electrons instead of light, the shorter wavelength of
electrons gives greater resolution
magnifies up to ~500,000 X
-can't use on living material
✔✔Scanning Electron Microscope (SEM) - ✔✔A microscope that uses an electron
beam to scan the surface of a sample, coated with metal atoms, to study details of its
topography.
-To see surface
-Can use false colored?
✔✔Transmission Electron Microscope (TEM) - ✔✔A microscope that uses an electron
beam to study the internal structure of thinly sectioned specimens.
,-To see internal structures, smallest specimens
✔✔Scanning Probe Microscopy (SPM) - ✔✔-does not use light or electrons, uses
probes
100,000,000x magnification
can be used to observe individual atoms on surfaces
✔✔Where does life come from? - ✔✔Spontaneous generation
-life arose from nonliving matter
Modern Cell Theory
- Endosymbiosis Theory Prof Lynn Margulis
✔✔Endosymbiosis Theory - ✔✔Mitochondria and chloroplasts, organelles found in
many types of organisms, have their origins in bacteria.
✔✔Prokaryotic cell shapes and arrangements - ✔✔large variety
✔✔Prokaryotic Cell Structures: External - ✔✔Flagella
Pili/Fimbriae
Glycocalyx: Capsule, S-layer
✔✔Prokaryotic Cell Structures: Envelope - ✔✔LPS (only 1 group)
Lipoprotein
Cell wall
Cell membrane
✔✔Prokaryotic Cell Structures: Internal - ✔✔Cytoplasm
Cytoskeleton
Nucleoid/chromosome
Ribosome
Inclusions
Endospore (only 1 group)
✔✔Archaea vs. Bacteria Cell Membrane - ✔✔Archaea -> Ether Linkage
Bacteria -> Ester Linkage
✔✔What cannot pass through a phospholipid bilayer? - ✔✔large, polar molecules
cannot pass (glucose, amino acids and water)
✔✔Isotonic Solution - ✔✔No net movement of water particles
Cell membrane is attached to cell wall
, ✔✔Hypertonic Solution - ✔✔Water particles move out of the cell. Cell membrane
shrinks and detaches from a cell wall
Water moves from high concentration to low concentration
20% solute concentration placed into 40% solute concentration
placed into higher concentration
✔✔Hypotonic Solution - ✔✔Water particles move into the cell. Cell wall counteracts
osmotic pressure to prevent swelling and lysis
20% solute concentration placed into 10% solute concentration
placed into lower concentration
✔✔Why are cell walls important and how does penicillin interact with it? - ✔✔Cell
protects against osmotic stress
Penicillin inhibits bacterial cell wall synthesis and result in bacteria lysis
✔✔What is the main component of bacterial cell walls? - ✔✔Peptidoglycan (or murein)
✔✔Gram Positive Cell Wall - ✔✔Has Lipoteichoic acid
Less complex than Gram negative
Peptidoglycan (cell wall) -> plasma membrane
Dyes purple
✔✔Peptidoglycan features - ✔✔alternating NAM and NAG
NAM cross linked to adjacent strands with peptide bonds
this cross-linking aids in protection, shape
cleaved by Lysozymes
also an antibiotic target
✔✔Peptidoglycan Staining Steps - ✔✔1. Crystal Violet dye
2. Iodine -> adhere to cell wall
3. Alcohol -> wash
4. Safranin -> dye adhere to gram negative
✔✔Gram Negative Cell Wall - ✔✔-Thin peptidoglycan layer
-More complex than Gram positive
