MIC 102 COMPREHENSIVE EXAM 2026 FULL
QUESTIONS AND CORRECT ANSWERS
◉ What subgroup does Algae and Protozoa make? Answer: Protists
◉ DESCRIBE THE ROLE OF A PLASMA MEMBRANE AND A
CELL WALL. Answer:
◉ What's the difference between Basic & Differential Stain? Answer:
Basic Stain: Allows you to determine the basic structure of a bacteria
(rod, etc)
Differential Stain: Uses more than one stain
--> most popular: the gram stain.
◉ Why would the cell wall be an important target for antibiotics?
Answer: Because the cell wall of Prokaryotes (like bacteria) has
peptidoglycan, which is not found in Eukaryotes.
◉ The structure that defines the existence of a cell is the _____ Answer:
cell membrane
,◉ Differences between Gram-Positive & Gram-Negative cells: Answer:
Positive:
- during staining, it retains a dark purple stain after the decolorizer step
- THICK. has 5 or more layers of peptidoglycan (which is why it stays
purple. more layers.)
-its peptidoglycan units - NAG & NAM are joined INdirectly via
Pentaglycine bridge.
Negative:
- during staining, it eventually becomes colorless after the decolorizer
step
- has only 1-3 layers of peptidoglycan
- its peptidoglycan units - NAG & NAM - are joined directly
◉ Archaea live in extreme conditions. What helps them accomplish this?
Answer: - having ether linkage (more stable instead of ester)
- methylated groups - tighter bonds
- monolayer instead of bilayer - stronger
- inserting/fusing ring structures
◉ O2 & CO2 can easily pass through membrane via passive transport
(aka diffusion) Answer:
,◉ If you have a high [solutes] inside the cell, water will rush in, pressure
builds up, and bacterial cell may lyse. What can help prevent this?
Answer: Cell wall! - provides rigidity
-> antibiotics can "hurt" the cell wall, resulting in the cell to burst, bc
most bacterial cells are found in hypotonic solutions (more solutes
inside, less solutes outside)
◉ mycoplasmas, have a cell membrane with ______ Answer: no outer
layers. (rare)
◉ Gram-Negative bacteria have inner and outer leaflets in their outer
membrane. Describe their composition. Answer: Inner leaflet: contains
phospholipid bilayer
Outer leaflet: composed of LPS (lipopolysaccharide)
◉ Most bacterial cell walls are made up of _________ Answer:
peptidoglycan (or murein).
--> which is basically a polysaccharide of repeating subunits of NAG &
NAM
◉ for GRAM-NEGATIVE BACTERIA: In order for the cross-links
between the repeating units N-acetylmuramic acid (NAM) & N-
acetylglucosamime (NAG) to occur, what important step must happen?
, Answer: The terminal D-Alanine group must be cleaved off in order for
the cross-links to form
◉ How does Penecillin work? Answer: It inhibits TRANSPEPTIDASE
(which is the enzyme that forms the cross-links found in peptidoglycan,
the structure base for the cell wall.)
--> thus it weakens the cell wall
**vancomyecin BINDS to terminal group
◉ What function does a "capsule" provide? Answer: It prevents the
bacterial cell (both + and -) from undergoing phagocytsosis by
macrophages. (bad for us)
◉ Mycobacteria have _____ cell envelopes Answer: Complex!
(drawback --> harder for nutrients to get in)
◉ he inward-facing leaflet of the outer membrane includes Answer:
lipoproteins that connect the outer membrane to the peptide bridges of
the cell wall
--> w/out this lipoprotein cell wouldn't be able to divide
◉ The outward-facing leaflet consists of a special kind of phospholipid
called ____, which has crucial medical importance because it acts as an
____ Answer: - Lipopolysaccharide (LPS)
QUESTIONS AND CORRECT ANSWERS
◉ What subgroup does Algae and Protozoa make? Answer: Protists
◉ DESCRIBE THE ROLE OF A PLASMA MEMBRANE AND A
CELL WALL. Answer:
◉ What's the difference between Basic & Differential Stain? Answer:
Basic Stain: Allows you to determine the basic structure of a bacteria
(rod, etc)
Differential Stain: Uses more than one stain
--> most popular: the gram stain.
◉ Why would the cell wall be an important target for antibiotics?
Answer: Because the cell wall of Prokaryotes (like bacteria) has
peptidoglycan, which is not found in Eukaryotes.
◉ The structure that defines the existence of a cell is the _____ Answer:
cell membrane
,◉ Differences between Gram-Positive & Gram-Negative cells: Answer:
Positive:
- during staining, it retains a dark purple stain after the decolorizer step
- THICK. has 5 or more layers of peptidoglycan (which is why it stays
purple. more layers.)
-its peptidoglycan units - NAG & NAM are joined INdirectly via
Pentaglycine bridge.
Negative:
- during staining, it eventually becomes colorless after the decolorizer
step
- has only 1-3 layers of peptidoglycan
- its peptidoglycan units - NAG & NAM - are joined directly
◉ Archaea live in extreme conditions. What helps them accomplish this?
Answer: - having ether linkage (more stable instead of ester)
- methylated groups - tighter bonds
- monolayer instead of bilayer - stronger
- inserting/fusing ring structures
◉ O2 & CO2 can easily pass through membrane via passive transport
(aka diffusion) Answer:
,◉ If you have a high [solutes] inside the cell, water will rush in, pressure
builds up, and bacterial cell may lyse. What can help prevent this?
Answer: Cell wall! - provides rigidity
-> antibiotics can "hurt" the cell wall, resulting in the cell to burst, bc
most bacterial cells are found in hypotonic solutions (more solutes
inside, less solutes outside)
◉ mycoplasmas, have a cell membrane with ______ Answer: no outer
layers. (rare)
◉ Gram-Negative bacteria have inner and outer leaflets in their outer
membrane. Describe their composition. Answer: Inner leaflet: contains
phospholipid bilayer
Outer leaflet: composed of LPS (lipopolysaccharide)
◉ Most bacterial cell walls are made up of _________ Answer:
peptidoglycan (or murein).
--> which is basically a polysaccharide of repeating subunits of NAG &
NAM
◉ for GRAM-NEGATIVE BACTERIA: In order for the cross-links
between the repeating units N-acetylmuramic acid (NAM) & N-
acetylglucosamime (NAG) to occur, what important step must happen?
, Answer: The terminal D-Alanine group must be cleaved off in order for
the cross-links to form
◉ How does Penecillin work? Answer: It inhibits TRANSPEPTIDASE
(which is the enzyme that forms the cross-links found in peptidoglycan,
the structure base for the cell wall.)
--> thus it weakens the cell wall
**vancomyecin BINDS to terminal group
◉ What function does a "capsule" provide? Answer: It prevents the
bacterial cell (both + and -) from undergoing phagocytsosis by
macrophages. (bad for us)
◉ Mycobacteria have _____ cell envelopes Answer: Complex!
(drawback --> harder for nutrients to get in)
◉ he inward-facing leaflet of the outer membrane includes Answer:
lipoproteins that connect the outer membrane to the peptide bridges of
the cell wall
--> w/out this lipoprotein cell wouldn't be able to divide
◉ The outward-facing leaflet consists of a special kind of phospholipid
called ____, which has crucial medical importance because it acts as an
____ Answer: - Lipopolysaccharide (LPS)
