MICR 4423 Detailed Study
Questions with Verified Answers
1. What characterized medicine before the late 19th century? - ANSWER
palliative and aggressive interventions
2. who defined the four humors theory? when was it defined? what are the four
humors? - ANSWER Galon 150 A.D
black bile, yellow bile, phlegm, and blood letting
3. What is the function of the bacterial cell wall? How many molecules
compose the cell wall surrounding an individual bacterium? - ANSWER 1.
give cell shape and resists turgor pressure (stuff that makes lettuce crunchy)
why turgor pressure? -due to cytoplasm being full of biomolecules and it wants
to dilute those molecules
2. one molecule composes the cell wall, and they are all covalently linked
together
4. Why do bacterial cells have to have carefully coordinated enzymatic
activities on the cell wall in order to grow? - ANSWER -it is a single
macromolecule, you have to be able to break bonds in order for it to grow,
but you must balance the growth of the wall but still break the bonds
-has to still do its job even while it continues
,5. For a rod-shaped bacterial cell, cell wall growth can be divided into two
distinct phases. What are they? Which of these is the only phase for a
spherical cell? - ANSWER 1. elongation and division
2. spherical=division
6. Describe a peptidoglycan precursor molecule in terms of the number of
smaller molecular groups that it is made from. You can draw a diagram. -
ANSWER 1. NAG connected to NAM
2. glycan strands coming off the NAM
3. nam= L-ala, D-gly, two D-ala, and mDAP
7. Which part of a PG precursor is used to build glycan strands? Peptide cross-
bridges? What are the names of the enzymes that polymerize glycan strands
and peptide cross-bridges, respectively? - ANSWER 1. NAG and NAM
2. peptide side chains make the cross-bridges
3. TGases: trans-glycosylases
4. transpeptidase activity
8. What part of a PG precursor is used to link it to the existing PG wall
structure? - ANSWER the penta peptide does it
-peptide--> transpeptidase activity hooking it up to free peptides
-the enzymes are making a new glycan strand, a pentapeptide coming off of it,
transpeptidase activity is hooking them up into the existing peptide strand
9. Where are PG precursors located when they are used by enzymes to build
new cell wall material? What is the whole precursor-carrier molecule called?
- ANSWER 1. the cytoplasmic membrane facing the exterior face of the
, membrane, AFTER FLIPPING THAT IT HAPPENS. no activity inside the
cell, always OUTSIDE
2. GRAM POS: all in extracellular space
3. GRAM NEG: in the paraplasm
precursor + carrying: LIPID II
10.What is the name of the lipid carrier upon which PG precursors are built and
transported? - ANSWER bactoprenol
11.Which positions on pentapeptides are typically linked together to form
peptide cross-bridges in PG? - ANSWER positions 3 and 4 (DAP to D-ala)
12.What type of fabric resembles the PG meshwork? - ANSWER spandex
13.why are the bacterial ribosomes and RNA polymerase good targets for
antibiotic action? - ANSWER there are differences between bacteria and
eukaryotic cells -they perform essential functions
14.what are the three tRNA-associated sites in the bacterial ribosome, and what
happens at each? - ANSWER A: aminoacyl --> where charged tRNA comes
in to see if it finds a match
P: peptidyl transfer--> growing peptide chain
E: exit site --> the empty tRNA exits, after it leaves, it gets recharged by
aminoacyl-tRNAsynthetase
, 15.what is the exit tunnel of a ribosome? which subunit includes it? -
ANSWER extends away from the APE sites and exits through the 50s
subunit-in the 50s subunit
16.what is the function of an aminoacyl-tRNA syntheses? how many are there?
- ANSWER it charges tRNA's, takes a tRNA and an amino acid and then
puts them together.
-there are 20
17.What is the biological function of DNA gyrase? Of topo IV? - ANSWER 1.
DNA gyrase: adds negative super coiling by using ATP (negative is easier to
unwind, it can relieve positive super coiling which does not require ATP).
Positive super coiling is in front of replication
2. Topo IV: inhibit the bacteria's ability to duplicate DNA--> Decants it,
relieves and supercoils
18.name a biological process that requires the action of topoisomerases because
it introduces topological strain on DNA - ANSWER the DNA gyrase
mechanism
19.which antibiotics that we have studied are fully synthetic? - ANSWER
oxazolidinones, fluoroquinolones, and sulfa drugs
how is folate important for making dTTP (the nucleotide building block of
DNA)?
20.what chemical group does the folate contribute? - ANSWER without the
folate, it would be unable to continue DNA synthesis
a methyl group that separates UTP from dTTP
Questions with Verified Answers
1. What characterized medicine before the late 19th century? - ANSWER
palliative and aggressive interventions
2. who defined the four humors theory? when was it defined? what are the four
humors? - ANSWER Galon 150 A.D
black bile, yellow bile, phlegm, and blood letting
3. What is the function of the bacterial cell wall? How many molecules
compose the cell wall surrounding an individual bacterium? - ANSWER 1.
give cell shape and resists turgor pressure (stuff that makes lettuce crunchy)
why turgor pressure? -due to cytoplasm being full of biomolecules and it wants
to dilute those molecules
2. one molecule composes the cell wall, and they are all covalently linked
together
4. Why do bacterial cells have to have carefully coordinated enzymatic
activities on the cell wall in order to grow? - ANSWER -it is a single
macromolecule, you have to be able to break bonds in order for it to grow,
but you must balance the growth of the wall but still break the bonds
-has to still do its job even while it continues
,5. For a rod-shaped bacterial cell, cell wall growth can be divided into two
distinct phases. What are they? Which of these is the only phase for a
spherical cell? - ANSWER 1. elongation and division
2. spherical=division
6. Describe a peptidoglycan precursor molecule in terms of the number of
smaller molecular groups that it is made from. You can draw a diagram. -
ANSWER 1. NAG connected to NAM
2. glycan strands coming off the NAM
3. nam= L-ala, D-gly, two D-ala, and mDAP
7. Which part of a PG precursor is used to build glycan strands? Peptide cross-
bridges? What are the names of the enzymes that polymerize glycan strands
and peptide cross-bridges, respectively? - ANSWER 1. NAG and NAM
2. peptide side chains make the cross-bridges
3. TGases: trans-glycosylases
4. transpeptidase activity
8. What part of a PG precursor is used to link it to the existing PG wall
structure? - ANSWER the penta peptide does it
-peptide--> transpeptidase activity hooking it up to free peptides
-the enzymes are making a new glycan strand, a pentapeptide coming off of it,
transpeptidase activity is hooking them up into the existing peptide strand
9. Where are PG precursors located when they are used by enzymes to build
new cell wall material? What is the whole precursor-carrier molecule called?
- ANSWER 1. the cytoplasmic membrane facing the exterior face of the
, membrane, AFTER FLIPPING THAT IT HAPPENS. no activity inside the
cell, always OUTSIDE
2. GRAM POS: all in extracellular space
3. GRAM NEG: in the paraplasm
precursor + carrying: LIPID II
10.What is the name of the lipid carrier upon which PG precursors are built and
transported? - ANSWER bactoprenol
11.Which positions on pentapeptides are typically linked together to form
peptide cross-bridges in PG? - ANSWER positions 3 and 4 (DAP to D-ala)
12.What type of fabric resembles the PG meshwork? - ANSWER spandex
13.why are the bacterial ribosomes and RNA polymerase good targets for
antibiotic action? - ANSWER there are differences between bacteria and
eukaryotic cells -they perform essential functions
14.what are the three tRNA-associated sites in the bacterial ribosome, and what
happens at each? - ANSWER A: aminoacyl --> where charged tRNA comes
in to see if it finds a match
P: peptidyl transfer--> growing peptide chain
E: exit site --> the empty tRNA exits, after it leaves, it gets recharged by
aminoacyl-tRNAsynthetase
, 15.what is the exit tunnel of a ribosome? which subunit includes it? -
ANSWER extends away from the APE sites and exits through the 50s
subunit-in the 50s subunit
16.what is the function of an aminoacyl-tRNA syntheses? how many are there?
- ANSWER it charges tRNA's, takes a tRNA and an amino acid and then
puts them together.
-there are 20
17.What is the biological function of DNA gyrase? Of topo IV? - ANSWER 1.
DNA gyrase: adds negative super coiling by using ATP (negative is easier to
unwind, it can relieve positive super coiling which does not require ATP).
Positive super coiling is in front of replication
2. Topo IV: inhibit the bacteria's ability to duplicate DNA--> Decants it,
relieves and supercoils
18.name a biological process that requires the action of topoisomerases because
it introduces topological strain on DNA - ANSWER the DNA gyrase
mechanism
19.which antibiotics that we have studied are fully synthetic? - ANSWER
oxazolidinones, fluoroquinolones, and sulfa drugs
how is folate important for making dTTP (the nucleotide building block of
DNA)?
20.what chemical group does the folate contribute? - ANSWER without the
folate, it would be unable to continue DNA synthesis
a methyl group that separates UTP from dTTP
