MCB 5252 Exam 4 Guide With
Complete Solution
Define chemotherapeutics - ANSWER therapeutic chemicals that treat
diseases including infectious diseases
Define antibiotics - ANSWER example of chemotherapeutic which are
antibacterial agents
Define antimicrobial agents - ANSWER chemicals that kill infectious agents
cidal agent - ANSWER kills microbes
toxic dose - ANSWER drug level at which drug becomes too toxic for the
patient
side effects - ANSWER undesirable effects of drugs on host cells
static agent - ANSWER inhibits growth of microbes
broad spectrum drugs - ANSWER attack many different pathogens
narrow spectrum drugs - ANSWER attack only a few different pathogens
which organisms make antibiotics and why - ANSWER Fungi-Penicillium
Bacteria
Bacillus, Actinomyces
Produced for antagonistic effect (killing competition for space and nutrients)
Not necessary for life, just for competition as it takes energy to make these
,antibiotics
Name the typical targets of antibiotics - ANSWER Cell wall
Protein synthesis
Metabolic antagonists
Nucleic acid synthesis inhibition
Cell membrane
what is meant by selective toxicity - ANSWER ability of drug to kill or inhibit
pathogen while damaging host as little as possible
Therapeutic dose vs Therapeutic index - ANSWER Therapeutic dose: drug
level required for clinical treatment
Therapeutic index: ratio of toxic dose to therapeutic dose
Toxic dose / therapeutic dose = therapeutic index
The higher the index the safer the drug
Define Therapeutic dose - ANSWER drug level required for clinical treatment
Define Therapeutic index - ANSWER ratio of toxic dose to therapeutic dose
List antibiotics that target cell wall synthesis - ANSWER cycloserine
glycopeptides (vancomycin)
Beta lactam (penicillins, cephalosporins)
bacitracin
cycloserine - ANSWER Affects synthesis of building blocks (NAM, NAG)
,glycopeptides (vancomycin) - ANSWER Block transpeptidation
Treat antibiotic resistant staph (MRSA) and enterococcal infections
Considered "drug of last resort" b/c rise in resistance to vancomycin is of
great concern
bacitracin - ANSWER Prevents transport across cell membrane
Beta lactam - ANSWER penicillins, cephalosporins
Penicillin:
Inhibit peptidoglycan synthesis
Inhibit last step in bacterial cell wall synthesis (leads to lysis of cell)
Acts only on growing bacteria that are synthesizing new peptidoglycan
Resistance to penicillin is growing
Beta-lactamase (penicillinase) is made by resistant organisms and hydrolyzes
the bond of the penicillin ring structure
1-5% of adults are allergic
Name steps in bacterial cell wall synthesis that could be target of antibiotics -
ANSWER Synthesis of building blocks
Transpeptidation
Peptidoglycan synthesis
What are the important features of vancomycin? - ANSWER Block
transpeptidation
Treat antibiotic resistant staph (MRSA) and enterococcal infections
, Considered "drug of last resort" b/c rise in resistance to vancomycin is of
great concern
it is a glycopeptide that inhibits cell wall synthesis by blocking
transpeptidation
List the classes of antibiotics that target protein synthesis mechanism, -
ANSWER aminoglycoside
tetracycline
macrolide (erythromycin, cholarmphenicol)
Mech of action for Aminoglycoside antibiotics - ANSWER (streptomycin,
gentamicin)
Bind to 30S ribosomal subunit and cause misreading of mRNA and
premature release of polypeptide
Mechanism of action for Tetracycline - ANSWER Broad spectrum, static
Combine with 30S ribosomal subunit and inhibit binding of aminoacyl-tRNA
molecules to A-site of the ribosome
Sometimes used to treat acne
Mechanism of action for Macrolide antibiotics (erythromycin,
chloramphenicol) - ANSWER Erythromycin
Broad spectrum - static
Binds to 23S rRNA of 50S ribosomal subunit and inhibits peptide chain
elongation
Used for patients allergic to penicillin
Complete Solution
Define chemotherapeutics - ANSWER therapeutic chemicals that treat
diseases including infectious diseases
Define antibiotics - ANSWER example of chemotherapeutic which are
antibacterial agents
Define antimicrobial agents - ANSWER chemicals that kill infectious agents
cidal agent - ANSWER kills microbes
toxic dose - ANSWER drug level at which drug becomes too toxic for the
patient
side effects - ANSWER undesirable effects of drugs on host cells
static agent - ANSWER inhibits growth of microbes
broad spectrum drugs - ANSWER attack many different pathogens
narrow spectrum drugs - ANSWER attack only a few different pathogens
which organisms make antibiotics and why - ANSWER Fungi-Penicillium
Bacteria
Bacillus, Actinomyces
Produced for antagonistic effect (killing competition for space and nutrients)
Not necessary for life, just for competition as it takes energy to make these
,antibiotics
Name the typical targets of antibiotics - ANSWER Cell wall
Protein synthesis
Metabolic antagonists
Nucleic acid synthesis inhibition
Cell membrane
what is meant by selective toxicity - ANSWER ability of drug to kill or inhibit
pathogen while damaging host as little as possible
Therapeutic dose vs Therapeutic index - ANSWER Therapeutic dose: drug
level required for clinical treatment
Therapeutic index: ratio of toxic dose to therapeutic dose
Toxic dose / therapeutic dose = therapeutic index
The higher the index the safer the drug
Define Therapeutic dose - ANSWER drug level required for clinical treatment
Define Therapeutic index - ANSWER ratio of toxic dose to therapeutic dose
List antibiotics that target cell wall synthesis - ANSWER cycloserine
glycopeptides (vancomycin)
Beta lactam (penicillins, cephalosporins)
bacitracin
cycloserine - ANSWER Affects synthesis of building blocks (NAM, NAG)
,glycopeptides (vancomycin) - ANSWER Block transpeptidation
Treat antibiotic resistant staph (MRSA) and enterococcal infections
Considered "drug of last resort" b/c rise in resistance to vancomycin is of
great concern
bacitracin - ANSWER Prevents transport across cell membrane
Beta lactam - ANSWER penicillins, cephalosporins
Penicillin:
Inhibit peptidoglycan synthesis
Inhibit last step in bacterial cell wall synthesis (leads to lysis of cell)
Acts only on growing bacteria that are synthesizing new peptidoglycan
Resistance to penicillin is growing
Beta-lactamase (penicillinase) is made by resistant organisms and hydrolyzes
the bond of the penicillin ring structure
1-5% of adults are allergic
Name steps in bacterial cell wall synthesis that could be target of antibiotics -
ANSWER Synthesis of building blocks
Transpeptidation
Peptidoglycan synthesis
What are the important features of vancomycin? - ANSWER Block
transpeptidation
Treat antibiotic resistant staph (MRSA) and enterococcal infections
, Considered "drug of last resort" b/c rise in resistance to vancomycin is of
great concern
it is a glycopeptide that inhibits cell wall synthesis by blocking
transpeptidation
List the classes of antibiotics that target protein synthesis mechanism, -
ANSWER aminoglycoside
tetracycline
macrolide (erythromycin, cholarmphenicol)
Mech of action for Aminoglycoside antibiotics - ANSWER (streptomycin,
gentamicin)
Bind to 30S ribosomal subunit and cause misreading of mRNA and
premature release of polypeptide
Mechanism of action for Tetracycline - ANSWER Broad spectrum, static
Combine with 30S ribosomal subunit and inhibit binding of aminoacyl-tRNA
molecules to A-site of the ribosome
Sometimes used to treat acne
Mechanism of action for Macrolide antibiotics (erythromycin,
chloramphenicol) - ANSWER Erythromycin
Broad spectrum - static
Binds to 23S rRNA of 50S ribosomal subunit and inhibits peptide chain
elongation
Used for patients allergic to penicillin
