GTC BIO 2117 TEST 4 REVIEW QUESTIONS AND ANSWERS
What do we call antibiotics that kill gram negative and gram positive bacteria? - CORRECT
ANSWER✅✅Broad spectrum drugs (antibiotics) are effective against both gram negative and gram
positive bacteria.
What do we call it when we give the patient 2 or 3 different antibiotics a once? Why would we do that? -
CORRECT ANSWER✅✅Combination chemotherapy. Pathogens are capable of becoming resistant to a
single agent, but combination chemotherapy (using more than one drug) makes it more difficult for the
pathogen to develop resistance.
What is chemotherapeutic index? - CORRECT ANSWER✅✅The relationship between toxicity of a
compound for the body and the toxicity for parasites.
If a drug has a low chemotherapeutic index, what does that mean? Is that good or bad? - CORRECT
ANSWER✅✅Drugs that have a low chemotherapeutic index often inhibit pathways or attack structures
found in the host cells. For example, cancer cells closely resemble normal body cells, therefore, it is
difficult to poison the cancer cells without poisoning the body. A low chemotherapeutic is bad. The
larger the therapeutic index, the better the chemotherapeutic agent, and the less toxic it is to the host.
Drugs often have high therapeutic indexes if the target of the drug is a structure or pathway not found
in the host organism.
A drug has a low selective toxicity. Is that a good or bad thing? - CORRECT ANSWER✅✅Selective toxicity
is the ability of a chemical or drug to kill a microorganism without harming its host, therefore, a low
selective toxicity is a bad thing.
Name four major methods by which antibiotics work: - CORRECT ANSWER✅✅1) inhibit cell wall
synthesis
2) inhibit protein synthesis
3) inhibitor of nucleic acid synthesis
4) inhibit folic acid synthesis
Penicillin is made by a ______? - CORRECT ANSWER✅✅fungus (mold/penicillium)
,Who discovered penicillin? - CORRECT ANSWER✅✅Fleming
How does penicillin harm bacteria? - CORRECT ANSWER✅✅Penicillin is in a group of "beta-lactam"
drugs that work by inhibiting the cross-linkages between the NAM-NAG layers of the peptidoglycan cell
wall. Results in faulty cell wall and lysis of bacteria: bacteriocidal.
What are three problems with penicillin? - CORRECT ANSWER✅✅1) overuse has led to resistance.
Many bacteria have beta-lactamase (penicillinase), an enzyme which inactivates the penicillin.
2) narrow spectrum
3) anaphylactic reaction: many people allergic
What types of microorganisms are affected by pencillin? - CORRECT ANSWER✅✅primarily for staph
and strep infections- also syphilis
What do we mean by semisynthetic penicillin? Are they only good for gram positive microorganisms? -
CORRECT ANSWER✅✅Altered natural beta-lactams create semisynthetic derivatives of penicillin. These
are synthetic and more expensive. They have a broader spectrum than penicillin due to their modified
chemical structures.
Why do they add clavulinic acid to penicillin? - CORRECT ANSWER✅✅The clavulinic acid inactivates the
penicillinase made by bacteria.
What is beta-lactamase? - CORRECT ANSWER✅✅A bacterial enzyme that catalyzes the hydrolysis of the
lactam ring in some penicillin antibiotics, rendering them ineffective. Beta-lactamase is also known as
penicillinase.
Cephalosporins are described as first generation, second generation, and third generation. What is the
difference? - CORRECT ANSWER✅✅first generation are generally used for gram positives. They are
narrow spectrum. second generation are more broad. They kill enterics (gram - and some gram +). Third
generation kills pseudomonas and is broad spectrum killing gram - and even more gram +.
, How do these work? - CORRECT ANSWER✅✅They work like penicillin by inhibiting cell wall synthesis.
They do this by inhibiting the cross linkages between the NAM and NAG layers of the peptidoglycan cell
wall. The cephalosporins are resistant to beta lactamase enzyme.
Why are these drugs better for some people than penicillin? - CORRECT ANSWER✅✅They are active
against more organisms and do not cause as many allergic reactions as penicillin.
Name four drugs other than penicillin that inhibit the synthesis of the cell wall: - CORRECT
ANSWER✅✅ABI V.
1. Augmentin
2. Bacitracin
3. Vancomycin
4. Isoniazid
Which of these drugs is used to treat MRSA? - CORRECT ANSWER✅✅vancomycin
Which of these drugs is for topical application? - CORRECT ANSWER✅✅bacitracin
Name 2 drugs that inhibit mycolic acid production/cell wall synthesis in Mycobacteria: - CORRECT
ANSWER✅✅isoniazid and ethambutol
Why can we give drugs that disrupt ribosomes? Wouldn't that also affect human ribosomes? - CORRECT
ANSWER✅✅The drugs only affect the 30s ribosomes in prokaryotic cells. Human cells are not affected
because they have 40s ribosomes since they are eukaryotic.
Aminoglycosides are effective against gram _____ bacteria - CORRECT ANSWER✅✅negative
What are some side effects of aminoglycosides? - CORRECT ANSWER✅✅1. hearing loss
2. kidney damage
What do we call antibiotics that kill gram negative and gram positive bacteria? - CORRECT
ANSWER✅✅Broad spectrum drugs (antibiotics) are effective against both gram negative and gram
positive bacteria.
What do we call it when we give the patient 2 or 3 different antibiotics a once? Why would we do that? -
CORRECT ANSWER✅✅Combination chemotherapy. Pathogens are capable of becoming resistant to a
single agent, but combination chemotherapy (using more than one drug) makes it more difficult for the
pathogen to develop resistance.
What is chemotherapeutic index? - CORRECT ANSWER✅✅The relationship between toxicity of a
compound for the body and the toxicity for parasites.
If a drug has a low chemotherapeutic index, what does that mean? Is that good or bad? - CORRECT
ANSWER✅✅Drugs that have a low chemotherapeutic index often inhibit pathways or attack structures
found in the host cells. For example, cancer cells closely resemble normal body cells, therefore, it is
difficult to poison the cancer cells without poisoning the body. A low chemotherapeutic is bad. The
larger the therapeutic index, the better the chemotherapeutic agent, and the less toxic it is to the host.
Drugs often have high therapeutic indexes if the target of the drug is a structure or pathway not found
in the host organism.
A drug has a low selective toxicity. Is that a good or bad thing? - CORRECT ANSWER✅✅Selective toxicity
is the ability of a chemical or drug to kill a microorganism without harming its host, therefore, a low
selective toxicity is a bad thing.
Name four major methods by which antibiotics work: - CORRECT ANSWER✅✅1) inhibit cell wall
synthesis
2) inhibit protein synthesis
3) inhibitor of nucleic acid synthesis
4) inhibit folic acid synthesis
Penicillin is made by a ______? - CORRECT ANSWER✅✅fungus (mold/penicillium)
,Who discovered penicillin? - CORRECT ANSWER✅✅Fleming
How does penicillin harm bacteria? - CORRECT ANSWER✅✅Penicillin is in a group of "beta-lactam"
drugs that work by inhibiting the cross-linkages between the NAM-NAG layers of the peptidoglycan cell
wall. Results in faulty cell wall and lysis of bacteria: bacteriocidal.
What are three problems with penicillin? - CORRECT ANSWER✅✅1) overuse has led to resistance.
Many bacteria have beta-lactamase (penicillinase), an enzyme which inactivates the penicillin.
2) narrow spectrum
3) anaphylactic reaction: many people allergic
What types of microorganisms are affected by pencillin? - CORRECT ANSWER✅✅primarily for staph
and strep infections- also syphilis
What do we mean by semisynthetic penicillin? Are they only good for gram positive microorganisms? -
CORRECT ANSWER✅✅Altered natural beta-lactams create semisynthetic derivatives of penicillin. These
are synthetic and more expensive. They have a broader spectrum than penicillin due to their modified
chemical structures.
Why do they add clavulinic acid to penicillin? - CORRECT ANSWER✅✅The clavulinic acid inactivates the
penicillinase made by bacteria.
What is beta-lactamase? - CORRECT ANSWER✅✅A bacterial enzyme that catalyzes the hydrolysis of the
lactam ring in some penicillin antibiotics, rendering them ineffective. Beta-lactamase is also known as
penicillinase.
Cephalosporins are described as first generation, second generation, and third generation. What is the
difference? - CORRECT ANSWER✅✅first generation are generally used for gram positives. They are
narrow spectrum. second generation are more broad. They kill enterics (gram - and some gram +). Third
generation kills pseudomonas and is broad spectrum killing gram - and even more gram +.
, How do these work? - CORRECT ANSWER✅✅They work like penicillin by inhibiting cell wall synthesis.
They do this by inhibiting the cross linkages between the NAM and NAG layers of the peptidoglycan cell
wall. The cephalosporins are resistant to beta lactamase enzyme.
Why are these drugs better for some people than penicillin? - CORRECT ANSWER✅✅They are active
against more organisms and do not cause as many allergic reactions as penicillin.
Name four drugs other than penicillin that inhibit the synthesis of the cell wall: - CORRECT
ANSWER✅✅ABI V.
1. Augmentin
2. Bacitracin
3. Vancomycin
4. Isoniazid
Which of these drugs is used to treat MRSA? - CORRECT ANSWER✅✅vancomycin
Which of these drugs is for topical application? - CORRECT ANSWER✅✅bacitracin
Name 2 drugs that inhibit mycolic acid production/cell wall synthesis in Mycobacteria: - CORRECT
ANSWER✅✅isoniazid and ethambutol
Why can we give drugs that disrupt ribosomes? Wouldn't that also affect human ribosomes? - CORRECT
ANSWER✅✅The drugs only affect the 30s ribosomes in prokaryotic cells. Human cells are not affected
because they have 40s ribosomes since they are eukaryotic.
Aminoglycosides are effective against gram _____ bacteria - CORRECT ANSWER✅✅negative
What are some side effects of aminoglycosides? - CORRECT ANSWER✅✅1. hearing loss
2. kidney damage
