GTC BIO 2117 Test 4 Review Actual Exam 2023 Graded A
What do we call antibiotics that kill gram negative and gram positive bacteria?
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?
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?
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?
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?
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:
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 ______?
fungus (mold/penicillium)
Who discovered penicillin?
Fleming
How does penicillin harm bacteria?
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?
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?
primarily for staph and strep infections- also syphilis
, What do we mean by semisynthetic penicillin? Are they only good for gram
positive microorganisms?
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?
The clavulinic acid inactivates the penicillinase made by bacteria.
What is beta-lactamase?
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?
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?
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?
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:
ABI V.
1. Augmentin
2. Bacitracin
3. Vancomycin
4. Isoniazid
Which of these drugs is used to treat MRSA?
vancomycin
Which of these drugs is for topical application?
bacitracin
Name 2 drugs that inhibit mycolic acid production/cell wall synthesis in
Mycobacteria:
isoniazid and ethambutol
Why can we give drugs that disrupt ribosomes? Wouldn't that also affect human
ribosomes?
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
negative
What are some side effects of aminoglycosides?
1. hearing loss
2. kidney damage
Tetracycline is considered a ______________ _____________ antibiotic.
What do we call antibiotics that kill gram negative and gram positive bacteria?
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?
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?
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?
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?
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:
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 ______?
fungus (mold/penicillium)
Who discovered penicillin?
Fleming
How does penicillin harm bacteria?
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?
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?
primarily for staph and strep infections- also syphilis
, What do we mean by semisynthetic penicillin? Are they only good for gram
positive microorganisms?
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?
The clavulinic acid inactivates the penicillinase made by bacteria.
What is beta-lactamase?
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?
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?
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?
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:
ABI V.
1. Augmentin
2. Bacitracin
3. Vancomycin
4. Isoniazid
Which of these drugs is used to treat MRSA?
vancomycin
Which of these drugs is for topical application?
bacitracin
Name 2 drugs that inhibit mycolic acid production/cell wall synthesis in
Mycobacteria:
isoniazid and ethambutol
Why can we give drugs that disrupt ribosomes? Wouldn't that also affect human
ribosomes?
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
negative
What are some side effects of aminoglycosides?
1. hearing loss
2. kidney damage
Tetracycline is considered a ______________ _____________ antibiotic.
