PLTW MEDICAL INTERVENTIONS ACTUAL EXAM SCRIPT
2025/2026 QUESTIONS WITH ANSWERS GRADED A+
✔✔Purpose of detergent in elisa test - ✔✔Detergent contains sodium laurel sulfate,
which cleans dishes by removing fats and proteins. It acts the same way in the DNA
extraction protocol, pulling apart the lipids and proteins that make up the membranes
surrounding the cell and nucleus. Once these membranes are broken apart, the DNA is
released from the cell.
✔✔ELISA Steps - ✔✔1. The sample is added to a plastic well, where the proteins are
bound to the cell wall. A detergent washes away unbound proteins while preventing
more proteins from binding to the cell wall.
2. The Primary Antibody binds to a specific antigen in the cell. Excess is washed away.
3. The Secondary Antibody, which is bound to the enzyme, is added. Excess is washed
away.
4. The enzyme substrate is added, causing the liquid to turn blue (oxidation)
✔✔Enzyme - ✔✔A protein serving as a catalyst; a chemical agent that changes the rate
of reaction without being consumed by the reaction
✔✔Serial Dilution - ✔✔A stepwise dilution of a substance in a solution
✔✔Nucleoid - ✔✔Contains the genophore
✔✔Plasmid - ✔✔Small, circular piece of DNA. Located in the cytoplasm and contain
information for antibiotic resistance.
✔✔Ribosomes - ✔✔Produce proteins
✔✔Cell Wall - ✔✔Differ between Gram-Positive (no outer membrane, stains blue) and
Gram-Negative (stains red, contains a second membrane)
✔✔Plasma Membrane - ✔✔Found in the envelope, protects the cell and controls what
goes in and out.
✔✔Capsule - ✔✔Most outer layer of the cell, protects it from phagocytosis (white blood
cells)
✔✔Flagella - ✔✔Responsible for movement
✔✔Pili - ✔✔(Fimbriae) Hollow hair-like structures that extend from the cell and allow it
to attach to other cells
, ✔✔Endotoxins - ✔✔Bacterial toxins, found in the cell wall of gram-negative bacteria.
They are released when the cell disintegrates.
✔✔Penicillins (B-lacfam) - ✔✔Interferes with the making of peptidoglycan, weakening
the cell wall so that the bacteria eventually bursts.
Resistance: Some bacteria create enzymes that destroy it
✔✔Gram positive bacteria - ✔✔Bacteria that have a think cell wall of peptidoglycan and
other polymers
✔✔Gram negative bacteria - ✔✔Bacteria that have an outer membrane of
phospholipids and bacterial lipopolysaccharides outside of their thin peptidoglycan layer
The space between the outer membrane and the peptidoglycan layer is called
periplasmic space
✔✔Tetracyclines - ✔✔Prevents bacteria from making necessary proteins. (Binds to
ribosome)
Resistance: Efflux pump
✔✔Fluoroquinolones - ✔✔Attack DNA Gyrase to prevent bacteria from replicating.
Resistance: Change in target, (DNA Gyrase)
✔✔Sulfa antibiotics (Sulfonamids) - ✔✔Inhibit the making of folate, which is an essential
nutrient. Does not hurt humans because we consume folate, but bacteria must
manufacture it.
Resistance: Enzyme changes
✔✔Meningitis (Positive or negative) - ✔✔Gram-Negative disease Sue and her college
friends had
✔✔Not taking medicines to completion
chance to mutate
Feeding antibiotics to farm animals to increase growth
chance to mutate - ✔✔What are we doing to help bacteria become resistant to
antibiotics?
✔✔Mutation - ✔✔DNA mutates, creating a change in the gene product (Form of
resistance to antibiotics)
✔✔Destruction/Inactivation - ✔✔Exchange enzymes that chemically degrade the
antibiotic (Form of resistance to antibiotics)
✔✔Conjugation - ✔✔Plasmid carrying resistance is transferred from one cell to another
using a pilus bridge (Form of sharing resistance)
2025/2026 QUESTIONS WITH ANSWERS GRADED A+
✔✔Purpose of detergent in elisa test - ✔✔Detergent contains sodium laurel sulfate,
which cleans dishes by removing fats and proteins. It acts the same way in the DNA
extraction protocol, pulling apart the lipids and proteins that make up the membranes
surrounding the cell and nucleus. Once these membranes are broken apart, the DNA is
released from the cell.
✔✔ELISA Steps - ✔✔1. The sample is added to a plastic well, where the proteins are
bound to the cell wall. A detergent washes away unbound proteins while preventing
more proteins from binding to the cell wall.
2. The Primary Antibody binds to a specific antigen in the cell. Excess is washed away.
3. The Secondary Antibody, which is bound to the enzyme, is added. Excess is washed
away.
4. The enzyme substrate is added, causing the liquid to turn blue (oxidation)
✔✔Enzyme - ✔✔A protein serving as a catalyst; a chemical agent that changes the rate
of reaction without being consumed by the reaction
✔✔Serial Dilution - ✔✔A stepwise dilution of a substance in a solution
✔✔Nucleoid - ✔✔Contains the genophore
✔✔Plasmid - ✔✔Small, circular piece of DNA. Located in the cytoplasm and contain
information for antibiotic resistance.
✔✔Ribosomes - ✔✔Produce proteins
✔✔Cell Wall - ✔✔Differ between Gram-Positive (no outer membrane, stains blue) and
Gram-Negative (stains red, contains a second membrane)
✔✔Plasma Membrane - ✔✔Found in the envelope, protects the cell and controls what
goes in and out.
✔✔Capsule - ✔✔Most outer layer of the cell, protects it from phagocytosis (white blood
cells)
✔✔Flagella - ✔✔Responsible for movement
✔✔Pili - ✔✔(Fimbriae) Hollow hair-like structures that extend from the cell and allow it
to attach to other cells
, ✔✔Endotoxins - ✔✔Bacterial toxins, found in the cell wall of gram-negative bacteria.
They are released when the cell disintegrates.
✔✔Penicillins (B-lacfam) - ✔✔Interferes with the making of peptidoglycan, weakening
the cell wall so that the bacteria eventually bursts.
Resistance: Some bacteria create enzymes that destroy it
✔✔Gram positive bacteria - ✔✔Bacteria that have a think cell wall of peptidoglycan and
other polymers
✔✔Gram negative bacteria - ✔✔Bacteria that have an outer membrane of
phospholipids and bacterial lipopolysaccharides outside of their thin peptidoglycan layer
The space between the outer membrane and the peptidoglycan layer is called
periplasmic space
✔✔Tetracyclines - ✔✔Prevents bacteria from making necessary proteins. (Binds to
ribosome)
Resistance: Efflux pump
✔✔Fluoroquinolones - ✔✔Attack DNA Gyrase to prevent bacteria from replicating.
Resistance: Change in target, (DNA Gyrase)
✔✔Sulfa antibiotics (Sulfonamids) - ✔✔Inhibit the making of folate, which is an essential
nutrient. Does not hurt humans because we consume folate, but bacteria must
manufacture it.
Resistance: Enzyme changes
✔✔Meningitis (Positive or negative) - ✔✔Gram-Negative disease Sue and her college
friends had
✔✔Not taking medicines to completion
chance to mutate
Feeding antibiotics to farm animals to increase growth
chance to mutate - ✔✔What are we doing to help bacteria become resistant to
antibiotics?
✔✔Mutation - ✔✔DNA mutates, creating a change in the gene product (Form of
resistance to antibiotics)
✔✔Destruction/Inactivation - ✔✔Exchange enzymes that chemically degrade the
antibiotic (Form of resistance to antibiotics)
✔✔Conjugation - ✔✔Plasmid carrying resistance is transferred from one cell to another
using a pilus bridge (Form of sharing resistance)
