PLTW Biomedical Innovation Problem 6: MCQ Test on DNA Techniques

Recombinant DNA

DNA that is artificially combined from different sources

Restriction enzymes

Proteins that cut DNA at specific recognition sites

EcoRI

A commonly used restriction enzyme

Plasmids

Vectors that carry foreign DNA into cells

Sticky ends

They make it easier to insert DNA fragments in the correct orientation

DNA ligase

An enzyme that joins DNA fragments together

Antibiotic resistance genes

Allow scientists to select bacteria that successfully took up the plasmid

Transformation

The process that allows bacteria to take up recombinant plasmid DNA

Good plasmid vector characteristics

It contains an origin of replication, has multiple restriction enzyme sites, and has a selectable marker like antibiotic resistance

Heat shock

Weakens the bacterial cell wall to allow DNA to enter

Lysis buffer

Digests proteins and breaks open the bacterial cells

RNase

Added during plasmid extraction to remove RNA contaminants

Isopropanol

Precipitates DNA, making it easier to collect

Gel electrophoresis

A technique to separate DNA fragments based on size

DNA movement in gel

DNA is negatively charged and moves toward the positive electrode

DNA ladder

Used in gel electrophoresis to determine the size of DNA fragments.

Cutting DNA

To cut the DNA into smaller pieces

Visualizing DNA

To help visualize DNA under UV light

Reference Sizes for DNA

To provide reference sizes for DNA fragments

Speeding Up Migration

To speed up the migration of DNA

Gel Result for Recombinant Plasmid

If a recombinant plasmid is successfully cut with EcoRI and XhoI, what will be seen on a gel?

Presence Confirmation of Recombinant Plasmid

How can gel electrophoresis confirm the presence of a recombinant plasmid?

Action of a Restriction Enzyme

Which of the following describes the action of a restriction enzyme?

Purpose of Two Restriction Enzymes

What is the purpose of using two different restriction enzymes when inserting DNA into a plasmid?

Plasmid Closure Without Insert

If a plasmid closes without an insert after ligation, what will happen?

Usefulness of Double Restriction Digest

Why is a double restriction digest useful?

Incomplete Cut by Restriction Enzyme

What happens if a restriction enzyme does not cut the plasmid completely?

Multiple Ligation Results

Why might multiple ligation results be possible in cloning?

Blue-White Screening

How does blue-white screening help in recombinant DNA technology?

Goal of Recombinant DNA Technology

What is the main goal of recombinant DNA technology?

Enzyme Cutting DNA

Which enzyme is responsible for cutting DNA at specific sequences?

Joining DNA Fragments

Which enzyme joins DNA fragments together?

Role of Plasmids

What role do plasmids play in recombinant DNA technology?

Commonly Used Restriction Enzyme

Which restriction enzyme is commonly used in cloning?

EcoRI

A commonly used restriction enzyme in cloning.

Gel electrophoresis

A technique used to separate DNA fragments by size.

DNA ladder

A tool used in gel electrophoresis to provide reference fragment sizes.

Isopropanol

A chemical used to precipitate DNA in plasmid extraction.

RNase

An enzyme added to the plasmid extraction process to remove RNA.

Supercoiled plasmid DNA

A plasmid that is tightly wound.

Lysis buffer

A solution that breaks open the cell membrane during plasmid DNA extraction.

Transformation

The process by which a bacterium takes up recombinant DNA.

Antibiotic resistance genes

Genes used in plasmid vectors to select for bacteria that successfully took up the plasmid.

Sticky ends

Single-stranded overhangs that allow specific base pairing during DNA ligation.

Blunt ends

DNA ends with no overhangs, requiring blunt-end ligation.

Ligation reaction outcomes

Possible results include plasmid closing with no insert, a single insert, or multiple inserts.

Recombinant plasmid map

A diagram showing restriction sites, insert locations, and important features like antibiotic resistance genes.

Double restriction digest

A method used to ensure DNA fragments are cut at two different sites to prevent unwanted re-ligation.

Recombinant DNA

A DNA molecule artificially created by combining DNA from different sources.

Restriction enzyme

An enzyme responsible for cutting DNA at specific sequences.

Ligase

An enzyme used to join DNA fragments together.

Electric current in gel electrophoresis

Used to separate DNA fragments based on size by moving negatively charged DNA through an agarose gel matrix.

Potassium acetate

A chemical that neutralizes DNA and helps separate debris during plasmid extraction.

SDS

A component of the lysis buffer that breaks open bacterial cells and denatures proteins.

Heat shock/electroporation

Methods used to facilitate the uptake of plasmid DNA by bacteria during transformation.

Band sizes in gel electrophoresis

Used to confirm the presence of an insert in a ligation reaction.

Helicase

An enzyme that unwinds the DNA double helix during replication.

DNA ligase

An enzyme that joins DNA fragments together by forming phosphodiester bonds.

Topoisomerase

An enzyme that alters the supercoiling of DNA.

Primase

An enzyme that synthesizes a short RNA primer to initiate DNA replication.

EcoRI

A restriction enzyme that recognizes and cuts the sequence GAATTC.

Restriction enzyme

An enzyme that cuts DNA at specific sequences.

Plasmid

A small, circular DNA molecule that can replicate independently of chromosomal DNA.

Recombinant DNA technology

A method for combining DNA from different sources.

DNA ladder

A set of known DNA fragment sizes used as a reference in gel electrophoresis.

Isopropanol

A reagent used to precipitate DNA during plasmid extraction.

RNase

An enzyme added to remove RNA during plasmid extraction.

Sticky end

A cut that creates single-stranded overhangs.

Ligation

The process of joining two DNA fragments together.

Antibiotic resistance genes

Genes used in plasmid vectors to select for bacteria that have successfully taken up the plasmid.

Lysis buffer

A solution used to break open the cell membrane during plasmid extraction.

Potassium acetate

A reagent that neutralizes DNA and helps separate debris during plasmid extraction.

DNA polymerase

An enzyme that synthesizes new DNA strands during replication.

RNA polymerase

An enzyme that synthesizes RNA from a DNA template.

Calcium chloride

A chemical used to treat cells to facilitate the uptake of plasmid DNA.

Heat shock

A method used to promote the uptake of plasmid DNA by cells.