18: Biotechnology Flashcards
Module 4, Lesson 1
Selective breeding is a type of…
Genetic manipulation
Selective breeding is also often called…
Artificial selection
____ uses controlled mating to produce an organism with the desired characteristics.
Selective breeding
Selective breeding is a ____ process.
Long-term
True or false:
Selective breeding only ever results in the selection of desirable traits.
False
It can often result in undesirable or harmful traits being accidentally selected.
Selective breeding typically results in a(n) ____ of overall genetic diversity in the species.
Decrease
True or false:
Selective breeding increases an organism’s vulnerability to disease.
True
The process of modifying an organism’s DNA using technology is called…
Gene editing
List three different variations of gene editing.
- Taking genes from one organism and inserting them into another
- Removing sections of DNA
- Editing individual DNA base pairs
List two examples of gene editing.
- Molecular cloning
- CRISPR/Cas9 system
List three benefits of gene editing compared to selective breeding.
- Much faster and more targeted
- Genes from one species can be inserted into another
- Helps prevent loss of genetic diversity
Lab-made molecules that are not naturally found in an organism are called…
Recombinant molecules
Many gene editing techniques use naturally-occuring…
Enzymes
____ are used in gene editing to cut DNA at specific locations.
Restriction enzymes/endonucleases
____ are a category of enzymes capable of cutting phosphodiester bonds between nucleotides.
Nucleases
Restriction enzymes are naturally a key component of…
Bacterial resistance to viruses
Which two components of DNA synthesis are often used in gene editing?
- DNA ligase
- DNA polymerase
During gene editing, DNA ligase is used to…
Seal the gaps between the original DNA and the inserted DNA segment
During gene editing, especially PCR, DNA polymerase is used to…
Amplify a sample of DNA
List the four basic steps of molecular cloning.
- Amplify DNA
- Cut out DNA
- Isolate cut DNA
- Insert DNA into new organism
Why is GFP, a gene for bioluminescent protein, useful for researchers?
It can be used to track movement of proteins in a living cell
The first step of molecular cloning, where the gene of interest is amplified, is…
Polymerase Chain Reaction
(PCR)
PCR takes place in a machine called a…
Thermocycler
List the three main steps of PCR.
- Denaturation
- Annealing
- Synthesis/Extension
PCR is a technique used to…
Amplify a gene of interest
During the denaturation phase of PCR…
DNA is unwound using extreme heat
True or false:
Unlike in a cell, during PCR all strands of DNA are unwound at once.
True
During the annealing phase of PCR…
The temperature is lowered so the primers can bind to the DNA
True or false:
The primers used in PCR only amplify the area of interest.
True
During the extension phase of PCR…
The DNA is elongated by DNA polymerase
The specific DNA polymerase used in PCR is called…
Taq polymerase
True or false:
Taq polymerase is sourced from human cells.
False
It comes from a thermophilic bacteria, so it doesn’t denature at high temperatures
By repeating PCR many times, it is possible to make ____ of copies of a single DNA fragment.
Millions
Restriction enzymes are a special class of…
Endonucleases
During molecular cloning, restriction enzymes are used to…
Cut the amplified DNA at precise locations
When choosing which restriction enzyme to use, it is important to ensure that…
The enzyme will not cut into the gene of interest
When restriction enzymes cut DNA, they leave overlapping…
“Sticky ends”
Why are the sticky ends of cut DNA important?
They allow two different segments of DNA to be easily connected
True or false:
Restriction enzymes can usually precisely cut out the gene of interest.
False
The DNA fragment containing the gene of interest is separated from the leftover fragments using…
Gel electrophoresis
During gel electrophoresis, ____ is used to move DNA fragments through a gel with many small pores.
Electric current
DNA molecules are ____ charged.
Negatively
During gel electrophoresis, DNA fragments will move from the ____ to the ____.
Cathode to anode
Gel electrophoresis separates DNA fragments by…
Size
Longer fragments travel ____ through the gel, so they are usually found near the ____ of the gel.
Slower, top
Shorter fragments travel ____ through the gel, so they are usually found near the ____ of the gel.
Faster; bottom
Researchers can use ____ to know exactly which nucleotide base the DNA fragments were cut at.
Restriction enzyme maps
A standard set of DNA fragments used to identify the sample fragments during gel electrophoresis is called a….
DNA ladder
A segment of DNA that the gene of interest will be added to is the…
Plasmid
During the process of ____, the gene of interest and the plasmid are combined.
Ligation
In order for the cut fragment and the plasmid to combine…
The same restriction enzyme must have been used to cut both
The result of ligation is a…
Recombinant DNA molecule
After the gene of interest and the plasmid have combined, ____ is used to seal gaps in the phosphate backbone.
DNA ligase
During the process of ____, the edited plasmid is inserted into an organism.
Transformation
Many plasmids have a ____, which is used to verify that the gene of interest has entered the cell.
Selection marker
To ensure that the plasmid can replicate within the cell, a(n) ____ is placed on it.
Origin of replication
Genetically altered animals are sometimes called…
(not GMOs)
Transgenic
Over 90% of soybean plants in the US have been genetically modified to resist…
Glyphosate
To insert a gene into a plant, the edited gene is made into a special plasmid called a…
Tumor inducing (Ti) plasmid
The ____ system has the ability to directly and rapidly edit the genes of living cells.
CRISPR/Cas9
The scientists who discovered CRISPR were studying…
Bacterial immune responses
When bacteria are infected with a virus…
They collect small fragments of viral DNA and incorporate them into the bacterial genome
Bacteria keep a “viral DNA library” called…
CRISPR
When a bacterium is re-infected by a virus, the CRISPR library…
Produces “guide RNA” that shows the Cas9 endonuclease where to cut the viral DNA
In bacteria, the ____ endonuclease cuts viral DNA at a precise location to prevent re-infection.
Cas9
The ____ system serves as a bacterium’s adaptive immune system.
CRISPR/Cas9
How can CRISPR/Cas9 be used as a gene editing tool?
Guide RNA can be developed for the gene of interest, then injected into the organism along with Cas9 proteins
List three ways that DNA can be edited using CRISPR/Cas9.
- Deleting DNA segments
- Inserting new DNA segments in place of cut DNA
- Inducing mutations in single base pairs
____ can be used to directly alter the gene of cells within or outside the body.
Gene therapy
Gene therapy is primarily used to target…
Genetic diseases
How can CRISPR gene therapy be used to treat sickle cell anemia?
Blood stem cells can be edited so that they have a functional hemoglobin gene
How can CRISPR gene therapy be used to treat HIV?
Immune stem cells can be edited to mutate the surface proteins important for HIV binding to T-cells
List three downsides of gene therapy.
- Inherent risks
- High cost
- Possible ethical concerns
Any cell that cannot form gametes is called a…
Somatic cell
With somatic gene editing, the edited genes are found in the new cells they generate but not…
In any other cells in the body
The benefits and risks of ____ gene editing are limited to the individual.
Somatic
Cells that form gametes are called…
Germline cells
If the DNA of a germline cell is altered, the alterations…
Will be found in every cell of the adult body, including reproductive cells
The benefits and risks of ____ gene editing impact both the individual and any future offspring.
Germline
True or false:
Somatic gene editing can affect evolution.
False
Germline gene editing can do this, but somatic editing cannot.
Germline gene editing in humans is considered…
Unethical and very risky
True or false:
The impacts of gene editing can be difficult to predict.
True
Altering or removing an organism can also impact…
Its ecosystem
One unintended consequence of herbicide-resistant crops is that…
Many weeds/wild plants have also gained the gene for herbicide resistance
Scientists are exploring eradication of malaria by…
Editing the genes of mosquitoes so they become infertile