Microbiology HW Ch. 9

What is the end goal of PCR?

To quickly increase the number of copies of a specific DNA sequence

PCR stands for

polymerase chain reaction.

Which of the following is an application that uses PCR?

Sequencing a gene, diagnosing a disease, and providing enough DNA for cloning into another organism

What is the function of the primers in PCR?

They provide a 3′ end for the DNA polymerase.

In which direction does DNA polymerase synthesize the new DNA strand?

5′ to 3′

What provides the energy for DNA polymerization in a PCR reaction?

Deoxyribonucleoside triphosphates

Why is DNA polymerase from Thermus aquaticus ideal for PCR?

It can withstand the high temperatures associated with PCR.

How do the strands separate during PCR?

The high heat of the denaturation step breaks the hydrogen bonds between the two strands.

What is a thermocycler?

The machine that controls the heat of the reaction, cycling between the different temperatures of the different steps during PCR

What is the sequence of the temperatures of a typical PCR reaction?

94 °C, 60 °C, 72 °C`

How do restriction enzymes cut DNA sequences?

They cut DNA at sites, called recognition sites, that have specific nucleotide sequences.

In general, how might recombinant DNA technology be used to prevent a genetic disorder caused by a mutation in a single gene?

In general, how might recombinant DNA technology be used to prevent a genetic disorder caused by a mutation in a single gene?

DNA ligase

attaches the target gene to a desired location

Why would a recombinant DNA molecule be inserted into a host cell?

It can be copied, transcribed, and translated into a desired protein.

statement best describes restriction enzymes

They are important for cloning applications because they can be used to cut DNA at specific nucleotide sequences

Which of the following is NOT a property of useful vectors?
– They always contain only one gene.
– They must have properties that allow their survival in the host cell.
– They must be able to self-replicate.
– They must be small enough to allow them to be manipulated prior to injection.

They always contain only one gene.

Which of the following pairings of recombinant DNA techniques and applications does NOT match?
-genetic modification of yeast: production of purified insulin
– PCR: making many copies of a segment of DNA
– gene therapy: replacing a defective gene
– gene silencing: production of subunit vaccines

gene silencing: production of subunit vaccines

Foreign DNA can be inserted into cells using a variety of different methods. Which method involves the formation of microscopic pores in the cell’s membrane?

electroporation

Why is baker’s yeast useful for expressing genetically engineered genes?

Yeast cells are eukaryotic and so would likely be successful in expressing eukaryotic genes.

Which of the following methods could be used to identify the source of an outbreak?

– DNA fingerprinting
– artificial selection
– reverse genetics
– production of a recombinant protein

DNA fingerprinting

Which of the following statements about recombinant DNA technology is FALSE?

-It allows researchers to make protein products of a gene.
– It has limited application because genes of interest cannot be moved from one type of cell to another.
– It can be used to screen individuals for many different types of genetic diseases.
– It allows researchers to make many copies of a gene of interest.

It has limited application because genes of interest cannot be moved from one type of cell to another.

Which of the following applications of recombinant DNA technology is NOT controversial?
-genetic food modification
– biological weapons development
– metagenomics
– genetic screening

metagenomics

Scientists like to use fluorescent proteins for various types of recombinant DNA procedures. You have a very small amount of the gene for a fluorescent protein. You’d like to make a fluorescent bacterium (!). Which of the following represents the correct sequence of procedures that you would use?

1. Amplify the gene using PCR. 2. Insert the gene into a plasmid vector. 3. Transform the vector into the bacteria.

Which statement regarding agricultural biotechnology is FALSE?
-Scientists have used gene silencing to create tomatoes with a longer shelf life.
– Scientists have created plants that are resistant to herbicides by using a mutant enzyme gene from Salmonella.
– Agricultural biotechnology is extremely limited because foreign genes cannot be inserted into plant cells.
– Scientists have created plants that produce an insect toxin originally found in bacteria.

Agricultural biotechnology is extremely limited because foreign genes cannot be inserted into plant cells.