Question 1

Two strands of DNA that have been cut by an endonuclease can be sealed together by a(n)
A)polymerase enzyme.
B)ligase enzyme.
C)exonuclease enzyme.
D)protease enzyme.

Accepted Answer

Ligase enzymes join the 3' end of one nucleotide to the 5' end of another nucleotide, forming a phosphodiester bond. This is necessary to seal together two strands of DNA that have been cut by an endonuclease.

Question 2

The PCR technique requires a DNA polymerase from an organism that can endure high heat, such as Thermus aquaticus.What step of the protocol makes the heat-stability most necessary?
A)Synthesis
B)Primer annealing
C)Denaturation
D)Antibody binding

Accepted Answer

Denaturation involves heating the sample to a high temperature to separate the double-stranded DNA into single strands, making them available for amplification by PCR. The DNA polymerase from Thermus aquaticus is necessary during this step to withstand the high temperature and remain active, allowing for successful denaturation and subsequent amplification. Without a heat-stable DNA polymerase, the enzyme would denature at high temperatures and become inactive, resulting in PCR failure. Therefore, the heat-stability is most necessary during the denaturation step.

Question 3

Crop plants have been protected from certain insects by the addition of a gene for a specific insect toxin from the bacterium
A)Agrobacterium tumefaciens.
B)Bacillus thuringiensis.
C)Herpes simplex.
D)Pseudomonas.

Accepted Answer

Bacillus thuringiensis (Bt) is a bacterium whose gene is used in genetically modified crops to produce a toxin that is effective against certain insects.

Question 4

Small circular, extrachromosomal DNA segments are known as _______.
A)vectors
B)plasmids
C)clones
D)RNA

Accepted Answer

Small circular, extrachromosomal DNA segments are known as plasmids. Vectors are DNA molecules used to transfer foreign DNA segments into host cells. Clones are genetically identical copies of a DNA fragment or organism. RNA is a type of nucleic acid that functions in gene expression.

Question 5

The most recent techniques developed in the biological sciences allow the manipulation of DNA with the ultimate goal of intervening directly with the _______ fate of organisms.
A)genetic
B)developmental
C)adult
D)mitotic

Accepted Answer

The manipulation of DNA directly affects an organism's genetic makeup and can ultimately determine its genetic fate. The other choices (B, C, D) are more specific and limited in scope compared to genetic fate.

Question 6

A commercially significant human protein now produced in bacteria is
A)hemoglobin.
B)gamma globulins.
C)AZT.
D)human insulin.

Accepted Answer

Human insulin is a commercially significant protein that is produced in bacteria through recombinant DNA technology, allowing for large-scale production for medical use.

Question 7

You have discovered a very small amount of DNA from an ancient organism that you want to save and study.What is the very first thing you should do to allow you to study this DNA in the lab?
A)RT-PCR
B)Gel electrophoresis
C)Polymerase chain reaction (PCR)
D)Insert the DNA into a vector

Accepted Answer

The first thing that should be done to study the small amount of DNA is to carry out a Polymerase Chain Reaction (PCR). PCR is a technique used to amplify a specific section of DNA to generate millions of copies, making the DNA easier to study in the lab. Once the DNA has been amplified using PCR, it can then be inserted into a vector for further study or analyzed using gel electrophoresis. However, these techniques can only be carried out after the DNA has been amplified through PCR.

Question 8

The _________ from Agrobacterium tumefaciens is used in genetic engineering involving crop plant genes.
A)restriction endonucleases
B)DNA
C) Ti vector
D) Ti plasmid

Accepted Answer

The Ti (tumor-inducing) plasmid found in Agrobacterium tumefaciens is often used in genetic engineering involving crop plants. The Ti plasmid contains the genes responsible for causing tumors in plants, but researchers can remove these genes and replace them with desired genes that can be used to enhance crop growth or add beneficial traits.

Question 9

Single-stranded ends generated by the same restriction enzyme are complementary to each other.They can be joined together,
A)even when the source of the DNA is different.
B)only when the source of the DNA is the same.
C)but the "sticky ends" will most likely have to be modified.
D)but the hybridization of the two ends may cause a problem with cloning.

Accepted Answer

Single-stranded ends generated by the same restriction enzyme are complementary and can anneal to each other, regardless of the DNA source, allowing DNA from different sources to be joined.

Question 10

Bacterial plasmids and artificial chromosomes are used as ______ to insert foreign DNA into host cells and create recombinant genomes.
A)clones
B)vectors
C)endonucleases
D)subunits

Accepted Answer

Bacterial plasmids and artificial chromosomes are commonly used as vectors to transport foreign DNA into a host cell. Vectors are small DNA molecules that are used as a delivery vehicle to transfer a desired DNA fragment, such as a gene of interest or a whole genome sequence, into a recipient cell. Endonucleases are enzymes that cleave DNA molecules at specific sites, and subunits are parts of macromolecules such as proteins. Clones can refer to a group of genetically identical organisms or cells, but it is not a term specifically related to genetic engineering or recombinant DNA technology. Therefore, the best choice is B for vectors.

Question 11

An enzyme that has been isolated from retroviruses and is used to generate cDNA is
A)transverse ligase.
B)reverse transcriptase.
C)reverse endonuclease.
D)recombinant RNase.

Accepted Answer

Reverse transcriptase is an enzyme that is used to generate cDNA from RNA. It is found in retroviruses and is used by the virus to convert its RNA genome into DNA.

Question 12

Identify a sequence that is most likely to be recognized by a restriction enzyme.
A)CGATGC
B)CCCTTT
C)TGGCCA
D)TCATCA

Accepted Answer

The sequence TGGCCA contains the recognition site for the restriction enzyme EcoRI, which recognizes the sequence 5'-GAATTC-3'. Therefore, TGGCCA is the sequence most likely to be recognized by a restriction enzyme.

Question 13

Single-stranded complementary tails that are produced by restriction digestion are called ______ ends.
A)sticky
B)orphaned
C)vectors
D)5'

Accepted Answer

Single-stranded complementary tails that are produced by restriction digestion are called sticky ends.

Question 14

The most common way to follow bacterial transformation with a plasmid is by
A)manufacturing the bacterial protein.
B)conferring antibiotic resistance.
C)separating the altered cell surface.
D)making the cells immortal.

Accepted Answer

Bacterial transformation with a plasmid is often followed by conferring antibiotic resistance, as the plasmid typically contains a gene for resistance to a specific antibiotic, allowing only transformed bacteria to grow in the presence of that antibiotic.

Question 15

Gel ________ is a process that separates DNA or protein fragments according to their size, by causing them to migrate within a gel in response to an electric field.
A)duplication
B)blotting
C)electrophoresis
D)migration

Accepted Answer

Gel electrophoresis is the process that separates DNA or protein fragments according to their size, by causing them to migrate within a gel in response to an electric field. Choice A (duplication) and D (migration) do not accurately describe the process of gel electrophoresis. Choice B (blotting) is a separate process that involves transferring DNA, RNA, or protein from a gel onto a membrane for further analysis.

Question 16

Restriction enzymes are
A)proteases.
B)lipases.
C)endonucleases.
D)exonucleases.

Accepted Answer

Restriction enzymes are a type of endonuclease that cut DNA at specific recognition sequences. They play a critical role in genetic engineering and DNA technology by enabling the manipulation of DNA sequences. Proteases and lipases are enzymes that work on proteins and lipids, respectively, while exonucleases work on the ends of DNA molecules.

Question 17

All of the following involve molecular biology techniques except
A)ligating DNA fragments together.
B)using restriction enzymes to cut specific sequences of DNA.
C)using a DNA polymerase to copy DNA via PCR.
D)creation of Okazaki fragments.

Accepted Answer

Creation of Okazaki fragments is a process that occurs during DNA replication and does not involve molecular biology techniques such as those listed in choices A-C.

Question 18

A key difference between transforming plant cells and human cells is
A)genes to be expressed in human cells require a eukaryotic promoter, and genes to be expressed in plants don't.
B)DNA cannot be introduced into human cells.
C)Agrobacterium is commonly used as a tool to directly transform plant cells but not human cells.
D)a vector is needed to introduce DNA into human cells and not plant cells.

Accepted Answer

Agrobacterium tumefaciens, a bacterium, is widely used to introduce foreign DNA into plant cells, a method not applicable to human cells due to differences in cell biology and infection mechanisms.

Question 19

Enzymes that cleave DNA at specific sites are called _____________.
A)vectors
B)peptidases
C)restriction endonucleases
D)DNAses

Accepted Answer

Enzymes that cleave DNA at specific sites are called restriction endonucleases. Vectors are DNA molecules used to transfer foreign genetic material into another cell. Peptidases are enzymes that break down proteins into peptides. DNAses are enzymes that hydrolyze DNA.

Question 20

You want to insert your favorite gene, which has been digested with Ncol endonuclease on both ends, into a vector.Ncol recognizes the DNA sequence C*CATGG.The vector you want to use contains many endonuclease recognition sites, but does not include an Ncol site.Which restriction endonuclease would be the most suitable replacement to digest the vector?
A)Sphl - G*CATGC
B)Sunl - C*GTACG
C)Kpnl - GGTAC*C
D)CViAll - C*ATG

Accepted Answer

Sphl has a DNA sequence recognition of GCATGC, which does not contain the Ncol cut site. Therefore, it can be used to digest the vector without affecting the Ncol digested gene insert.

Quiz 17: Biotechnology

Two strands of DNA that have been cut by an endonuclease can be sealed together by a(n)

The PCR technique requires a DNA polymerase from an organism that can endure high heat, such as Thermus aquaticus.What step of the protocol makes the heat-stability most necessary?

Crop plants have been protected from certain insects by the addition of a gene for a specific insect toxin from the bacterium

Small circular, extrachromosomal DNA segments are known as _______.

The most recent techniques developed in the biological sciences allow the manipulation of DNA with the ultimate goal of intervening directly with the _______ fate of organisms.

A commercially significant human protein now produced in bacteria is

You have discovered a very small amount of DNA from an ancient organism that you want to save and study.What is the very first thing you should do to allow you to study this DNA in the lab?

The _________ from Agrobacterium tumefaciens is used in genetic engineering involving crop plant genes.

Single-stranded ends generated by the same restriction enzyme are complementary to each other.They can be joined together,

Bacterial plasmids and artificial chromosomes are used as ______ to insert foreign DNA into host cells and create recombinant genomes.

An enzyme that has been isolated from retroviruses and is used to generate cDNA is

Identify a sequence that is most likely to be recognized by a restriction enzyme.

Single-stranded complementary tails that are produced by restriction digestion are called ______ ends.

The most common way to follow bacterial transformation with a plasmid is by

Gel ________ is a process that separates DNA or protein fragments according to their size, by causing them to migrate within a gel in response to an electric field.

Restriction enzymes are

All of the following involve molecular biology techniques except

A key difference between transforming plant cells and human cells is

Enzymes that cleave DNA at specific sites are called _____________.