Question 1

The DNA sequence recognized by restriction endonucleases is generally ____ base pairs long.

Accepted Answer

Restriction endonucleases typically recognize specific DNA sequences that are 4-8 base pairs in length. This allows them to cut DNA at or near these specific sequences.

Question 2

In which situation would gene cloning occur?

Accepted Answer

Gene cloning occurs when a DNA fragment is inserted into a plasmid, which is then introduced into a bacterium where the plasmid replicates, allowing for the amplification of the DNA fragment.

Question 3

When cloning DNA into bacteria, the ____.

Accepted Answer

DNA cloning typically involves inserting the DNA sequence into a plasmid, which is then introduced into bacteria for replication and expression.

Question 4

The characterization of whole genomes, including their structures (sequences), functions, and evolution is called ____.

Accepted Answer

Genomics is the study of the entirety of an organism's genes, including their structure, function, and evolution.

Question 5

Plasmids are ____.

Accepted Answer

Plasmids are circular DNA molecules that replicate independently of the chromosomal DNA in bacteria and some other organisms, often carrying genes that can provide advantageous traits such as antibiotic resistance.

Question 6

Bioinformatics combines the fields of ____ to extract information from biological data.

Accepted Answer

Bioinformatics is an interdisciplinary field that combines mathematics and computer science to analyze and interpret biological data.

Question 7

Genetically altered organisms are ____.

Accepted Answer

Genetically altered organisms are created through natural mutations or by using DNA technologies.

Question 8

DNA is cut by ____.

Accepted Answer

Nucleases are enzymes that cut DNA molecules by cleaving the phosphodiester bonds between the nucleotides. Proteases cut proteins, stem cells are undifferentiated cells, Ti plasmids are used in genetic engineering for plants, and restriction fragment length polymorphisms (RFLPs) are a technique used in DNA analysis, not an entity that cuts DNA.

Question 9

Copies of recombinant DNA are produced in a genetically engineered organism by ____.

Accepted Answer

DNA polymerase is the enzyme responsible for synthesizing new DNA strands, thus producing copies of recombinant DNA in a genetically engineered organism.

Question 10

A researcher wants to insert a DNA fragment into a plasmid. Which enzyme will join the two DNA molecules together?

Accepted Answer

DNA ligase is the enzyme responsible for joining two DNA molecules together by forming phosphodiester bonds, making it essential for DNA insertion into plasmids in molecular cloning.

Question 11

What is the natural function of restriction endonucleases?

Accepted Answer

Restriction endonucleases naturally function as a defense mechanism in bacteria, protecting them against viral infections by cutting the DNA of invading viruses.

Question 12

If a restriction endonuclease cuts a linear DNA three times, how many fragments should there be after the DNA is subjected to electrophoresis through an agarose gel?

Accepted Answer

When a restriction endonuclease cuts a linear DNA molecule three times, it produces four distinct fragments. Each cut divides the DNA into two pieces, so three cuts result in four fragments.

Question 13

Some restriction endonucleases cut DNA in such a way that short, single-stranded regions known as ____ ends are created.

Accepted Answer

Sticky ends are created by some restriction endonucleases when they cut DNA at specific recognition sites, leaving overhanging single-stranded DNA regions that can form hydrogen bonds with complementary sequences.

Question 14

Most genetic alterations performed by researchers aim to change the ____.

Accepted Answer

Most genetic alterations are intended to change the genotype of an organism, which typically results in a change in phenotype, as the genotype directly influences the physical characteristics and behaviors of an organism.

Question 15

When the sequence of nucleotides read in the 5'→ 3' direction on one strand is same as the sequence read in the 5'→ 3' direction on the complementary strand, the sequence is called a(n) ____.

Accepted Answer

A palindrome in DNA is a sequence of base pairs that reads the same backward and forward on complementary strands. This characteristic is due to the antiparallel nature of DNA, where the 5' to 3' sequence of one strand matches the 5' to 3' sequence of its complement when read in reverse.

Question 16

Recombinant DNA is ____.

Accepted Answer

Recombinant DNA refers to DNA molecules that are formed by laboratory methods of genetic recombination to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in the genome.

Question 17

Restriction endonucleases break ____ bonds.

Accepted Answer

Restriction endonucleases cleave the phosphodiester bonds between nucleotides in DNA strands.

Question 18

An organism whose genome has been modified to change a genetic trait or traits by using traditional breeding techniques, classical genetic approaches, or modern molecular manipulation techniques is called a ____.

Accepted Answer

Genetically altered organism (GAO) is the correct term for an organism whose genome has been modified to change a genetic trait or traits, which can be achieved through various techniques including traditional breeding, classical genetics, or modern molecular manipulation.

Question 19

Bacteria protect restriction sites in their own DNA from being cut by restriction enzymes by ____.

Accepted Answer

Bacteria protect their own DNA from restriction enzymes by methylating or otherwise chemically modifying the bases within their restriction sites, which prevents the enzymes from recognizing and cutting these sites.

Question 20

If a restriction endonuclease cuts a circular DNA three times, how many fragments should there be after the DNA is subjected to electrophoresis through an agarose gel?

Accepted Answer

When a circular DNA is cut three times by a restriction endonuclease, it will produce three fragments. These fragments can be separated by electrophoresis through an agarose gel, and will appear as three distinct bands on the gel.

Quiz 18: Dna Technology: Making and Using Genetically Altered Organisms, and Other Applications