DNA tools and biotechnology

Question 1

What is DNA technology?

Answer 1

DNA sequencing and other techniques for manipulating DNA

Question 2

What is nucleic acid hybridization?

Answer 2

the base pairing of one strand of a nucleic acid to a complementary sequence from another nucleic acid strand, either DNA or RNA.

Question 3

What is genetic engineering?

Answer 3

the direct manipulation of genes for practical purposes

Question 4

What is DNA sequencing?

Answer 4

exploiting the principle of complementary base pairing to determine the complete nucleotide sequence of a DNA molecule

Question 5

What is DNA cloning?

Answer 5

isolate a segment of DNA carrying that gene and make multiple identical copies of it

Question 6

What are plasmids?

Answer 6

small, circular DNA molecules that are replicated separately. A plasmid has only a small number of genes; these genes may be useful when the bacterium is in a particular environment but may not be required for survival or reproduction under most conditions.

Question 7

What is a recombinant DNA molecule?

Answer 7

a molecule containing DNA from two different sources, very often different species. The plasmid is then returned to a bacterial cell, producing a recombinant bacterium.

Question 8

What is gene cloning?

Answer 8

The production of multiple copies of a single gene is a type of DNA cloning called gene cloning.

Question 9

What is a cloning vector?

Answer 9

a DNA molecule that can carry foreign DNA into a host cell and be replicated there. Bacterial plasmids are widely used as cloning vectors

Question 10

What are restriction enzymes?

Answer 10

enzymes that protect the bacterial cell by cutting up foreign DNA from other organisms or phages. also called restriction endonucleases

Question 11

What is a restriction site?

Answer 11

where a restriction enzyme restricts a particular short DNA sequence. enzymes cuts both DNA strands at precise points within this restriction site.

Question 12

What are restriction fragments?

Answer 12

The dna fragments cut from the restriction enzyme.

NOTE: Since restriction enzymes always cut at the same exact DNA sequence, copies of any given DNA molecule exposed to the same restriction enzyme always yield the same set of restriction fragments.

Question 13

What is gel electrophoresis?

Answer 13

Proccess in which DNA is separated and visualizes the fragments.

Question 14

What is the polymerase chain reaction?

Answer 14

process in which we start with genomic DNA from the particular species of interest and obtain many copies of the desired gene by using a technique called the polymerase chain reaction, or PCR. (three major steps)

Question 15

What is a expression vector?

Answer 15

a cloning vector that contains a highly active bacterial promoter just upstream of a restriction site where the eukaryotic gene can be inserted in the correct reading frame.

Question 16

What is electroporation?

Answer 16

a brief electrical pulse applied to a solution containing cells creates temporary holes in their plasma membranes, through which DNA can enter.

Question 17

What is a nucleic acid probe?

Answer 17

a short, single-stranded nucleic acid (either RNA or DNA) complementary to the mRNA of interest; this is called a nucleic acid probe

Question 18

What is in situ hybridization?

Answer 18

ex with drosophilia: Each probe molecule is labeled during synthesis with a fluorescent tag so we can follow it. A solution containing probe molecules is applied to Drosophila embryos, allowing the probe to hybridize specifically with any complementary sequences on the many mRNAs in embryonic cells in which the gene is being transcribed.

Question 19

What is the reverse transcriptase polymerase chain reaction? (three major steps)

Answer 19

RT-PCR begins by turning sample sets of mRNAs into double-stranded DNAs with the corresponding sequences. This a process ( 3 steps)

1. the enzyme reverse transcriptase is used to synthesize a complementary DNA copy (a reverse transcript) of each mRNA in the sample.
2. The mRNA is then degraded by addition of a specific enzyme, and a second DNA strand, complementary to the first, is synthesized by DNA polymerase.
3. The resulting double-stranded DNA is called complementary DNA (cDNA)

Question 20

What is a complementary DNA (cDNA)?

Answer 20

Double stranded DNA that is the product of the RT-PCR.

Question 21

What is RNA sequencing?

Answer 21

In RNA-seq, the mRNA (or other RNA) samples are isolated, cut into shorter, similar-sized fragments, and converted into cDNAs

. These short cDNA stretches are sequenced, and a computer program reassembles them, either mapping them onto the genome of the species in question (when available) or simply putting the fragments in order from scratch based on overlapping sequences of multiple RNAs.

Question 22

What are DNA microarray assays?

Answer 22

An older method of genome-wide expression studies

A DNA microarray consists of tiny amounts of a large number of single-stranded DNA fragments representing different genes fixed to a glass slide in a tightly spaced array, or grid, of dots.

Ideally, these fragments represent all the genes of an organism.

Question 23

What is ‘in vitro mutagenesis?’

Answer 23

Process in which specific mutations are introduced into a cloned gene, and the mutated gene is returned to a cell in such a way that it disables (“knocks out”) the normal cellular copies of the same gene.

Question 24

What is gene drive?

Answer 24

engineering the new allele so that it is much more highly favored for inheritance than the wild-type allele.

Question 25

What is RNA interference? in terms of biotech

Answer 25

experimental approach uses synthetic double-stranded RNA molecules matching the sequence of a particular gene to trigger breakdown of the gene’s messenger RNA or to block its translation.

Question 26

What is the idea behind genome-wide association studies?

Answer 26

researchers look for genetic markers, DNA sequences that vary in the population. In a gene, such sequence variation is the basis of different alleles, as we have seen for sickle-cell disease

Question 27

Explain single nucleotide polymorphism?

Answer 27

A single base-pair site where variation is found in at least 1% of the population is called a single nucleotide polymorphism

Question 28

What is a Stem Cell?

Answer 28

is a relatively unspecialized cell that can both reproduce itself indefinitely and, under appropriate conditions, differentiate into specialized cells of one or more types. Stem cells have great potential for regenerating damaged tissues.

Question 29

Explain the term “totipotent” ?

Answer 29

In plants, mature cells can “dedifferentiate” and then give rise to all the specialized cell types of the organism; any cell with this potential is said to be totipotent.

Question 30

Explain a Progenitor cell?

Answer 30

Biological cell that, like a stem cell, has a tendency to differentiate into a specific type of cell, but is already more specific than a stem cell and is pushed to differentiate into its “target” cell; can divide only a limited number of times.

Question 31

Explain the term “pluripotent”?

Answer 31

capable of differentiating into many different cell types

Question 32

Explain the term biotechnology

Answer 32

the manipulation of organisms or their components to make useful products.

Question 33

Explain what personalized medicine is and the applications?

Answer 33

a type of medical care in which each person’s specific genetic profile can provide information about diseases or conditions for which the person is especially at risk and help make health-care decisions . DNA technology advancements could potentially make this a reality.

Question 34

What is the idea of Gene therapy?

Answer 34

the introduction of genes into an afflicted individual for therapeutic purposes—holds great potential for treating the relatively small number of disorders traceable to a single defective gene. The aim of this approach is to insert a normal allele of the defective gene into the somatic cells of the tissue affected by the disorder.

Question 35

What is a transgene?

Answer 35

a gene that has been transferred into one organism from another.

Question 36

What does transgenic mean?

Answer 36

organism that expresses its new, “foreign” gene. From means of a transgenes in the genome of the organism.

Question 37

Explain the term “genetic profile? “

Answer 37

(This term is preferred over “DNA fingerprint” by forensic scientists, who want to emphasize the heritable aspect of these markers rather than the fact that they produce a pattern on a gel that, like a fingerprint, is visually recognizable.) useful in forensic studies.

Question 38

What are short tandem repeats (STRs)?

Answer 38

These are tandemly repeated units of two- to five-nucleotide sequences in specific regions of the genome. The number of repeats present in these regions is highly variable from person to person (polymorphic); even for a single individual, the two alleles of an STR may differ from each other.

Question 39

What are genetically modified organisms (GMOs)?

Answer 39

A GMO is a transgenic organism that has acquired one or more genes from another species or from another variety of the same species.

EX: Some salmon have been genetically modified by addition of a more active salmon growth hormone gene