Recombinant DNA and Genetic Engineering

Question 1

Genetic engineering-

Answer 1

modifying the DNA of an organism to new genes w new traits

Question 2

Biotechnology-

Answer 2

use of organisms to benefit humanity

Question 3

Recombinant DNA technology-

Answer 3

researchers splice together DNA

from different organisms

Question 4

steps and info recombinant DNA tech

Answer 4

Scientists introduce foreign DNA into the cells of microorganisms; When cell divides, the foreign DNA is replicated and transmitted to daughter cells; DNA sequence is therefore cloned to provide millions of identical copies
geneticists cut both foreign DNA and plasmid DNA with the same restriction enzyme. The two types of
DNA are mixed together and combined

Question 5

Restriction enzymes

Answer 5

are used to cut DNA molecules only in specific places; Each enzyme recognizes and cuts the DNA at different site; Many cut at palindromic sequences; Cuts both strands, but in a staggered fashion- produces
sticky ends; If sticky ends of two molecules are put together, they are sealed by DNA ligase

Question 6

origin of restriction enzymes

Answer 6

Derived from bacteria cells, which use these enzymes as defense against viral DNA

Question 7

palindromic sequences-

Answer 7

base sequence of one strand reads the same as its complements when both are read in the 5’ to 3’ direction

Question 8

sticky ends-

Answer 8

tails which can base pair with a complementary

tail of any other DNA fragment or molecule cut by the same restriction enzyme

Question 9

Plasmid-

Answer 9

very small circle of extra DNA found in bacterial cells that has a few genes and is replicated along w the other bacterial DNA.

Question 10

Transformation

Answer 10

DNA (plasmids) from one cell can be taken up by other bacterial cells; Useful to bacteria because it can offer resistance to antibiotics

Question 11

vector

Answer 11

carrier capable of transporting a DNA fragment into a cell. plasmids, viruses, etc.

Question 12

vector capabilities

Answer 12

Vector can only carry a certain size of DNA fragment

smaller than 10 kb E. coli, up to 23 kb bacteriophage

Question 13

recombinant tech diagram

Answer 13

vector page

Question 14

Genomic library-

Answer 14

collection of thousands of DNA fragments that

represent all the DNA in a genome

Question 15

Genomic library- process

Answer 15

Each fragment from genomic library is inserted into a plasmid, which also
contains the gene for
antibiotic resistance
• Plasmid is then inserted into
bacterial cell
• Cells are incubated on a medium containing antibiotics, so those bacteria that do not contain the plasmid will die, while those that incorporated the plasmid will grow

• Entire genome is therefore stored in collection of
recombinant bacterial cells

Question 16

Genomic library- diagram

Answer 16

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Question 17

Chromosome library-

Answer 17

containing all DNA fragments of a specific chromosome

Question 18

cDNA library-

Answer 18

contains DNA derived

from mRNA after processing- does not contain introns

Question 19

cDNA

Answer 19

complementary DNA

Question 20

cDNA diagram

Answer 20

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Question 21

genetic probe

Answer 21

To find a gene of interest in a library, a genetic probe is used- radioactively labeled segment of single-stranded DNA that can hybridize, or base-pair, to complementary sequences in the target gene

Question 22

genetic probe diagram

Answer 22

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Question 23

Polymerase Chain Reaction (PCR) purpose

Answer 23

Can amplify a tiny sample of DNA millions of times in a few

hours (discovered in 1985)

Question 24

Polymerase Chain Reaction (PCR) process

Answer 24

done in a thermocycler
Mix together sequence of DNA, primers, nucleotide bases, and a special polymerase called Taq polymerase which does not denature in heat
• Heat and cool mixture over and over, allowing the DNA strands to separate and copy
- DNA doubles with every cycle, so after only 20 cycles, over 1m copies are made

Question 25

PCR diagram

Answer 25

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Question 26

gel electrophoresis

Answer 26

method that separates different molecules using

a charged field

Question 27

gel electrophoresis diagram

Answer 27

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Question 28

gel electrophoresis process

Answer 28

DNA or RNA is loaded into a gel
o An electric current is applied, making one end
positive and one end negative (- by the wells)
o DNA and RNA have a slight negative charged due to
negatively charged phosphate groups- therefore they
migrate toward the positive pull
o Different fragments travel at different speeds:
Shorter fragments travel faster thru the gel
Larger fragments travel slower thru the gel
o If DNA of a known size is added, scientists can compare these to the fragments to figure out the molecular weight

Question 29

DNA fingerprint-

Answer 29

a unique combination of DNA sequences that are inherited from parents.

Question 30

tandem repeats-

Answer 30

some parts of DNA fingerprints
many copies of the same short base sequences, one after another ex–four repeats of TTTC in one person as compared to 15 repeats in another person.

Question 31

Restriction Fragment Length

Polymorphisms (RFLPs)

Answer 31

tandem repeats–Restriction enzymes that cut the DNA will produce different size fragments based on the number of repeats; these different size fragments will be visible in a gel electrophoresis. The banding pattern of DNA fragments (5 – 10 RFLP regions are
used) is the DNA fingerprint. Can determine
paternity; Suspects from crime scene can be proven innocent.

Question 32

Designer Plants:

Answer 32

application of DNA tech. Can hybridize plants with other varieties of plants in order to transfer desired genes.Use a plasmid to infect plants from the bacteria called
Agrobacterium tumefaciens- causes tumor (mass of cells) of recombinant DNA. New plants can then be regenerated from individual cells. Plasmid is therefore called Ti plasmid

ex–insert a built-in insecticide gene into cotton plants so farmers don’t have to use so many insecticides,

Question 33

designer plants diagram

Answer 33

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Question 34

DNA fingerprint diagram

Answer 34

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Question 35

Gene therapy-

Answer 35

In individuals with single gene disorder, a new functional gene can be inserted into the cells Must be cells that actively divide in the body so new
gene will be replicated. Must be disease that can be cured by production of the normal protein. New gene can be inserted into cells using a harmless virus as a vector

Question 36

Transgenic animals-

Answer 36

animals in which foreign genes have been introduced. Transgenic animals can often be engineered to produce foreign proteins of therapeutic or commercial importance. Often done in mice to study certain genes- ex- injected mouse embryo cells with gene for rat growth hormone.

Question 37

Transgenic animals- creation

Answer 37

Produced by injecting DNA of a particular gene into the nucleus of a fertilized egg cell or nucleus of embryonic stem cells, Then the egg (or stem cells) is placed into the uterus of a female
and allowed to develop.

Question 38

Transgenic animals can often be engineered to produce foreign proteins of therapeutic or commercial importance–give example

Answer 38

Ex- foreign gene can be inserted into gene that codes for milk proteins. So foreign gene is activated only in
mammary tissues involved in milk production- whenever
the animal (cow, goat, sheep) is milked, that protein is
produced

Question 39

Human Genome Project

Answer 39

Using all these techniques, scientists have been able to sequence all 3
billion bases of the human genome
- Completed in 2003
- Estimated that there are about 20,000 genes, yet there are almost as many pseudogenes- inactivated, nonfunctional copies of genes- as there are genes
- Discovered that protein-coding genes make up less than 2 percent of
our genome. Millions of transposable elements repeated over and
over make up more than half of it.

Question 40

Production of pharmaceutical products:

Answer 40

Insulin used to be derived from animals, but many diabetics were allergic to insulin from animal source. Using recombinant DNA, the gene for insulin can be spliced into E. coli–> e coli produces human insulin. Similarly, human growth hormone (only used to be available from cadavers) can also be manufactured in bacteria.