Biology Study Guide: Genetic Engineering Techniques (13-1,2)

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Dec 11, 2012 (4 years and 12 days ago)

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Biology Study Guide: Genetic Engineering Techniques

(13.
1,2)


1.

What is
selective breeding
? [1]




2.

Explain

how selective breeding has been used to create dairy cows that produce twice as much milk per year as the
ir

ancestors

that lived less than 100 years ag
o. [3]







3.

Restriction enzymes

are naturally occurring bacterial enzymes that cut DNA. Hundreds of different types of these
enzymes have been isolated from
various

species of bacteria. Restriction enzymes are
absolutely essential

to the work
of genetic e
ngineers because they allow scientists to cut
the sugar
-
phosphate “backbones” of DNA molecules precisely

they

way they would like. How are the many types of restriction enzymes different from one another? [1]




4.

Certain restriction enzymes (like EcoRI on p
.322) are said to produce “
sticky ends
.” What happens after a restriction
enzyme like EcoRI binds to a specific sequence of nucleotides (its “recognition sequence”) on DNA? [2]






5.

What does the technique of
gel
electrophoresis

allow molecular
biologists

and genetic engineers to do?
[1]







6.

Why do DNA molecules migrate
toward the (+) end of a gel electrophoresis chamber? [1]







7.

What
happens to DNA molecules of different sizes when they are “run” in a

gel electrophoresis

apparatus
? [1]







8.

The
Jello
-
like substance

that makes up the brick of gel in an electrophoresis chamber is composed of a dense network
of protein fibers
and water
. There are only small gaps between the fibers. Given this information, why do you think
smaller molecules of DNA migrate

farther than larger ones toward the (+) electrode in a given amount of time? [2]




9.

When trying to isolate a gene to study, scientists must first remove it from the chromosome on which it lies.
Chromosomes may contain many hundreds of genes.
Outline how

r
estriction enzymes

and
gel electrophoresis

might
be
used to try and isolate
just

the gene of int
erest from a huge chromosome? [3
]










10.

What does the
polymerase chain reaction

(PCR) give scientists the ability to do? [1]






11.

What is the role of the fol
lowing in performing
one cycle of
PCR? [
From notes
:
1 each]


(a)

Heating






(b)

Add primers, and cool






(c)

Add individual DNA nucleotides and heat
-
stable DNA polymerase enzymes (from a thermophilic bacterium)






What is a transgenic organism?



How can a gene
of interest be inserted into a bacterial plasmid?