Genetic Mutations & Genetic Engineering

polarbearfellowshipΒιοτεχνολογία

12 Δεκ 2012 (πριν από 4 χρόνια και 11 μήνες)

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Genetic Mutations &
Genetic Engineering

Ch. 12
-
4 (pgs. 307
-
308)

Ch. 13
-
2 thru 13
-
4 (pgs.
322
-
333)

12
-
4 Mutations


Mutations
= Changes in genetic material


2 Types of mutations :


Chromosomal and Gene



Gene Mutations
=
Changes to the
codons & genetic message


Point Mutations
: Caused by changes in one or
a few nucleotides


EX: substitutions, insertions or deletions


12
-
4 Mutations


Gene Mutations Cont…


Frameshift Mutations
: Occur from
insertions

or
deletions
because they shift the “reading frame” of
the genetic message.


They never occur from substitutions



Chromosomal Mutations
:
Involve changes in
the # or structure of chromosomes:


EX: Inversions, duplications, deletions & translocations


Some neither help nor harm, some are beneficial for
genetic variation, some cause disorders and cancer

13
-
2 Manipulating DNA

Scientists have discovered how to use
their knowledge of DNA to study &
change DNA molecules


EX: Extract DNA from cells, cut DNA into smaller
pieces, identify sequence of bases in DNA, make
unlimited copies of DNA

13
-
2 Manipulating DNA


Genetic Engineering
: Making changes
in the DNA code of a living organism.
Occurs by:


DNA Extraction
: The cells are opened &
DNA is separated from other cell parts


Cutting DNA
:

Uses restrictions enzymes to
cut specific sequences of nucleotides creating
“sticky ends” that will match up with
complimentary bases

13
-
2 Manipulation DNA

Restriction enzyme cutting DNA between
Guanine & Adenine

13
-
2 Manipulation DNA


Separating DNA
= Commonly done by
gel electrophoresis. Electric volts applied
to DNA cause negative DNA fragments
to move to positive ends of the gel

EX: 2 DNA samples showing identical bands of the

same size and thickness show: same amount

of DNA, fragments of the same size, the

same DNA molecules


Locates specific genes, compares genetic
composition like paternity tests

13
-
2 Manipulation DNA


Knowing the sequence of an Organisms
DNA allows scientists to study specific
genes


Reading DNA Sequences
= Enzymes trigger
DNA replication by adding nitrogenous bases
(A,T,G,C) to an unknown single
-
stranded DNA
template


Uses fluorescent dyes

to label the different
nitrogenous bases & stop replication


Uses nucleotide bases

to trigger & stop replication


Uses gel electrophoresis

to show DNA bands

13
-
2 Manipulating DNA


Making Copies:
Uses PCR (polymerase
chain reaction).


Triggers DNA replication by using
complimentary “primers” added to single
-
stranded DNA molecule that scientist wants to
copy


DNA polymerase makes copies of the area
between the two primers

13
-
3 Cell Transformation

Transformation
: A cell takes in DNA from outside the cell

Plasmid:

Foreign DNA formed into a small circular DNA
molecule. Used to incorporate foreign DNA into bacteria
that will replicate allow it to be replicated

Genetic Marker:

Gene that makes it possible to distinguish
bacteria that carry plasmids from those that don’t.


EX: Gene for antibiotic resistance is used to select for
bacteria that carry plasmids when that antibiotic is added

13
-
3 Cell Transformation


Transforming Plant Cells Can Occur 3
Ways:


Use bacteria that are able to insert plasmids
into the plant


Remove plant cell walls so plasmid DNA is
taken in by the nucleus


Insert DNA directly into the cell

Cell Transformation


Transforming Animal Cells Can Occur
By:


DNA injected directly into the nucleus


Enzymes help injected DNA become
incorporated in the cell’s chromosomes


Foreign DNA contains genetic markers that to
determine which genes have been
transformed

13
-
4 Applications of Genetic
Engineering


Transgenic Organism
: Organism that
contains genes from other species


Scientists use
Genetic Engineering
to make
transgenic organisms

13
-
4 Applications of Genetic
Engineering


Transgenic Microorganisms
: bacteria
transformed w/ human genes produce
pharmaceutical compounds like insulin


Transgenic Animals:

Have been used to
study how human genes function


EX: Mice are created with human
-
like immune
systems


Transgenic Plants:

Have been important to
increasing the food supply.


EX : Plants have genes that code for natural
insecticides



13
-
4 Applications of Genetic
Engineering

Clone: Member of a population of
genetically identical cells produced from
a single cell.



EX: a bacterium taken from a

bacterial colony


First Mammal cloned was Dolly
-

a sheep
cloned in Scotland in 1997