Chapter 13

Genetic Engineering

I. Selective Breeding

A. Only those organisms with desired characteristics to produce the next generation

C. Example: domesticated animals, farm animals, plants

II. Hybridization

A. Cross dissimilar individuals to bring together the best of both organisms.

B. Hybrids usually hardier than parents

B. Humans use selective breeding to pass desired traits on to the next generation of organisms

13-1

III. Inbreeding

A. Continued breeding of individuals with similar characteristics

C. Serious genetic problems can result from excessive inbreeding

B. Maintain desired characteristics of an organism

D. Ex: Pure breeds for dogs

1. Greater risk of two recessive alleles = genetic disorder

1. Blindness, joint deformities

IV. Increasing Variation

A. Sometimes breeders want more variation

1. Induce mutations with radiation or chemicals

B. New kinds of Bacteria

1. Hundreds of useful bacteria strands have been developed

Ex. Clean up oil spills

2. Used because small and reproduce quickly

C. New kinds of Plants

1. Prevent chromosomal separation = polyploidy

13-2 Manipulating DNA

I. Genetic Engineering: Make changes in DNA code of living organism

A. Different techniques1. DNA Extraction: Chemical procedure takes out DNA

2. Cutting DNA: Restriction enzymes cut DNA into smaller pieces at a specific nucleotide sequence

Recognition sequences

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3. Separating DNA: Gel electrophoresis can locate and identify 1 gene out of millions

Gel Electrophoresis

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II. Using DNA Sequence

A. Allows researchers to study specific genes &/or compare

B. Techniques used to read and change DNA sequence

1. Reading sequence through gel

2. Cutting and Pasting: Splicing DNA with fragments of synthetic DNA = recombinant DNA

3. Making Copies: Polymerase chain reaction (PCR)

13-3 Cell Transformation

I. Transformation = Cell takes DNA from outside and combines it with own DNA

A. Bacteria

1. Foreign DNA is joined to plasmid (circular DNA)

3. DNA is inserted into bacterial cell

4. When bacteria reproduces = reproduces the foreign DNA

2. Plasmid has genetic marker = gene to distinguish bacteria

Transforming Bacteria

Recombinant DNA

Gene for human insulin

Gene for human insulin

Human Cell

Bacterial cell

Bacterial chromosome

Plasmid

DNA recombination

Bacteria cell containing gene for human growth hormone

DNA insertion

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B. Plants

1. Tumor-producing bacterium inserts DNA plasmid

2. Gen Engineers inactivate tumor-causing gene- insert desired DNA in bacterium; bacterium naturally “infects” plant cell; plant cell will take up with new desired DNA

C. Animals

1. DNA directly inserted into nucleus of an egg cell

2. Replace gene with recombinant DNA

13-4 Applications of Genetic EngineeringI. Transgenic Organisms

A. Contains genes from other organisms

B. Biotechnology-vectors- transport desired foreign DNA; plasmids, viruses, micropipettes, or “bullets”

C. Help produce important substances

1. Bacteria - used to produce insulin, human growth hormone, clotting factor because small, reproduce quickly, & easy to grow

2. Animals – study genes, improve food supply

a. Livestock with extra growth hormone = grow faster, less fatty

3. Plants – may contain genes for: pest-resistance, drought-resistance, freeze-resistance

II. Cloning

A. Member of population of genetically identical cells from a single cell

B. 1997 – Ian Wilmut cloned a sheep

C. Process:

1. Egg cell nucleus removed

2. Fused with donor nucleus (original) by electric shock

3. Fused cell divides

4. Placed in surrogate

5. Develops & born (identical to donor nucleus)

D. cloned animals may suffer from genetic defects and health problems.

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Cloning Dolly

13-1

The usual function of selective breeding is to produce organisms that

A. are better suited to their natural environment.

B. have characteristics useful to humans.

C. can compete with other members of the species that are not selected.

D. are genetically identical.

13-1

Crossing a plant that has good disease-resistance with a plant that has a good food-producing capacity is an example of

A. inbreeding.

B. hybridization.

C. polyploidy.

D. crossing over.

13-1

New species of plants that are larger and stronger are a result of

A. monoploidy.

B. diploidy.

C. polyploidy.

D. haploidy.

13-1

The function of inbreeding is to produce organisms that

A. are more genetically diverse.

B. are much healthier.

C. are genetically similar.

D. will not have mutations.

13-1

Increasing variation by inducing mutations is particularly useful with

A. animals.

B. bacteria.

C. plants.

D. fungi.

13-2

Restriction enzymes are used to

A. extract DNA.

B. cut DNA.

C. separate DNA.

D. replicate DNA.

13-2

During gel electrophoresis, the smaller the DNA fragment is, the

A. more slowly it moves.

B. heavier it is.

C. more quickly it moves.

D. darker it stains.

13-2

The DNA polymerase enzyme Kary Mullis found in bacteria living in the hot springs of Yellowstone National Park illustrates

A. genetic engineering.

B. the importance of biodiversity to biotechnology

C. the polymerase chain reaction.

D. selective breeding.

13-2

A particular restriction enzyme is used to

a. cut up DNA in random locations.

B. cut DNA at a specific nucleotide sequence

C. extract DNA from cells.

D. separate negatively charged DNA molecules.

13-2

During gel electrophoresis, DNA fragments become separated because

A. multiple copies of DNA are made.

B. recombinant DNA is formed.

C. DNA molecules are negatively charged.

D. smaller DNA molecules move faster than larger fragments.

13-3

Plasmids can be used to transform

A. bacteria only.

B. plant cells only.

C. plant, animal, and bacterial cells.

D. animal cells only.

13-3

One reason plasmids are useful in cell transformation is that they

A. are found in all types of cells.

B. prevent gene replication.

C. counteract the presence of foreign DNA.

D. have genetic markers indicating their presence.

13–4

Insulin-dependent diabetes can now be treated with insulin produced through the use of

A. transgenic plants.

B. transgenic animals.

C. transgenic microorganisms.

D. transgenic fungi.

13–4

Transgenic tobacco plants that glow in the dark were produced by transferring the gene for luciferase from a

A. clone.

B. bacterium.

C. lightning bug.

D. jellyfish.

13–4

The first mammal to be cloned was a

A. sheep.

B. horse.

C. dog.

D. cat.

13–4In producing a cloned animal, an egg cell is taken from

a female and its nucleus is removed. A body cell is taken from a male. The clone from this experiment will

A. look just like the female.

B. be genetically identical to the male.

C. have a mixture of characteristics from both animals.

D. resemble neither the male nor the female.

13–4

Animals produced by cloning have been shown to

A. all be perfectly healthy.

B. suffer from a number of health problems.

C. live longer than uncloned animals.

D. be less intelligent than uncloned animals.