Day 7 September 18th Chapter 5

Dr. Amy B HollingsworthThe University of Akron

Fall 2014

Controlling Gene Expression

Transcription factors• Proteins that bind to specific regulatory

sites on the DNA

“Positive control”

“Negative control”

Three types of mutations – spontaneous, radiation-induced, or chemically-induced

Why is it dangerous to be near the core of a nuclear power plant?

Radiation-induced mutations

Mutations are alterations in a single base or changes in large segments of DNA that include several genes or more.

They are rare, but when they do occur, they may disrupt normal functioning of the body (although many mutations are neutral).

Extremely rarely, mutations may have a beneficial effect.

They play an important role in evolution.

5.10 Faulty genes, coding for faulty enzymes, can lead to sickness.

How can people respond so differently to alcohol?

A single difference in a single pair of bases in their DNA.

From mutation to illness in just four steps:

1. A mutated gene codes for a non-functioning protein, usually an enzyme.

2. The non-functioning enzyme can’t catalyze the reaction as it normally would, bringing it to a halt.

From mutation to illness in just four steps:

3. The molecule with which the enzyme would have reacted accumulates, like a blocked assembly line.

4. The accumulating chemical causes sickness and/or death.

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5.11–5.13

Biotechnology is

producing

improvements in

agriculture.

Genetic Engineering

Adding, deleting, or transplanting genes from one organism to another, to alter the organisms in useful ways

5.11 What is biotechnology?

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Take-home message 5.11

The methods rely on naturally occurring restriction enzymes for cutting DNA, the polymerase chain reaction for amplifying small amounts of DNA, inserting the DNA into bacterial or viral vectors, and cloning and identifying the cells with the transferred DNA of interest.

5.12 Biotechnology can improve food nutrition and make farming more efficient and eco-friendly.

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How might a genetically modified plant help 500 million malnourished people?

Nutrient-rich “golden rice”

Almost everyone in the United States consumes genetically modified foods regularly without knowing it.

What foods are responsible for this?

Insect Resistance

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How can genetically modified plants lead to reduced pesticide use by farmers?

Herbicide Resistance

Faster Growth and Bigger Bodies

5.13 Fears and risks: Are genetically modified foods safe?

Fear #1: Organisms that we want to kill may become invincible.

Fear #2: Organisms that we don’t want to kill may be killed inadvertently.

Fear #3: Genetically modified crops are not tested or regulated adequately.

Fear #4: Eating genetically modified foods is dangerous.

Fear #5: Loss of genetic diversity among crop plants is risky.

Fear #6: Hidden costs may reduce the financial advantages of genetically modified crops.

5.14–5.17

Biotechnology

has the potential

for improving human

health (and criminal

justice)

5.14 The treatment of diseases and production of medicines are improved with biotechnology

Prevent diseases

Cure diseases

Treating diseases

• The treatment of diabetes

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Why do some bacteria produce human insulin?

Recombinant DNA technology

Several important achievements followed the development of insulin-producing bacteria, including:

1. Human growth hormone (HGH)

2. Erythropoietin

What is “blood doping”?

How does it improve some athletes’ performance?

5.15 Gene Therapy: biotechnology can help diagnose and prevent diseases

But it has had a limited success in curing them

1. Is a given set of parents likely to produce a baby with a genetic disease?

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2. Will a baby be born with a genetic disease?

cystic fibrosis

sickle-cell anemia

Down syndrome

others

3. Is an individual likely to develop a genetic disease later in life?

breast cancer

prostate cancer

skin cancer

Ethical Dilemmas

Discrimination

Health insurance

How to proceed with the information?

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Why has gene therapy had such a poor record of success in curing diseases?

Gene Therapy Difficulties1. Difficulty getting the working gene

into the specific cells where it is needed.

2. Difficulty getting the working gene into enough cells and at the right rate to have a physiological effect.

Gene Therapy Difficulties

3. Difficulty arising from the transfer organism getting into unintended cells.

4. Difficulty regulating gene expression.

5.16 Cloning—ranging from genes to organs to individuals—offers both promise and perils

Are there any medical justifications for cloning?

5.17 DNA as an individual identifier: the uses and abuses of DNA fingerprinting

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What is a DNA fingerprint?