Day 8 September 23rd 2014Chapter 5

Dr. Amy B HollingsworthThe University of Akron

What exactly is a gene?

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?

Continuity and varietyLectures by Mark Manteuffel, St. Louis Community

College

Chapter 6: Chromosomes and Cell Division

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There are different

types of cell

division.

Mitosis and Meiosis

6.1 Immortal cells can spell trouble: cell division in sickness and health.

Telomeres

The telomere is like a protective cap at the end of the DNA.

Every time a cell divides, the telomere gets a bit shorter.

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Progeria – rarely live past 13

“Cancer cells are those which have forgotten how to

die.”—Harold Pinter

6.2 Some chromosomes are circular, others are linear.

6.3 Prokaryotes divide by binary fission.

6.5 Cell division is preceded by replication.

Persistence and propagation

Replication

The process of DNA duplication

Complementarity The characteristic that in the double-stranded

DNA molecule the base on one strand always has the same pairing-partner (called the complementary base) on the other strand

Every “A” (adenine) pairs with “T” (thymine) and vice-versa.

Every “G” (guanine) pairs with “C” (cytosine) and vice-versa.

Errors sometime occur when DNA duplicates

itself.

Why might that be a good thing?

Mutation A variety of errors can occur during

replication.

Several DNA repair processes occur after replication.

If an error remains, however, the sequences in a replicated DNA molecule (including the genes) can be different from those in the parent molecule.

6.6 Most cells are not immortal: Mitosis generates replacements.

What is dust?

Why is it your fault?

Mitosis has just one purpose:

To enable cells to generate new, genetically identical cells.

There are two different reasons for this need:

1. Growth2. Replacement

Apoptosis

The pre-planned process of cell suicide

Certain cells are targeted for apoptosis.

Mitosis

The number of (somatic) cells that must be replaced by mitosis every day is huge.

The rate at which mitosis occurs varies dramatically.

6.7 OverviewMitosis leads to duplicate

cells.

Parent cells daughter cells

6.8 The Details

Mitosis is a four-step process.

Preparation for Mitosis: The

Chromosomes Replicate

Animal chromosomes are linear.

So why do they look like the letter “X” in pictures?

Sister Chromatids

A chromosome and its identical replicated copy, joined at the centromere.

6.9 Cell division out of control means cancer.

Cancer

Unrestrained cell growth and division…

…can lead to tumors…

…the second leading cause of death in the United States! (20%, leading is heart disease)

Tumor Growth

Unregulated cell division

Cancer cells have several features that distinguish them from normal cells, including…

Benign and Malignant Tumors

What is cancer?

How does it usually cause death?

Why is the treatment for cancer often considered as bad as the disease?

Cancer is unrestrained cell growth and division.

Cancer can lead to large masses of cells called malignant tumors that can cause serious health problems.

Treatment focuses on killing or slowing the division of the cells using chemotherapy and/or radiation.