Day 8 september 23rd 2014
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Transcript of Day 8 september 23rd 2014
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
Insert figure 5-33
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
Insert figure 5-39
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?
Insert figure 5-41
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?
Insert figure 5-42
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
Insert figure 5-45c
What is a DNA fingerprint?
Continuity and varietyLectures by Mark Manteuffel, St. Louis Community
College
Chapter 6: Chromosomes and Cell Division
Insert new photo (Jackson 5)
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.
Insert new fig 6-1
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.