SC430 Molecular Cell Biology

• Welcome to Unit 8 Seminar with Dr Hall-Pogar

• Tonight we will discuss – Stem Cells– I will be available at AIM:KaplanHallPogar

before and throughout the seminar if you have any questions or issues.

• We will begin promptly at 8:00pmEST

2

Unit Review

• DB

• Quiz

• No Project!

Topics

I. Stem Cells – The Basics

II. Cloning – Therapeutic and Human

III. Opinions: The Politics – State, National, International

Importance Disease

• Diabetes, Spinal cord injury, Parkinson’s disease, heart disease

Genetic based Disease• Cystic fibrosis,

Huntington’s

I. Stem Cells• Genetic engineers are trying to harness

the healing powers of human stem cells• Stem cells are undifferentiated

– A cell that is not specialized

• They may someday be used to replace damage from accidents or due to degenerative diseases

I. Stem Cells• The use of embryonic stem cells in research

fuels a heated national debate• In 2001, President Bush

banned federal funding for reaching using embryonic stem cells

• In 2009, President Obamareversed the decision and allowed research

I. Stem Cell Characteristics• They can live essentially forever -- without forming

tumors!• Capable of dividing and renewing themselves for

long periods of time • They can take a hint.

– Their development is directed by subtle chemical cues that vary according to location and conditions in the body.

• They can divide unequally. Instead of forming two identical daughter cells -- the usual result of cell division -- one daughter cell is more specialized, while the second is a stem cell.

I. What are embryonic stem cells?

• Fertilization– Union of egg & sperm to form zygote

• Ten cell stage– Outer cell mass – placenta– Inner cell mass – embryo

I. totipotent• Fertilized cell, and its immediate descendents,

are called "totipotent" stem cells – Because they form every tissue in the body– Specialization starts almost immediately, as the

multiplying cells form a ball called a blastocyst.– Inside the blastocyst are "pluripotent" or

"embryonic" stem cells that can form just about every cell except the placenta

I. Can you harvest stem cells from adults?

• Adults have stem cells that are “committed”; they are not completely totipotent

• Example: bone marrow has blood progenitor cells (“blood stem cells”)

Answer: NO

I. Stem Cell Differentiation

I. Where do we get stem cells?

• Frozen embryos

I. What are frozen embryos?

• Infertility Procedures– Woman given hormones so as many as 20

eggs are ovulated (instead of one)– Eggs fertilized in a small plate– Embryos that appear healthy are implanted in

woman’s uterus in hopes that one survives

I. What are frozen embryos?

• What happens to the rest of the embryos?– Two options

• 1: discard• 2: freeze and save (just in case…)

– Result: 100,000s of frozen embryos

I. Stem Cell Cultivation

II. Do embryonic stem cells have anything to do with cloning?• There are two types of cloning:

– 1. Reproductive cloning• Production of a new organism

– 2. Therapeutic Cloning• Technique using stem cells that are developed

into a particular tissue or organ

iii. What are the ethical and legal issues?

Human DignityTwo competing models

1. There is something special about being human, even at the embryonic stage, which sets us apart from animals.

2. It is more important to support attempts to restore dignity to adult humans than to honor the dignity of an embryo that has not yet become an individual.