Genes

Engage! Why should we study DNA?

Quick Review… The Nucleus Contains master set of instructions that determine what each cell will become Instructions carried on CHROMOSOMES Each species has a specific number of chromosomes in the nucleus of the cell

The DNA Code Chromosomes made of deoxyribonucleic acid (DNA) Chromosomes DNA Genes Genes: segments of DNA – Provide instructions for making proteins

Protein Production Proteins are responsible for… – Build body parts – Act like couriers (carrying messages) – enzymes

Altering Genes

Four DNA building-blocks produce the code for proteins in all types of organisms – Adenine, thymine, cytosine, and guanine Genetic Engineering: combining DNA from different species

What is the Potential for Transgenic Organisms? On your own, think about different ways that transgenic organisms could be useful (quietly to yourself) Write down your best answer on a piece of paper (initial your answer) and make it into a ball When told to, toss you it to another person When you get a new sheet, read the answer and write a different answer on it (initial it as well)

Uses of Transgenic Organisms Medicine – treatment of diabetes Crops – resistant to pests or drought Animal growth – more food Organs – human organs grown in pigs

Questions… 1.Why is the genetic code describe as being universal? 2.In what ways are organs from certain kinds of transgenic organisms potentially significant to human health? 3.Think about what you have eaten in the last two days. Do you think any of it was genetically modified? If so, what?

Testing for Disease Think back to the movie we watched during class (the NOVA movie) What is DNA screening?

Ethical Issues in Biology There is a shortage of tissues and organs needed for transplantation all over the world Some countries encourage people to sell their organs (India) – Accounts for roughly 6000 transplants a year Shortage is so great, some people have organs removed without consent How can we address this situation?

Advancing Cell Biology Technology Gene Therapy – Involves inserting healthy genes to help organs function normally – A virus is used to carry the gene – Virus injected into patient

Advancing Cell Biology Technology Cloning – Creates genetically identical organisms – Possible in plants and animals Where do you stand – should we clone organisms? – Form a line from strongly agree to strongly disagree

Mutations Results from a change in the DNA code For example, Sickle Cell Anemia is a result from a mutation in the gene code for hemoglobin Can occur randomly or can be caused by mutagens (e.g. X rays, UV rays) Not all mutations are harmful (may help organisms adapt to environment)

Homework Pg. 120 # 2, 3, 11, 12, 13, 15