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Academic Integrity in Biology 100/101

I have read and understand Part #4 of the University of Illinois Student Code, which deals with Academic Integrity.

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Please use the "Talk to Sarah and Ed" Forum in Moodle if you wish to discuss the assignment further.

Don't overlook the links to web resources and references to text pages below that WILL be useful in answering these questions. Activities in lecture, discussion, and laboratory classes will also address these questions.

Completion of these questions will help you achieve most of the objectives for lecture #16 - Control of Gene Expression and Objectives 1-3 of lecture #18, Biotechnology: Recombinant DNA and PCR .

Question 1. Control of Gene Expression: (12 points)

Introduction:

Estrogen is a naturally occurring fat soluble, steroid hormone that is involved in the changes that occur during a woman's monthly menstrual cycle and during pregnancy. With each monthly cycle, new cells must be produced for the lining of the milk glands in the breast and the endometrium in the uterus. Estrogen acts to stimulate cell division in breast tissue by signaling the activation of genes that control cell division. Estrogen interacts with intracellular hormone receptor proteins and transcription factors to affect the expression of several genes.

The cells of certain types of breast cancer actually require estrogen to continue to live and divide. Without the stimulus of estrogen, they will die. Anti-hormone breast cancer treatments involve the use of chemotherapy drugs that act to block estrogen receptors. The older drug, Tamoxifen, is effective in blocking estrogen in breast tissue, but has been shown to actually increase the risk for uterine cancer. A newer drug, Raloxifene, appears to be effective in treating breast cancer without many of the negative side effects of Tamoxifen

Write a description or develop a diagram illustrating how the factors in the list below interact to initiate expression of a cell division gene, normally under the control of estrogen, in a breast cell. Include and BOLD or HIGHLIGHT the terms in the table below in your explanation or diagram.

Include in your drawing - or write a description explaining how and where the breast cancer drugs, Tamoxifen and Raloxifene block the action of estrogen in a breast cancer cell. (They both work the same way.)

There is a limited discussion of this topic in Lewis' text, so refer to lecture Outline #16 dealing with Control of Gene Expression.

These Links may also be helpful:

• Fat soluble hormone, like estrogen interacting with a hormone receptor protein. (Lewis, et. al. text, pg 660, fig 34.3) University.
• Examples of gene control by Steroid Hormones - Sex Hormones in Women and Men
• How estrogens and progesterone achieve their effects
• The general mode of action of steroid hormones, like estrogen (glucocorticoid hormone)
• Steroid Receptor Molecules are proteins that bind to the promoter regions of genes.
• Breast Cancer from cancerquest.org.
• Cancer treatments - see Hormonal Treatments from cancerquest.org.
• Breast Cancer - Selective Estrogen Receptor Modulators (SERMs) from cancerquest.org.
• Select "Targeted therapies" and then "Blocking receptors" from insidecancer.org.

Question 2. Biotechnology (8 Points)

Question 1. Erythropoeitin (EPO) is a human protein that is produced and secreted by specific cells of the kidney. The EPO gene is located on chromosome #7. Erythropoeitin is a hormone that is produced by cells in th ekidney when the oxygen level in the blood passing through the kidney is low. EPO is secreted into the blood stream and flows past all the cells of your body. The hormone interacts with EPO receptor proteins on the surface of red blood cell precursor cells in the bone marrow and stimulates the activation (transcription and translation) of genes that produce proteins that control the maturation of red blood cells. Increasing the number of red blood cells carrying hemoglobin in the blood increases the ability of the blood to carry oxygen from the lungs to all the cells of your body needing oxygen for aerobic respiration.

EPO is used to treat certain types of anemia caused by kidney failure, anemia secondary to AZT treatment for HIV/AIDS, and anemia associated with cancer..

A researcher wants to transfer the normal, dominant EPO allele to a bacterium in order to produce large quantities of the EPO hormone (a protein). Describe or create a simple diagram to explain how recombinant DNA techniques could be used to do this. Include and BOLD or HIGHLIGHT the terms in the table below in your explanation or diagram.

See the web resources listed at the bottom of the Discussion Objective page for this topic

See also the Recombinant DNA section of lecture outline #18.