Biology Homework Chapter 11: Cloning and Cancer
Textbook assignment: Chapter 11: The Control of Genetic Expression, sections 12-19.
- 11.12 Plant cloning is a common way of propagating plants without worrying about the possibility of mis-breeding them. Plant cells retain all their genetic potential and in many cases, we can grow a whole plant (leaves, stems and roots) from only one type of tissue (roots, for example). [This is why mowing dandelions makes your weed problem worse.]
- 11.13 Nuclear cloning methods. Even adult DNA strands contain all the genetic material for an organism. When placed in an embryonic cell, the resulting offspring cells will produce an animal which is genetically identical (a clone) of the parent source.
- 11.14 Stem cell research. While embryonic stem cells retain their ability to differentiate into more tissue types than adult stem cells, harvesting embryonic stem cells has until recently resulted in the destruction of embryos. New research is leading to promising methods of increasing the ability to use adult stem cells and avoid the ethical issues of embryonic stem cell use.
- 11.15 Cancer mutations. Most forms of cancer arise from mutations in somatic (body, non-gametic) cells that cause the mutated cells to lose their ability to control mitotic reproduction.
- 11.16 Mechanisms leading to the development of cancer More than one such change is required to give rise to most malignant cancers, so such diseases generally occur in older patients.
- 11.17 Malfunctioning proteins can interfere with signal transduction. One way that cancers arise occurs when a tumor suppressant gene is turned off, and the tumor suppressing factor or protein is either not produced, or not produced effectively.
- 11.18 Chemicals introduced as part of normal or extraordinary life styles (eating habits, drug use) that can cause somatic cell mutations leading to cancer are carcinogens, which can be inorganic materials like tobacco smoke or salt, organic nutrients such as alcohol, normal hormones in abnormal amounts, or viruses. Individuals can reduce their risk for cancer by choosing diets and lifestyles that limit the intake of carcinogenic substances. Proactive testing can also ensure that treatments begin when they can be effective in limiting damage or removing the cancer entirely.
Read the following weblecture before chat: Differentiation of Cells
Take notes on any questions you have, and be prepared to discuss the lecture in chat.
Perform the study activity below:
Use the Gene Expression Essentials exercise below (from PhET):
- Chose the Expression option first.
- Click on the positive transcription factor and move it into place. (The outline will show up on the regulatory region).
- Click on the RNA Polymerase complex and move it into place. When the RNA Polymerase complets its run, move it back to the starting point of the gene and make another mRNA copy of the gene.
- Move a ribosome into the cell area and feed an mRNA sequence into it at the crease. You can make several copies of the same protein with the same mRNA.
- What happens if you try to position the negative transcription factor on this gene?
- Click on "Next Gene". Figure out what transcription factors you need so that the RNA polymerase will attach to the start of the transcription region. Use the mRNA you manufacture with a ribosome to make more proteins of this new type.
- Do this again for the final gene. Use the mRNA Destroyer to clean up the mRNA you made on the final round. See if you can figure out what the negative transcription factor does!
- Use the mRNA exercise to explore how the concentrations of transcription factors and RNA polymerase affect the rate of mRNA production. What conditions are necessary for mRNA production? What conditions increase production?
- If you have time, use the Multiple cells exercise to see how the concentrations and affinities of factors and destroyers affect the level of proteins in the cell.
- Required: Complete the Mastery Exercise with a score of 85% or better.
- Optional: Test yourself with the textbook multiple choice questions and note any that you miss that still don't make sense. Bring questions to chat!
- Go to the Moodle and take the quiz for this chapter.
Read through the lab for this week; bring questions to chat on any aspect of the lab, whether you intend not perform it or not. If you decide to perform the lab, be sure to submit your report by the posted due date.
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