L09 GRQs Mitosis, Development, and Cancer PDF

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Guide reading questions for lecture 9...

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Unit 2: Genetics Guided Reading Questions Purpose: These Guided Reading Questions (GRQs) are designed to help you identify the key concepts in each reading assignment and provide you with a structure to take notes and check your understanding. Learning biology requires your time and attention. Before each class you will be asked to read from your textbook and answer questions online (Modified Mastering Biology) to assess how well you understand concepts before coming to lecture. These GRQs will help you prepared in a comprehensive and efficient manner. How to answer the GRQs: Research shows that highlighting text and re-outlining the textbook in your notes is not an effective way to learn. You may choose to answer GRQs as you read or you may choose to answer these questions after you read an assigned section. Do not wait until right before an exam to answer GRQs, but do use the completed GRQs as a study guide for the exam(s). GRQs – why bother? Learning requires repeated interaction with the concepts you are trying to master. These GRQs are designed to give you a structure to study a little bit of biology every day instead of cramming everything in at the last minute (research shows this strategy increases the likelihood of success!). There is a strong relationship between how much you invest (time and attention) in this class and your academic performance.

Mitosis, Development and Cancer Guided Reading Qs (Reading from textbook: Chapter 8 introduction-8.10 AND one article posted about breast cancer) Reading Objectives:  Contrast asexual and sexual reproduction in outcome and types of organisms/cells that use each.  Recognize/describe the stages of mitosis, contrasting animal and plant cells.  Articulate how the cell cycle differs in normal, dividing cells compared to nerve cells or cancer cells.  Explain the significance of a mutated BRCA-1 gene in terms of risks and consequences. Chapter 8 reading: 1. What are the options for a woman with stage 0 breast cancer? Lumpectomy, single or double mastectomy, and radiation therapy. What does it mean when cells are cancerous? Cancer cells divide and may spread, invading other tissues, disrupting organ function, and killing the host 2. Contrast asexual from sexual reproduction. In asexual reproduction, there’s no participant of sperm and egg. The asexual reproduction means the creation of genetically identical offspring by a single parent. What does cell division have to do with human embryonic development? Cell division enables sexually reproducing organisms to develop from a single cell into an adult organism.

3. When prokaryotes divide, which is called __binary fission____, what needs to be divided to daughter cells? Chromosome 4. True or false? Correct false statements:  Prokaryotes have one circular chromosome. True  Eukaryotes have more genes than prokaryotes. True  Humans are smarter and more complex than hedgehogs, therefore we have more chromosomes. False, we have less chromosome than hedgehogs  Each human chromosome has one gene on it. True  Humans have over 100,000 genes. True 5. How is DNA compaction/coiling analogous to moving to a new apartment? You gather the belongings up and pack them into small containers to make them more easily sorted and transported. 6. A chromosome replicates and stays joined to its replicated partner. These are now called ____sister___ chromatids. Once they separate from each other to move into different daughter cells, each will be known as a centromere__ again. 7. You find a cell that is currently replicating its DNA. What part of the cell cycle is it in? Interphase What will happen next? The chromosomes are doubled and the cell will completes preparations for cell division 8. You view an animal cell through a microscope and observe dense, duplicated chromosomes lined up in the middle of the cell. Which stage of mitosis are you looking at? __Metaphase __ For a spindle to form in which chromosomes move along its microtubules, what cellular structure must dissolve during prophase and prometaphase? Nuclear envelope How would you know if a cell was in anaphase? The two poles of cell have equal collections of chromosomes 9. Why does cytokinesis differ between plant and animal cells? (think about differences in structure!) Because the cell walls in the plant cell prevent contraction. 10. Scientists have learned how to grow cells outside of the body in plastic trays (although not all cells of the body cooperate and divide). You may find yourself in a lab in the future asked to “maintain cells in tissue culture”. This is what we call this technique. Describe, not simply list, three factors (chemical or physical) that influence how normal cells divide, based on what scientists have learned from these cell cultures. Growth Factor: some mammalian cells will divide only if certain proteins are present. Anchorage Dependence: cells must be in contact with a solid wurface

Density-dependent inhibition: cells stop dividing when they touch on another 11. How are nerve cells and muscle cells different from many other cells of the human body relative to the cell cycle? Nerve cells and muscle cells are in the G0 phase. A different set of genes are active in muscle cells which allow it to perform particular functions 12. If the cell cycle is carefully controlled by proteins that are present only temporarily to help turn on the cell cycle (i.e. growth factors) and other proteins that halt the cycle (checkpoint proteins), what do you suppose would happen if a cell was continuously exposed to growth factors? Cancer What do you supposed would happen to a cell in which checkpoints were faulty? The cell cycle is halted. How does all of this relate to one of our major themes—interactions within and between systems? Each stage in the cell cycle interacts with each other. If one has some problems, it will affect the whole cell cycle. 13. What makes a tumor malignant? A mass of abnormally reproducing cells that can spread into neighboring tissues and invade other parts of the body. What does the word immortal mean in cell biology? A stable or decreasing rate of mortality from cellular senescence as a function of chronological age. 14. Are the words tumor and cancer interchangeable? Why or why not? Yea, because A tumor is not necessarily a cancer. The word tumor simply refers to a mass. 15. Scientific thinking: Is the study described a prospective or retrospective observational study? Retrospective What scientific question did scientists hope to answer with the study? Whether cancer therapy can be personalized What did they find? About 20% of DCIS patients bear a substantially high risk of death. How does the knowledge they discovered affect women in society? Women should consider the most aggressive treatment options. 16. Go to http://www.myriad.com/patients-families/disease-info/breast-cancer/ People with a gene mutation in either BRCA-1 or BRCA-2 genes are at what risk of developing breast cancer by age 70? _breast cancer__ How does this compare to the general population (people without these mutations?)

They have a significantly increased risk of developing a second cancer in the future Carrying a defective BRCA gene affects your risk of breast cancer, but also significantly increases your risk of what other kind of cancer in women? __HBOC__ Who is a good candidate for gene testing? (i.e. what are the risk factors?) Have had breast cancer at age 50 or younger Have had triple negative breast cancer Have ever had ovarian cancer Are male and have had breast cancer at any age Have had a male relative diagnosed with breast cancer 16. Read the “Breast Cancer” New York Times article on our sakai site. Deb Lindner’s mother who had breast cancer had a defective BRCA-1 gene. When Deb was awaiting her results, what was the chance (%) that she was going to find out that she was a carrier of this defective gene too? __50%___

How old was Deb’s mother when she was diagnosed with breast cancer? ____63

4. What was Deb’s more immediate decision (at age 33) after finding out she was indeed a BRCA-1 mutation carrier? She enrolled in a stepped-up surveillance program that required alternating mammograms and sonograms with M.R.I.'s every six months What will she do before she turns 40? Remove her breast...