The Eukaryotic Cell Cycle and Cancer – Flashcards
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Compare and contrast the reasons cell division is important for unicellular and multicellular organisms.
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Cell division is the only way single-celled organisms can reproduce. Multicelled organisms need cell division to grow and replace dead or damaged cells.
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Provide an example of why cell division remains important to an adult organism even after it is fully developed.
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After growth, division remains important in normal cell turnover, such as in our skin and gut, where cells are continuously removed. Other cells have to divide to heal wounds like skin cuts or broken bones.
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What is the role of growth factors?
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To signal a cell that it is time to divide.
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Cells divide, differentiate, or die. What is differentiation?
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Differentiation is when cells stop dividing to develop specialized structures such as a neuron developing an axon.
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What is apoptosis? Explain its purpose.
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Apoptosis is "programmed cell death." Gets rid of unnecessary cells during development or damaged cells in a mature organism.
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Organisms maintain the right number of cells by regulating the cell cycle. What are "cell cycle regulators"?
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Cell cycle regulators are molecular signals that may stimulate or halt cell division, instruct cells to differentiate, or initiate cell death.
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Name the general location along the villius where the following processes occur: Cell division, cell differentiation, and apoptosis.
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Cell division occurs in stem cells at the bottom of the villius in the crypt, the specialization comes as cells move up the villius, and apoptosis occurs after cells have lived out their lives at the top of the villius.
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Name one harmless result of too little cell division.
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Hair loss is an outcome of too few cells.
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Name one harmless result of too much cell division.
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Warts are an outcome of too many cells.
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List, in order, the four events we collectively call the "cell cycle." Next to each event, write the correlating cell cycle phase name.
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Growth-the G1 phase; DNA Replication-The S Phase; Preparation for Division-The G2 Phase; Cell Division-The M Phase.
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In general, what is the purpose of a checkpoint in the cell cycle?
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To make sure that the cell is healthy and has resources to continue through the cell cycle.
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What is one potential outcome when errors occur in this highly regulated cell cycle process?
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Errors in regulation of the cell cycle can lead to cancer.
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What type of protein that regulates the cell cycle is encoded by proto-oncogenes genes?
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Proteins that stimulate the cell cycle are regulated by proto-oncogenes.
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What type of protein that regulates the cell cycle is encoded by tumor suppressor genes?
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Proteins that inhibit the cell cycle are regulated by tumor suppressor genes.
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The most important cell cycle regulators are the:
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Cyclin-Dependent Kinases (CDKs).
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What is a kinase and what does it do?
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Kinases are enzymes that phosphorylate other proteins and activate or inhibit them.
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When are cyclin-dependent kinases (CDKs) present inside the cell during the cell cycle?
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CDKs are always present in the cell, but only become active when bound to other proteins called cyclins.
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When are cyclins present inside the cell during the cell cycle?
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Cyclins' concentration inside the cell cycles up and down, depending on the phase of the cycle.
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CDKs form molecular complexes with cyclins. What do activated CDK-cyclin complexes do?
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Activated CDK-Cycling complexes stimulate the cell cycle, moving the cell towards division.
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What happens during interphase and which phases does it include?
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G1, S, and G2 make up interphase: the period during which a cell grows and replicates its DNA. A dividing cell repeatedly cycles through interphase and mitosis; in other words, it goes through cycles of cell division.
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What three factors determine whether a cell enters the G0 phase?
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Whether or not a cell exits the cell cycle depends on the organism's stage in development, the type of cell, and the resources available.
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What is an example of a fully differentiated cell that is permanently in G0?
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Fully differentiated neurons and muscle cells never leave G0.
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What is an example of a fully differentiated cell that can leave G0 to progress through the cell cycle and divide again?
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If liver cells are injured, they will leave G0 and progress through the cell cycle to repair the damaged portion of the liver.
