...N Driving the Cell Cycle Through Metabolism Ling Cai and Benjamin P. Tu Annu. Rev. Cell Dev. Biol. 2012.28. Downloaded from www.annualreviews.org by Ecole Polytechnique Federal Lausanne on 06/20/12. For personal use only. Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9038; email: benjamin.tu@utsouthwestern.edu Annu. Rev. Cell Dev. Biol. 2012. 28:3.1–3.29 The Annual Review of Cell and Developmental Biology is online at cellbio.annualreviews.org This article’s doi: 10.1146/annurev-cellbio-092910-154010 Copyright c 2012 by Annual Reviews. All rights reserved 1081-0706/12/1110-0001$20.00 Keywords cell growth, cell proliferation, metabolic cycle, growth control, nutrients, yeast Abstract For unicellular organisms, the decision to enter the cell cycle can be viewed most fundamentally as a metabolic problem. A cell must assess its nutritional and metabolic status to ensure it can synthesize sufficient biomass to produce a new daughter cell. The cell must then direct the appropriate metabolic outputs to ensure completion of the division process. Herein, we discuss the changes in metabolism that accompany entry to, and exit from, the cell cycle for the unicellular eukaryote Saccharomyces cerevisiae. Studies of budding yeast under continuous, slow-growth conditions have provided insights into the essence of these metabolic changes at unprecedented temporal resolution. Some of these mechanisms by which cell growth and proliferation...
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...morphologically, producing black perithecia containing asci with eight dark ascospores in a linear arrangement. These species share a number of characteristics that are advantageous for genetic studies. They all have a short life cycle, usually 7–12 days, and are easily grown in culture. Most species are self-fertile and each strain is isogenic. All kinds of mutants are easily induced and readily obtainable with particular ascospore color mutants. These visual mutants aid in tetrad analysis, especially in analysis of intragenic recombination Eukaryotic cell cycle The division cycle of most cells consists of four coordinated processes: cell growth, DNA replication, distribution of the duplicated chromosomes to daughter cells, and cell division. In bacteria, cell growth and DNA replication take place throughout most of the cell cycle, and duplicated chromosomes are distributed to daughter cells in association with the plasma membrane. In eukaryotes, however, the cell cycle is more complex and consists of four discrete phases. Although cell growth is usually a continuous process, DNA is synthesized during only one phase of the cell cycle, and the replicated chromosomes are then distributed to daughter nuclei by a complex series of events preceding cell division....
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...University of Phoenix Material Comparing Cell Cycles Complete the Cell Cycle charts below. Describe the events in each phase for Cell Cycle A. Compare the steps in mitosis and meiosis for Cell Cycle B. Cell Cycle A |Phase |Describe the events in each phase | |G1 (1st growth stage) |This is the portion of the cell cycle just after division, but before DNA synthesis. During this| | |time the cell grows by producing proteins and organelles. | |S (Synthesis) |DNA synthesis (or replication) occurs during this phase. At the beginning of the phase, each | | |chromosome is single. At the end, after DNA replication, each chromosome consists of two sister | | |chromatids | |G2 (2nd growth stage) |This third subphase of interphase is a period of metabolic activity and growth. During this | | |phase the cell makes final preparations for division. | |Prophase of mitosis |Prophase occupies over half of mitosis. The nuclear membrane breaks down to form a number...
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...the cell cycle, including the steps of Interphase. G1 phase - growth and synthesis. Gap phase 1 begins at the completion of mitosis and cytokinesis and lasts until the beginning of S phase. This phase is generally the longest of the four cell cycle phases and is quite variable in length. During this phase, the cell chooses either to replicate its deoxyribonucleic acid (DNA) or to exit the cell cycle and enter a quiescent state (the G0 phase). S phase Replication of the chromosomes is restricted to one specific portion of interphase, called S phase (DNA synthesis phase), which typically lasts about 6 h. In mammalian cells, the start of S phase—the actual initiation of DNA synthesis—takes place several hours after the cell has committed to carrying out DNA synthesis. During S phase, each chromosome replicates exactly once to form a pair of physically linked sister chromatids. In animal cells, a pair of centrioles is also duplicated during S phase. G2 phase - Preparation for division The portion of interphase that follows S phase is called gap phase 2. Some cells can exit the cell cycle from G2 phase, just as they can from G1 phase. M phase M phase includes the overlapping processes of mitosis and cytokinesis. Mitosis is divided into five stages: prophase, prometaphase, metaphase, anaphase, and telophase. Cytokinesis usually begins during anaphase and ends at a point after the completion of mitosis. At the end of cytokinesis, the parent cell has...
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...BY 101 Study Guide Chapter 9 – Cell Division Cell division is an elegant process that enables organisms to grow and reproduce. Through a sequence of steps, the replicated genetic material (chromosomes) in a parent cell is equally distributed to two daughter cells. While there are some subtle differences, mitosis is remarkably similar across organisms. Before a dividing cell enters mitosis, it undergoes a period of growth called interphase. Interphase is the "holding" stage or the stage between two successive cell divisions. In this stage, the cell replicates its genetic material and organelles in preparation for division. The cell cycle, or cell-division cycle, is the series of events that take place in a cell leading to its division and duplication (replication). The cell cycle consists of four distinct phases: G1 phase, S phase (synthesis), G2 phase (collectively known as interphase) and M phase (mitosis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's chromosomes are divided between the two daughter cells, and cytokinesis, in which the cell's cytoplasm divides forming distinct cells. Activation of each phase is dependent on the proper progression and completion of the previous one. Cells that have temporarily or reversibly stopped dividing are said to have entered a state of quiescence called G0 phase. Mitosis is composed of several stages: * Prophase * Metaphase * Anaphase * Telophase Prophase ...
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...Kaitlyn Hainline Biology-4 The Cell Cycle Lab I. Design A. Problem/Research Questions 1. What is the relative time it takes for a cell to go through each phase? B. Variables 1. Independent Variable- The independent variable is the different cell phases (Interphase, Prophase, Anaphase, and Telophase/Cytokinesis). 2. Dependent Variable-The dependent variable is the percentage of cells that are each cell phase. C. Controlled Factors- The magnification is a control factor because I was able to decide what magnification the microscope was on and mine was at (400x). Another control factor was the temperature because it stayed at room temperature throughout the whole experiment. D. Apparatus/Materials Needed * 2 pre stained onion root slides * A microscope at 400x magnification * Calculator * writing utensil * paper E. Procedure 1. Observe every cell in one high-power field of view and determine which phase of the cell cycle the cell is in. 2. Count at least two full fields of view. If you have not counted at least 200 cells, then count a third field of view. 3. Record, process and present your data. II. Data Collection and Processing A. Data Collection 1. Mass of | Number of cells in each phase + 1cell | Percent of cells in each phase (%) | Time spent in each phase (hours) | 2 slides tested | Slide 1 | Slide 2 | Slide 1 | Slide 2 | Slide 1 | Slide 2 | Interphase | 75 | 215 | 32% | 77% |...
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...Ruth Lin, 47985106 FRST302 Assignment 2 Jan 31, 2015 Describe the activities of chromosomes and microtubules in the cell cycle, including all phases of mitosis and meiosis. Mitosis is a part of the M phase in a cell’s life cycle process whereby cellular division occurs to form two genetically identical daughter cells. The cell cycle consists of the interphase phase and the M phase. The interphase phase represents the period between cells divisions, where the cell grows and develops. The M phase (mitotic phase) represents the period of active cell division, whereby copies of the cell’s chromosomes (sister chromatids) separate, so that a duplicate set of genetic information can be passed down to each of the daughter cells. Mitosis is often...
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...However, for Cell Biology we will touch upon those concepts that complement the cellular aspects of transcription. In particular, we will look at the genetic code, called the CODON, frameshift mutations, the structure of theTRANSCRIPTIONAL UNIT, and the phases of transcription. I will point out those aspects of transcription that I feel are important to this course. The study guide will also help you to focus on those parts of transcription that the examination will cover. CHAPTER 19 1. What important event (related to DNA) occurs in G1 before the cell enters the S phase? 2. What important event (related to DNA) occurs in G2 before the cell enters mitosis? 3. Why are G1 and G2 called gap phases? What happens during S phase? 4. Can mitosis occur without cytokinesis? (hint, Drosophila) 5. During which phase of mitosis do sister chromatids separate? 6. How do the experiments of Meselson and Stahl verify the semiconservative model of DNA replication? 7. What is the name of the locus (location) from which DNA replication begins? Does DNA replication occur uni- or bi-directionally? 8. Name the two major components of the primosome. 9. What are the functions of DNA polymerase III, the primosome, primase, DNA polymerase I, and DNA ligase? 10. What structure along the lagging strand allows the replisome to replicate both strands in the same direction? 11. How does cell cycle relate to cell type? 12. What is MPF? What two molecules make up MPF? Which one cycles in concentration...
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...1. Cyclin is a key regulator to the cell cycle. Each type of cyclin is specific for a particular phase. It is essential in order for necessary events to occur during various periods. For the cell cycle to progress, proteins inside the cell must be either activated or deactivated by cyclin. The events can take place when cyclin works with CDKs (cyclin dependent kinases), which are a group of enzymes. Their function is made possible when cyclin properly binds to an inactive form. When cyclin is not broken down, CDK remains inactive, which means target cells, cannot be reached and therefore not modified. As a result, the S phase cannot begin. The enzymes of DNA replication cannot be activated. This in turn affects MPF (maturation-promoting factor) not being able to drive transitions of the cell cycle. Ultimately, the activities of the cell cycle cannot be regulated. Thus if cyclin is not broken down through mitosis, a rapid production will occur leading to mutations and cancer. 2....
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...Chapter 8 The Cellular Basis of Reproduction and Inheritance Multiple-Choice Questions 1) The creation of offspring carrying genetic information from a single parent is called A) asexual reproduction. B) sexual reproduction. C) a life cycle. D) regeneration. E) spontaneous generation. Answer: A 2) Which of the following statements regarding sexual and asexual reproduction is true? A) Cell division only occurs after sexual reproduction. B) Only offspring from asexual reproduction inherit traits from two parents. C) Sexual reproduction typically includes the development of unfertilized eggs. D) Sexual reproduction is more likely to increase genetic variation than is asexual reproduction. E) Only asexual reproduction results from the union of a sperm and an egg. Answer: D 3) Strictly speaking, the phrase "like begets like" refers to A) all forms of reproduction. B) sexual reproduction only. C) asexual reproduction only. D) production of gametes from a premeiotic cell. E) sexual reproduction between different species. Answer: C 4) Asexual reproduction requires ________ individual (s). A) 0 B) 1 C) 2 D) 3 E) 4 Answer B 5) With the exception of identical twins, siblings who have the same two biological parents are likely to look similar, but not identical, to each other because we have A) identical chromosomes, but different genes. B) identical genes but different chromosomes. C) the same combination of traits...
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...BSC 1020- Reflection Unit E Making Babies and Splitting Up Chapter 8 focuses on cellular reproduction. Cellular reproduction is the process of producing cells into new ones. In cell division chromosomes are duplicated, new cells grow, and this allows for reproduction. There are two types of reproduction which are sexual and asexual. Asexual does not require the fertilization of an egg by a sperm and uses meiosis for reproduction. In asexual reproduction there is one parent and the offspring have identical genes from the single donor. Sexual reproduction uses both meiosis and mitosis because it requires the fertilization of eggs by the sperm. In sexual reproduction the genetic material of the offspring is varied because the two donors...
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...Cell division is the basic of reproduction for all living things. It is important and indeed in all living organisms. It enables the multicellular organisms to grow until the adult size, when the cell division plays role in reproducing cell into more new cells. Besides, cell division also replaces the worn-out or damaged cells in order to maintain the total cells numbers in a mature individual relatively constant. For instance is, there are millions of cells in human’s body will divide themselves every second, keeping the total number of them in about 100 trillion (Campbell, Reece, Taylor, Simon & Dickey, 2012). Process of cell division is a main component of the cell cycle. A cell cycle is known as an ordered sequence of events that extends...
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...Joe Sawaya Introduction: Mitosis is a process when a cell divides into 2 daughter cells that genetically identical to each other and to the parent cell. All cells come from preexisting cells by mitosis. Cell division involves a karyokinesis (division of the nucleus) and a cytokinesis (division of the cytoplasm). Mitosis produces the same number of chromosomes in each daughter cell as in the original nucleus which are inherited form a generation to another. It also causes a growth in the organism by increasing the number of cells. Not all somatic cells divide; muscle cells, blood cells, cardiac cells, nerve cells don’t divide. Every cell undergoes a series of steps through its life in a cycle called the cell cycle. It’s divided into 4 stages: the G1 (first gap) phase, the S (synthesis) phase, the G2 (second gap) phase and the M (mitosis) phase. -In the G1 phase, the DNA begins to replicate, the cell is in a period of growth and cellular activity. Its duration is about 10 hours. -In the S phase, the DNA is replicated and series of preparation for division occur. -The G2 phase is a second period of growth and cell’s life. It ends when mitosis begins and its duration is about 4 hours. These 3 stages are grouped into one phase which is interphase. -Mitosis is the final stage in the cell cycle. It ends with cytokinesis and its duration is about 1 hour. At its turn, mitosis contains 4 phases: prophase, metaphase, anaphase and telophase which are discussed below. The process...
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...Levels Reflect a Nexus of Oncogenic Signaling during Cell Transformation. Cancer can be defined as the disease caused by abnormal cell proliferation in parts of the body or a malignant growth of a tumor resulting from these cells. However, it is not just one disease instead a large group of diseases since the action can happen in any part of the body. There is this ability the cells have to migrate from the site of origin abnormal growth and spread to distant sites. One out of every four deaths in the United States is from this disease which drives scientists to study Cancer Biology and its pathways. In studying the different pathways, there is the hope that we can either make a cure or prevent these pathways from occurring to cause these cells to override the apoptosis. In order to understand the author specific point of research we must first understand SV40-small T antigen, Rb, and p27. To begin, SV40 is a proto-oncogene which is capable of transforming several of cell types. It seems to disturbed pRb function regulating cell cycle progression, and equivalent to a light switch turning transcription in cells. Compared to pRb functions in cell cycle suppression, it prevents the cell from replicating damaged DNA by preventing its progression of the cell cycle through G1 to S phase. In general, when it binds to E2F it act as a growth suppressor and prevents the cell from going through the cell cycle. Similarly, p27 controls cell proliferation by binding and regulation the activity...
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...visit the Writing Center in the Student Success Center. | Part 1: An organism is born, lives, and then dies. Similarly, a cell has a life cycle.After reading pages 164 – 165 in your textbook, outline the six stages of the cycle of a cell. | 10 points | Answer:1. Interphase- when the cell is going about regular activities 2. Prophase- when the DNA chromosomes first become visible 3. Metaphase- When the chromos line up in the middle 4. Anaphase- when the chromos form pairs and are apart 5. Cytokinesis- when the cell has two separate nuclei and is about to split into two different cells | Part 2: The portion of the life cycle that involves the separation of the nuclear (DNA) material of the cell is termed mitosis. Two cells that are formed from one during this type of division are identical to each other and to their parent cell. So as to understand this complicated process, scientists have identified and named specific events that occur. After reading pages 166 – 167 in your textbook, outline the six stages of mitosis. | 10 points | Answer: 1. Early Prophase 2. Prophase 3. Transition to Metaphase 4. Metaphase 5. Anaphase 6. Telophase | Type your name here: Chanulae M. Smith Type your name here: Chanulae M. Smith (See next page for part 3) Part 3: Mitotic cell division needs to be finely regulated. The cell cycle has checkpoints that...
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