...There are four steps, known as phases, in mitosis. The phases are prophase, metaphase, anaphase, and telophase. The phases must perform in the exact order for the phases to work together properly. Prophase is the first of the four phases in mitosis. There are a lot of steps in prophase that has to be done before moving to metaphase. The first step in prophase is when the chromatin change by reducing to form chromosomes. Another major step in prophase is when the centrioles drift to each end of the cell. Once the centrioles have traveled to each end, the nuclear envelope disappears. After the disappearance of the nuclear envelope, the spindle fibers located in the centrioles project towards the middle, known as the equator. After the process of prophase, metaphase is up next. The one and only job of metaphase is for the chromosomes to be drawn and migrate to the center, or equator, of the cell. Anaphase is next in the four phases of mitosis. During anaphase the chromatids, located in the chromosomes, detach. Two identical chromosomes then appear, because the chromatids detached. The separate chromatids are known as chromosomes, thus leading them to be doubled. The process of anaphase comes to an end when the chromosomes are moved by the spindle fibers towards each end of the cell at the poles. The final step in mitosis is telophase. The final journey of each set of chromosomes has been completed. In telophase the nuclei separate and form two nuclei separated and surrounded...
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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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...2/24/2013 Cell division • The human body is made up of trillions of cells… Mitosis and Meiosis • …But started with one Understanding Cell Division • What instructions are necessary for inheritance? • How are those instructions duplicated for distribution into daughter cells? • By what mechanisms are instructions parceled out to daughter cells? Reproduction • Parental cells produce a new generation of cells or multicelled individuals like themselves • Parents must provide daughter cells with hereditary instructions, encoded in DNA, and enough metabolic machinery to start up their own operation The roles of mitosis Chromosome • A DNA molecule & attached proteins • Duplicated in preparation for mitosis 1 2/24/2013 Chromosomal Organization A chromosomes is DNA associated with proteins. The entire complex is tightly wound and compressed into a discrete, linear structure. The Cell Cycle • • • • • Interphase Usually longest part of the cycle Cell increases in mass Number of cytoplasmic components doubles G1, S, and G2 phases Chromosomes duplicate in S phase of interphase Chromosome Duplication a One chromosome (unduplicated) Duplication allows a whole copy of the genome to reside in each daughter cell one chromatid one chromatid b One chromosome (duplicated) two sister chromatids Each duplicated chromosome will split. One sister chromatid will be in each new daughter cell 2 2/24/2013 Chromosome Number • Sum total...
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...Unit 5: Mitosis and Meiosis SC.912.L.16.5 Explain the basic processes of transcription and translation, and how they result in the expression of genes. Processes of Transcription and Translation A. Genetic information from DNA in transcription is transcribed in RNA. Using the mRNA instruction translation makes body structures. SC.912.L.16.14 Describe the cell cycle, including the process of mitosis. Explain the role of mitosis in the formation of new cells and its importance in maintaining chromosome numbers during asexual reproduction. Cell Cycle and Mitosis A. The cell cycle is the growth and division of cells. There are three main parts of the cell cycle: Interphase,mitosis, and cytokinesis. 1. In Interphase the cell begins to grow...
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...Checkpoint: Mitosis and Meiosis Mitosis is where the parent cell divides. The first step is prophase, the beginning of mitosis. This is where the chromatin begins to condense into chromosomes. The sister chromatids are held together at the middle called centromeres. The next step is metaphase. In this step the chromosomes align at the center of the cell. Anaphase is the next step. This is where chromatids, which are now separate chromosomes, are pulled toward the poles. After this happens the cell enters into the telophase. In this phase the chromosomes begin to loosen up from being condensed as the cleavage furrow begins. The final phase is cytonkinesis. In this final phase the cleavage furrow splits the cell making two individual cells. The steps of Meiosis are similar to mitosis with a difference in the fact the daughter cells end up with half the number of chromosomes of the parent cells. In prophase I, the members of homologous pairs become closely affiliated. They become perfectly aligned. In metaphase I the aligned pairs move to the equator together. When the pairs separate and begin to move to the poles this is called the anaphase I. Telophase I is where the chromosomes become clustered and a nuclear envelope begins to develop as the cells begin to divide. The next step is prophase II is where the chromosomes become dense again. Metaphase II is the stage where homologous pairs are gone and the chromosomes line up in the middle of the cell...
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...assignment. Cell Cycle Questions for Cell Cycle 1) . Briefly describe all phases of the cell cycle and tell what happens in each. a) Interphase: G1 phase, S phase, G2 phase Interphase: Before a cell can enter cell division, it needs to take in nutrients. All of the preparations are done during the interphase. Interphase proceeds in three stages, G1 phase, S phase, G2 phase. Cell division operates in a cycle. Therefore, interphase is preceded by previous cycle mitosis and cytokinesis (Module 3 Readings). a. G1 phase: The cell increases the supply of proteins and increases its organelles. b. S phase: Linear chromosome is replicated. c. G2 phase: Increases protein preparing to replicate. (Module 3 Readings) b) M phase: M phase is a method of indirect cell division by means of which the two daughter nuclei normally receive identical complements of the number of chromosomes of the somatic cells of the species. 2) Which phase is the shortest? Anaphase is the shortest phase of mitosis because its where the chromatids twins are all pulled apart at the centromere by the spindle fibers. 3) What is G0 (Gap 0/Resting phase)? A resting phase is when or where the cell has left the cycle and has stopped dividing. 4) If a cell never entered the resting phase would it be a problem? Why? It would continually reproduce, bypassing all the reproduction checkpoints, which would greatly increase the chance of it becoming cancerous or making defects and...
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...Activity Instructions Analyze the data presented in the graph and table below. Then answer/discuss the 7 questions/topics at the bottom of this page. You can just save and attach page 2 to the 3.06 assessment. 1. The histogram below shows the total estimated new breast cancer cases diagnosed in 2003. © 2011 FLVS 2. The results in this table below are from a 2007 study investigating BRCA mutations in women diagnosed with breast cancer. All of the women in the study had a family history of breast cancer. BRCA Mutations in Women Diagnosed with Breast Cancer BRCA1 mutation BRCA2 mutation No BRCA mutation Total Number of patients 89 35 318 442 Average age at diagnosis 43.9 46.2 50.4 Preventative mastectomy* 6 3 14 23 Preventative oophorectomy* 38 7 22 67 Number of deaths 16 1 21 38 Percent died 18 2.8 6.9 8.6 *A mastectomy is the surgical removal of one or both breasts, either partially of fully. An oophorectomy is the surgical removal of an ovary or ovaries. You can just answer/discuss the 7 topics below or them in essay form. You should have at least 2 sentences for each one except number 2. 1. Describe how mutations lead to genetic variations. 2. Which appears to be more dangerous: the BRC1 or BRC2 mutation? 3. Analyze a woman’s risk of dying of cancer if she carries a mutated BRC1 gene. 4. How do heredity and inheritance relate to the data presented in these charts? 5. What data would you need to see in order to draw conclusions about...
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...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 of | | |small...
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...Unknown0-00-00 Name: ____________________________________ Mitosis - Internet Lesson In this internet lesson, you will review the steps of mitosis and meiosis and view video simulations of cell division. You will also view an onion root tip and calculate the percentage of cells at each of the stages of cell division . Mitosis Tutorial at http://www.cellsalive.com/ On the left side of the screen is a navigation bar, click on the link to “MITOSIS” Read the text on this page and view the animation, you can slow down the video by clicking step by step through the phases. 1. Which stage does the following occur: Chromatin condenses into chromosomes | Prophase__________________________________________ | Chromosomes align in center of cell. | __Metaphase_________________________________________ | Longest part of the cell cycle. | _Interphase__________________________________________ | Nuclear envelope breaks down. | _Prometaphase__________________________________________ | Cell is cleaved into two new daughter cells. | _Cytokinesis__________________________________________ | Daughter chromosomes arrive at the poles. | _Telophase__________________________________________ | Chromatids are pulled apart | __Anaphase_________________________________________ | Watch the video carefully.2. The colored chromosomes represent chromatids. There are two of each color because one is an exact duplicate of the other. -How...
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...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 formed its two G1 phase progeny and the cell is ready to repeat the cycle 2. What are the 4 stages of mitosis? Draw a...
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...Phases And Subphases Generally, there are two phases in cell cycle. Those are interphase and mitotic phase. Figure 1.0: The cell cycle Interphase consist of G1, S, and G2. The name of G actually represent as “gap” while S represent as “synthesis”. So, the name for G1 is also known as “first gap”, S is “synthesis”, and G2 is “second gap”. There is a reason why it is called “gap”. It is because, when the cells were observed long time ago, it appeared as inactive which in inactive period, it create a gap between S phase and mitotic phase. However, as the world hurtles down the path of fast scientific development, we now know that there is a growth and metabolic activity inside cells. The mitotic phase is divided into two, mitosis and cytokinesis. Mitosis consist of prophase, prometaphase, metaphase, telophase, and anaphase. 2.1.2 Duration Of Cell Cycle Approximately, G1 takes about 5 – 6 hours, S takes about 10 – 12 hours, and G2 takes about 4 – 6 hours. Mitotic phase takes less than 1 hour. Overall, a normal human cells take about 24 hours to complete a cell cycle. 2.1.3 Events In The Cell Cycle In each subphases, several events occurred in well ordered. Starting from G1, the growth of cells occurred in this phase by producing proteins and cytoplasmic organelles. Until at the end of G1, the enzymes required for DNA synthesis become more active. The process continue with S phase, in this entire phase, the chromosome starts to duplicate and replicates forming two sister...
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...Page - rtm1 Mitosis in Onion Root Tip Cells A quick overview of cell division The genetic information of plants, animals and ot her eukaryotic organisms resides in several (or many) individual DNA molecules, or chromosomes . For example, each human cell possesses 46 chromosomes, while each cell of an onion possesses 8 chromosomes. All cells must replicate their DNA when dividing. During DNA replication , the two strands of the DNA d ouble helix separate, and for each original strand a new complementary strand is produced, yielding two identical DNA molecules. DNA replication yields an identical pa ir of DNA molecules (called sister chromatids ) attached at a region called the centromere . DNA replication in eukaryotes is followed by the process called mitosis which assures that each daughter cell receives one copy of each of the replicat ed chromosomes. During the process of mitosis, the chromosomes pass through several stages known as prophase, metaphase, anaphase and telophase . The actual division of the cytoplasm is called cytokinesis and occurs during telophase. During each of the preceding stages, particular events o ccur that contribute to the orderly distribution of the replicated chromosomes prior to cytokinesis. The stages of mitosis Prophase. During prophase, the chromosome s supercoil and the fibers of the spindle apparatus begin to form between centrosomes located at the pole of the cells. The nuclear membrane also disintegrates at this...
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...Student Name: Shania Group members: Shania and AJ Introduction: This practical was based upon Mitosis and Meiosis in both animal and plant cells. The way we will be studying this is by looking through multiple different slides closely by looking through a microscope. Hypothesis: We predict that we will be able to see a clear image of both Meiosis and Mitosis through the microscope on each slide. Equipment: • Microscope • Multiple slides with different types of Meiosis and Mitosis Method: 1. Pick a slide of your choice 2. Put it under the microscope 3. You have to make sure to start on the lowest zoom 4. Slowly change the adjustment of the zoom until you see a clear image of the subject on the slide. Results: Locust- Locust testis...
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...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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...meiosis Prophase of mitosis * Prophase I of meiosis Question 3 A child with Down Syndrome has 3 copies of chromosome 21 (trisomy 21). Which statement could be true in regards to this child? The sperm could have had 2 copies of chromosome 21. One gamete had 2 copies of chromosome 21 and the other gamete had 1 copy. * All these answers could be true. The egg could have had 2 copies of chromosome 21. None of these answers could be true. Question 4 What is the purpose of meiosis? To allow an organism to replace damaged cells * To enable an organism to produce gametes To allow for growth Question 5 What advantage does sexual reproduction have over asexual reproduction? All other selections are true. Sexual reproduction doubles the number of chromosomes in a species Sexual reproduction is more efficient * Sexual reproduction provides more genetic variability Question 6 Mitosis results in ______ cells and meiosis results in _______ cells. haploid, haploid diploid, diploid * diploid, haploid haploid, diploid Question 7 Mitosis results in ________ and meiosis results in ________. gametes, somatic cells * somatic cells, gametes gametes, gametes somatic cells, somatic cells Question 8 Homologous chromosomes separate and are pulled to opposite sides of the cell during what stage of cell division? (Read each option carefully.) Anaphase of mitosis * Metaphase I of meiosis ...
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