Download Daughter cell

 G1 Phase (the first Gap Phase): the first Stage of Interphase During the G1 phase or the Gap 1 phase, the protein synthesis and the RNA synthesis within the cell resumes that was interrupted during the process of mitosis. Growth and young cell maturation occurs, which accomplish the physiological function. G1 phase is the phase during which the cell cycle starts with the synthesis of RNA and proteins required by the young cells for their growth and maturity. The time period of the G1 phase of the interphase is varied highly among the different species’ eukaryotic cells. For example, faster renovation tissues like the mucosa and the endometrial epithelium require very short G1 periods as compared to the muscles or connective tissues that do not require frequent repair or renovation. G1 phase is usually termed as the prior to DNA synthesis phase. S Phase: the Second Stage of Interphase S phase:The DNA synthesis place as the name suggests, S which stands for synthesis. Soon after the G1 phase, DNA checking and subsequent repair occurs during the variable pause phase before the transition of the cell cycle to the S phase. The S phase of the interphase deals with the semi-­‐conservative synthesis of DNA occurs. Replication of cellular DNA begins with the S phase, which when gets duplicated with the cell containing nearly double the amount of chromosomes, the cells from the S phase move into the G2 phase. G2 Phase (the Second Gap Phase): the third Stage of Interphase During the G2 phase, there is an increase in the synthesis of the RNA and the protein, which is followed by another round of proof reading and subsequent repair among the newly synthesized DNA sequences before the cell cycle transits to the mitotic cycle. The mitotic spindle formed from the cytokinetic fibers start forming and the cell ensures the number of chromosomes and the organelles present, which further leads the cell cycle from the interphase to the mitotic phase. http://www.tutorvista.com/biology/the-­‐three-­‐stages-­‐of-­‐interphase What type of cells stay in Go? Neurons are the most common type of cells that stay in the Go phase. What is the approximate time a skin cell stays in each phase of the cell cycle? A skin cell goes thru the cell cycle 22 hours of the day. 3 facts • Most cells divide once or more every day! • Cells are passed down from generation to generation! • Each sex cell only has half the required amount of chromosomes and if there is the normal amount of chromosomes it will cause a miscarriage! http://www.bbc.co.uk/schools/gcsebitesize/science/images/9_sex_cells.gif How does cancer occur? Cancer occurs when the cells of a certain part of the body start growing in number at a faster rate, due to several unknown reasons. Later on those growing cells take an odd shape and encumber that part of the body to which they belong from performing its normal functions. Nevertheless cancer is not incurable anymore. Advancements in technology have enabled medical science to help a person get rid of the disease on a convenient basis. However there are some restraints to this solution. The first and foremost is the stage of cancer that the patient is enduring. If the person is at an early stage, the cancer lump could be removed by surgery or killed by treatment of X-­‐rays or gamma rays. Otherwise the growing numbers of cells start spreading through the entire body and start creating trouble in other parts of the body too, resulting in serious consequences. What carcinogens are we exposed to everyday? •
Tobacco smoke •
Radiation •
Asbestos •
Nickel •
Cadmium •
Uranium •
Radon •
vinyl chloride •
Benzene Mitosis produces the cells of the body. When they split they produce identical cells with a complete set of DNA. They are exactly like their parents. It only has one division and that leads to two cells. Meiosis produces the gametes or the "sex cells" such as sperm and eggs. Meiosis goes through two divisions, one in meiosis 1 and one in meiosis 2. In the end, it results in four cells and each cell only contains half of the genetic material. At fertilization male and female gametes come together to form a new being with half of its mothers genes and half of its fathers genes. googleimages.com googleimages.com Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets, in two separate nuclei. It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two cells containing roughly equal shares of these cellular components. Mitosis and cytokinesis together define the mitotic (M) phase of the cell cycle—the division of the mother cell into two daughter cells, genetically identical to each other and to their parent cell. This accounts for approximately 10% of the cell cycle. Mitosis occurs only in eukaryotic cells and the process varies in different species. For example, animals undergo an "open" mitosis, where the nuclear envelope breaks down before the chromosomes separate, while fungi such as Aspergillus nidulans and Saccharomyces cerevisiae (yeast) undergo a "closed" mitosis, where chromosomes divide within an intact cell nucleus. Prokaryotic cells, which lack a nucleus, divide by a process called binary fission. The process of mitosis is fast and highly complex. The sequence of events is divided into stages corresponding to the completion of one set of activities and the start of the next. These stages are interphase, prophase, prometaphase, metaphase, anaphase and telophase. During mitosis the pairs of chromatids condense and attach to fibers that pull the sister chromatids to opposite sides of the cell. The cell then divides in cytokinesis, to produce two identical daughter cells which are still diploid cells. http://www.mc.vanderbilt.edu/histology/labmanual2002/labsection1/Nucleus03_files/imag
e002.jpg Vocabulary: Parent cell: A cell that is the source of other cells, as a cell that divides to produce two or more daughter cells, or a stem cell that is a progenitor of other cells or is the first in a line of developing cells. Daughter cell: Either of the two identical cells that form when a cell divides. Chromosomes: Any several threadlike bodies, consisting of chromatin, that carry the genes in a linear order. Chromatid: One of two identical chromosomal strands into which a chromosome splits longitudinally preparatory to cell division. Spindle fiber: One of a network of achromatic filaments that extend inward from the poles of a dividing cell, forming a spindle shaped figure. Centrioles: One of two cylindrical cellular structures composed of nine triplet microtubules and forming the mitotic astrospheres. Nuclear membrane: The double membrane surrounding the nucleus within a cell, also called a nuclear envelope. A human has 46 chromosomes but they are refered to as pairs and the phrase “diploid number” refers to the 23 pairs not to 46 chromosomes. Mitosis is division of cytoplasm to form two cells. Before mitosis starts, during interphase, the DNA in the nucleus duplicated itself so at the beginning of mitosis there are 46 “Pairs” of chromosomes. During the process of mitosis, these pairs divide with half going to one side of the cell and half going to the other side. When the cytoplasm divides and becomes two cells, each daughter has a diploid number (23 pair) of chromosomes or a total of 46 single. googleimages.com What is the purpose of meiosis? The purpose of meiosis is to produce gametes (sex cells) which are also known as sperm and egg. How many viable cells are produced by males? Females? What are the resulting cells called? 80% of males sperm are viable cells and 99.9% of females eggs are viable cells. The resulting cells are called haploids. Explain what would happen to the total number of chromosomes if meiosis did not occur? The chromosomes would double from 46 to 92 and the mother would experience a miscarriage. If meiosis did not occur, how many chromosomes would humans have after five generations? 460 STAGES OF MEIOSIS Prophase
Anaphase
Prometaphase Telophase Metaphase www.googleimages.com Cytokinesis Prophase: Homologous chromosomes pair and form synapses. Paired chromosomes are called bivalents. Chromosomal condensation allows to be viewed under microscope. Bivalent has two chromosomes and four chromatids. One chromosome comes from each parent. Prometaphase: The nuclear membrane disappears. One kinetochore forms per chromosome rather than one per chromatid. Chromosomes attached to spindle fibers begin to move. Metaphase: Bivalents composed of two chromosomes align at metaphase plate. The orientation is random with either parental homologue on a side. This means that there is a 50-­‐50 chance for daughter cells to get either a mother’s or a father’s homologue for each chromosome Anaphase: The daughter chromosomes move away from eachother to opposite ends of the cell. Each daughter cell is now a haploid, and each chromosome has two chromatids. Telophase: Nuclear envelopes reform or cells star meiosis II Cytokinesis: Two daughter cells form www.googleimages.com Vocabulary: Chromosomes: cell structures that can carry genetic material that carry the genetic material that is copied and passed from generations of cells Chromatid: long strands of DNA condense to form chromosomes Crossing over: exchange of genetic material between non-­‐sister chromatids from homologous chromosomes during prophase of meiosis Tetrad: a group of four chromatids formed by four synapsis at the beginning of meiosis. Spindle fibers: cell structures composed of microtubule fibers forms between the centrioles during prophase and shorten during amaphase pulling apare sister chromatids Centrioles: in animal cells, a pair of small cylindrical structures composed. Parent cell: a cell that is the source of other cells, as a cell that divides to produce two or more daughter cells, or a stem cell that is a progenitor of other cells or is the first in a line of developing cells. Daughter cell: either of the two identical cells that form when a cell divides. Diploid: having two similar complements of chromosomes. Meiosis II is the second part of meiotic process and occurs after Meiosis I. This stage contains four phases and goes in the very similar way as Mitosis and Meiosis stage: from one parent cell creates one daughter cell. During these phases, the following changes happen in each part of process: Prophase II http://0.tqn.com/d/biology/1/0/s/2/lilypro2.gif In this phase, the nuclear membrane divides, if necessary. At the same time, spindle network shows up and the chromosomes commence migrating in the direction of cell’s equator, or to Metaphase II plate. Metaphase II http://0.tqn.com/d/biology/1/0/q/2/lilymeta2.gif The chromosomes line up at the metaphase II plate at the cell's center. The kinetochores of the sister chromatids point toward opposite poles. Anaphase II http://0.tqn.com/d/biology/1/0/o/2/lilyana2.gif During the Anaphase II, sisters chropatids move to the opposite cell poles, after they separate from each other. Telophase II http://0.tqn.com/d/biology/1/0/t/2/lilytelo2.gif This phase defines the forming of the distinct nuclei at the opposite poles, also cytokinesis occurs during this phase. At the end of meiosis II, there are four daughter cells each with one half the number of chromosomes of the original parent cell. Mitosis is a process of cell division where a cell will produce an exact duplicate of itself with the same number and patterns of genes and chromosomes. Meiosis, on the other hand, is a special process in cellular division where cells are created containing gene patterns of different types and combinations with 50% of the number of chromosomes of the original cell. Meiosis is used in sexual reproduction of organisms to create a combination of male and female chromosomes, through the spermatozoon and egg, to build a new, unique biological organism. Mitosis is used by single celled organisms to reproduce, or in the organic growth of tissues, fibers, and membranes. Comparison chart
Number of
Daughter Cells
produced:
Creates:
Definition:
Produces:
Steps:
Meiosis
Mitosis
4
2
Sex cells only of both male and
female gender
A type of cellular reproduction in
which the number of
chromosomes are reduced by
half through the separation of
homologous chromosomes in a
diploid cell.
Four haploid daughter cells
Responsible for non-sex cell
division
A process of asexual
reproduction in which the cell
divides in two producing a
replica, with an equal number of
chromosomes in haploid cell
The steps of meiosis are
Interphase, Prophase I,
Metaphase I, Anaphase I,
Two daughter cells with the
same number of chromosome as
parent cell
The steps of mitosis are
Interphase, Prophase,
Metaphase, Anaphase,
Steps:
Discovered by:
Type of
Reproduction:
Genetically:
Cytokenesis:
Number of
Divisions:
Pairing of
Homologues:
Chromosome
Number:
Karyokinesis:
Crossing Over:
Centromeres Split:
Occurrence
of
Crossing
Over:
Occurs
in:
The steps of meiosis are
Interphase, Prophase I,
Metaphase I, Anaphase I,
Telophase I, Prophase II,
Metaphase II, Anaphase II and
Telophase II.
Oscar Hertwig
Sexual
The steps of mitosis are
Interphase, Prophase,
Metaphase, Anaphase,
Telophase and Cytokinesis
Different
Occurs in Telophase I &
Telohpase II
2
identical
Occurs in Telophase
Yes
No
Reduced by half
Remains the same
Occurs in Interphase I
Mixing of chromosomes
The centromeres separate
during anaphase II
Yes
Occurs in Interphase
Does not occur
The centromeres split during
Anaphase
No
Humans, animals, plants, fungi
all organisms
Walther Flemming
Asexual
1
Similarity Chart
Mitosis Divides from somatic cells 2 Daughter cell Mitosis & Meiosis Ways for cells to divides Same # of chromosomes as the original cell Meiosis Divided from a reproductive cell 4 daughter cells 5 phases Both have the basic phases All daughter cells have 23 chromosomes 9 phases Resources
• Biology.arizona.edu/cell/bio/meiosis • Phschool.com • http://0.tqn.com/d/biology/1/0/o/2/lilyana2.gif • tutorvista.com • .http://au.answers.yahoo.com/question/index? •
www.diffen.com/difference/Meiosis_vs_Mitosis
• Pbs.org •
www.blurtit.com/q572358.html
• Biology book