Joyce Balingit BIOL 196 - 1006 Instructor: Austin McKenna 30 October 2015 Writing Assignment #3 Part A In meiosis, the cell goes through the same stages as mitosis twice. The stages of Meiosis I are: prophase I, metaphase I, anaphase I, and telophase I. The stages of Meiosis II are: prophase II, metaphase II, anaphase II, and telophase II. Meiosis generates four haploid cells, which begins with the division of one diploid cell. Diploid means having two sets of chromosomes, and haploid means having half the number of genetic information as diploid (or one set). To begin, late interphase is the phase when the DNA in the diploid parent cell is replicated. Then, in prophase I, the chromatin condenses and the chromosomes become visible. The homologous …show more content…
In which case, the nuclear envelope is visible again and the DNA uncoil into chromatin. No DNA replication occurs during interphase II. In prophase II, the nuclear envelope disintegrates again, and the chromosomes stay in sister chromatid form (if they unraveled into chromatin during interphase II they condense again). In metaphase II, spindle fibers from opposing poles of the cell attach to the centromeres of each sister chromatid. Sister chromatids are two identical copies/strands connected by one centromere that results from the replication of a chromosome during the S phase. The sister chromatids line up alone the equatorial line. During anaphase II, each sister chromatid begins to move to its respective pole thus the pairs begin to separate. In telophase II, the sister chromatids reach their respective poles. Cytokinesis takes place, and the nuclear envelope becomes visible, resulting in four haploid …show more content…
Sadava, Richard W. Hill, and Mary V. Price. Principles of Life. 2nd ed. Sunderland: Sinauer Associates, 2014. Print. • Andres, Andrew. Biology 196: Principles of Modern Biology I Laboratory Manual. Minneapolis: Bluedoor, LLC, 2015. Print. Part B – Down’s Syndrome In 1866, John Langdon Down, a British physician, identified a group of people whose symptoms were very similar. These were: eyes that were upwardly slanting, a flattened back of the head, and fissured and poorly controlled tongues. The term “mongolism” was coined to describe these people with Down’s Syndrome. In 1959, Jerome Lejeune identified the disorder as a chromosomal condition. He saw that those with the condition had 47 chromosomes in their cells instead of the normal 46. Later it was discovered that it was the result of an extra copy of chromosome 21. The nondisjunction that results in an extra copy of chromosome 21 occurs during anaphase I in meiosis I. The genetic mutation is trisomy 21 (3 copies of chromosome 21). The characteristic phenotypic occurrences that are distinct to the disorder: poor muscle tone, stout neck, flat face, small head, mouth, and ears, eyes slanting upwardly, Brushfield spots, and stout fingers and
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During random fertilization, no gamete has a greater chance than the other with fusing together in sperm and zygote fusion. These processes contribute to the production of genetic variety because of the many opportunities of unique combinations, unlike the process of mitosis, in which identical daughter cells are always the
The film briefly examines different services that are available for the families. However, the film demonstrated that the most precious resource is the role of parents and caregivers to believe in their child and never limit their abilities. Down syndrome has specific characteristics that are unique to this exceptionality. The most shared features associated with Down syndrome that were evident in the children in this film include; Flat facial features, with a small nose, Upward slant to the eyes, Small skin folds on the inner corner of the eyes and an Enlarged tongue. My major is Communication Disorders
Trisomy 18, or Edwards Syndrome, was discovered by a man named John Hilton Edwards in 1960, and is a condition that causes severe developmental delays because of an extra chromosome 18. Edwards was a professor of genetics at Birmingham and Oxford, he first saw Trisomy 18 in stillborn and abnormal babies. Trisomy 18 is the second most common trisomy after Trisomy 21. Trisomy 18 is not inherited, but completely random, it is caused by an error in cell division known as meiotic disjunction. The following essay will go over the signs, symptoms, mutation, and how to make the child with Trisomy 18’s everyday life as normal as possible.
During the first cycle of replication in meiosis, Prophase is the same but crossing over occurs along side of the nuclear membrane dissolving, chromosomes developing, and the spindle fibers forming. Crossing over is the process in which homologous chromosomes from both parents pair up and exchange DNA. Also during metaphase and anaphase homologous chromosomes are separated and pulled to opposite sides. During this second cycle of replication the cells grows through Prophase II, Metaphase II, Anaphase II, Telophase II, and its final cycle of cytokinesis which is the exact same as during mitosis. I will play a quick review of this process.
The sister chromatids are pulled towards oppsite poles of the cell. (http://andrewhulse.weebly.com/archive-blog---life-in-room-213206209/archives/01-2014) Telophase:the chormatids are now called chormosomes. The nuclear envelope reforms arounds the two sets of chromosomes to form two new nuclei and in each nucleus the nucleolus reforms. The spindle fibres disappear and the chromosomes become uncoiled, elongated and are no longer visible.
What is the Microsporidia life cycle? 1. The spore infuses the infective protoplasm into the eukaryotic host cell through the polar tubule. 2.At the point when the spores increment in number and totally fill the host cell cytoplasm, the cell film is disturbed and discharges the spores to the environment. There are many places that Microsporidia can be found in.
Cells in the human body can undergo two types of division: meiosis, or mitosis. Mitosis is for somatic cells while meiosis is for gametes/non-somatic cells. The purpose of this lab is to observe and identify the stages of mitosis and meiosis, and view chromosomes under a compound light microscope. Mitosis would be observed in a preserved onion root-tip slide to view and identify the different stages of the process: interphase, prophase, metaphase, anaphase, telophase, and cytokinesis. The stages examined in this lab for mitosis were interphase, prophase, metaphase, anaphase, and telophase.
The chromatids are separated by the centromere and move towards the centrioles, while the spindle fibers disappear. At this time the hereditary material (the DNA strands) has already been divided in two parts in an identical way. Now the chromatids are called chromosomes. Anaphase is the crucial phase of mitosis, because in it the distribution of the two copies of the original genetic information takes place. TELOPHASE
Based on the observations collected over the three species, interphase is by far the longest phase, and metaphase, anaphase, and telophase are similar in length, with telophase being slightly shorter. In the broad bean, almost all of the cells were in interphase, for reasons stated in the previous question. In the onion root, about 3/4 of the cells were in interphase, with most of the rest in prophase, and a few in metaphase, anaphase, and telophase. The whitefish had about 70% in interphase, with most of the rest in prophase (15%) , and more in metaphase than in the previous species (6%). The whitefish could have had more cells in metaphase because being animal cells, they require the centrosomes to align at opposite poles, which may cause it to take longer.
During S phase, DNA is replicated. During G2, the cell is at the end of interphase, going into “M” phase, or Mitosis. Mitosis is when the nucleus divides. Mitosis is followed by cytokinesis (division of cytoplasm) resulting in two cells. Cell division is complete after cytokinesis.
Sexual reproduction is most common type of reproduction among the plants and animals. They are of following types; 1) Syngamy: The fusion of gametes takes place completely, if male and female gametes are produced by same cell or organism and both gametes fuse together to form a zygote, this is called as Autogamy, paramecium is its example. Another is Anisogamy in which some organisms produce two types of gametes. Both types of gametes differ from each other in their shape and size and are known as an isogametes or heterogametes. Male gametes are motile and small in size and are known as micro gametes.
Every cell in the human body has a nucleus, where genetic material is stored in genes. Genes carry codes responsible for our inherited traits. Typically, the nucleus of each cell contains 23 pairs of chromosomes. Down syndrome occurs when an individual has a full or partial extra copy of chromosome 21. I could continue talking about this, but since this isn’t science class, thank God, and I’m obviously not a science teacher, I’m just going to leave it here.