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The produced haploid daughter cells then develop further to form gametes (egg & sperm). In summary, meiosis consists of two nuclear divisions whilst mitosis is followed in one division though both of these processes involve the interphase, prophase, metaphase, anaphase and telophase stages.
hile mitosis is important in cell growth, tissues repair and several types of cells through asexual reproduction, meiosis is vital in developing the eggs and sperms through sexual reproduction. hereas mitosis does not produce genetic variability of daughter cells, the several processes in meiosis result in considerable genetic variability. These several processes in meiosis are the independent assortment of chromosomes, crossing over and sperm fertilizing the egg randomly.
The process of crossing over in meiosis an important driving force of evolution and after synapsis (the coming together of chromatids) has taken place. In the crossing over process, segments of DNA from one chromatid pass to another chromatid…… [Read More]
In meiosis the chromosomes are reduced in half, with the phases being: Interphase, Prophase I, Metaphase I, Anaphase I, Telophase I, Prophase II, Metaphase II, Anaphase II and Telophase II. Finally, mitosis creates all other cells with the exception of sex cells, while meiosis creates egg and sperm cells only (Meiosis vs. Mitosis, 2008)
Phases -- Meiosis: 1) Meiosis 1 -- separates chromosomes in half; DNA is exchanged and chromosomes coil and uncoil and share information; 2) Metaphase 1 -- Chromosomes align along an equatorial plane; 3) Anaphase 1 -- Kinetochore (bipolar spindles) shorten and pull the chromosomes apart; 4) Telophase 1 -- the chromosomes arrive at the pole and each daughter cell has 1/2 the number of chromosomes; 5) Meiosis II -- final process in which chromosomes are pulled apart and form four haploid cells. Mitosis: 1) Interphase -- preparation for cell division by production of proteins; 2) Preprophase…… [Read More]
Mitosis vs. Meiosis
Mitosis and meiosis are both processes of cell reproduction.
Mitosis is the process by which eukaryotes reproduce asexually and also how multi-celled eukaryotes reproduce cells for bodily growth. Meiosis is the process by which eukaryotes sexually reproduce. Using humans as the examples, new humans are created by meiosis, but within the human, mitosis reproduces cells. Mitosis results in two identical cells, that is the two cells are clones of each other. Meiosis results in four cells that are not identical, the process of meiosis shuffles the genetic information. By describing the two processes, we will see how this occurs.
In mitosis first the chromosome duplicates, creating two sister chromatids, these sister chromatids are identical. The sister chromatids line up in the center of the cells in what is known as a centromere. A spindle then attaches to each chromatid and the cell divides, with one of…… [Read More]
How variations arise within a phenotype?
Phenotype is the specific characteristics that are displayed by the organism. Phenotypic variation is a prerequisite for evolution due to natural selection, thus without the former, there is no latter. Qualitative traits are traits that show a difference between phenotypes like skin color, sex, and eye color. However, such descriptions are controlled by a small number of genes so environmental influence on these traits is low since it involves the genetics of individuals. Quantitative traits are traits that exhibit a continuous range from one phenotype to another. Therefore, there is no difference between phenotypes and are usually influenced by several gene pairs while the environment has a significant influence on the trait. This type of trait involves the genetics of populations. It is a combination of genetic and environmental factors to produce phenotypes that blend into each other. Phenotypic variance or VP is…… [Read More]
living things are characterized by the following seven characteristics namely mobility, respiration, excretion, sensitivity or response to external stimulus, growth, feeding, and reproduction. Though there may be variations between animal and plant kingdom (ex, plants take in carbon dioxide and prepare their own food), these characteristics are commonly observed among all living things.
iology is a very broad field that encompasses the study of characteristics of living things. It includes botany, zoology and all other sub-disciplines that range from microbiology to evolution and ecology.
Evolution is the branch of biology that deals with the study of natural development of living organisms and the changes in them over time. Evolution refers to the heritable changes that occur in a population over a period of time. All the diversity that is observed currently in plant and animal kingdom can be ascribed to evolution over a long period of time.
Atoms are the…… [Read More]
Timing and Principle Characteristics of Developing Female and Male Germ Cells From Differentiation in Early Embryo to Point of Fertilization
Principle Characteristics Male and Female Germ Cells
The female and male germ cells are reproductive cells that fuse with one another during fertilization (Encarta, 2005; Burfoot, 1999). Each possesses unique characteristics and molecular structure during the prefertilization phase of development and post fertilization. These characteristics are influenced by the production of various hormones in the male and female body.
Fertilization occurs when the materials from two gametes come together to form an embryo. The female gamete is often referred to as the egg or female germ cell whereas the male gamete is often referred to as sperm or the male germ cells (Encarta, 2005; Burfoot, 1999). Developing female germ cells are generally large and contain nutrient reserves including what is referred to as the egg 'yolk' or sometimes white and…… [Read More]
Female copperhead snakes are capable of both asexual and sexual reproduction. In essence, sexual reproduction has got to do with the development of a new organism via “the fusion of two sex cells, the male and female gametes” (Smith and Smith, 2015, p. 198). Asexual reproduction, on the other hand, “is the ability of an organism to produce an offspring without the union of sex cells (i.e. gamates)” (Smith and Smith, 2015, p. 199). It is important to note that in terms of genetic diversity, sexual reproduction is of greater relevance than asexual reproduction. This is more so the case given that in comparison to the parent organisms, the egg and sperm produced have different gene combinations. Meiosis is, according to Smith and Smith (2015), involved sexual reproduction. In basic terms, meiosis involves not only the cell DNA doubling, but also the rearrangement of genes, and the division of the…… [Read More]
Edwards Syndrome, Trisomy 18 8 sources ( 4-5 Print Sources 3-4 online Sources) All questions answered essay ( mandatory): -What ? (Discription genetic disorder) -What genes chromosomes linked disorder? -Describe populations affected Edwards Syndrome (Include gender, age & number affected USA wordwide.
Edwards syndrome which is also known as Trisomy 18 is a genetic disorder that is caused by the presence of a third copy of chromosome 18 instead of the normal two copies. The extra 18th chromosome comes as a result of nondisjunction of the chromosomal material during meiosis. As a result of failure in the segregation of a chromosome to the daughter cells, there can be errors in the meiotic division leading to an extra chromosome. This extra chromosome usually occurs before conception and it is the second most common autosomal trisomy that carries to term after Down syndrome though it is more common in females than males…… [Read More]
All living things are complex organisms that are made up of cells. Some are made up of a single cell while others comprise of numerous cells working together. Cells are the basic functional and structural units of living organisms and are known to be the building blocks of life. In humans it is from a group of cells that tissues are made and from tissues that organs are made which enable beings to live.
Cells obtain food and oxygen through their membranes and each membrane has a specific area which can serve contents of only a given volume. Any increase in volume of the cell requires that the area of the membrane increases. Basically, when cells grow the membrane becomes insufficient in aiding the movement of substances in and out and thus to maintain a favourable surface area to volume ratio, cell division must take place. Furthermore, cell…… [Read More]
Darwin's Theory Of Evolution
The construct of irreducible complexity is a pivotal aspect of genetic theory and of Darwinian theory. Irreducible complexity is a nexus of the older science of biology from which Darwin built his theory and modern genetic engineering. Darwin's words for irreducible complexity, most commonly associated with his argument about the construction of the eye, were "Organs of extreme perfection and complication," and Darwin further explicates,
"Reason tells me, that if numerous gradations from a simple and imperfect eye to one complex and perfect can be shown to exist, each grade being useful to its possessor, as is certainly the case; if further, the eye ever varies and the variations be inherited, as is likewise certainly the case and if such variations should be useful to any animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed…… [Read More]
Hermaphrodite is an organism in which a single individual has both male and female gametes. Many plants and some animals are naturally hermaphroditic and can self-fertilize and reproduce themselves from a single organism. (Omoto & Lurquin, 2004, p. 209) While some species actually reproduce asexually, such as single celled organisms and other creatures, this is not the same as being hermaphrodite. There are benefits to the species in some sense in being able to self-fertilize and reproduce in this way. Sexual reproduction in effects cuts the population's growth rate in half. Only females produce offspring, not males. If half the population is male, then the speed of population growth is half that of an all-female population. An all-female species can quickly out produce a male/female species, allowing an all-female species to survive in high mortality habitats where a male/female species can't succeed. This result is also true in hermaphrodite species,…… [Read More]
These proteins include homologous members of yeast. The presences of these proteins suggest that E. histolytica is skilled to perform homologous recombination, which is the same as in other organisms. DNA damage was evaluated by TUNEL assay. In yeast and in human cells, histone H2AX becomes rapidly phosphorylated when DSs are introduced into chromatin (Lavi et al.).
Studies show that histone as a protein plays a significant role in the transition between the expression of a fetal gene and that of the adult gene. The adult gene's metabolism becomes oxidative in order to adapt to air and to weight, as it generates methylated transmitters and creatine phosphate. The muscles get used to life on the ground as compared to the fetal life which takes place in an aquatic environment. Regulated proteins allow the muscles to respond in a more adequate manner to this environment.
Now, let us see how histone…… [Read More]
Alternation of Generations
Alteration of Generations
"Alternation of Generations" is a term used to explain the life cycle and pattern of reproduction in certain vascular plants, protists and fungi. Usually generations of a species take one complete life cycle; therefore, in order to avoid confusion, this term is usually replaced with the term "Alternation of Phases of a single generation."
In "Alternation of Generations," the process of reproduction is different from other reproductions; it keeps moving back and forth from a sexual from of reproduction in one generation to an asexual form of reproduction in the other generation (Polunin, 1960). Each phase of the life cycle of organisms possessing "Alternation of Generations" contains one or two independent living organism gametophyte and a sporophyte. Sporophyte and gametophyte come from the concepts: spore bearing stage (sporophyte) and gamete bearing stage (gametophyte). Genetically, a gametophyte (which can be a tissue or plant) is…… [Read More]
Macroevolutionary Transition of Cetaceans Back to the Sea
Today, one of the best known examples of macroevolution is that which can be speculated upon and observed in relation to marine mammals. ales, porpoises and dolphins, members of the Catacean order, share a number of distinctions in the marine ecosystem, not the least of which is their high intelligence. Additionally, that these species are mammals that must ascend to the surface for respiration has underscored long-standing zoological speculation as to their origins. As the question of macroevolution suggests, these origins may well denote that the species in question originated on land.
According to the research by Bajpai et al. (2009), the speculative nature of the macroevolutionary theory was given some of its strongest evidence to date by fossil finds in the Indian and Pakistan region. These have suggested that whales in particular can be shown to have evolved into aquatic creatures…… [Read More]
Prokaryotic & Eukaryotic Cells
Cells can be divided into two categories: prokaryotic and eukaryotic cells. Prokaryotic cells are significantly smaller than eukaryotic cells. This size difference is due to the many contents inside a eukaryotic cell that prokaryotic cells do not have. To begin with, prokaryotic cells are always going to be unicellular, while eukaryotic cells can also be unicellular but are many times multicellular (Murray & Baron, 2007). Prokaryotic cells do not have any membrane-bound organelles inside them, such as the nucleus, mitochondria, or lysosome as eukaryotic cells do. The DNA of eukaryotic cells is linear and is contained within the nucleus, while DNA in prokaryotic cells is circular and is contained within the nuclear body, a non-membrane surrounded structure (Murray & Baron, 2007). The number of ribosomes inside a prokaryotic cell is a lot less than those contained in a eukaryotic cell. Prokaryotic ribosomes are about 70s while…… [Read More]
Genetically Modified Crop Plants
The term genetically modified organisms, popularly referred to as GMOs, constitute crops, animals and even microorganisms that have undergone development my man and technology. Through the great leaps man has developed in technology, it is now possible to 'create' organisms and plants through the combination of genes considered superior, resistant and quick-maturing. Farming and animal rearing land brings a challenge in the current world, due to population explosions. This trend has been brought about by the necessity to feed the ever-increasing food demand by world populations.
The world today carries over six billion people, a number that increases every day. The natural means of plant reproduction cannot support to feed this population due to the long time taken to grow to maturity, poor yields and the limited space for planting. Therefore, genetic modification has gained an edge in the development of such crops as…… [Read More]
Diversity and Organisms
Phylogeny is the patterns of lineage branching, produced by the true evolutionary history of the organisms being considered (UCMP Web site). Speciation is the changes in related organisms to the point where they are different enough to be considered separate species. This occurs when populations of one species are separated and adapt to their new physiological, geographic, or behavioral environment (Evolution Library Web site).
Plants have a reproductive cycle, which has an "alternation" between a haploid (n=one copy of each chromosome) gametophyte generation and a diploid (2n=two copies of each chromosome) sporophyte generation. The haploid gametophyte produces haploid gametes, which fuse to form a diploid zygote. The zygote grows by mitosis into the diploid multicellular sporophyte, in which meiosis occurs in special regions creating haploid spores. The spores disperse, germinate into haploid gametophytes starting the cycle anew (Kennesaw Web site).
As plants have evolved, the sporophyte has…… [Read More]
gender and how the characteristic is addressed within the precincts of play, poem, or short story. Further, a comparison of literary elements will be made, in the play, poem, or short story.
Gender and how it is handled in the confines of short story, play, or poem.
Poem -- Thomas Stearns Eliot's The Waste Land
A careful reading of T. S. Eliot's poem, The Waste Land depicts the author's profound anticipation of an important collection of concepts, considered as post-modernism for a major part of the second half of the 20th century. While it is well-understood that the poem by Eliot comprises of a portrayal of theatrical voices, critics are yet to fully understand the fact that a foundational portion of this drama is presentation of gender. Certainly, Eliot, who is, at times, openly positioned as an embodiment of male sexual/poetic hierarchy, is a pioneering 20th-century figure who depicted what…… [Read More]
Trisomy 13 or Patau Syndrome is a genetic disease in which the person has 3 copies of the genetic material from chromosome 13 instead of having 2 copies. It occurs when the extra DNA from chromosome 13 appears in some or all of the body's cells. The treatment of this disorder differs from child to child and depends on the symptoms.
Trisomy 13 (Patau Syndrome)
Background (description of the disease, its symptoms, and impacted population)
Klaus Patau was a German-American geneticist, and together with his research colleagues, described the condition in 1960. The syndrome's clinical appearances were described in 1657 for the first time by Erasmus Bartholin, but he did not know its aetiology (Patient Information, n.d.). Trisomy 13 is a chromosomal condition linked with severe physical and intellectual disability. Those suffering from Trisomy usually have spinal or brain abnormalities, heart defects and smaller, not fully developed eyes -a condition…… [Read More]
Environment Influences the Body Plan of Organisms
The distinction between adiata and Bilateria, or organisms with a radial or bilateral symmetry, is that the latter have a dorsal/ventral polarity resulting in bilateral body axes (reviewed by Martindale and Henry, 1998). By comparison, species with radial symmetry, the adiata, have a single anterior/posterior axis in their body plan and no dorsal/ventral polarity. Another general distinction is the presence of three germ layers in the Bilateria, which are the endoderm, ectoderm, and mesoderm. These three pluripotent cell types will give rise to organs and internal epithelial layers, skin and nervous tissues, and muscle and connective tissues, respectively.
ole of Environment
adiata contain a digestive tract that is perpendicular to radial structures (reviewed by Martindale and Henry, 1998). For example, the cnidarians have a mouth that is surrounded by radial pattern of tentacles. After the food enters the mouth, it collects in a…… [Read More]
eligion or Science?
Since the enaissance, there has been a vocal debate between religion and science. Galileo was imprisoned and sanctioned because of his views of the universe, the sun, and the way planets moved. As science progressed, this debate became even more heated. However, in the late 20th century, there has also been a mitigating discussion about the way that religion and science can actual coexist as explanations of the universe. In fact, as physicists look into the wondrous world of smaller and smaller particles, they find that the laws we through governed the universe do not really fit in with the abstract dimensions of time, space, quarks, and the study of the basic attributes of matter and the universe (Schroeder, 2010, p.xi ). On some level, the debate between science and religion is based on the notion of reason (the scientific method) versus faith. eason implies what can…… [Read More]