Abstract In this article, the writer notes that assisted reproductive technology (A.R.T.) has received a great deal of attention in recent years. The writer explains that couples who have difficulty having children are now seeking out assisted reproductive technology to conceive children. The writer examines the developments and advancements in assisted reproductive technologies. The technologies examined include: Zygote intra fallopian transfer, donor egg or embryo, surrogacy/gestational carrier, in vitro fertilization (IVF), intra cytoplasmic sperm injection and gamete intra fallopian transfer (GIFT). The writer concludes that the research indicates that there are many alternatives available to infertile couples and that IVF and GIFT remain among the most popular and successful types of reproductive technologies.
Outline:
Introduction
Zygote Intra fallopian Transfer
Donor Egg or Embryo
Surrogacy/Gestational Carrier
In Vitro Fertilization
Intra cytoplasmic Sperm Injection
Gamete Intra fallopian Transfer
Future Technologies and Conclusions
From the Paper "In addition to egg donation, embryos can also be donated. In most cases embryos are donated by couples that have undergone IVF and still have some additional frozen embryos; couples can choose to donate these embryos, have them used for medical research or have them destroyed. When the embryos are donated they are given to couples that have problems creating their own embryos."
"The author also points out that as it relates to having to use donor eggs, there are certain emotions that a woman may experience. The author asserts that these emotions are similar to the emotions that a man may experience when he discovers he is sterile. Relying on a donor egg or embryo also means that the woman will have no genetic link to the child."
Abstract In this paper, the writer discusses that there are a number of methods that have been developed with varying degrees of success to help women who have difficulty becoming pregnant. The writer points out that these include some of the most contemporary technologies, such as in vitro fertilization (IVF), intra-cytoplasmic sperm injection (ICSI), and various other procedures. In essence, the writer explains that assisted fertilization refers to technologies and techniques that can be used to enhance sperm-egg interaction. This paper outlines some of the most prevalent and contemporary of the infertility techniques in use today. The writer concludes that the suggestion is that reproductive cloning will advance, in a similar fashion to the acceptance of techniques like IVF, and that new techniques will be developed to improve upon existing methods of infertility assistance.
Outline:
Introduction
In Vitro Fertilization (IVF)
Intra-cytoplasmic Sperm Injection (ICSI)
GIFT: Gametic Intra-fallopian Transfer
Other Techniques
New Techniques and Reproductive Cloning
From the Paper "There are a number of advantages to this procedure, including the fact the embryo can be fertilized inside the oviduct in its natural environment. The process also takes only about an hour and can also be performed on an outpatient basis."
"There are a number of variations to both GIFT and in vitro fertilization that are important to note. These include blastocyst transfer, or the transfer of a more mature embryo; as well as the use of donor eggs from another woman and the use of a surrogate mother and the transfer of frozen embryos."
Abstract Presented in a graph form, this paper provides great detail about the digestive systems of the smallest of creatures in the "kingdom animalia". It explains how lysosome produces a digestive enzyme to breakdown bigger molecules of fat, protein, and carbohydrates, into simple protein, monosaccharides and fatty acid to send to cytoplasm for the cell's life, then converted into energy for cell growth.
From the Paper "The higher phyla, starting from Cnidaria develops extracellular digestive system as well as it develops into radial body symmetry. Cnidarian possess incomplete gastrovascular cavity, tube-like digestive system in which water and other smaller organisms are transported in. Such organism like hydra has digestive layer called gastrodermis, which excretes digestive enzymes to assimilate food. This system is also adapted by Platyhelminthes, which also has similar gastrovascular cavity, mouth without anus."
Abstract This report explains in detail the function, structure and assembly of flagella in E.coli and Salmonella, using plain language and a number of diagrams. Movement (chemotaxis) is the primary function of flagella but its design also incorporates efficient repair capability and antigenic variation. In Salmonella and E.coli the flagellar filament is a homopolymer of flagellin monomers, although other species (such as Helicobacter) build their flagella from mixtures of two types of subunit. All the properties of the functioning filament are reflected in the structure of the flagellin monomer, which has conserved and variable regions, regions targeted by chaperones and coiling enzymes and regions evolved specifically for interaction between monomers. Chemotaxis is driven by a proton motive force (as in oxidative phosphorylation) and the basal complex that converts this energy into rapid rotation of the flagellum is highly complex.
From the Paper "Many bacteria are motile and exhibit chemotaxis ? migration through the extracellular medium towards attractants (e.g. carbon sources), and away from repellents (e.g. antibiotics). The majority move using flagella ?protein structures variable in number and position (Box 1) that generate thrust by rotating like propellers. Flagella are 15nm in diameter and can be observed under light microscopy after thick metal staining or using advanced microscopy techniques such as electron microscopy. Because of the competitive advantages of chemotaxis, there has been strong selection for efficient chemotactic apparatus and flagellar efficiency. The flagellum is based in the bacterial surface layers where a complex array of proteins forms the flagellar motor. Resembling the electric rotary motor and the membrane-bound F1F0-ATPase, and powered by a proton influx across the inner membrane, this highly efficient machine is merely 30nm in diameter. Its mechanism is the subject of ongoing research."
Abstract This paper provides a brief overview of the evolutionary process and the concepts known as protein folding and selective expression. The paper begins with a look at the role of DNA and continues with an account of the history of DNA sequencing and a discussion of the different applications for genome sequencing. The paper also discusses the importance of the study of genomes of different species, known as comparative genomics, and explains an aspect of genome sequencing known as hemology.
From the Paper "The study of genomes of different species would present us with a better picture as to the evolutionary trends, bioarcheology and anthropology. Researchers have identified that 99.9% of the genome information is common for the different human races stressing once again the possibility of a common ancestral origin. In the same vein they have also found that the chimpanzees have about 98.4% of genetic information common with humans. [ Hecht, J] So the improvements in genome science is helping us ascertain our evolutionary trends better than ever before. Similarly mouse and human beings are found to share 97.5% of the DNA material implicating a common ancestral origin some hundred million years ago. [Cohlan, A]"
Abstract This paper briefly explains the basic principles behind plant growth and reproduction. It looks at the cell division process, describes the inner and outer cell layers and what is inside a cell and finally explains the process of cell division and photosynthesis.
From the Paper "In order to understand exactly how plants grow and how they reproduce, one must first have a basic understanding of the principles behind these two biological functions. In essence, the so-called "building blocks" are known as cells which exist in a great variety of shapes and forms with each cell having a specialization for bring about certain functions and biological operations. All of these specialized cells develop from identical cells through a process called cell differentiation, "a highly regulated process in which specialized chemical reactions control the cell's length and width, the mass and architecture of its walls and the nature of its internal structure." 1 Due to the fact that the growth of a plant involves the development of roots, stems, leaves, flowers and related structures, a continuous supply of new materials is required which is made possible through a process known as cell division."
Abstract This paper describes the model that was used to study the role of microtubule-associated proteins in mitosis. The paper explains that microtubules play a significant role in a number of cellular processes, including mitosis, cell motility, and intracellular vesicle transport. It also points out that the dynamic behavior of microtubules plays a significant part both in cell cycle actions and in cell segregation.
From the Paper "Kinesins and dyneins play significant roles throughout cell dissection. By means of RNA intrusion (RNAi) to reduce individual or groupings of motors along with immunofluorescence and time-lapse microscopy, the mitotic roles of cytoplasmic dynein and all 25 kinesins in Drosophila S2 cells are examined. It is shown that four kinesins are concerned in bipolar spindle assembly, four kinesins are involved in metaphase chromosome alignment, dynein plays a role in the metaphase-to-anaphase transition, and one kinesin is needed for cytokinesis. efficient redundancy and alternative pathways for completing mitosis were observed for many single RNAi knockdowns, and failure to complete mitosis was observed for only three kinesins. As an example, inhibition of two microtubule-depolymerizing kinesins originally formed monopolar spindles with unusually long microtubules, but cells ultimately formed bipolar spindles by an acentrosomal pole-focusing mechanism. From our phenotypic data, we construct a model for the distinct roles of molecular motors during mitosis in a single metazoan cell kind. ."
Abstract In this article, the writer explains that the Na+-K+-ATPase (Sodium Pump)The Na+-K+-ATPase, or sodium pump is a highly-conserved integral membrane protein existing in almost all cells in higher organisms. The writer further explains that a human at rest contains cells that consist roughly of 25% cytoplasmic ATP which is hydrolyzed by sodium pumps. Approximately 70% of ATP is consumed to fuel sodium pumps in nerve cells. In the body, the autonomic nervous system heart cells are regulated through these receptors to modulate certain ion-kinetic structures to influence ion movement. The writer concludes that the sodium pump is involved in cell junction maintenance, thus ensuring that the heart cells stay connected with one another. The writer also notes that without this sodium pump, the body cannot function and the heart never develops.
From the Paper "Description of the structure of this molecule is still uncertain, but information is available to define the amino acids involved in ATP and cation binding. The sodium pump, which is located within the outside membrane of the cell, grabs sodium and releases it on the other side of the membrane, repositioning itself to do so, then grabs potassium and releases it within the cell: Within the cell, ATP is bound to the empty pump, the N/A+ ions approach the pump, are bound to the pump until the pump is loaded with (3) Na+ ions, ATP is hydrolyzed, the pump phosphorylated, the pump reorients in the membrane and the Na+ ions start to fall off outside of the cell. As the Na+ ions are released, (2) K+ ions approach the pump, are bound and dephosporylation takes place. The ATP is bound to the pump, a conformational change takes place when the K+ is in the cell and they are delivered into the interior of the cell and the pump is ready to start again. Although it is difficult to explain the structure of this "pump," based on primary amino acid sequence, it probably possesses 8 or 10 transmembrane domains."
Abstract In this paper, the writer notes that in the past few decades, several advanced current-day fertilization techniques for women that have difficulties conceiving children have emerged at the forefront of medical technology. The writer points out that medical professionals are now able to prescribe a few different treatment options for women that are unable to get pregnant naturally. If treatment has not resulted in pregnancy after four to six menstrual cycles, fertilization techniques may be considered. The writer concludes that it appears that different techniques have roots in in vitro fertilization, which is predicted to see improvements over the next few years. The writer maintains that the future of human fertilization appears bright.
Outline:
Introduction
In Vitro (test tube) Fertilization
Third Party Donor
Gametic Intra-fallopian Transfer
Intra-cytoplasmic Sperm Injection
Conclusion
From the Paper "Currently, in due to improvements in ultrasound imaging, surgery is no longer necessary for most in vitro fertilization patients. Technological progress has allowed for the use of a sonographically-guided needle to replace the surgical procedure which previously was used to recover eggs. This procedure, called Transvaginal Oocyte Retrieval, requires neither hospitalization nor general anesthesia. Instead, the woman undergoes about two weeks of intensive preparation, including hormonal therapy with fertility drugs. Blood tests and ultrasound scans of the ovaries are used to determine the optimal time to retrieve the eggs from the ovary, and at the proper time, an outpatient procedure under local anesthesia will allow the female's eggs to be visualized by ultrasound and retrieved from the ovary by placing a needle through the vaginal wall. The woman experiences pain similar to a pap smear and is able to return home and resume normal activities. The embryologist places the sperm with the eggs when they are ready for fertilization, maintaining them in a laboratory dish in a nutrient mixture which acts as a substitute for the environment that would otherwise have been provided by the fallopian tubes."
