Cell Structure Essay Example for Free

Cell Structure Essay After completing the exercise, I was able to: a) Prepare the specimens for staining. b) Observe and identify the unique and typical structures of the microscopic world. c) Identify and use different stains for different types of organelles. Introduction Cell is the simplest unit of life as we see it now. All organisms are made from cells. It is first explained by Robert Hooke in the year 1665 and it is now known to be of almost universal occurrence in organisms. Cell theory refers to the idea that cells are the basic unit of structure in every living thing. Development of this theory during the mid 1600s was made possible by advances in microscopy. In the hierarchy of biological organization, the cell is the simplest collection of matter that can live. There are diverse forms of life that exist as single-celled organism or complex organism. Though in general, most cells are similar, they still show considerable diversity especially in their contents, shape and function. However, with the creation of microscope, scientists and researchers are able to study the specimen of a cell and identify its different structure. Big structures such as the cell wall, cell membrane and nucleus could be seen under the light microscope. Nevertheless, some smaller structures are still too small to be identified without first staining it. Stains can be used to enhance contrast in microscopy image. The choices of stain are important because different stains react or concentrate in different parts of a cell or tissue. This can be seen when acetocarmine stains the nucleus and its contents; iodine solution stains starch grains. Through this experiment, we will be able to determine the structures in the cell. Results and Discussion I. Epidermal Cells of Plants Low power| | The diagram drawn is the upper layer of the cell of the Rheo Discolours leaf. From the diagram, we can see that the cells structured together, that is it seems to be a layer of over-lapped plant cells. Some of the cell have rhombus shaped object. Most of the cells have thick cell wall. After adding the stain iodine, the nucleus of the cell can be seen clearly on the few cells with a few smaller dark spots, that is the starch grains. High power| | The diagram drawn above shows the lower side of the Rheo Discolours leaf cells. While the upper surface has the simple structures such as cell membranes, cell walls and vacuole, the lower structure consists of all that and also a clearer view of the epidermal cells of the leaf. When magnified, the guard cells and also the stomata. The guard cells are lip-shaped, surrounding the stomata. Most of the cells have thick cell wall, with signs of the parenchyma cells on the surface layer and the lower layer of the cell. There are signs of collenchymas especially when there are thickening around the edges of the cell wall when both corners are joined at the cell wall on both surfaces. The lower surface have definitely larger amount of guard cells and stoma compare to the upper surface of the leave. The cell that contains green plastids is the guard cells which contain the chloroplast. II. Cell Wall and Middle Lamellae | The structure drawn above is the transverse section of celery cell. The cell wall is seen from the microscope, surrounding the structure and keeping it intact. A cross-section of a celery sample is composed of many cells. Transparent cells are in pith, vascular tissues and endodermis. Endodermis is like a border between the inner and outer parts of a leaf. In the inner part of the leaf, the vascular tissue can be seen quite clearly grouped together, although the difference whether it is a xylem or phloem is indistinguishable. Collenchyma cell can also be seen in this cell when the walls are joined angularly at the corners. The fine channel in the cellulose that connects the adjacent cells is the plasmodemata. III. Yeast Cells (Saccharomyces) The cell drawn above is the structure of the yeast cell which is small when observed under the microscope. Yeast is a tiny form of fungi or plant-like microorganism (visible only under a microscope) that exists in or on all living matter. Inside the yeast, one could see the nucleus, which are the dark colour dots, a liquid solution of protoplasm, protein, fat and mineral matter that the yeast is mainly composed of and the dark patches called the vacuole. However, it can be seen that the yeast cells do have irregular shaped cell walls. In a way, yeast cell resembles the plant cells as they also have a cell wall. Budding is a type of asexual reproduction commonly seen in yeast cells. New individuals will arise from the outgrowths of existing ones. Budding allows the cell to grow without the fusion of the egg and sperm cell. Therefore, individual cells can also reproduce without a mate. I can conclude that yeast is neither a plant nor an animal cell; it is a type of fungi like mushroom. IV. Blood cells The structure above shows the drawing of the red blood cells. The red blood cells are so small that none of the structures are distinguishable. However, I could be sure that the red blood cell does not contain any nucleus. It is irregular in shape, so the cell wall is also absent. The blood cells mostly clump together. They differ from the regular animal cell in the sense that it does not contain any nucleus whatsoever and it has no starch grains. The red blood cell is surrounded by a type of liquid, named the plasma. V. Spirogyra Cells The Spirogyra cells are cells that consist of a chain of elongated cells joined end to end. It consists of the basic structure seen in the plant cells, which is cell wall, cell membrane, nucleus, small starch grains and most importantly the chloroplast which is the most visible under the microscope. The chloroplast consists of stacks of grana that can be seen clearly spiraling along the elongated cells. Chloroplast is important for the plant during photosynthesis as it converts sunlight and carbon dioxide into oxygen and energy. VI. Flagellum The cell drawn above is the Euglena cells. It is a one body cell that exists individually. It is very small even under the microscope and is barely visible even with staining. The euglena cell is green in colour. However it is not a plant cell because the shape is an irregular shape. Some of the Euglena has a tail structure that comes from the top of the cell. This tail is called the flagellum. It seems that the flagellum is its mode of transport. Conclusion In a cell, whether an animal or a plant cells or cells from other groups in the animal kingdom, there are also smaller molecular structures that can only be seen with a high power microscope. Some structures require staining in order to be visible to the eye even with a microscope. Every staining is unique in order to see certain structures of the cell. Different types of cells have different structures and shapes. Every cell has their own special characteristics in these structures.

Loyalty In Book Characters Essay examples -- essays research papers

Can the perfect ideal of loyalty ever be achieved? What is loyalty, how can you become loyal person? How do the people of today compare to the heroes in the stories that we read Beowulf Sir Gawin and the Green Knight and Camelot. When do you know you are a loyal person, is it something that you are born with or do you learn to become loyal? Is loyalty a valuable human characteristic?How does someone become a loyal person? In Sir Gawin he proved to be loyal when he showed up to a challenge that no normal man could ever win, but he did he went to get his chopped off he was very loyal to his word. Today if you want to become loyal you do not need to do some heroic. That is not good the word loyalty today is used to loosely. If you do something as little as going to work everyday and you are loyal. That is not loyalty that is making money so you can eat. A very good example of loyalty is serving your country at any cost, if you go to war there is a good chance that you will not come back, but you put that aside just to keep the rest of the country safe. That is the ultimate sign of loyalty when you have to face death. So I think that people of today need to make sure that a word is not used just for simple thing, but the correct thing so young people can understand what the word means. Can the perfect ideal of loyalty ever be achieved? In our times I think that loyalty is almost never achieved, why do I think this? The people of today don't know the proper terminology of a w...

A map to the next world

Joy Harjo’s poems are filled with so many images and passages that let’s one ponder and think about the complexity of the work.   She is able to balance contemporary American life and ancient tribal truths magnificently.She is able to brilliantly attach the reader to the character.   In â€Å"A Map to the Next World†, one knows that the poem is most probably addressed to a younger member of her family, a young daughter, or a grand daughter, in fact.   But one feels that Harjo is personally talking to you – we are put in the shoes of a member of a kin.In this poem (A Map to the Next World) one can see how the idea of survival is central to the individual and the Native Americans as a people.   And the way she addresses this survival is by emphasizing the importance of memory (a very central theme in Native American culture) – how one should not forget one’s heritage.And she writes:   â€Å"Keep track of the errors of our forgetfulne ss; a fog steals our children while we sleep†.   She asks her readers to remember their heritage and find solace in it – to â€Å"Remember the hole of our shame marking the act of abandoning our tribal grounds†.The poem promotes an awareness and understanding of the strength of memory – a latch on the value on the powers of memory that all Native American cultures have. Moreover, one can see how survival and continuance are very strong bases for this poem.According to Harjo, in this world, one can easily forget about one’s heritage.   â€Å"What I am telling you is real, and is printed in a warning on the map.   Our forgetfulness stalks us, walks the earth behind us, leaving a trail of paper diapers, needles and wasted blood.†Ã‚   Harjo emphasizes the function of courage in the entire scheme of things, for keeping one’s spirit honest and vital.There seems to be a sense of loss of land, love, innocence and heritage that escalates within.   She discusses the importance of courage by alluding to many Native American spiritual tremors – â€Å"The place of entry is the sea of your mother’s blood, your father’s small death as he longs to know himself in another.†Ã‚   There has to be an understanding of the past for one to be able to move forward.This discipline is central to many Native American cultures.   In this case, Harjo alludes to her mother’s heritage (her blood), and how her father was lost in a sea of identities.â€Å"There is no exit.†, she says.   One must have courage to survive.   One must have courage to go on.   One must have courage to be as tenacious as to venture out alone – to be able to trust oneself.   â€Å"The map can be interpreted through the wall of the intestine – a spiral on the road of nowledge.†Coursing through survival and courage, Harjo moves in out of the realms of dream and reality.   She focuses on bot h hope and despair, and survival and extinction at the same time.   By showcasing these diverse strands of life, she is able to bring a harmonious balanced experience to the reader in the context of cultural allusions.â€Å"You will travel through the membrane of death, smell cooking from the encampment where our relatives make a fest of fresh deer meat and corn soup, in the Milky Way.†Ã‚   In this passage, she focuses on the point that to survive this world, one must not forget.   To go through life and remember, one must travel the way our forefathers did.â€Å"Through the membrane of death† reminds one of the cultural belief in reincarnation – that through dying, one is born.   â€Å"Encampment   †¦ fresh deer meat† both paint the picture of a Native American village dinner – together around a fire, feasting on the day’s hunt.This melding of dream visions, memories, myths and history promotes a centeredness in deep reverence for the natural world (a very Native American ideology), where one should find solace in one’s own heritage and mythology.   But Harjo does not necessarily talk about her own heritage (Cherokee) alone, but includes other Native American tribal traditions.There are snippets of other traditions which she brings in as a way to universalize experiences.   In a way, she is striving to resolve polarities to bring the world into a balance through the awareness of the unspoken superiority one feels as a bearer of ancient culture.   All one has to do is remember – â€Å"They have never left us; we abandoned them for science†.

Essay Gender Stereotypes in Culture - 1756 Words

1. Describe our cultural gender stereotypes, objectification, and media portrayals of women and how these lead to violence against women. Gender is the psychological characteristics and social categories that are created by human culture. Doing gender is the concept that humans express their gender when they interact with one another; it is done every day without thinking about it. Messages about how a male or female is supposed to act come from countless places. According to Helen M. Eigenberg in Woman Battering in the United States, â€Å"Gender construction starts with assignment to a sex category on the basis of what the genitalia look like at birth. Then babies are dressed or adorned in a way that displays the category because†¦show more content†¦This encompasses the concept that impressionable young men may remain unaware of the impact of this violence by the omission of certain facts from news articles. It is also significant to see how the media contributes to the way in which the abused women see their role in the creation of this violence. Media within our society constantly degrades women and sends negative messages about the ways in which women should be treated; women are becoming objectified in the sense they are viewed as objects with diminutive value. The media, which seems to endlessly show women as sexual objects, has the capability of limiting a woman’s potential and damaging her self-worth. More often than not the media depicts the manner people go about their daily life. People look to the media to determine how they should dress, act, and in some cases, even how they should perform sexually. Not only are most magazines directed at women, but the ones that are directed towards men are about vocation and political affairs, not about how to improve his complexion or satisfy his woman. 2. Explain how our culture engages in victim blaming and how that affects our attitudes regarding violence against women. It is a ritual to blame victims for their troubles. Rape victims are often accused of enticing their attacker, and sex abuse victims are made to feel somehow responsible for the abuse. Many victims reveal that the ways they wereShow MoreRelatedGender Stereotypes in Popular Culture730 Words   |  3 PagesGender Stereotypes in Popular Culture For thousands of years, established gender roles have been a part of our society. Women are commonly known as sensitive, emotional, or passive. On the contrary, men are described as rational, competitive, independent, or aggressive. Believing women are more emotional than men is stereotyping. However, the stereotype is not entirely untrue. 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