Exchange and Transport in Protozoa
The exchange of gases between the environment and cells occurs via the process of diffusion. Diffusion depends on:
· The amount of surface area available for diffusion. The larger the surface area the greater the rate of diffusion.
· The concentration gradient. An organism which respires very quickly will have a much lower concentration of oxygen in the cells and a higher than normal concentration of Carbon Dioxide. So the greater the concentration gradient across the respiratory surface the quicker the rate of diffusion.
· The thickness or length of the diffusion path. The greater the thickness of the path the slower the rate of diffusion because the gases will have to travel a larger distance. So the respiratory surface must be as thin as possible.
The relation of the three points above can be summed up by Fick’s Law:
However, the amount of gas which an organism needs to exchange is greatly proportional to its volume, nevertheless, the amount of gaseous exchange which takes place is proportional to the surface area over which the exchange happens.
For single celled/unicellular organisms the surface area to volume ratio is large, however, for larger organisms the surface area to volume ratio decreases. The larger the object gets the more complicated it gets.
The smaller the object the larger the surface area to volume ratio. This is where single celled organism have an advantage. Organisms like Amoeba can exchange gases with environment quickly and easily. However exchange surfaces need to attain certain properties to maximise gaseous exchange. They are:
· Need to have a good blood supply- high concentration gradient
· Moist- Dissolve gases
· Large Surface Area
· Thin walls
· Permeable
As single celled organisms are small so they do not have to have specialised systems like much larger organisms like mammals. Single celled organisms like amoeba do not have to have transport systems or specialised systems because they are so small so [IMAGE]substances do not have to travel far to get to their desired destination.
The contractile vacuole in this amoeba is used for water regulation.
Biology 2A03 Lab 4 Respiratory Gas Exchange in a Mouse Lab Manual. Winter Term 2014 (2014). Biology Department. McMaster University.
This cell membrane plays an important part in Diffusion. Cell membrane and Diffusion Diffusion is the movement of the molecules of gas or liquids from a higher concentrated region to a lower concentration through the partially permeable cell membrane along a concentraion gradient. This explanation is in the diagram shown below: [IMAGE] Turgor When a plant cell is placed in a dilute solution or a less concentrated solution then the water particles pass through the partially permeable membrane and fill the cell up with water. The cell then becomes Turgor or hard. An example of this is a strong well-watered plant.
All of these substances cross the membrane in a variety of ways. From diffusion and osmosis, to active transport the traffic through the cell membrane is regulated. Diffusion is the movement of molecules form one area of higher concentration to an area of lower concentration. Concentration gradient causes the molecules to move from higher concentration to a lower concentration.
The purpose of this lab was to see firsthand the diffusion of a substance across a selectively permeable membrane. Diffusion is the movement of molecules from an area of high concentration to an area of lower concentration until both concentrations are equal, or as you could more professionally call it, equilibrium. This concept is one that we have been studying in depth currently in Biology class.
The novel, The Handmaid’s Tale, written by Margaret Atwood exaggerates and embellishes the stereotypical roles of men and women. Margaret Atwood is a Canadian poet, novelist, and activist. Many of her books include some form of feminism, and her protagonists are often women with little rights. The novel takes place in a futuristic United States, renamed the Republic of Gilead. The idea of rights and choice has been almost completely destroyed. People have been brainwashed to do whatever the government tells them. Three main themes in the novel are feminism, gender conflict, and sexuality.
"The Handmaid's Tale in context: a dystopian text such as The Handmaid's Tale can be seen as a commentary on the context in which it was written. Amanda Greenwood shows how the practical and philosophical choices available to women in the mid-1980s inform the novel." The English Review, vol. 20, no. 2, 2009, p. 10+. General OneFile, go.galegroup.com/ps/i.do?p=GPS&sw=w&u=avlr&v=2.1&id=GALE%7CA210222997&it=r&asid=def760fa99b60e8d412b205ec7185a24. Accessed 5 Nov. 2017
Margaret Atwood takes readers through a dark, dystopian experience in her work “The Handmaid’s Tale”, where woman no longer have any use beyond childbearing. This work was completely based on a dystopian society, under complete government control. In order for Atwood to take her readers on this journey she incorporated key literary devices.
...riority come in affect in a way that he only knows how and that is through emphasizing his dominance, physical strength, and his interpretation of male honor.
At first glance, Margaret Atwood’s The Handmaids Tale would seem like a straightforward feminist text. The narrative takes place in a hypothetical future where gender discrepancies are explored in a complete patriarchy in which women are exclusively domesticated in the house, used for the purpose of breeding, or otherwise banished to the Colonies. The women are categorized by their ability to reproduce children and participate in society according to such placement. Though The Handmaids Tale is supposed to promote awareness of such an oppressive society to women, Atwood demonstrates a more accepting culture of Gilead by women with an overarching theme of complacency. Instead of arguing against such a society, Atwood further oppresses women by implying that women would simply accept this new culture without much of a fight. This implication makes The Handmaids Tale less of a feminist text and more of masculism and power.
The harsh message and unhappy tone in the Handmaid’s Tale makes it difficult to comprehend sometimes. It is a novel of a world we do not want, but could possibly see, and a reminder that we must embrace our freedoms and fight back when anyone, especially the Government tries to take them away. Atwood has intentionally placed the events of the novel in a historical context, as she urges us to think and see that such a fate is not far off, but imaginable, especially in societies like Piexoto’s that mask their sexi...
This earthquake that only lasted 48 seconds was along the San Andreas fault, originating in the Francisco Bay area. The significance or magnitude of the earthquake could not be properly measured on the contemporary Richter scale gauge because it was not invented until 1935. When the earth had stopped moving and shaking people had realized what happened, immediately power lines came down, , the force of this horrific, monstrous quake tore apart buildings and roads. Water lines burst causing a mess, bacteria, debris, sewage everyplace, and gas lines twisted until they erupted, the result ignited a major series of fires and explosions throughout the city. (Schmachtenburg
Types of violence may include physical abuse such as: hitting, punching, slapping, kicking, choking, biting, burning, using objects or weapons, locking up or confining, depriving of food or income and restricting mobility or access to necessities. Sexual violence acts may include forcing a partner to perform sexual acts, forcing partner into prostitution or interfering with birth control. Criticizing, name calling, decision making and playing mind games are some signs of the many forms of emotional abuse. Financial abuse can be putting partner in debt or not allowing them access to money. Threatening the victim with objects or verbally threatening to hurt them or take something away is also a form of abuse. There are several ways that an abuser can manipulate a victim to gain control and maintain it.
These victims have experienced high levels of violence. Most victims are more likely to be reassaulted, they will experience more frequent levels of violence and suffer worse injuries. When violence escalates the likelihood of a weapon being used increases. Evidence points to the actual separation from an abusive partner only intensifies the violence. Further quantitative and qualitative research as Stoever (2014) states that, “high-level violence is often the result of the abuse survivor’s departure from the relationship, not the survivor’s failure to leave.” For this reason, a study found that seventy-five percent of the victims were already separated from their batterers when reported being reassaulted. Attempted homicides occurred as the abused women were attempting to leave their relationships,” (Stoever, 2014, p.1025 &
...s immense problem that affects everyone. We have used the excuse that it is none of our business and that we don’t want to get involved for far too long. Although we have since made progress in our society through education and awareness of domestic violence, it still remains an issue. Because society has, for a very long time, placed such a high value on family privacy and male authority, the criminal justice system has struggled criminalize acts of domestic violence. These views and attitudes have since undergone revision and over the last two decades society has witnessed an increased understanding of the cause of domestic violence, the behavior patterns of abusers and the reaction of their victims. However, there are still many questions left unanswered about the ways to conceptualize domestic violence and the establishment of acceptable intervention strategies.
Dystopia is a very negative, bleak picture of the world in which oppressive societal regime creates an illusion of a perfect society. Margaret Atwood creates a nightmare world where a group of the religious extremists overthrown the government and started a sexual revolution. She wrote this novel during the rise of the feminist movement in the 1960s in America. Therefore, some people might argue that she portrays a typically feminist vision of the dystopian society. For a long time feminist’s fight for the liberation of woman’s rights and freedom of thoughts, however, Republic of Gilead is a theocratic state founded on the traditional values installed by God in the Old Testament that subjugates women’s identity. The Handmaid’s Tale is still