BIOLOGY ESSAY HIV transmission and prevention The point of this essay is to write about what is HIV and how does it transmission work and how to prevent it. AIDS (Acquired Immune Deficiency Syndrome) is one of the worst pandemics the world has ever known. HIV (Human Immunodeficiency Virus) is the virus that causes AIDS was first discovered in a remote area of central Africa. It has since swept across the globe, infecting millions in a relatively short period of time. Since then AIDS has killed more than 28 million people that we know of.
But irst I am going to talk about living and non-livin characteristic of a virus. These are the characteristics for something to be considered living: 1 . Homeostasis (Regulation of the internal environment to maintain a constant state) 2. Organization (Being composed of one or more cells, which are the basic units of life) 3. Metabolism (Consumption of energy by converting nonliving material into cellular components and decomposing organic matter) 4. Growth (Maintenance of a higher rate of synthesis than catabolism. A growing organism increases in size in all of its parts, ather than simply accumulating matter.
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The particular species begins to multiply and expand as the evolution continues to flourish) 5. Adaptation (The ability to change over a period of time in response to the environment) 6. Response to stimuli 7. Reproduction Viruses lack cellular structurea and viruses do not have their own metabolism and require a host cell to make new products. Also, viruses cannot reproduce outside a host cell. Accepted forms of life use cell division to reproduce, but viruses Just spontaneously assemble within host cells. Because of these virsues are considered non-living.
HIV infects one particular type of immune system cell. This cell is called the CD4+T cell, also know as a T-helper cell. Once infected the T-helper cell turns into a HIV-replicating cell. HIV will slowly reduce the number of T-cells until the person develops AIDS. These are the basic parts of an HIV VIRUS: 1 . Vlral envelope – This is the outer coat of the virus. It is composed of two layers of fatty molecules, called lipids. Embedded in the viral envelope are proteins from the host cell. 2. p17 rotein – The HIV matrix protein that lies between the envelope and core 3.
Viral core – Inside the envelope is the core, which contains 2,000 copies of the viral protein. These proteins surround two single strands of HIV RNA each containing a copy of the viruses nine genes. The replication of an HIV virus can be represented in seven steps: 1. Binding – The HIV attaches to the immune cell. The viral core enters the T-helper cell and the virion’s protein membrane fuses with the cell membrane. 2. Reverse transcription – The viral enzyme reverse transcripts and copies the viruses RNA into DNA. 3.
Integration – The newly created DNA is carried into the cell’s nucleus by the enzyme and it binds with cells DNA. HIV DNA is called a provirus. 4. Transcription – The viral DNA in the nucleus separates and creates messenger RNA (mRNA) using the cells own enzymes. The mRNA contains the instructions for making new viral proteins. 5. Translation – The mRNA is carried back out of the nucleus by the cells enzymes. The virus then uses the cells natural protein-making mechanisms to make long chains of viral proteins and enzymes. 6. Assembly – RNA and viral enzymes ather at the edge of the cell.
An enzyme cuts the polypeptides into viral proteins. 7. Budding – New HIV virus particles pinch out from the cell membrane and break away with a piece of the cell membrane surrounding them. This is how enveloped viruses leave the cell. In this way the host cell is not destroyed. I have explained how HIV replicates and now I am going to explain how HIV can be transmitted: 1 . Sexual contact 2. Sharing contaminated intravenous needles 3. Breast feeding (mother to baby) 4. Infected mother to fetus during pregnancy or birth 5. Blood transfusions (Rare)
There is also a slight chance of transmission through open-mouth kissing and biting. There have been very few cases of HIV being transmitted through either method. HIV does not transmit through the air or surface contact like cold and flu viruses do. HIV is a fragile virus and doesn’t survive well outside the human body. This fragility makes the possibility of environmental transmission very remote. Outside of a host cell, HIV doesnt survive for very long. Scientists studying the evolutionary history of HIV found that it is closely related to other viruses.
Those viruses include SIV which infect primates, and the more distantly related FIV which infect cats. Studies of these related viruses showed something surprising. Primates with SIV and wild cats with FIV do not seem to be harmed by the viruses they carry. If scientists can figure out how non-human primates and wild cats are able to live with these viruses, they may learn how to treat HIV infections or prevent them altogether. HIV alreday killed more than 28 million people but there are almost 14000 new casses of HIV every day.
The egions with the greatest number of people living with HIV/AIDS, according to the World Health Organization, include: Sub-Saharan Africa – 25. 8 million South and Southeast Asia – 7. 4 million Latin America – 1. 8 million North America – 1. 2 million Eastern Europe/Central Asia – 1. 6 million Today the HIV infected population are living longer than ever. Some people consider this disease chronic rather than a prescription for death. This is due in part to the rieless reseach that has gone into combatting this disease, and the new drug therapies that are abailable today for the HIV patient.