Human Immunodeficiency Virus

Human immunodeficiency virus (HIV) is a lentivirus (a member of the retrovirus family) that causes Acquired Immunoeficiency Syndrome (AIDS), a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive. Infection with HIV occurs by the transfer of blood, semen, vaginal fluid, pre-ejaculate, or breast milk. Within these bodily fluids, HIV is present as both free virus particles and virus within infected immune cells. The four major routes of transmission are unsafe sex, contaminated needles, breast milk, and transmission from an infected mother to her baby at birth (perinatal transmission). Screening of blood products for HIV has largely eliminated transmission through blood transfusions or infected blood products in the developed world.

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Mutation

Two classes of mutations are spontaneous mutations (molecular decay) and induced mutations caused by mutagens. In molecular biology and genetics, mutations are changes in a genomic sequence : the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus.

They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic chemicals, as well as errors that occur during meiosis or DNA replication. They can also be induced by the organism itself, by cellular processes such as hyper mutation.

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Virus

A virus is a small infectious agent that can replicate only inside the living cells of organisms. Most viruses are too small to be seen directly with a light microscope. Viruses infect all types of organisms, from animals and plants to bacteria and Archaea.

Although there are millions of different types. Viruses are found in almost every ecosystem on Earth and are the most abundant type of biological entity. The study of viruses is known as virology, a sub-speciality of microbiology.

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Gene

A gene is a unit of heredity in a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living things depend on genes, as they specify all proteins and functional RNA chains. Genes hold the information to build and maintain an organism's cells and pass genetic traits to offspring, although some organelles (mitochondria) are self-replicating and are not coded for by the organism's DNA. All organisms have many genes corresponding to various different biological traits, some of which are immediately visible, such as eye color or some of which are not, such as blood type or increased risk for specific diseases, or the thousands of basic biochemical processes that comprise life.

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about DNA

DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. Nearly every cell in a person’s body has the same DNA. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA).

The chromosomes inside the nucleus (control centre) of the cell are made of DNA. Lots and lots of DNA. It is very fine and tightly coiled but there may be as much as a metre in a single cell. DNA is really a code. It is divided up into sections. These sections are genes, which carry all the instructions for making up our body. So there is a gene that tells the body to have brown hair and so on. Each gene is a code for a particular protein. Our bodies are made up of proteins. So the genes dictate how we are made and what our bodies look like.

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about RNA

Ribonucleic acid (RNA) is a chain of nucleotides present in the cells of all life. RNA has a number of important functions for living organisms, ranging from the regulation of gene expression to assistance with copying genes. Severo Ochoa, Robert Holley, and Carl Woese all played critical roles in discovering RNA and understanding how it worked, and more research on RNA is constantly being performed.

Many people are familiar with deoxyribonucleic acid (DNA), a nucleic acid which is often referred to as the “building blocks of life” because it contains the genetic material for its parent organism. RNA is equally important, even if it is lesser known, because RNA plays a critical role in helping DNA to copy and express genes, and to transport genetic material around in the cell. RNA also has a number of independent functions which are no less important.

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