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.

» Read More...

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.

» Read More...

DNA and RNA

DNA and RNA are two different nucleic acids found in the cells of every living organism. Both have significant roles to play in cell biology. DNA and RNA structure are similar because they both consist of long chains of nucleotide units. However, there are a few structural details that distinguish them from each other, and if you are to compare DNA and RNA, these would be the results:

» Read More...