Graphics Gallery - Influenza A Virus Replication

Process by which a virus enters a host cell and infects it by reproducing its own genetic material and assembling into virus particles.

The influenza virus is a class of viruses containing RNA as its hereditary material. It replicates by entering a host cell and using this cell's resources to produce hundreds of copies of the viral RNA.

The virus attaches to the outside of the host cell and its RNA enters into the cell. The viral genes are transcribed and translated by the cell's enzymes and ribosomes. In this way, the virus takes over the cell's productivity. Now, instead of producing only new cellular material, the cell produces hundreds of new virus particles. The new virus particles are eventually released from the cell and drift off, and some may land on a host cell of their own to pirate.

Graphics Gallery - Illustration of three viruses

Illustration of three viruses: the tobacco mosaic virus (TMV), the T4 bacteriophage, and the Human Immunodeficiency Virus (HIV).

Tobacco mosaic virus(TMV): consists of a single long RNA molecule (6000 nucleotides) enclosed in a cylindrical protein coat (2130 copies of the same coat protein). It is approximately 300 nanometers long and 15 nanometers wide.

T4 bacteriophage: consists of a DNA molecule tightly packaged in a protein head. The virus attaches to the surface of a bacteria cell and injects its DNA into the cell through its tail.

Human Immunodeficiency Virus (HIV): consists of an outer lipid envelope derived from the host cell. It is a retrovirus, i.e., an RNA-containing virus that replicates by making a DNA intermediate.

Apoptosis

Apoptosis (pronounced apo tō' sis) is a process of suicide by a cell in a multicellular organism. It is one of the main types of programmed cell death (PCD), and involves an orchestrated series of biochemical events leading to a characteristic cell morphology and death. The apoptotic process is executed in such a way as to safely dispose of cellular debris.

Everything you need to know about Apoptosis in one great poster

image courtesy of Dr. Arroway

Graphics Gallery - Experimental Demonstration that DNA is the Genetic Material

Graphics Gallery is a series of labeled diagrams with explanations representing the important processes of biotechnology. Each diagram is followed by a summary of information, providing a context for the process illustrated.

by the Access Excellence the National Health Museum Rescource Center

Avery, MacLeod, and McCarty demonstrate that DNA is the genetic material. These researchers prepared an extract from the disease-causing S strain and identified the "transforming principle" that would permanently change R-strain pneumococci into the lethal S strain as DNA. This was the first evidence that DNA could serve as the genetic material

Graphics Gallery - Mutation of Chromosomes

Graphics Gallery is a series of labeled diagrams with explanations representing the important processes of biotechnology. Each diagram is followed by a summary of information, providing a context for the process illustrated.

by the Access Excellence the National Healt Museum Rescource Center

Legend: Illustration of the mutation of chromosomes.

A permanent structural alteration in DNA. In most cases, such DNA changes either have no effect or cause harm, but occasionally a mutation can improve an organism's chance of surviving and passing the beneficial change on to its descendants.