A virus always has at least two parts: an outer capsid composed of protein units, and an inner core of nucleic acid- either DNA or RNA. The viral genome has at most several hundred genes; a human cell contains thousands of genes. The classification of viruses is based on (1) type of nucleic acid, including whether it is single stranded or double stranded, (2) viral size and shape, and (3) the presence or absence of an outer envelope. It is now believed that viruses are derived from the very cell they infect; the nucleic acid of viruses came from their host cell genomes. Therefore, viruses must have evolved after cells came into existence, and new viruses are evolving now. Viruses, like other organisms, can mutate, and this habit can be quite troublesome because a vaccine that is effective today may not be tomorrow. .
Viruses are specific to a particular host cell because portions of the capsid bind in the lock-and-key manner with a receptor on the host cell plasma membrane. After viral nucleic acid enters the cell, it takes over the metabolic machinery of the host so that more viruses are produced. The lytic cycle may be divided into five stages: attachment penetration, biosynthesis, maturation, and release. During attachment, portions of the capsid combine with a receptor on the rigid bacterial cell wall in the lock-and-key manner. During penetration, a viral enzyme digest away part of the cell wall, and viral DNA is injected into the bacterial cell. Biosynthesis of viral components begins after the virus brings about inactivation of host genes not necessary to viral replication. The virus takes over the machinery of the cell in order to carry out viral DNA replication and production of multiple of the capsid protein subunits. During maturation, viral DNA and capsids are assembled to produce several hundred viral particles. Lysozyme, an enzyme coded for by a viral gene, is produced; this disrupts the cell wall, and the release of new viruses occurs.
These are the times that I appreciate the course I took in college - Microbiology. I may not be as well informed as I was years ago in the field of Microbiology, but at least I still have an idea of what the avian flu is about. The first time in years that I took an interest again in Microbiology was when the SARS virus came out. ...
Food spoilage Bacteria, yeast and moulds may cause putrefaidion, fermentation and moulding in food. Most kinds of food are subject to microbiological spoilage unless special methods are used for their protection. Microorganisms are usually found on the skins membranes of food. They penetrate the in...
Bacteria are single celled microbes. The cell structure is simpler than that of other organisms as there is no nucleus or membrane bound organelles. Bacteria are classified into 3 groups according to their basic shapes: spherical (cocci), rod (bacilli), and spiral. Bacteria are also classified by ce...
SCCO requires its students to have completed one semester of calculus, organic chemistry, microbiology, and statistics, along with two semesters of psychology. SCO mandatory courses include: one semester of calculus, organic chemistry, microbiology, statistics, psychology, and biochemistry. UHCO requires one semester of calculus, organic chemistry, microbiology, statistics, anatomy, physiology, biochemistry, and psychology to be taken by incoming students. ...
(Microbiology Lecture Notes, 1/10/03) Francesco Redi, performed an experiment in the early 18th century regarding spontaneous generation and disproved it. ... (Microbiology Lecture Notes, 1/10/03) Louis Pasteur, compelled to disprove the theory of spontaneous generation, performed the "swan neck tube experiment."" ... (Microbiology Lecture Notes, 1/10/03) Joseph Lister, a British surgeon, was one of the great innovators in antiseptic surgery. ...
Since the dawn of time, bacteria have made their presence known on the earth on a unimaginable scale. Such a profileration of microbes, has put the human race as we know it, at risk to an assortment array of diseases. Taylor estimates about "one half of all human diseases are caused by pathogenic...
In Eukaryotic cells there is also a distinct nuclear membrane Prokaryotic cells are smaller than Eukaryotic cells, according to "Pharmaceutical Microbiology" the majority of bacteria fall within the general dimensions of 0.75 to 4mm compared to the size of common eukaryotic cells which can be up to 40 times larger than Prokaryotic cells and measure between 50 and 150mm. ...
Principle Duties Preparation and servicing of equipment in trays Delivery and collection of equipment to and from the laboratories Ensuring kits in labs are kept stocked Making up stock solutions of chemicals Cleaning glassware basic servicing of equipment e.g. microscopes Making minor repairs to equipment Assisting in stock control/ordering of equipment Preparation and disposal of microbiological media Maintenance of lab materials Setting up practical assessment material a willingness to learn about desktop computing and databases College based Health & Safety within...
In their 2005 book, "Making Modern Science: A Historical Survey," Peter J. Bowler and Iwan Rhys Morus claim that a "new biology" came into existence in the second half of the nineteenth and early twentieth centuries and in fact, the word "biology" itself was not commonly used until this time. Prior ...
