Understanding Viruses: Structure, Classification, and Diseases
Virus Structure and Composition
Viruses, existing on the borderline of life, are acellular entities smaller than bacteria. They lack independent motion, feeding, and reproduction, thus parasitizing other living organisms. They form their own kingdom: the Virus Kingdom.
A virus consists of a protein structure (capsid) made of capsomeres, and genetic material (DNA or RNA). Some viruses possess receptors around the capsid for better cell attachment, and some have a membrane derived from the host cell.
Read MoreCommon Swine Diseases: Symptoms, Diagnosis, and Control
Rhinitis, Atrophic
Infectious and chronic condition characterized by hypoplasia and destruction of nasal turbinates. It is progressive and chronic.
- Progressive: Stronger. Caused by two bacteria: Bordetella bronchiseptica, Pasteurella multocida type D.
- Non-progressive: Caused only by Bordetella bronchiseptica.
Etiology
Multifactorial. Bacteria: Bordetella bronchiseptica, Pasteurella multocida type D (dermonecrotic toxin-producing).
Predisposing factors: Excess ammonia gas, inadequate ventilation, overcrowding,
Read MoreCellular Respiration and DNA: The Building Blocks of Life
Cellular Respiration
Cellular respiration is the set of biochemical reactions occurring in most cells. Pyruvic acid, produced by glycolysis, is split into carbon dioxide (CO2) and water (H2O), producing 38 molecules of ATP. The general formula is: C6H12O6 + 6O2 —-> 6CO2 + 6H2O, releasing 38 ATP molecules in eukaryotic cells. This process occurs in the mitochondria in three stages:
- Oxidation of pyruvic acid
- Tricarboxylic acid cycle (Krebs cycle)
- Respiratory chain and oxidative phosphorylation
Cell Biology: Cytoplasm and Cytoskeleton
Cytoplasm
The cytoplasm is the part of the cell contained between the plasma membrane and the nuclear membrane. It consists of the hyaloplasm (cytosol) and organelles, with a cytoskeleton immersed within. The hyaloplasm is a 70-85% water solution, with the remaining 15-30% composed of dissolved or suspended components: carbohydrates, lipids, amino acids, proteins, nucleosides, nucleotides, nucleic acids, mineral salts, and ions.
Cytoskeleton
The cytoskeleton is a network of long, thin protein filaments
Read MoreGenetic Engineering and Immunology
Genetic Engineering
Genetic engineering is the manipulation of DNA to change the genome of a living being. Changes include:
- Introducing new genes into a genome
- Deleting existing genes from a genome
- Modifying the information contained within a gene
- Changing gene expression
- Cloning beings, organs, or tissues
Cloning
Cloning is making a genetically identical copy (may be a gene, cell, or organism).
- Molecular Cloning: Isolates the DNA fragment containing the genes of interest, binds it to a DNA fragment in
Cell Cycle: Phases, Significance, and Genetic Control
Cell Cycle: Interphase and Mitosis
The cell cycle is the ordered set of events from one cell division to another, comprising interphase and mitosis.
Interphase
The cell does not divide, but genetic material duplicates, and cell growth occurs. It’s divided into:
- G1 Phase: Cell growth, doubling of organelles, and cytoplasmic structures. Some cells enter a resting phase.
- S Phase: DNA replication and centriole duplication. Errors can lead to mutations.
- G2 Phase: Preparation for mitosis, cell size increases,