Understanding Cell Division: Mitosis and Cytokinesis
Cell Division Stages
This process involves two stages: the division of the nucleus (mitosis or karyokinesis) and the division of the cytoplasm (cytokinesis or cytodieresis).
Nuclear Division: Mitosis or Karyokinesis (Equational Division)
Prophase
Most animal cells have a centrosome surrounded by dense pericentriolar material. At the beginning of prophase, a second centrosome forms next to the first one. The pericentriolar material generates microtubules, forming the aster. The two asters move to opposite
Read MoreUnderstanding Infectious Diseases and Immunity
Infectious Diseases and Immunity
2. Transmission of Infectious Diseases
2.1. Diseases Transmitted by Bites
- Rabies: Transmitted by the bite of dogs, cats, and bats. The virus attacks the nervous system, and symptoms appear three to eight weeks after the bite. These include fever, hyperactivity, hallucinations, and confusion.
- Tetanus: Causes violent involuntary muscle contractions, such as in the neck and jaw.
- Gas Gangrene: The exotoxin secreted causes tissue degeneration and releases a large amount of
Mitosis and Meiosis: Cell Division Processes
Mitosis
Across the dividing cell, mitosis is characterized by two key components: the chromatic and achromatic apparatus. The chromatic apparatus consists of chromosomes and the nucleolus. The achromatic apparatus is formed by centrioles, asters, and the spindle.
Prophase
Between G2 and prophase, the cytoskeleton reorganizes. In plant cells, the cell wall remains rigid.
Metaphase
During metaphase, microtubules move chromosomes to opposite poles. Longer kinetochore microtubules exert a stronger pull.
Read MoreBone Cytology and Pathology: A Comprehensive Guide
General Features of Fine Needle Aspiration (FNA)
What is FNA?
FNA is a histological study performed using a fine-gauge needle to extract cells or fluid from a mass. The extracted material is then examined cytologically. This procedure can be guided by imaging techniques such as CT scans, ultrasounds, or X-rays.
Advantages of FNA
- Simple technique
- Few complications
- Quick and inexpensive
- Wide application for both palpable and non-palpable masses
Procedure
FNA should be performed by a pathologist or clinician
Read MoreAsexual & Sexual Reproduction: Cycles, Structures & Functions
Asexual Reproduction vs. Sexual Reproduction
Asexual Reproduction
Origin: 3500 million years ago
Cell Division: Mitosis
Parents: 1 progenitor
Cell Type: Normal cells
Characteristics:
- Simple and profitable reproduction
- Genetically identical individuals
- No recombination of genes or characters
- Rapid growth in the number of individuals
Sexual Reproduction
Origin: 1500 million years ago
Cell Division: Meiosis
Parents: 2 (almost always)
Cell Type: Specialized cells
Characteristics:
- Constructive and complex reproductive
Lipids: Classification and Properties
Saponifiable Lipids
Saponifiable lipids contain fatty acids, which are monocarboxylic acids that may or may not be unsaturated. When subjected to alkaline hydrolysis, they undergo saponification, forming soaps (salts of fatty acids). Examples include glycerides, waxes, phospholipids, and sphingolipids.
Unsaponifiable Lipids
Unsaponifiable lipids do not contain fatty acids and therefore do not undergo saponification reactions. This group includes terpenes, steroids, and prostaglandins.
Fatty Acids
These
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