Instrumentation 6

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Microscopy is the study of objects or samples that are too small to be seen by the naked eye. There are several types of microscopy, each with its own advantages and limitations. Here are the main types of microscopy: 1. Optical microscopy: This is the most common type of microscopy, which uses visible light to illuminate a sample. Optical microscopy can be further divided into several subtypes, such as brightfield, darkfield, phase contrast, fluorescence, and confocal microscopy. Optical microscopy is a technique that uses visible light to observe the sample under a microscope. It consists of several components, including an objective lens, an eyepiece lens, and a light source. The working of optical microscopy involves the following steps. The sample to be viewed is prepared by fixing it onto a glass slide and adding a stain or dye to enhance its contrast. The light source, located beneath the sample, emits light that is directed through the condenser lens to focus the light o...
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The cell cycle

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The cell cycle is the process by which a single cell divides into two genetically identical daughter cells. It is a series of events that takes place in a cell leading to its division and duplication. The cell cycle is divided into two main stages: interphase and the mitotic phase.

 

Interphase:

Interphase is the period between cell divisions. During this stage, the cell grows, replicates its DNA, and prepares for cell division. Interphase is divided into three phases:

 

G1 phase: During the G1 phase, the cell grows and synthesizes RNA and proteins needed for DNA replication.

 

S phase: During the S phase, DNA replication occurs, resulting in two identical copies of the genetic material.

 

G2 phase: During the G2 phase, the cell prepares for cell division, synthesizes microtubules, and checks the integrity of DNA.


Mitotic Phase:

 

The mitotic phase is the period during which the cell divides into two daughter cells. The mitotic phase is divided into four stages:

 

Prophase: The chromatin condenses into discrete chromosomes, the nuclear envelope breaks down, and the spindle apparatus begins to form.

 

Metaphase: The spindle apparatus aligns the chromosomes along the equatorial plane of the cell.

 

Anaphase: The sister chromatids separate at the centromeres and are pulled apart by the spindle apparatus towards opposite poles of the cell.

 

Telophase: The nuclear envelope re-forms around the two sets of chromosomes, and the spindle apparatus disintegrates.




 

Cytokinesis:

Cytokinesis is the final stage of the cell cycle, during which the cell physically divides into two daughter cells. In animal cells, a contractile ring of actin and myosin filaments forms around the cell, which eventually pinches the cell membrane inwards to divide the cytoplasm into two. In plant cells, a cell plate is formed from Golgi-derived vesicles, which eventually divides the cell into two.


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