الرئيسية / cell biology topics / cell biology topics : About Biology scientific

cell biology topics : About Biology scientific

cell biology topics

cell biology topics : About Biology scientific

cell biology topics
cell biology topics

Cell biology topics, or cytology, is the science that studies the structural and functional

cell biology

 units common to the organization of all living things. A cell biology topics represents the fundamental unit of every living being, it is the smallest portion of living matter that can isolate itself and reproduce itself

The first microorganisms were seen and described by Antonie van Leeuwenhoek (1632 – 1723), a cloth merchant from the Netherlands. It is undoubtedly in exercising his profession that he seeks to improve the magnifying power of magnifying glasses, he created a simple microscope obtaining high magnifications (300 ×), he invented the first optical microscope (or photosnic microscope), observing all what came to hand, cell biology was born. Today, various observation techniques make it possible to study cells

cell biology topics
cell biology topics

Cell biology tepics : A morphological study, using

optical microscopy (or photonic) that allows magnifications of the order of 2000 times
Electron microscopy allows larger magnifications of the order of 200,000 to 2,000,000 times

A functional and physico-chemical constitution study

Cytochemical study

fixation of the cell, use of dyes with different affinities with chemical compounds according to their pH (eg DNA in green, RNA in pink) use of antigen-antibody reactions then revelation of the immune complex by a dye and visualization under the light microscope.

Cell fractionation

grinding then centrifugation to isolate the different organelle populations and biochemical study of the different organelles.

cell biology topics
cell biology topics

In vitro culture

allows to study cells in various conditions
Micro-surgery: allows ablation or organelle transplants (study of organelle functions)

Autoradiography

radioactive precursor (therefore detachable) incorporated by the cells and detected by radiographyStudy of the kinetics of the marked structure thanks to serial samplings

Prokaryotes can be divided into two groups: eubacteria and archaebacteria

Cell Theory

• Cells are the fundamental unit of life – nothing less than a cell is

alive.

• All organisms are constructed of and by cells.

• All cells arise from preexisting cells. Cells contain the

information necessary for their own reproduction. No new

cells are originating spontaneously on earth today.

• Cells are the functional units of life. All biochemical processes

are carried out by cells.

• Groups of cells can be organized and function as multicellular

organisms

• Cells of multicellular organisms can become specialized in form

and function to carry out subprocesses of the multicellular

organism.

Prokaryotic cell structure

small, with a plasma membrane surrounded by a rigid cell wall
in many the cell wall is made of a carbohydrate
cross-linked with polypeptides
cell wall may be covered with a capsule made of polysaccharides
few or no membrane
enclosed spaces
within the cytoplasm
no nucleus – DNA is
in a region called the
nucleoid
DNA is circular and
naked (has no protein associated with it)

Why are cells small

As cell size increases the volume increases much faster than the surface area. Cells obtain nutrients, gain information and rid waste through their plasma membrane. As cell size increases, a cell’s ability to exchange with its environment becomes limited by the amount of membrane area that is available for exchange

Cell Theory

 Cells are the fundamental unit of life – nothing less than a cell is
alive
All organisms are constructed of and by cells
All cells arise from preexisting cells. Cells contain the
information necessary for their own reproduction. No new
cells are originating spontaneously on earth today
Cells are the functional units of life. All biochemical processes
are carried out by cells
Groups of cells can be organized and function as multicellular
organisms
Cells of multicellular organisms can become specialized in form
and function to carry out subprocesses of the multicellular
organism

Ribosomes –

protein synthetic machinery • two subunits – large and small – each made of protein and ribosomal RNA (rRNA) • subunits associate when they are synthesizing proteins • protein synthesis occurs on ribosomes that are free-floating in the cytoplasm and on ribosomes attached to ER • rRNA is synthesized in the nucleolus 18 Golgi Apparatus – a collection of membranes associated with the ER composed of flatten sacs called concentrates and packages proteins synthesized on the

 

:    Golgi Apparatus –
a collection of membranes associated with the ER
composed of flatten sacs called
concentrates and packages proteins synthesized on the ER

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