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Cell structure and function

The cell is considered to be the most vital part of life. From unicellular prokaryotic bacteria to multicellular, complex eukaryotes, all living beings are made up of billions of cells. Furthermore, each cell is made up of pre-existing cells. As a result, the cell executes all of the tasks required for life to exist.

Cell Structure

The cell is surrounded by a membrane made up of lipids, proteins, and carbohydrates. Singer and Nicolson introduced the "fluid mosaic model" of bio membranes. According to this theory, the cell membrane comprises a dense fluid matrix composed of two phospholipids molecule layers. Instead of forming a continuous layer, protein molecules or their complexes occur in the membrane as individual particles organized asymmetrically in a mosaic pattern. As a result, some of them are loosely connected at lipid polar surfaces. The extrinsic protein spectrin, for example, attaches to the cytosolic face. In addition, because of the quasi-fluid nature of the lipid, protein may migrate laterally within the overall bi-layer. Thus, there are two types of transport in the plasma membrane:

Cell Structure & Function

  1. Passive transport: It involves the movement of molecules across the cell membrane without a need for energy. Osmosis and diffusion are examples. Neutral solutes, for example, move around the membrane through diffusion across the general surface.
  2. Active transport: Active transport occurs when molecule and particle move against such a concentration gradient across the cell membrane. It typically moves from low-concentration areas to higher-concentration areas, such as the. .g, Na+-K+ pump.

One of a cell's most important constituent structures is the cell wall. It is the cells' complex, support, and surface coatings. Plants, fungi, prokaryotes, and certain protists also include it. It is made up of proteins, cellulose, hemicellulose, and pectin. A cell wall serves as an apoplast, forming a protoplasmic continuity through plasmodesmata known as symplast. Another essential feature in plant cells is the plasmodesmata. A protoplasmic bridge comprises a small hole in the cell wall and a plasma membrane-lined middle lamella from two adjacent cells that includes a fine tubule termed desmotubule. It links two cells' ER.

A vast number of organelles reside inside the cell. An endomembrane system is a membranous organelle with coordinated activities. The endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles are all part of it. However, the components mentioned above do not consider the functions of chloroplasts, mitochondria, or peroxisomes. As a result, they are not included in the endomembrane system.

The Nucleus is a repository for genetic data. It Is only one of a cell's most important structures. Robert Brown was the first to describe Nucleus. It is a protoplasmic body with two membranes that carry genetic information. A double and porous nuclear envelope separates the Nucleus from the adjacent cytoplasm—perinuclear spaces between the outer and inner nuclear envelopes. Nuclear pores allow the Nucleus to interact with the cytoplasm. The nucleolus is a non-membranous structure found inside the Nucleus that contributes to the production of rRNA and ribosomal subunits. The nucleolar structuring area of SAT chromosomes produces nucleoli.

Cells contain specialized structures for locomotion. Prokaryotic cells, for example, have basic flagella composed of flagellin. Flagella in eukaryotes are specialized and organized in a 9+2 pattern. For locomotion, certain unicellular organisms have pili, cilia, pseudopodia, and other structures. All of the cell organelles float in the cytoplasm, which is fluids. It's also referred to as cytosol, which is a jelly-like semi-liquid substance.

Functions of cell

The cell is where an organism's essential metabolic development takes place. A cell in a single-celled organism like an amoeba splits into two daughter cells through binary fission. Cells divide mitotically to produce younger somatic cells, while germ cells divide through meiosis to produce haploid gametes in humans. A cell membrane separates the internal components of a partition from outside the surroundings. The rough endoplasmic reticulum contains a range of proteins within the cells. The Golgi apparatus then changes it, and vesicles expel it. The cell is the location of oxidative phosphorylation, which produces energy. Mitochondria are involved in the ATP production process with the help of the electron transport chain. Multiple pigments present within cells give them their various colours. Chloroplasts, for example, are responsible for the green colour of plant cells, whereas leucoplast and chromoplast, respectively, are responsible for the white and red colours of tomatoes. The Nucleus of cells helps secure all of an organism's genetic information.

Summary

Every living organism is composed of cells, which are the fundamental unit of life. Each cell divides to produce more cells. The endomembrane system of a cell comprises many organelles that work together to keep the cell functioning properly. All of an organism's major chemical processes take place inside its cells.

 

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