Are all plant cells the same

The different cell types

Although the researcher was unable to reveal the exact function of the small nucleus, it seemed to somehow control embryonic development.

Even if Brown had not yet recognized the cell as the building block of life - he had discovered the cell nucleus. His research was the basis for cell theory.

Today the components of cells and their functions have been extensively researched. Scientists differentiate between three types of cells: animal cells, plant cells and bacterial cells.

The animal and plant cells are called eukaryotes, cells with a real nucleus. Cells without a nucleus are called prokaryotes. These include the bacteria.

Those skilled in the art refer to the cell as "the smallest viable unit". It can combine with other cells to form tissues, organs and organisms. But one thing almost always stays the same: whoever lives consumes energy.

So cells need reliable sources to generate energy. Waste should also be disposed of. And a skin should somehow protect from the outside.

In order to cope with these tasks, a cell needs different components - here the most important ones.

Membrane - the skin of the cell

In prokaryotes such as eukaryotes, the membrane separates the cell interior from the outside world. It consists of a double layer of fat molecules. Hydrocarbons are arranged between the fat molecules and channels are built in.

The components in the cell are also surrounded by membranes. Some structures of the eukaryotes such as the nucleus or the mitochondria are even delimited by double membranes - i.e. two double layers.

In plant cells, the cell membrane is also known as the plasmalemma.

Hereditary information - the blueprint of the cell

In eukaryotes, the blueprint of the cell, the genetic information, is only available in the cell nucleus. It consists of a double strand of DNA molecules. These lie opposite one another in the form of a rope ladder and are twisted into one another like a screw.

DNS stands for deoxyribonucleic acid (English DNA = deoxyribonucleic acid) and denotes a core acid, which among other things consists of sugar molecules, each of which is missing an oxygen atom.

Prokaryotes lack a nucleus, so the genetic information is free in the cell. In most types of bacteria, the DNA is not arranged as a linear double strand, but as a closed, ring-like molecule. Only a few prokaryotes, such as Borrelia, have a linear DNA double strand.

Cell nucleus - the control center of the cell

The nucleus is only found in eukaryotes. It contains the genetic information of the cell and controls all processes of the cell like a control center.

The nucleus can communicate with other cells through tiny channels. The core is surrounded by a shell made up of a double membrane.

Mitochondria - the power plants of the cell

Mitochondria are also only found in eukaryotes. They are the power plants of the cell. To do this, they gain small usable energy building blocks (ATP = adenosine triphosphate) and burn sugar with the help of oxygen.

This process creates water and carbon dioxide. Mitochondria also have a double membrane that separates them from the rest of the cell.

Endoplasmic reticulum - a branched canal system

The endoplasmic reticulum (ER) of eukaryotes is a richly branched canal system. It penetrates the entire cell and is surrounded by a simple membrane.

The channels are in direct connection with the cell nucleus and form vesicles and protuberances.

The rough ER is covered with ribosomes from the outside and is used to build proteins and the cell membrane. The smooth ER, with no attached ribosomes, plays an important role in the metabolism of fats, carbohydrates and hormones.

It is also crucial for cell detoxification. It can store calcium, for example in muscle cells.

Golgi apparatus - transport system made from vesicles

Only eukaryotes have a Golgi apparatus, which is enclosed by a simple membrane. It exchanges cell components with other organs of the cell via tiny vesicles.

Proteins in particular are reassembled in the Golgi apparatus. But it also sends bubbles to the cell membrane and transports waste materials or hormones to the outside.

The transport via enclosed vesicles is supposed to prevent premature chemical reactions in the cell.

Cell wall - protective layer

Plant cells and most bacteria are surrounded by a thick cell wall in addition to the cell membrane. This lies outside the membrane and envelops the cell.

The plant cell wall is mainly made up of cellulose, a multiple sugar. The wall protects against liquids that would otherwise flow into the cell. In addition, it offers strength and lifts the plant body upwards.

Stored substances such as lignin (wood pulp) provide additional stability and allow trees to grow high. In addition, the wall counteracts the water pressure that presses from the inside of the cell outwards.

In the bacterial wall, the basic building block is not cellulose, but murein, a structure made of sugar and amino acids.

Basically, bacteria can be divided into two categories in the laboratory, depending on the coloration: Gram-negative and Gram-positive bacteria. The latter have a multi-layer Mureinwand, from which dyes are difficult to wash out. Your cell wall turns purple.

Gram-negative bacteria remain colorless because their cell wall is so simply built that no dyes can accumulate. The wall also has a protective function against bacteria and counteracts the pressure inside the cell.

Vacuole - storage for cell juices

Only plant cells need a vacuole. They store all water-soluble cell juices in it. The juices can also be colored, for example in red cabbage or beetroot. In interaction with the cell wall and the cell juices, the vacuole maintains the internal pressure of the cell.

Chloroplasts - energy supplier for plants

Plant cells need chloroplasts to survive. Like mitochondria and the cell nucleus, these are surrounded by a double membrane and give green leaves their color.

In sunlight, a small miracle always occurs in these tiny places: photosynthesis. It is the basis of all life on earth.

The plant uses the energy of sunlight to extract sugar and oxygen from carbon dioxide and water. This is exactly the opposite of the process that takes place here as in mitochondria, where sugar and oxygen produce water and carbon dioxide.

Because the plant cell has mitochondria and chloroplasts and can thus keep the oxygen and carbon dioxide cycle going, plants can exist without humans and animals - but we cannot exist without plants.

For us they are vital suppliers of energy and oxygen.

The dyes of the plastids are not always green. In roots like the carrot, for example, they are orange in color.

In addition, the dyes are not water-soluble like those in the vacuole. This explains why water turns red when we cook red cabbage, but not orange when we cook carrots.

Metabolism in bacteria

Bacteria do not contain mitochondria or chloroplasts. However, they can have structures that undertake similar chemical reactions.

However, these are then simple invaginations of the membranes or simple cell components and not separate reaction spaces as in eukaryotes.