CELL AND ITS WORLD- CELL AND ITS ENVIRONMENT

There is a need to have a detailed study about the cell we posses as human beings and how they interact.

[Source- Pixabay]

THE NEED FOR ORGANELLES

All of the processes of life takes place within a single cell. Cell chemistry works because each reaction is controlled by an enzyme. This is a protein designed to control the rate of a very specific reaction.

It also makes sure that it takes place without becoming mixed up with any other reaction. What is more, the enzymes involved in different chemical processes are usually found in different chemical processes are usually found in different parts of the cell.

So for example, most of the day enzymes controlling the reactions of respiration are found in the mitochondria.

The enzymes controlling the reactions of photosynthesis are found in the chloroplasts in plant cells and the enzymes involved in protein synthesis are found on the surface of the ribosomes.

These compartments or organelles help to keep your cell chemistry well under control.

STRUCTURES AND FUNCTIONS IN UNSPECIALIZED PLANT CELLS

Plants are very different from animals. They do not move their whole bodies about, and they make their own food by photosynthesis. Plant cells have all the features of a typical animal cell including a nucleus, cell membrane, cytoplasm, mitochondria and ribosomes.

However, they also have unique structures which are needed for their very different way of life. The cell wall is made mainly of a carbohydrates called cellulose, which strengthens the cell and gives it support.

It is found outside the cell membrane. It contains large holes so that substances can move freely through it in either direction.

In other words, it is freely permeable. Many(but not all) plant cells also have other features.

. Chloroplasts are found in all of the green parts of a plant. They contain the green pigment chlorophyll, which gives the plant in colour.
The chlorophyll enables the plant to absorbs energy from light to make food by photosynthesis.

. A permanent vacuole is a space in the cytoplasm filled with cell sap, a liquid containing sugars, minerals ions and other chemicals dissolved in water.

The vacuole is important for keeping the cells rigid to support the plant. Pressure in the vacuole pushes the cytoplasm against the cell wall, which keeps the whole structure firm. A permanent vacuole is often a feature of mature(adult) plant cells.

SINGLE CELLED ORGANISMS

Organisms such as Amoeba, paramecium and Euglena carry out all of the functions of life within a single cell. They move about, feed reproduce and grow.

They are also sensitive to stimuli, they respire and they excrete.

In single organisms, the surface area which means the volume ratio means that they can take in materials (such as oxygen) from their environment and get rid of water products(such as carbon dioxide) by simple diffusion across the cell surface membrane.

Some of these single-celled organisms for example Amoeba and paramecium feed on other smaller organisms such as bacteria.

They produce enzymes in special vacuoles inside the cell that digest the food. They move in different ways. Amoeba moves by the flowing of the cytoplasm into regions called pseudopodia. Paramecium is covered with ciliw, tiny hair-like extension that beat backwards and forwards to move the organisms along.

Other single CELLED organisms such as Euglena contain chloroplasts and can make their own food by photosynthesis. However, Euglena moves about independently as well. They have characteristics that are similar to both animals and plants.

COLONIES, FILAMENTS AND TISSUES

Not a single cell organisms are free living like paramecium and Euglena. Some live together in large groups cells. Some simple organisms form long strands or FILAMENTS made up of cylindrical cells joined together. One example is spirogyra, a filamentous green algae.

Each algal cell contains at least one large, spiral chloroplasts and the algal mass makes food by photosynthesis.

Other organisms form masses known as colonies. For example, Volvax is made up of a mass of individual cells in a jelly-like mass. Each cell had an eyespot that is sensitive to light, at least one flagellum that beats to enable the colony to move towards the light, and a large chloroplasts so that they can carry out photosynthesis.

Colonies can contain anything from around 500- 50000 cells. Single cell organisms do not contain or form tissues.

However, in multicellular organisms, many cell of the same type can work together to carry out a particular function in the body and this is known as a tissue. For example the muscle tissue.

THE CELL AND ITS ENVIRONMENT

Your cells need to take in substances such as oxygen and glucose, and to get rid of waste products and chemicals which are needed elsewhere in your body.

In humans beings, just like in all other living organisms, dissolved substances can move into and out of your cells across the cell membrane in three different beats. These are diffusion, osmosis and by active transport.

DIFFUSION

When you go home from school, you will probably know if there is a meal cooking before you get home. You know this because the smell reached you by diffusion. In the sea, the blood from an injured fish spreads through the water by diffusion and attracts sharks. Diffusion happens when the particles of a gas or any substances in solution spreads out

Diffusion is the net(overall) movement of particles from an area of high concentration to an area of lower concentration. It takes place because of the random movement of the particles of a gas or of a substance in solution in water.

All the particles are moving and bumping into each other, and this moved them all around. Although the molecules are moving in both directions, there are more particles to move in the area of high concentration and so the net (overall) movement is away from the area of high concentration towards the area of low concentration.

Imagine an empty room containing a group of boys and a group of girls. If everyone closes their eyes and moved around briskly but randomly, people will bump into each other and scatter , until the room contains a mixture of boys and girls. This gives a good working model of diffusion

A simple way to demonstrate diffusion is to ask your teacher to spray some perfume or aftershave at the from of your class, or wave a strongly scented flower. Start timing as the spray is released and then put your hand up when you can smell the perfume. You will see a wave of hands moving from the front to the back and sides of the class as the molecules spread out by diffusion and you can time how long it takes to reach the last person.

CONCLUSION

I will have love to go deeper in this topic today but I am not feeling myself. I am kind of feeling headache so I will continue next time in my next post.

REFERENCES

. https://en.m.wikipedia.org/wiki/Cell_(biology)
. https://www.britannica.com/science/cell-biology