Properties And Functions Of The Cell

properties and functions of the cell

 

Session Objectives

1) Feeding in plant,
2) Feeding in amoeba (engulfing),
3) Feeding in paramecium,
4) Nutrients,
5) And Culture Solution.

Last class we discussed about turgidity and plasmolysis, but if you are just joining us, “well welcome” here is the link to the session Turgidity And Plasmolysis,

Today we will be discussing about the characteristics of living things, which are, feeding, excretion, respiration, growth, reproduction and response to the environment.

Properties And Characteristics Of Living Things

Feeding

a] Feeding : is the process by which an organism obtains the nourishment which provides it with the energy for life activities and as well as materials for growth and maintenance of good health.

In Plants, the food needed by the plant is manufactured by the plant itself from the raw materials extracted from its environment through a process called photosynthesis e.g green plant, green plant manufactured there own food by extracting sunlight from its environment to produce mainly starch (glucose) which are stored as glycogen.top↑
Another example is Fungi, it extract its food from the decaying organic matter on which they grow e.g mucor

But in animals, animals cannot manufactured there own food, but instead they feed on food substances made by other organisms.

Properties And Characteristics Of Amoeba

Feeding In Amoeba

Amoeba is a unicellular organism which has no mouth but yet it feeds.
Amoeba feeds through a process called engulfing. It make use of its pseudopodia which is also refers to as fingers of cytoplasm to engulfs the particle of food.
The pseudopodia flow round the food particles and gradually enclose, that is, engulf the food, along with a drop of water into the body of the animal.
There is a food vacuoles inside amoeba, inside which digestion takes place with the aid of digestive enzymes produced by the protozoan.
please note the above point, “digestion take place in food vacuoles in amoeba”.top↑
The digested food is diffusable and it is absorbed into the surrounding protoplasm while the undigested and indigestible portions of the food are left behind by the cell. The undigested and indigestible food flows away from the protoplasm, this “flows” is called a reverse of the engulfing action.

Engulfing Feeding Action In Amoeba

Below are the images of engulfing processes;

Amoeba First approach during engulfing
That is the first approach

Amoeba second approach during engulfing
The second approach

Amoeba third approach during engulfing
That is engulfing.

Amoeba has no definite mouth or anus and its mode of feeding is typically of animals with a very simple cell organisation.top↑

Another example of protozoan is paramecium;

Properties And Characteristics Of Paramecium

Mode Of Feeding In Paramecium

Paramecium feeds mainly on bacteria but it however ingest any small organic particles.
Paramecium has an oral groove which is lined with fine beating hairs called cilia
I remember we have discussed about paramecium before, at the beginning of this topic (The Cell) do you want to take that session again or you are new here, well here is the link to the session Paramecium

So back to the mode of feeding in paramecium.
Food from the surrounding water is drawn in a cone of water into the gullet, by the beating of the cilia, the small food particles are directed down the gullet where the mouth part is and large food particles are prevented from entering into the gullet by a crossed arrangement of cilia at the base of the gullet.top↑

The food particles enters the cytoplasm at the cytostome and a food vacuoles quickly forms around it. The food vacuoles begins to move along a characteristic path round the body.
Note : digestion and absorption in paramecium is similar to that in amoeba.
However, the undigested food are expelled from the cell through the anal pore

During digestion, the content of the food vacuole is initially acidic (about pH 4) but becomes alkaline (over pH7) in the course of digestion. Paramecium stores its excess food in form of glycogen.

Nutrient

Nutrient in biology means a substance which the cell requires for normal growth and development.

Macronutrients And Micronutrients

Recall that nutrients are required by organism for providing energy as well as providing materials needed for growth and repair. In chemical terms, the main nutrients needed by the plant are made up of the following elements potassium, calcium, hydrogen, oxygen, nitrogen, carbon, sulphur, magnesium and phosphorus, these nine elements are called macro nutrientstop↑
These elements are required in relatively substantial quantities by the cell.

Some other nutrients e.g Zinc, manganese, molybdenum, boron and copper are called micronutrients and they are required in small quantities.

Iron is also one the essential element for plants. The quantity of iron required by plant is less than that of a macronutrient but more than that of a micronutrient.

Unicellular organisms in an aquatic environment obtain its nutrients from the water which surrounds it.
In higher plants, higher plants obtain their nutrients from soil in form of mineral salts except the gaseous nutrients.

Culture Solution

Culture Solution is a solution of water mixed with nutrients I.e micronutrients and macronutrients which an organism needs to grow and survive and it is usually used to experiment on microscopic bacteria.

Recommendation For The Preparation Of A Culture Solution

Element lacking And Preparation

1) Magnesium : Substitute potassium tetraoxosulphate (vi) magnesium tetraoxosulphate (vi).

2) Sulphur : Substitute calcium chloride for calcium tetraoxosulphate (vi) and magnesium chloride for magnesium tetraoxosulphate (vi).top↑

3) Phosphorus : Substitute calcium trioxonitrate (v) for calcium tetraoxophosphate (v).

4) Potassium : Substitute calcium trioxonitrate (v) for potassium trioxonitrate (v).

5) Calcium : Substitute potassium tetraoxosulphate (vi) for calcium tetraoxosulphate (vi) and sodium tetraoxophosphate (v) for calcium tetraoxosulphate (vi).

6) Nitrogen : Substitute potassium chloride for potassium trioxonitrate (v).

7) Iron : Leave out iron (iii) chloride (ferric chloride).

Till next class. Our next topic is Anabolism And Types Of Feedingtop↑

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Next Topic : Anabolism And Feeding In Living Organisms


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