prokaryote the small microbes~

Today’s topic is on prokaryotic cells.

Eventhough I have learnt this topic since my secondary school then go on in my matriculation studies, I still learnt it now. I’m telling you it’s not going to be boring as long as you are still want to figure out and still want to know about it more and the fact is, I still can’t remember the name of the microbes that I’ve learnt before.

What have I learnt about prokaryotic is that they are very tiny microorganism and they are also simple compare to eukaryote. As everyone very familiar with these microorganisms, these prokaryote are divided into two categories which is the bacteria and archae. Both of them are similar but they are different. Bacteria can be differentiate with it cell wall either they lack of peptidoglycan or not and one of them have bigger periplasmic space which is the gram negative bacteria which the space contain hydrolytic enzyme.
Here are the cell wall structure for gram positive bacteria that i would like to share

this the cell wall structure of gram negative bacteria:

as you can see from above picture, the differences that they have is the gram negative does no contain techoic acid and it has thin layer of peptidoglycan compared to gram positive bacteria.

They also have these kind of external structure of cell wall which is glycocalyx, flagella, axial filament and pili. The structure that I thing I’ve never heard before is the glycocalyx. Glycocalyx is a coating that is secreted by the bacteria which is they use it to protect them from dehydration. It also contribute to bacterial virulence to which it can cause disease. they also known as capsule when it is organized and firmly attached to cell wall. when it is unorganized and loosely attached it is called slime layer.

They also have the structures internal to cell wall which include the plasma membrane, cytoplasm, nuclear area, ribosomes and inclusion. All of them are very familiar to me and all of my colleague. So I would like to share about the inclusion part which I’m not so familiar with it.

This inclusions are very important to the bacteria which is it act and serve as a basis of identification. The types of inclusions are:

·         Metachromatic granules

Which known collectively as volutin. It can be found in algae, fungi and protozoa. It contain polyphosphate for synthesis of ATP.  Example of algae that can be found is the Corynebacterium diphtheria.

Metachromatic granules

·        -  Polysaccharide granules

Consist glycogen and starch

·         - Lipid inclusions for lipid storage. It is stain by the Sudan dye

·         - Sulphur granules

It present in sulphur bacteria (thiobacillus) which they use sulphur as energy reserve.

·        -  Carboxysome

Contain enzyme ribulose 1,5-diphosphate carboxylase which is used for carbon fixation. They can be found in photosynthetic and nitrifying bacteria.

·        - Gas vacuoles

Found in aquatic prokaryotes in order to maintain buoyancy so that the cell can remain at the desire depth in the water.

·         Magnetosome

It act like a magnet to decomposed hydrogen peroxide which protect the cell from hydrogen peroxide accumulation.

Bacteria also produce endospore when they are in unfavourable conditions. This is because the endospore is highly resistant to environmental stress such as:

-         -  High temperatures

-         -  Irradiation

-          - Strong acid

-         -  Disinfectants

What I’m hoping from this topic is that I hope that I can be more interested to study about this microbe world because for me I’m not that good in remembering it really well about their characteristic with its functions because I might find it very difficult. So that I hope I can have more time to do some search on this this prokaryote topic.