GRAM POSITIVE VS GRAM NEGATIVE BACTERIA

Bacteria have cell walls made up of polysaccharides that give them strength and rigidity. This is important since bacteria often experience variations in osmotic strength from solutions of their environment, and their cell walls prevent them from shrinking or swelling. As a reminder, osmosis is the process by which solvent molecules pass through a semipermeable membrane from a less concentrated solution to a more concentrated one, equalizing the concentration on either side of the membrane. Nearly all bacterial cell walls have a peptide-polysaccharide layer called peptidoglycan, or sometimes murein. Peptidoglycan is a polymer made up of sugars and amino acids which forms a kind of mesh.
Bacteria can be classified based on their reaction to the Gram stain, which identifies them based on the chemical and physical properties of their cell walls, as gram positive or gram negative. Gram positive bacteria have a thick cell wall, which consists of up to around 30 layers of peptidoglycan. This cell wall surrounds a monoderm, which is a single plasma membrane. Gram negative bacteria have a MUCH thinner cell wall, consisting of a single layer of peptidoglycan. This layer of peptidoglycan is sandwiched between two lipid bilayer membranes called diderms.
We can differentiate between gram positive and gram-negative bacteria by dying them with crystal violet and then washing them with a decolorizing solution. Then, a counterstain is added, for example safranin or fuchsine. Gram positive bacteria will retain the crystal violet dye and remain purple, while the gram-negative bacteria will be stained pink. Note that gram positive bacteria also pick up the pink colour of the counterstain, however this is not visible when they are dyed with the darker purple colour of the crystal violet stain.
The reason for these staining differences is due to differences in cell wall structure, which is the chief difference between gram positive and gram-negative bacteria. The gram stain detects peptidoglycan, and since Gram positive bacteria have a thick, multilayered peptidoglycan layer, they retain the crystal violet dye. Gram-negative bacteria do not retain the dye for two reasons – they have an outer membrane getting in the way of the crystal violet and they lack peptidoglycan to retain the stain.
Although both gram positive and gram-negative bacteria can be pathogenic, gram negative bacteria are more resistant to antibodies because of their impenetrable cell wall. Unfortunately, these bacteria also develop resistance more quickly.
Not all bacteria can be reliably classified through Gram staining. Acid-fast bacteria or Gram-variable bacteria for example, do not respond to Gram staining. Acid-fast bacteria have cell walls that retain stains particularly well. Although they aren’t closely related to gram-positive bacteria, they can appear purple after the gram stain test. Gram-variable bacteria show a mix of pink and purple cells when stained.

[wllm]

I'm a lab tech. The depiction of the bacteria as happy or depressed is PRICELESS!!! From now on I will always think of this when doing my Gram stains!

[swap_agrawal]

This is the cutest educational animation I've those bacterias were so cute and this animation helped me a lot to visualise them and now i don't need to mug up the differences between them I got crystal clear like I've physically met those bacteria

[robertrosenthal]

Thanks for an explanation to "What is a Gram Positive or Gram Negative Bacteria?" question without giving a biology lecture on the chemistry of the contents of the cell walls.

[ywsl]

Although I'd studied profoundly the difference between Gram plus and Gram negative bacteria, it was quiet a while ago and sometime it's so nice, to go back to the basic.The same goes for DNA synthesis, Avogadro's number, T cells vs B cells and so on.

[robertbostrom]

This has really helped me with my 4000 word essay

[One-qqof]

This 3:09 mins video has helped me more than my teacher discussing it for hours. Lol

[KHess-e]

Peptidoglycan! I just finished my college micro class and that is my fav word from that class. I finished with an A!

[Electroblade]

I Love How The Gram-Positive Bacteria Is Joyful And Happy And The Gram-Negative Bacteria Is Depressed, Nice Touch

[monkixx]

God this is so helpful, I'm studying food science and my major depend on a simple explaining like this!! you way more better than most of my professor, thank you very much keep going

[-psithur]

whenever i read up on bacteria on wikipedia, i always wondered what the difference was. thank you for enlightening me ♥

[rameshmahajan]

Short but packed information with wonderful illustrations.

[biologyexamsu]

Interesting explanation, bacteria cartoon pics really interesting. Concise, interesting in 4 minutes..Great job. Thank you so much

[tlili]

this video explains it so much more interestingly than my prof does

[yoon]

i do not neeeed to see this rn just when i am abt to sleep i swear every waking moment i think abt micro

[User-koun]

2:09 don't both cells retain the violet dye first, and when the alcohol/decolorizer is added, in gram negative bacteria outer phospholipid bilayer is removed first, and that the single layer peptidoglycan stretches, creating holes to allow Iodine-Violet complex(after adding iodine) to flow out? Not because the phospholipid bilayer is present?

[pkoriya]

Thank you you make videos of biological science in a ultimate different way than others make

[AakashKumar_]

0:07 the 3rd image labelling is wrong; It should be written as
"Lower conc outside cell"

[brainnkeh]

Great, brief and direct teaching. Thank you sir

[salvadorhirth]

Hello, nice video and since you asked for suggestions, here it goes: I'd like to suggest a video about bacteriophages therapy, the restriction enzymes that bacteria produce that often attack palindromic segments of bacteriophages genomes and the palindromic repeats in the human genome. Don't hurry, it's a lot! And thanks!

[thejoyfulsound]

You didn't explain why the gram-negative bacteria was said to be more anti-body resistant because of its "impenetrable" cell wall though the gram-positive bacteria is the one with the "thick multi-layered peptidoglycan" membrane. Can you clarify?