# What is the biggest single-celled organism? – Murry Gans

The elephant is a creature
of epic proportions, and yet it owes its enormity to more
than 1,000 trillion microscopic cells, and on the epically small end of things, there are likely millions
of unicellular species, yet there are very few we can see
with the naked eye. Why is that? Why don’t we get unicellular elephants, or blue whales, or brown bears? To find out, we have to peer into
a cell’s guts. This is where most
of the cell’s functions occur, enclosed by a cellular membrane that acts as the doorway into
and out of the cell. Any resources the cell needs to consume, or waste products it needs to expel, first have to pass through this membrane. But there’s a biological quirk
in this set up. A cell’s surface and volume increase
at different rates. Cells come in many shapes, but imagining them as cubes will make
the math easy to calculate. A cube has six faces. These represent the cell membrane,
and make up its surface area. A cube measuring one micrometer
on each side, that’s one millionth of a meter, would have a total surface area
of six square micrometers. And its volume would be
one cubic micrometer. This would give us six units
of surface area for every single unit of volume, a six to one ratio. But things change dramatically
if we make the cube ten times bigger, measuring ten micrometers on each side. This cell would have a surface area
of 600 square micrometers and a volume of one thousand
cubic micrometers, a ratio of only .6 to one. That’s less than one unit of surface area
to service each unit of volume. As the cube grows, its volume increases
much faster than its surface area. The interior would overtake the membrane, leaving too little surface area for things
to quickly move in and out of the cell. A huge cell would back up with waste
and eventually die and disintegrate. There’s another plus to having multitudes
of smaller cells, too. It’s hardly a tragedy if one gets
punctured, infected, or destroyed. Now, there are some
exceptionally large cells that have adapted to cheat the system, like the body’s longest cell, a neuron that stretches from the base
of the spine to the foot. To compensate for its length,
it’s really thin, just a few micrometers in diameter. Another example can be found
in your small intestine, where structures called villi
fold up into little fingers. Each villus is made of cells with highly
folded membranes that have tiny bumps called microvilli
to increase their surface area. But what about single-celled organisms? Caulerpa taxifolia, a green algae
that can reach 30 centimeters long, is believed to be the largest
single-celled organism in the world thanks to its unique biological hacks. Its surface area is enhanced with
a frond-like structure. It uses photosynthesis to assemble
its own food molecules and it’s coenocytic. That means it’s a single cell
with multiple nuclei, making it like a multicellular organism
but without the divisions between cells. Yet even the biggest unicellular organisms
have limits, and none grows nearly as large
as the elephant, whale, or bear. But within every big creature
are trillions of minuscule cells perfectly suited in all their tininess to keeping the Earth’s giants
lumbering along.

## 100 thoughts on “What is the biggest single-celled organism? – Murry Gans”

1. Kyla King says:

I love it when he says micrometer xD

2. Ironicist says:

Lost me at cubes…..

3. Jayank Tyagi says:

*Opens the video just to comment "Ostrich egg" and leaves without watching it.*

no satisfaction

5. Theresa Tran says:

@ 00:30 "Because we don't want to be killed, absorbed, and dissolved by a unicelluar organism!" š

6. 1000 subsciber without video says:

eh.Embrio

7. Ken Calvelo says:

Can I ask you something?, why is a bacteria desire Iād to live if it doesnāt have an organ particularly the brain?

8. Toprak says:

It's MICRO METER not MIKE ROMITTER.

9. MegaloMitchell YT says:

Itās kirby

10. THE THIN. G Fait says:

amoeba proteins

11. Nathan Bu says:

Kirby

12. JavenE says:

Wouldn't it mean a single celled organism is just a giant cell with multiple parts added to it .

13. Sophie Yan says:

This is confusing ( maybe because i am only a 10 year old in 4th grade)

14. Duolingo Bird says:

Are those square cells in Minecraft animals, monsters, etc.?

15. The All Seeing Eye says:

Villi reminds me of fractals….

16. Zynax says:

get to the point plz I learned this stuff in biology

Guys… A single celled bear would be tiny yea? And wouldnāt that make a fantastic house pet? A tiny blue whale in a fish tank… that would be awesome too! But this is never gonna happen š

18. Red5rainbow says:

An ostrich egg?

19. mew the mew says:

An egg

20. Wbannie Dylan says:

caesonjil25 bellow me is 100 percent true go to this www.youtube.com/watch?v=MUWUHf-rzks

21. Ben Kawam says:

Physarum polycephalum

22. å¼ äø says:

We interrupt "What is the biggest cell" to bring you "Why cells are small"

23. FLOCKA FLOCKA says:

an egg is a single cell

24. gardener ben says:

the universe.

25. WM57 Toxic says:

It's an ostrich egg yolk

26. OWER says:

The cell body of a motor neuron is approximately 100 microns (0.1 millimeter) in diameter and as you now know, the axon is about 1 meter (1,000 millimeter) in length. So, the axon of a motor neuron is 10,000 times as long as the cell body is wide.

27. FrankProgramming03 says:

Actually, no. The biggest unicellular organism is Xenophyophorea. They can reach 20cm of diameter.

https://en.m.wikipedia.org/wiki/Xenophyophore

The biggest Xenophyophorea is Syringammina Fragilissima

28. S. D. says:

Fantastic explanation!

29. Nate says:

Algae using bioligical hacks

30. Momina Aman says:

31. Subscribers are overrated says:

The powerhouse is the mitochondria of the cell š

32. Gaming with sb says:

Nice video

33. Mande Gianfala says:

aka killer algae

I find the intro very cringy.

35. Nate says:

36. C Catgames says:

Hi

37. Rangsa Marak78 says:

I have caluerpa taxifolia in my sump. Ćt's beautiful but toxic to the fishes. It is banned in many countries and States of USA.

38. susyyy yyy says:

I haveee nothiiiinnngg tooo saayyyy

39. THE SAVAGE says:

You forgot about xenophiophores they can grow to be 8"

40. Alookio says:

well i can see a egg soo

41. Statiscube says:

Despite being incredibly tiny, unicellular organisms are also massively complex. And the human body has trillions of these hyper complex machines working to do so many different uncountable functions at any one time.

My question: If a bunch of atoms were to suddenly merge such that it made an atom by atom replica of me and had enough energy to keep going, would it be able to reproduce with us?

If so, should it be considered a living human being?

42. dew tamy says:

Minecraft cells

43. Owl Official says:

My book says ostrich eggs are the largest cell

44. Brian Wuoti says:

@3:43 is that a sea-bear?

45. Ansh Gupta says:

Isn't ostrich egg is the biggest cell

46. Skating Commentator says:

Correct me if I am wrong but i am a bit confused about the surface area to volume ration discussed at 1:18. I do not see the reasoning behind this guys logic. So, he is saying that a regular shape, that has been dilated to a certain sizes will have a shifted surface area to volume ratio? And if he is saying that it would make this hypothetical situation true.

So take a 1 mm cube (and just so you guys know that is millimetre not micrometer the abbreviation was wrong in the video the abbreviation for micrometre is Āµm so what the hark Ted-ed? It really was pretty annoying to see the wrong abbreviations.) So taking this 1 mm by 1 mm cube you will get a total surface area of 6 mmĀ² and a total volume of 1mmĀ³ (a 6:1 ratio). So using his next example a cube that is 10 mm by 10 mm by 10 mm, we get a 1 cm cube. This makes sense since 10 mm is 1 cm. Next, we can see that a 1 cm cube has a surface area (not surprisingly) of 6 cmĀ² and 1 cmĀ³. So, we are back to the 6:1 ratio.
So if we created x system of measure could you always keep the ratio (volume to surface area) of a cube 6:1?

Overall the explanation in the video seems inconsistent can someone answer my question?

47. Icezblaster9023 says:

This does not answer my question :(. I wanted a example of SINGLE CELL Organism.

48. really fun at parties says:

Oh… I thought the biggest single celled organism was a liberals brain. My apologies.

49. DJ Dastidar says:

Wonderful clip.I will be delighted if you upload a clip telling how we think or work even we many different cells?

50. Gyabu Games says:

It would be easier with plant cells

51. Alex DoesCartoons says:

700th!

52. Guybrush Threepwood says:

The mitochondria is the powerhouse of the cell.

53. Shiny sylveon M.L.G. says:

The mitochondria is the powerhouse of the cell.

54. Mandeep Vayeda says:

Joe tribianni

55. Boris Chan says:

based on the title, I was hoping you dive deeper than just talking about 1 large single cell organism. give more examples man, disappointing clickbait

56. Elmer Henriquez says:

To much math for today. I will be back tommorow

57. Fellipe Parreiras says:

I wonder what would it feel like to rip apart this cell just like a normal plant

58. Kegan Hall says:

So not an ostrich egg…?

59. Peter Bergmann says:

Why is it that Ted-Ed always ends their videos with some of the most beautiful sentences ever.

Egg

61. Xavier Mahele says:

62. Lars Candland says:

63. Prestigete says:

Wait …
I expected that the slime mold might be the largest single cell. I mean ā¦ That is like an giant amoeba!

64. Teenis Teenis says:

valonia ventricosa

65. Jakub A says:

Do we really need this refresher on third grade geometry?

66. Evil Sharkey says:

You know, you could just say āmicronā. Itās the same as a micrometer.

67. Jeremy Cornwell says:

68. General Ramos says:

Egg?

69. Yun Hin says:

What about the slime mould ?

3:00 is when the real topic begins…..and sadly ends tooš

71. Nate says:

72. djoana says:

Iām lost the moment he calculated the cube š

73. K1naku5ana3R1ka says:

As for that bit about the surface area and volume of a cell, Iāve heard it called the square/cube law; basically, an objectās surface area scales with the square of its length, but the volume scales with its cube, so the latter increases more when an object is scaled up. Just thought they could have explained that better.

74. Allan Reyna says:

There is an 8 inch amoeba (Dont know how to spell)

75. Giampiero Baggi says:

4:06 of video for a 15 seconds answer…

76. Lucca Rebocho says:

77. Chris Yunge says:

On land today, the biggest single celled organism is an ostrich egg, in the ocean i would hazard a jelly fish, in thw invisible world i would guess an amoeba……!!!!

78. Eamin Yashed says:

But what is the biggest rock?

79. 100 subs with no video? says:

80. ThatRaelSnake says:

The mitochondria is the powerhouse of the cell

81. Bazooka Llama Productions says:

isnt an ostrich egg a single cell? i win.

82. Bazooka Llama Productions says:

the mitochondria is the powerplant of the cell.

let the hate comments commence š

83. imaginasean says:

The biggest single-celled organism is President of America now š

84. K1naku5ana3R1ka says:

Another aspect you didnāt mention is the radical difference in how things move in the microscopic and macroscopic worldās (I think thereād a Ted-Ed about Reynolds numbers, great additional material); the way animals like the elephants and grizzly bears you mentioned eat and move and reproduce involves a whole mess of rigid skeletons and muscles and specialized cells that likely would be impossible for a unicellular creature to mimic, while a cellās tricks with microtubule āskeletonsā and flagellae would not work at macroscopic scales.

85. Heath Craig says:

Isnt 1000 trillion just a quadrillion?

86. samiamrg7 says:

I remember an experiment we did in science class once to demonstrate the difficulty presented by volume increasing faster than surface area. We cut 2 cubes of some kind of gel, one big and one small, and out them in a colored water solution and left them over night. When we cut them open the next day, the smaller cubes were mostly saturated but the larger ones were not.
This applies to cells because they rely a lot on the passive diffusion of water (osmosis) in order to save energy. It would take a lot of energy to speed up the transfer of chemicals by using a process other than osmosis.

87. Ohmark Veloria says:

caulerpa taxifolia

88. Mehedikp - says:

Biggest unicellular organism's length 5-10cm š¶

89. NeExtraOleas says:

What is the biggest rock?

90. vilma vaitonyte says:

"what is the biggest single-celled organism?" is now interrupted by "W0W0W0W0W0 ELEPHANTS ARE HUUGEEEE CHECK OUT THE CELLS ON THIS THING W 0 0 0 W"

91. Captain Virtu says:

Micrawmetre

92. Win Aye says:

Stentor?

At first I read it as single-celled organ and thought it must be Donald Trumps brain.

94. Jeff_ D says:

āThis āMitochondria is the powerhouse of the cellā will haunt me until the day I die.ā -Doctor Mike

95. Mitchell Rose says:

Is not an Ostrich egg a single cell organism?

96. LOLi PLAYZ ! says:

Who expected him to mention the cell theory?š

Question : But what are Tess's initial dimensions ??? … Since we know the final ones well !!! … ( Height 5' 4Ā¼" (1,63 m) ) …

98. Cynthia L. M. Brown says:

"Enormity" isn't quite the correct word to use!

99. OhaiSenpai says:

Bio Exam: Whatās the biggest single cell organism?

Me when I donāt know the answer: