Why are there no unicellular creatures one foot in diameter??

Question

Please provide link if possible.

Answer 1

Why are there no multicellular creatures with cells that are one foot in diameter? Cells only get so big before it becomes inefficient, and division makes more sense.

Answer 2

There are structural, as well as transport issues. The surface to volume ratio decreases with diameter, and the surface is an important point of exchange (nutrients in and waste out), so smaller cells (generally 10-100 micrometers in diameter) are favored. Bacteria are smaller. Cellular communication within the cell is also a limitation. Without some type of solid structure, the cell will collapse upon itself. That said, there are some rather large cells. Bird eggs, like that of the ostrich, are the largest in diameter. Certain nerve cells can be in the range of a meter long in humans, and about 5 meters in a giraffe. Cotton fibers are single cells, and they can be up to 5 cm in length.

Answer 3

This is good question. First, the atoms make elements and compounds. Proteins, phospholips, carbohydrates and lipids are mixtures which forms the cells. For example, the cell wall composed of phospholipids and proteins inserted inside it. Then the cells aggregate to form tissues. Tissues form organs. Organs form systems. Systems form whole creature. The living being can be located from any of these organizition or only proteins with carbohydreates such as viruses.

Also, the unicellular organism need certain environment. This environment includes exchange of the water and food with the environment dirctly. So it is not possible to live

Answer 4

Its all got to do with the ratio of surface area to volume. A cell needs to take in nutrients from its environment and eliminate wastes into its environment. It needs a large surface area to volume ratio to do this efficiently. The surface area to volume ratio decreases as the cell gets bigger. At a certain size it becomes inefficient for the cell to get any bigger, because diffusion becomes less efficient with distance. At a certain size it would take too long for nutrients to reach the centre of the cell and not enough nutrients could be absorbed due to the small surface area to volume ratio.

Surface Area of a Sphere = 4 pi r squared
volume of sphere = 4 pi r cubed

So a cell with a radius of 5 mm has a surface area of 104 mm^2 and a volume of 523 mm^3, whereas a cell with a radius of 0.5 mm has a surface area of 1.05 mm^2 and a volume of 0.52 mm^3. Hence the smaller the radius, the great the surface area to volume ration.

Answer 5

Because the components of the cell are generally of one size, and that size is very tiny. If you kept increasing the size of the cell, you would quickly end up with components that could not do their job because they were too small to carry it out, or had too far to travel, or could not satisfy their energy requirements because they were too far from the cell wall or the cells energy centers. Plus, the area of your cell increases exponentially while the circumference of the cell will only increases in a linear fashion, so it will take continually greater energy ratios to keep the cell alive as it gets larger.

Answer 6

I think it's better for a creature that is a foot long or longer to have more than one cell. I can't remember why. Maybe you should type your question into a search engine and see if you can figure this out.

Answer 7

Greetings;

Two words: Surface area. The greater the size of the cell the larger the volume:surface area ratio.

Answer 8

Unicellular organisms respire thru their skin, since they rr really small the ratio of surface area of their skin to their body volume is really large, but for a 1 foot diameter animal it would be extremely small so it would die off coz it would not be able to get the O2 it needs. That's why we hav lungs coz our ratio is really really small.

Answer 9

You just answerred it. There are no cells, 1 foot in diameter. But, ther are a lot of foot in mouths.

Answer 10

thats because if the cell is too big, more nutrients is needed for the cell, hence by making it very big, the surfave area to volume ratio would decrese, its just like a cube, with a side of 1cm each and a cube with side 2 cm each. the sides of 2cm each would have lost 3 of it original surface area, if the cell is very big, its is very hard for diffucion to occur