If you do a Google search on “human body is home to”, you’ll find many interesting articles hawking many varied facts on the number of bacterial cells the body carries. They range from “millions!” to “hundreds of trillions!”, or “one bacterial cell for every human cell” to “ten to one” all the way up to “one hundred to one!”. A few mention on average three pounds per person. Whatever. Point being, there is ridiculous disparity in estimates. What’s the straight dope?
About 10:1 or 700 trillion bacterial cells compared to about 70 trillion somatic cells is the figure I see most commonly on reputable sites, including Wikipedia.
Errr…that should read 100 trillion and 10 trillion, respectively. Why did I type 1’s as 7’s?
Are all bacteria single celled? IE, 100 trillion individual lifeforms? Of not, how many?
Yes, all bacteria are single celled.
How many cells are in a Diplococcus? Hint: the name is diplococcus.
How many cells in Streptomyces? Hint: The root myces means “fungus”.
Contrary to what smeghead just posted a great many bacteria are muticellular. Some such as the diplococci are composed of two cells, other such as the actinomyctes and filamentous cyanobacteria they are composed of huge numbers of cells arranged in chains or even sheets.
If it is multicelluar, t is not a bacterium. If it has a nucleus, it is not a bacterium. If it has even a mitochondrian, it is not a bacterium. That said, sometimes, as in diplocpccus, they join up in pairs or even filaments, but they are still individual organisms each with its own DNA and they reproduce separately. I assume actinomycetes is a fungus and certainly not a bacterium.
Not only are baceria single-celled, they are mostly very tiny compared to eukaryotic cells (those that have nuclei, mitochondia, and other cytosomes–photosynthesizing plants have chloroplasts or similar bodies.
When I was in graduate school about 10 years ago, the cell count estimate for the human brain ranged from about 20 billion to several trillion. The general consensus at that time was towards the middle but I have noticed that the estimates have creeped up a great deal even since. You wouldn’t think those types of rough estimates would be that difficult but apparently they are.
Have you ever tried to count a few trillion things? 
As a molecular biologist, I concur: bacteria are unicellular. Just because they can associate, or even interlink, in characteristic forms does not mean that the single cell is not the basic, fundamental sustainable unit of life in these organisms.
Also, just being unicellular doesn’t make an organism a bacterium. Yeasts are fungi, not bacteria, but are generally unicellular (possibly always, but I can’t vouch for that offhand). IIRC, cellular slime molds, like Dictyostelia, live most of their lives as free-roving single cell organisms, but may aggregate to larger macroscopic multicellular free-roving masses, and eventually highly differentiated “fruiting bodies”, with very distinct organs and tissues in various parts. Though one-celled Dictyostelia are capable of reproducing independently, the multicelled differentiated (="having distinct tissues with diffferent properties and structures) fruiting bodies work as multicellular organisms: only certain specialized cells/tissues reproduce by creating spores, while the once free-living cells in, say, the foot or stem of the fruiting body do no reproduce (unless the body dissocates into free-living cells again – I’m not sure, if all species of cellular slime milds routine dissociate after aggregating, but some do)
Don’t be silly. A diplococcus is a bloody great dinosaur with a long neck.
I’m sure you know this, Shagnasty, but I think it’s an interesting factoid for others.
Part of the diversity of estimates is due to a slowly evolving understanding of what truly constitutes a “brain cell”. It is now generally accepted that various types of (e.g.) macroglial cells play a more active role in CNS functions (including, probably, “thought”) than previously believed and should there fore be considered “brain cells” in every sense. It was formerly believed that they only played a supportive role (guiding neuronal or axonal development, sustaining a hospitable local chamical environment for neurons, etc.). Many researchers didn’t consider these to be “brain cells” any more than they considered connective tissue cells or immune histiocytes in a muscle to be “muscle cells”.
Not many people know that it consisted of just two cells.
Maybe they didn’t consider them “brain cells”, per se, but surely they at least considered them “cells”, and recognized that they were part of the human body?
I thought it was a diplomat with a bloody long…
Well, duh. But, considering the post you quoted was about the number of brain cells, specifically, I fail to see how this is relevant.
why debate the numbers? Let’s just compromise, and agree that there are zillions of cells.
Hmm. All those people saying that all bacteria are unicellular may want to have a look at the Google returns for the term. I won’t even bother at this stage to list the numerous articles on science journals referring to multicellualr bacteria.
Suffice it to say at this stage that a lot of universities, hospitals and journals seem quite convinced that numerous bacteria, including diploccocci and streptomyces are multicellular.
Now would those contending otherwise care to present some evdience or references aside from their personal opinions?
1 zillion = 1 x 10[sup]a whole lot[/sup]