Hair is described by howstuffworks as dead tissue, keratin and proteins. What makes a protein “dead”? What are some various ways that protein dies (cooking perhaps)? Can your body ingest and use dead protein for nutrition?
… I understand about denatured protein from being cooked to death. Could you explain the difference between denatured protein and dead protein?
Proteins are neither dead nor alive. They’re just chemicals, albeitly extremely complex ones, assembled from amino acids.
Howstuffworks describes the hair as dead tissue, not protein being dead. Protein cannot be dead because it was never alive.
What about the life on the atomic level? Can atoms lose their spin or polarity and be called dead that way?
By dead, they mean not alive, in the sense that a rock is not alive, not that the protein in hair was once living and is now deceased.
In the lab, we use the term “dead” to describe enzymes that have been denatured, so they no longer have activity. But this is essentially lab slang. Truth be told, the term “dead protein” is simply wrong. It is more accurately called “inert” in that it is not participating in any cellular or intercellular actions.
Now, it is possible for a tissue to be “dead” in the sense that it is composed entirely of non-living cells.
The english language will allow you to have modifier that spans several nouns, but in this case I believe that the adjective “dead” only applies to “tissue” and shouldn’t also be applied to “protiens” or “karatin”
Khadaji, my thoughts exactly. And of course the body has enzymes that denature (and deamminate) proteins and amino acids, to be used by the body.
Yeah, in the sense that it would be "Hair is made up of dead tissue. It is also made up of keratin and proteins.
Huh?? Life is not about atomic spin or polarity. An atom in living matter is no different from an atom in dead material.
The slang use of the terms denatured->dead in the lab, needs a little clarification with respect to hair proteins. The [symbol]a[/symbol]-Keratins that make up hair take the shape of alpha-helices, which in turn super-coil around other alpha-helices to form the hair fibre. This structure is maintained by heat sensitive disulfide bonds, which is why you can straigthen, or stretch a heated hair. Despite being dead, in the sense of being non-living, the protein molecules in normal hair are not denatured.
Perhaps they mean that the keratin strands (intermediate filaments?) are no longer in a dynaic state of being made and unmade as they would be in a living cell - they are the remains of the keratin structural network that are left after the cells themselves have died? Since hair only grows from the follicle, then it could be understood that the cells on the strand of hair are no longer alive, AND their keratin is no longer in a dynamic state, and the other proteins are no longer biologically active?
Are raw meat or multi-vitamins composed of non-living cells? Certainly, a living human beings’ cells are living… how long after someone dies do the cells become dead? I would think after oxygen was cut off, it would happen rather quickly…
I apologize for asking these questions without having much background in this subject. But I figure you guys don’t mind talking about this stuff… I am just trying to grasp the difference between the nutritional value of the protein and vitamins/minerals found in a raw, freshly-picked spinach leaf and a two-year-old multi-vitamin who got some of it’s minerals from coal! Thanks to anyone who can sort of point my thinking in the right direction.
Cells in a live body are able to sustain themselves, nurture, and reproduce. Hence, they are living. Cells in a dead body are not able to do this and are not living.
Vitamins in tablets lose their efficacy after time, the time depending upon how you store them (heat, light, etc.) and the nature of the vitamin.
I don’t want to get caught up too much about what we all think is life. I just want to know the difference between useable, biologically valuable sustenance (fresh apple) and sub-par, age-allowing, second-hand “nutrition” (meat). I want to go deeper than just saying the a vitamin is a vitamin, no matter how hot it get’s or how long it exists away from amongst a living, oxygen-processing, or photosynthesis organism. I want to go to the cellular and atomic level for differences, if that’s even relevant information fro determining nutrional value.
See, this is what i am looking for. I posted about dead and living vitamins a couple of weeks ago and everyone hounded me saying that a vitamins is a vitamin. Dang it! Let’s get the Straight Dope here once and for all.
Any and ALL differences (chemical, biological, physical, anatomical, cellular, ect.) between nutrition in a dead body (meat) and a living body (fresh apple).
Thanks Dopers, I know you won’t let me down with this question!
Well, the apple is dead after you take it away from the tree… What it has is stored nutrients to be used by the seed (plant embryo, the only thing capable of living in that apple)
OK.
What is the status of the stored nutrients, say, 3 days after being picked? Physically, digestably, all factors taken into consideration, any different in any way?
Let’s refrain from using the words “living or dead” in this thread from now on, please?! This will help bring ambiguity down to a manageable level.
After you cut an apple, notice the browning of the inside. This is oxidation, which causes the loss of vitamin C, which is a very fragile vitamin. If the skin is intact, not much is lost right away, but over time, vitamin C will be lost. Apples give out ethylene gas, and if you have one in the fridge container that goes rotten, all the rest will soon get rotten too. As long as the skin is intact and the apple is not rotting, not much is lost.