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Middle school biology - NGSS
Course: Middle school biology - NGSS > Unit 3
Lesson 2: Food and energy in organismsFood and energy in organisms
Within individual organisms, food moves through a series of chemical reactions in which it is broken down and rearranged to form new molecules, to support growth, or to release energy. Created by Khan Academy.
Want to join the conversation?
- If we are what we eat, does that mean that I am 95% Hot Cheetos?(17 votes)
- If that's what you eat, then yes.(3 votes)
- What is the meaning of atoms and molecules(0 votes)
- Atoms and molecules are the building blocks of almost everything in the world. Think of something around your room. For example, a TV. The TV is made of many different types of atoms and molecules.
The difference between atoms and molecules is that atoms make up molecules. Molecules are two or more atoms. Hope this helps.(25 votes)
- so if i where to eat a human i’d be some percentage human?(3 votes)
- u already are part human(4 votes)
- I always did wonder where all the skin comes from when you grow, as in, the amount of skin you have when you're a baby is like 1/10th of the amount you have as an adult.(7 votes)
- Your skin grows as you grow, and you slowly get more of it, just like how your fingers grow longer or your feet get bigger. You get more skin cells just like you get more bone and muscle cells as your other body parts grow, like fingers and feet.(0 votes)
- is the food that we eat applied to like, literally everything in our body like our brains, our organs, and everything else, or is it just applied to different specific things?(2 votes)
- The food we eat when we're young and still growing gives molecules to our WHOLE body in order for it to grow! That includes organs! But once we grow all the way we just need food as fuel in stead of building blocks (unless your injured and then some molecules in food are used to help repair that).
I hope this was helpful! (If a worded it in a confusing way someone please tell me! I don't usually make things as straight-forward as people would like)(3 votes)
- "I don't know, gushy stuff, whatever babies eat." I don't think he has or had a child, so I don't think he's married.(3 votes)
- alright fine ima go eat a cat i have alwayas wanted to be a cat :D(3 votes)
- When you showed a picture of all the animals why did you put a black family 🧐(1 vote)
- omg lol, I promise he wasn't being racist it was just an example of humans who happened to be black.(4 votes)
- Our atoms are based on how we eat(2 votes)
- "We are what we eat..." I should stop eating people fr(2 votes)
Video transcript
- [Instructor] Hey,
quick question for you. You ever look at a person's baby pictures and wonder how people go from
being small to, well, big? I mean, yes, I get it. People grow up, but
here, I'm thinking more on the level of the atoms and molecules that make up the body because A, I'm a scientist
and that's kind of what we do, and then also B, because after all, all the changes we see
on these larger scales are just reflections of
very many changes occurring on the molecular scale. And so if you think about it that way, then it's likely reasonable to assume that because the adult's body is bigger, it has more molecules
and/or larger molecules than the baby's body. And so this means that there
are some molecules in this baby and those molecules are
interacting and combining with some other source
of molecules in the world in order to become this adult. And generally speaking, the source of those molecules
is going to be our diet, AKA our food. And to kind of understand this, we can actually make a comparison here between food and wood. So what I mean by that is that the molecules in food interact with the molecules on our bodies in two primary ways. The first is as a source of
molecular building blocks, or in other words, molecules the body can use
to build new structures. And the second is going to be as a source of molecules for fuel, much like a campfire or
firewood, like what we have here. But in order to understand how and why this can happen, we need to briefly discuss
the molecular basis of food. So what are the molecules in food? Let me introduce you. All right, 'cause generally speaking, food is made up of these
three classes of molecules. First up are fats, then we've got sugars, and finally some protein. I'd imagine some of these
sound reasonably familiar. These molecules are made basically from just a few elements. So this is color-coded and
the gray balls are carbon. The white ones are hydrogen. Those are the big ones. So most of life's molecules are made mostly of carbon and hydrogen. But we've also got oxygen here in red and nitrogen in blue, those are the other two big ones. And every now and then, we'll also find small amounts
of some other elements, like this sulfur here in yellow. But the super interesting part here is that these are actually
the same exact elements that make up most of
the cells in your body. So you may notice on this right-hand side the same colors is what
we have on the left. So this is where the whole
Molecular Lumber thing comes in. Our cells can take food and break it down into
small building blocks and then use those building blocks in order to build new
structures in our body. So is how we grow. This is how babies become adults. Turns out, we actually are what we eat. It's pretty amazing. All right, but before we get too excited, let's bring it in. So let's switch gears for a second here to talk about the other side of things because I told you before
that food is like wood. And we can use wood to
build new structures, sure. But when we need to, we can also burn wood to get energy. So we can start a campfire. And if we do, we know that
we're gonna get some energy in the form of light, we'll get some energy in the form of heat, and maybe some other things like sound. And food is actually the same way, and so we can take those
same food molecules that we broke down before
to get building blocks and instead use them as fuel
to generate cellular energy. And then we can use that cellular energy to fuel all of the building
that we just talked about. And likewise, if our cells
work together, which they do, they can use this energy
to do things like running, thinking, and all the other
things that we humans do. All right. Let's step back just one more time because what we'll see is
that these two processes that we've just described, so food is lumber and food is fuel actually explain so much of life. So this is not just us. Every living thing on
this planet is doing this. So you feed your dog to fuel his or her molecular
construction projects as well. So right there and then, we've already kind of answered
our question from before, which, reminder, was: how do people go from small to big? So what's happening is that
this baby becomes an adult by eating food, milk,
formula, gushy stuff, I don't know, whatever babies eat. And some of the molecules in that food will be used as fuel to generate energy, and then some of that energy will be used to combine food molecules with molecules in the baby to build up a larger baby, AKA an adult. All right, I hope that helps. Let's wrap it here. See you in the next one.