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Health and medicine
Course: Health and medicine > Unit 1
Lesson 2: Respiratory system introductionPeople and plants
Learn more about photosynthesis and cellular respiration through a classic story: Jack and the Beanstalk. Rishi is a pediatric infectious disease physician and works at Khan Academy. Created by Rishi Desai.
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- Atwe are told that plants make an excess of oxygen and that some is shared with Jack and some is used by the plant. What percentage goes to Jack and what percentage goes to the plant? 6:02(18 votes)
- He is saying there using each other to get the type of air they need.(2 votes)
- ATP stands for Adenine TriPhosphate , Doesn't it?(0 votes)
- The "A" actually stands for adenosine, rather than adenine. :)(26 votes)
- Just to clear something, What is celluar respiration? I searched "respiration" in a dictionary which came up as the act of breathing, But plants don't breathe (at). So celluar respiration must mean something else. What does it mean? And, at 5:33, Dr. Rishi says plants have enough oxygen to be used by Jack and itself. Do plants need oxygen? I thought they only needed CO2. 6:12(7 votes)
- Plants need oxygen for Cellular Respiration and they need C02 for Photosynthesis.(2 votes)
- how is jack getting chemical energy if chemical enery if for objects? Confused(5 votes)
- I think you misunderstood what Rishi was saying. Plants and humans alike use and produce ATP (chemical energy). Plants use the ATP molecule during photosynthesis, and animals produce it during cellular respiration. Jack is getting his chemical energy from cellular respiration.(8 votes)
- if there was no oxygen in water with there be a difference(3 votes)
- The water wouldn't be water anymore, it would be hydrogen.(7 votes)
- Why do we worry about Global Warming if there is less than 1 % carbon dioxide in the atmosphere?(3 votes)
- Technically, global warming is a normal process the Earth goes through. It traps some of the Infrared Rays (IR) reflected from the surface or the clouds in the sky in order to keep the planet in a a stable condition (around 15~18 degrees Celsius). The greenhouse gases, including carbon dioxide, are the ones that do this.
Therefore, global warming is actually a standard activity of the Earth. What we are most concerned about is the increase of greenhouse gases. The more we emit into the atmosphere, the more IR are trapped in the Earth (usually 50% goes into space), and more heat are kept inside. For now, the Earth's average temperature is still rising. A single degree Celsius increased may cause a huge change of the ecosystems, resulting in chaos. Although there is less than 1% of carbon dioxide in the atmosphere, the rapid increase of it is worrying, and it is a life-threatening issue that should not be ignored.(1 vote)
- Population has increased considerably.Is there any change in oxygen and carbon dioxide percentage?(3 votes)
- Compared to the total plant biomass of the planet, the number of humans breathing oxygen and exhaling CO2 is negligible. However, we are significantly altering the atmosphere by the rapid release of CO2 by burning of fossil fuels.(3 votes)
- Would it be bad if we breathed in ONLY oxygen? How would it affect our lungs?(3 votes)
- No and yes, it wouldn't be bad for us to only breath oxygen. It would be bad for the plants because we give off carbon dioxide. Plants give us oxygen.(2 votes)
- Why do we need nitrogen in our atmosphere, if it stays in the atmosphere doing nothing then why is it useful in the air?(3 votes)
- Nitrogen is crucial for stabilizing the climate, influencing the ecosystem, and controlling the production of aerosols.(2 votes)
- Why We Need Plants To breath In?(3 votes)
- Plants perform a process called photosynthesis. This is a process by which plants make food. There is already 21% of oxygen in air which we inhale. During photosynthesis in the day, the plants take in carbon dioxide for this process and release oxygen as a product. This released oxygen is inhaled by us for cellular respiration.(2 votes)
Video transcript
There's a classic
story out there and it has to do with
a character named Jack. And you may have
heard this story, but I'm sure that there
is parts of that story that you have not heard. And so I'm actually going to
just try to fill in those parts that you get a complete
idea of what happened. Now Jack came across, a long
time ago, a famous, now famous beanstalk. So this beanstalk was
growing and growing and had these huge leaves. And actually Jack
used these leaves to make his way
up this beanstalk. And so, this is how this
beanstalk became very famous. Because it basically allowed
Jack to use it like a ladder. Now the part that
we don't hear about is what was going on between
Jack and the beanstalk. He was exercising, right? So he was actually making
a lot of carbon dioxide. He was making a lot of this
gas, this carbon dioxide gas, as kind of a waste
product as he was running, scampering up the beanstalk. And the beanstalk was helping
him physically, but also was actually providing him
with very precious oxygen. In fact, if the
beanstalk didn't do that, he may not have even made it. And we also, we
don't know for sure, but we think that perhaps
some of this story may have taken place
during the day. And in fact, we
know that sunlight is quite important
for this process. And we think that this process,
the name that we give it for the beanstalk anyway,
is photosynthesis. And so what is really
happening-- we're actually going to kind of write it
out here-- between Jack and the beanstalk, and really
between all plants and animals? What is this process
between them? We know that on
the one hand, you have beanstalks
doing photosynthesis, and on the other hand,
you have folks like Jack doing cellular respiration. And there's this really kind
of interesting symbiosis. And by that I just
mean that the two are kind of relying on each
other to really work. So you kind of need both
of them to work well. And so let's actually
take a moment to write out these
processes that are happening between
Jack and the beanstalk. So let's start with the
process of photosynthesis, the beanstalk. So on the one hand,
you've got what? You've got water
because, of course, the beanstalk needs water,
and you've got carbon dioxide. And I'm going to do
carbon oxide in orange. So it's taking in water
and carbon dioxide. And it's going to
put out, it's going to actually take
these ingredients if you want to think of
it as kind of cooking, it's going to take
these ingredients and it's going to put out. It's going to put out what? Oxygen and glucose. So I'll put glucose up
top and oxygen down below. So these are the inputs and
outputs of photosynthesis. And on the other side, you've
got something very similar. You've got inputs. You've got glucose
and oxygen going in. You're going to start seeing
some serious similarities here. You've got glucose
and oxygen going in. So Jack is taking
in those two things. And he is again, of
course, processing them. And he's putting out
water and carbon dioxide. So this looks really,
really nice, right? Looks perfect actually. Because everything
is nice and balanced. And you can see how it
makes perfect sense that, not only did Jack
need the beanstalk, but actually it sounds like
the beanstalk needed Jack, based on how I've drawn it. Now remember, none
of this would even happen if there was no sunlight. So we actually
need light energy. In fact, that's the whole
purpose of this, right? Getting energy. So you have to have
some light energy. I'm going to put
a big plus sign, and I might even circle it
because it's so important. I don't want you to
lose track of it. And on the other
side, of course, Jack is getting
something as well. He's getting chemical energy. In fact, he's using
the chemical energy to help him climb the beanstalk. And so the chemical
energy comes in the form of what we call ATP, which is
just a molecule of high energy. And so Jack and the
beanstalk are basically going from light energy to
chemical energy using these two equations. Now here's the part that
people don't always appreciate. And I'm actually going to
take just a moment to show you that this isn't the full story. There's actually something
else going on as well. And that is that
there's actually some cellular respiration
happening on the plant's side. So remember, not only does
the human, or the Jack, need energy, but
so does the plant. The plant needs energy as well. And in fact, if it takes
in light energy right here, it needs to find
a way to actually, eventually get some
chemical energy itself, so that it can do all the
things it needs to do. It doesn't need to run
because plants don't move in that sense, but it
might need to make new roots, and may need to make a
flower, and all these things take energy. So actually, photosynthesis
is happening during the day, but at all times plants
are also capable of doing cellular respiration,
just like humans are. So humans and plants
have actually more in common than you might think. So, this brings up
an obvious question. Why in the world would a plant
send its glucose and oxygen this way, when it
needs it itself? You know, why would it
actually get rid of it? Well, the truth is, that the
glucose ends up oftentimes in fruits and
vegetables that we eat. But as far as the oxygen goes,
it makes an excess of oxygen. So there is actually
enough oxygen to go both to us, or to Jack
and to be used by itself. So it actually has an excess
of oxygen that it's making. So this is actually kind of
interesting and good to know. Now if you think
about it, if I was to, let's say sketch out a planet. Let's draw a little planet over
here, and ask you the question. If this was your planet
Earth, and you've got thousands, instead of
just one Jack, let's say now you have thousands of Jacks
and thousands of beanstalks, in fact, not even thousands. Let's say billions, because
really, that's what we have. We have a planet full of humans,
and full of other animals, and full of plants. What would the
atmosphere look like? This is the atmosphere. What would the
atmosphere look like? Well you'd guess that
the atmosphere is gas. And so what would
those gases be? Well, the way I've
drawn things again, it looks like I've got
lots of oxygen and lots of carbon dioxide. So I would say well, I guess
there must be, I don't know, maybe 50-50 carbon
dioxide and oxygen based on what we know so far. And the truth is, that's
actually not true. That if you actually look at
air, if you actually break down the atmosphere or air-- I'm
just going to write "air" here-- if you actually break
it down, turns out that the ratios are
actually a little different. So for example, oxygen makes
up about 21% of our air. This is our air breakdown. And carbon dioxide makes
up about less than 1%. So, that leaves you wondering,
what the heck is making up all that other parts of air? What is it made of? And in truth, it's
about 78% nitrogen. Now you know, you've got
nitrogen in your proteins, we've got nitrogen in our DNA. So nitrogen is part of us and
is part of many, many living things. But nitrogen gas,
specifically, is actually N2. And N2, this nitrogen gas,
really is not too reactive. It kind of just
hangs out by itself, does not like to
react with things. So, looking at our
little atmosphere graph, if you want to now
think about it, knowing that we've got very
little carbon dioxide and about 21% oxygen-- you could
think of oxygen being, let's say, something like
that-- well then relative to that nitrogen
would be much more. You have much more
nitrogen hanging out. And so this is really what
our atmosphere looks like. It looks more filled with
nitrogen than anything else. And in terms of
carbon dioxide, it's just got a little smidge
of carbon dioxide. Maybe right there. That could be carbon dioxide,
maybe even less than that. So this is really what
our atmosphere looks like, visually. And the nitrogen again,
it's making up the majority. And if you actually wonder where
all that nitrogen is coming from, because I didn't mention
it in any of the equations, most of that nitrogen
has been around, scientists think,
since the beginning of when earth even
had an atmosphere. And that nitrogen,
we're just kind of carrying with
us at all times. And that's why it just
remains around 78%, and will probably remain there
for many, many years to come.