Cells require o2to serve as a final electron acceptor in the...

Cells require O2 to serve as a final electron acceptor in the process of cellular respiration, a series of enzymatic reactions that function to oxidize organic molecules to produce ATP. CO2 is a byproduct of cellular respiration and needs to be removed from tissues. The human respiratory system works with the circulatory system to move these gases around the human body. Below is a series of steps in the process of gas exchange. Reorganize the steps so that they are in the correct order. We have listed the first step in this process below (see "START"). Organize the remaining steps. START: Rib cage and diaphragm muscles contract, increasing the volume of the lungs, creating negative pressure allowing for fresh air to enter the lungs. O2 dissociates from hemoglobin and diffuses out of red blood cell across systemic capillaries. Blood containing oxygenated hemoglobin (in red blood cells) moves through arteries to systemic capillaries. CO2 diffuses from the capillaries into the alveoli and is ultimately exhaled into the environment. O2 diffuses across the cells of the alveoli into the capillaries. Blood containing CO2 moves through the capillaries into the veins. CO2 produced during cellular respiration in active tissues diffuses from cells into the blood in capillaries (some CO2 associates with hemoglobin and most is carried in the plasma). O2 diffuses into individual cells to the mitochondria where it is utilized in cellular respiration, the process that generates ATP for the cell. O2 binds to hemoglobin in red blood cells.

Transcript

00:01 All righty, so this question wants us to put the steps of gas exchange via respiration in order.

00:07 And so to do this, we have to kind of think about the levels of organization within an organism.

00:12 So at the simplest form, we have cells that make up tissues, that make up organs, that make up organ systems, and all of these work together to create an organism.

00:21 So with gas exchange, we have the organism taken in oxygen from the environment.

00:26 It's going through the different organs and tissues and eventually to end up.

00:30 Individual cells, cellular respiration occurs, co2 is released as a byproduct, and this process goes kind of in reverse where the cells, the co2 goes from the cells through the tissues and organs and eventually outside of the organism and into the environment.

00:48 And so the first step is done for us.

00:50 It says that the rib cage and the diaphragm muscles contract.

00:57 And so when this happens, a pressure, a difference in pressure occurs between the lungs and the environment.

01:06 And so what happens is this pressure differential or difference causes the oxygen to rush into the lungs, right? and so now that we have the air or oxygen in the lungs, it has to go from that organ into the tissues.

01:25 And so the lungs have specialized tissue called alveoli that are organized into alveolar sacs.

01:34 And these alveolar sacs are very thin.

01:38 The walls or the tissues are very thin.

01:41 And this allows for gases to diffuse through.

01:45 So the next step is that the oxygen is going to diffuse across the cells of the avioli and into the capillaries.

01:57 And so now that we are in the capillaries, we are in the blood vessel network.

02:04 And now we are going to encounter red blood cells or blood.

02:12 So now that we are encountering blood vessels and blood, oxygen is going to hop onto red blood cells.

02:23 And it's going to do this because red blood cells have a protein called hemoglobin that sits on the red blood cell and accepts gases.

02:35 And so what happens is oxygen binds to hemoglobin on red blood cells.

02:43 And i'm going to write red blood cells out this time, but i'm going to abbreviate it in the future as rbcs.

02:55 And so now that we or that this oxygen has kind of hitched the ride on the red blood cells the red blood cells are going to go through the blood vessel network and so what happens is these red blood cells or the blood that is now oxygenated because the oxygen has bound to the hemoglobin on the red blood cells so blood with oxygenated hemoglobin is now going to try.

03:29 Travel from the capillaries and into the arteries.

03:34 And we know that arteries take blood away from the heart and through to the rest of the body.

03:42 And so it's now going to get into what are called systemic capillaries.

03:48 So blood with oxygenated hemoglobin.

03:51 Sorry, i'm going to write that out.

03:53 Oxygenated hemoglobin.

03:59 Oxygenated hemoglobin is going to go through moves from the arteries to those systemic capillaries.

04:15 So now it's kind of, it was centralized near the heart and lung area.

04:23 So now it has gotten into systemic circulation.

04:26 And this means that it is going to go through or to the different systems of the body.

04:33 And get into all of the different places of the body.

04:39 So now that we are in systemic circulation, i'm going to scroll down here to give us some more room.

04:46 Now that we are in systemic circulation, we are going to go to the areas that need oxygen.

04:54 So what happens is, let's say you're working out.

04:56 You know when you're working out and you feel the burn, right? this is because your muscles are, the cells of your muscles are doing a lot of cellular respiration and using that oxygen to make atp energy, right? and so what happens is after cellular respiration, co2 is created.

05:17 And co2 build up is what is causing this burn.

05:21 And so there's a lack of oxygen and this high level of co2.

05:27 And this is causing a change in the environment.

05:30 It's making the environment in that area more acidic.

05:34 And so that's why you feel that burn.

05:38 And that acidity is what is going to cause a change with the hemoglobin on the red blood cells.

05:45 And this is going to cause oxygen to jump off of hemoglobin at the area where there is a need for oxygen...