Answer:
Once the oxygen diffuses across the alveoli, it enters the bloodstream and is transported to the tissues where it is unloaded, and carbon dioxide diffuses out of the blood and into the alveoli to be expelled from the body. Although gas exchange is a continuous process, the oxygen and carbon dioxide are transported by different mechanisms.
Transport of Oxygen in the Blood
Although oxygen dissolves in blood, only a small amount of oxygen is transported this way. Only 1.5 percent of oxygen in the blood is dissolved directly into the blood itself. Most oxygen—98.5 percent—is bound to a protein called hemoglobin and carried to the tissues.
Hemoglobin
Hemoglobin, or Hb, is a protein molecule found in red blood cells (erythrocytes) made of four subunits: two alpha subunits and two beta subunits (Figure 20.19). Each subunit surrounds a central heme group that contains iron and binds one oxygen molecule, allowing each hemoglobin molecule to bind four oxygen molecules. Molecules with more oxygen bound to the heme groups are brighter red. As a result, oxygenated arterial blood where the Hb is carrying four oxygen molecules is bright red, while venous blood that is deoxygenated is darker red.
Answer:
gravity
Explanation:
gravity pulled the ball down so that's why it hit the ground
Answer:
The answer would be a single celled organism.
Explanation:
Even though transforming genetically any organism is not an easy task, as it requires the whole organism to be changed, it's more practical to do in a unicellular organism. For example, bacteria mutate very easily due to its ability to incorporate new genes by horizontal transfer. Anyway, unicellular organisms have mechanisms to avoid strange genetic material to get into their DNA, that's why scientists have to use such tools as vectors and more.
