Answer:
A red blood cell, sitting in the right atria of the heart is chocolate-brown in color since its a deoxygenated red blood cell with carbon dioxide rather than oxygen in its hemoglobin.
First
The tricuspid valve pumps it through the right ventricle
Secondly
pulmonary valve pumps it from the right ventricle to the pulmonary circulation.
Then
In the alveoli of the lungs, gas exchange occurs during pulmonary circulation
The end product is oxyhemoglobin( bright red colour) I.e oxygenated blood
The next step
pulmonary veins is the means whereby the red blood cell go to the left atria from the pulmonary circulation through the aortic valve
to mitral valve then to the aorta and systemic circulation
Therefore
oxygen is replaced by carbon dioxide during systemic circulation indicating a end to cellular respiration
Lastly
It's transported back to the right atrium of the heart completing the cardiac cycle.
