Question

$CO_2$ is carried from blood in the form of what?

Answer 1

Cell metabolism in the mitochondria produces carbon dioxide. The amount produced is determined by the rate of metabolism as well as the proportions of carbohydrate, fat, and protein metabolised.

Complete solution:
Carbon dioxide is delivered through the blood from tissue to the lungs via three routes:
1. Dissolved in fluid- 7%
2. Buffered with water as carbonic acid- 70%
3. Attached to proteins, particularly haemoglobin- 23%
Carbon dioxide molecules are delivered in the blood from bodily tissues to the lungs in one of three ways: directly into the circulation, by binding to haemoglobin, or as a bicarbonate ion. Carbon dioxide transport in the circulation is influenced by several factors. Carbon dioxide dissolves more easily in blood than oxygen. In the plasma, about 5 to 7 percent of all carbon dioxide is dissolved. Second, carbon dioxide has the ability to connect to plasma proteins as well as penetrate red blood cells and bind to haemoglobin. When $CO_2$ binds to haemoglobin, a compound known as carbaminohemoglobin is created.

Note:
Other molecules, like carbon monoxide (CO), cannot easily connect and detach from haemoglobin. Carbon monoxide binds to haemoglobin more strongly than oxygen. As a result, when carbon monoxide is present, it preferentially binds to haemoglobin over oxygen. As a result of the inability of oxygen to bind to haemoglobin, relatively little oxygen is delivered throughout the body.