AP BIOLOGY

Previous
Next

ANIMAL PHYSIOLOGY

OSMOREGULATION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Plants contain hemoglobins that function in a variety of processes including binding nitrous oxide from the soil, delivering oxygen to plant tissues, and supporting symbiotic relationships with fungi. This information tells us that:
A
Hemoglobin’s origin probably predates multicellular life.
B
Hemoglobin evolved in mammals and spread to plants.
C
Hemoglobin is not useful for other processes other than oxygen transport.
D
Hemoglobin evolved in plants and animals but not arthropods.
Explanation: 

Detailed explanation-1: -In plants, hemoglobin was first studied within symbiotic nitrogen-fixing root nodules, where “leghemoglobin” (legHb) plays a key role transporting free oxygen away from the oxygen-sensitive-nitrogenase enzyme.

Detailed explanation-2: -The rate that hemoglobin reacts with nitric oxide (NO) is limited by how fast NO can diffuse into the heme pocket. The reaction is as fast as any ligand/protein reaction can be and the result, when hemoglobin is in its oxygenated form, is formation of nitrate in what is known as the dioxygenation reaction.

Detailed explanation-3: -The Heme group gives myoglobin and hemoglobin the ability to bind oxygen because of the presence of iron atom. It also contributes to the red color found in muscles and blood. Each heme group contains an iron atom that is able to bind to one oxygen (O2) molecule. Each hemoglobin protein can bind four oxygen molecules.

There is 1 question to complete.
Previous
Next