a) Make a thoughtful environmental argument for developing the impossible burger and products like it. Explain why is it a good idea environmentally?
b) Leghemoglobin (found in plants) and myoglobin (found in muscle cells) and the subunits of hemoglobin (it is made up of 2 chains of alpha-globin and 2 chains of beta-globin) are all similar proteins that function to bind oxygen.
For hemoglobin, myoglobin, and leghemoglobin, explain why each needs to bind oxygen
c) Alpha-globin, beta-globin and myoglobin are all very similar proteins that evolved from a common ancestor protein. Just as a species can be split into two isolated populations which then become genetically different from one another over time, gene duplications occur, creating two "populations" of a gene. Assume you started with a single gene for hemoglobin but, because of a gene duplication that spread through the population, you ended up with 2 copies of that
hemoglobin gene in every individual. Explain how the two copies could diverge over time so that eventually one of them takes on a new function
d) Fetal hemoglobin is, like adult hemoglobin, composed of 4 subunits. However, fetal
hemoglobin contains two alpha subunits and 2 gamma subunits.
Explain and drawn a phylogenetic tree for globin genes that correctly shows the information shown below. Put a time scale on your phylogeny and draw your lines to reflect that scale, showing the divergence points.
1. Beta globin and Gamma globin share a most recent common ancestor globin protein 40 million years ago (mya).
2. Alpha globin shares a most recent common ancestor protein with the group (beta and gamma globins) approximately 500 mya.
3. Myoglobin shares a most recent common ancestor protein with the group (alpha, beta, and gamma globins) about 1.1 billion (= 1100 million) years ago.
4. Leghemoglobin diverged from the animal globin genes approximately 1.6 billion (=1600
million) years ago