Hi I would like to drouble check my answers. Choose the best answer and give a brief explanation please. Thank you!
1.A protein is made and inserted into the membrane of the rough endoplasmic reticulum. A particular stretch of this protein is situated so that it faces the lumen of the ER. If this protein is then moved to other endomembranes, at which surface of the membranes given below is this stretch unlikely to be found?
The internal face of a lysosome membrane.
The lumen face of a secretory vesicle.
The internal face of the Golgi apparatus membranes.
Facing the intermembrane space of the nuclear envelope membranes.
The cytosolic face of the plasma membrane.
2.Sickle-cell disease is caused by a mutation in the ?-hemoglobin gene that changes a charged amino acid, glutamic acid, to valine, a hydrophobic amino acid. Where would the glutamic acid likely be found in the normal (non-mutant) protein?
Making a disulfide bridge.
Participating in a hydrophobic interaction with a polar side chain from a different part of the protein.
In the interior of the protein, away from water.
On the exterior surface of the protein.
Hydrogen bonded to a non-polar side chain from a different part of the protein.
DNA and polypeptide sequences from closely related species are more similar to each other than sequences from more distantly related species.
In the alignment shown below, the letters give the sequences of the 146 amino acids in ?-globin from humans, rhesus monkeys, and gibbons. Because a complete sequence would not fit on one line, the sequences are broken into segments. The sequences for the three different species are aligned so that they can be compared easily. For example, for all three species, the first amino acid is V (valine) and the 146th amino acid is H (histidine).
Based on the ?-globin alignment, which is the best hypothesis about how humans, monkeys and gibbons are related?
Both monkeys and gibbons are equally unrelated to humans because neither monkeys nor gibbons have the exact same ?-globin sequence as humans.
Monkeys are more closely related to humans than gibbons are because the monkey ?-globin sequence is a closer match with the human sequence.
Monkeys are more closely related to humans than they are to gibbons because monkey ?-globin sequence is a closer match to the human sequence than it is to the gibbon sequence.
Gibbons are more closely related to humans than monkeys are because the gibbon ?-globin sequence is a closer match with the human sequence.