Updated 2026/2027 (Graded A+)- American Public University
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Question 1 2..5 points
If an integrin protein is mutated what cell function might be affected?
communication between cytoskeleton and proteglycan
fluidity of phospholipids
cellular motility
cytoplasmic communication
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Question 2 2..5 points
You and your roommate are grocery shopping. “I don’t get it,” she says. “My doctor said I should buy this special milk because
I don’t digest it well. But this brand says ‘lactose-free’ and this brand says ‘lactase added’ – which do I want?”
You reply: “The
is a sugar in milk that you have trouble digesting, and
is an enzyme that will digest it for you.
lactase, lactose
lactose,lactase
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Question 3 2..5 points
What is the first step in Na+-K+ pump?
The carrier protein has a reduced affinity for Na+
shape change increases the carrier's affinity for K+ ions
Carrier protein binds to 3 Na+
ATP is hydrolyzed by a protein carrier
Phosphate group is removed and K+ attach
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Question 4 2..5 points
What examples describe the second law of thermodynamics? Select all that apply.
, Donuts nutrients are used to help you exercise.
Question 5 2..5 points
In biological macromolecules like proteins, the hydrophobic residues tend to clump together in the interior of the folded
structure. What is the best explanation for why this occurs?
Hydrophobic residues bind each other, while polar residues cannot bind each other. Therefore the hydrophobic ones end
Protein folding machinery interprets the amino acid code to pack hydrophobic residues into the center of proteins. This
process must be important, because the cell expends large amounts of ATP to precisely coordinate protein folding.
Hydrophobic residues bind to each other in specific ways. For instance, Ala forms di-methyl bonds, and phenylalanine
binds isoleucine. This creates a tightly bound hydrophobic inner core.
Question 6 2..5 points
Cardiac muscle requires junctions that allow electrical signals through. Cardiac muscle also relies on calcium to contract.
What junction is involved and what organelle stores calcium?
desmosomes, smooth ER
plasmodesmata, rough ER
gap, smooth ER
tight, rough ER
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Question 7 2..5 points
Before the battery in the car is jumped, the individuals notice the hook-ups on the battery are corroded by acid. What
substance can be used to clean the acid?
orange juice
baking soda
urine
black coffee
lemons
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Question 8 2..5 points
are used for energy storage.