Which is an example of a positive feedback system? Select one: a. An increase in

Question

Which is an example of a positive feedback system?

Select one:

a. An increase in glucose in human blood causes activation of liver cells to take up glucose, lowering its levels in blood.

b. The concentration of a specific amino acid in a cell reaches a level that causes genes needed for synthesis of the amino acid to be turned off.

c. A puppy suckling on its mother causes an increase in levels of a hormone in the mother’s body that activates milk production.

d. The human kidney retains water in response to high blood sodium levels and releases water in response to low blood sodium levels.

e. A hormone that stimulates bones to release calcium when blood calcium levels are low is turned off when calcium levels return to normal.

My guess is C

Phospholipids differ from triglycerides in that phospholipids

Select one:

a. are amphipathic.

b. are not derivatives of glycerol.

c. do not have both hydrophilic and hydrophobic components.

d. are used to store energy for the cell.

e. do not contain fatty acids.

My guess is C

Glucose is a

Select one:

a. disaccharide.

b. pentose.

c. six-hydrogen molecule.

d. polysaccharide.

e. hexose.

My guess is d

All of the following molecules are examples of the octet rule except

Select one:

a. CO2.

b. H2O.

c. H2.

d. C2H6.

e. CH3.

My guess is e

The molecular evolution studies of sodium channels in puffer fish is used primarily to

Select one:

a. produce new molecules by in vitro evolution.

b. save puffer fish from extinction.

c. study protein function.

d. determine the evolutionary history of gene families.

e. combat disease.

My guess is e

Explanation / Answer

Which is an example of a positive feedback system?

c. A puppy suckling on its mother causes an increase in levels of a hormone in the mother’s body that activates milk production.

Phospholipids differ from triglycerides in that phospholipids

a. are amphipathic.

Why the other options are not valid is given below;

Phospholipids and triglycerides contain glycerol

Both are hydrophobic

Triglycerides are used to store energy

Both have fatty acids – triglycerids 3 and phospholipids 2

Glucose is a

e. hexose

a hexose is a monosaccharide with six carbon atoms

All of the following molecules are examples of the octet rule except

Ans: e

The molecular evolution studies of sodium channels in puffer fish is used primarily to

d. determine the evolutionary history of gene families.

The number of genes responsible for sodium channels has increased due to gene duplication and impacted the evolution of three groups of fishes.

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