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2.9 A: Molecular Basis of Exchange Quiz
1.
A plant has stunted growth and yellowing leaves because it is unable to synthesize key proteins
due to a nutrient deficiency. In which nutrient is the plant most likely deficient?
(A) Carbon, because it is an essential element in all organic molecules
(B) Nitrogen, because it is an essential element of amino acids
(C) Oxygen, because it is an essential element in both nucleic acids and proteins
(D) Phosphorus, because it is an essential element of nucleic acids
2.
An unknown molecule is extracted from a cell. An analysis of the molecule’s atomic makeup is
shown in the table below.
Based on the data in the table, the unknown molecule should be classified as which type of
molecule?
(A) A carbohydrate
(B) A protein
(C) A fatty acid
(D) A nucleic acid
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2.9 A: Molecular Basis of Exchange Quiz
3.
The diagram below shows an endergonic reaction in which a dipeptide is formed from two amino
acids in a cell.
Which statement best explains this reaction?
(A) This is a hydrolysis reaction because a water molecule is produced when the amino acids
bond to form the dipeptide.
(B) This is a dehydration synthesis reaction because a hydrogen atom is removed from one
amino acid and a hydroxyl group is removed from the other amino acid in order to form the
dipeptide.
(C) This is a dehydration synthesis reaction because the hydroxyl group in the water molecule
donates an electron to one of the amino acids, which is used to form the dipeptide.
(D) This is a hydrolysis reaction because a water molecule is used to fuse two amino acids
into a dipeptide.
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2.9 A: Molecular Basis of Exchange Quiz
4.
An experiment was done to test the effects of saliva on two carbohydrates: starch and maltose.
Each carbohydrate was mixed with water only or saliva only and then tested for the presence of
starch and maltose. The results are shown in the table below.
Which statement best explains the results observed in the experiment?
(A) Enzymes in the saliva digest the starch via a hydrolysis reaction to produce maltose.
(B) Enzymes in the saliva synthesize starch via dehydration synthesis from maltose
molecules.
(C) Enzymes in the saliva produce maltose from starch molecules via biosynthesis.
(D) Enzymes in the saliva produce starch from maltose molecules via digestion.
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