AP Biology : 1.7 Proteins - Exam Style questions with Answer- MCQ - New Syllabus -2025
Question
Which of the following correctly illustrates a dipeptide and an amino acid in the optimal position to form a tripeptide?
Answer/Explanation
Ans:A
This option is correct. It demonstrates an ability to refine and/or interpret a representation to explain the synthesis of a biological polymer. Peptides or proteins are polymers of amino acid monomers arranged in a unique linear sequence. Each of the 20 amino acids consists of a carbon atom surrounded by an amine group\( (NH_2)\), a carboxyl group (COOH), a hydrogen, and an R (variable) group. When two amino acids are positioned so that the carboxyl group of one amino acid backbone is adjacent to the amine group of another amino acid backbone, they can join by a dehydration reaction.
Question
The FtsZ protein is present in prokaryotes and in chloroplasts. The protein is structurally and functionally similar to tubulin proteins of eukaryotic cells. Which of the following is a likely conclusion to draw from this information?
(A) FtsZ and tubulin proteins were both present in a common ancestor.
(B) Microtubules are involved in the mechanics of photosynthesis.
(C) Tubulin genes are evolutionarily derived from the gene that codes for the FtsZ protein.
(D) The sequences of the genes encoding the FtsZ and tubulin proteins are identical.
Answer/Explanation
Ans:C
This option is correct. The evidence states that the FtsZ gene is present in prokaryotes and in chloroplasts. Chloroplasts evolved from endosymbiotic prokaryotes. The tubulin protein is structurally and functionally similar to FtsZ and is found in eukaryotes, inferring evolutionary descent.
Question
Reaction that converts proteins to amino acids
(A) Hydrolysis
(B) Phosphorylation
(C) Reduction with hydrogen
(D) Amination
(E) Decarboxylation
Answer/Explanation
Ans:A