AP Bio Practice Exam 2: Questions & Answers: Latest Updated A+ Score Solution

Which of the following best explains the mechanism by which alanine inhibits pyruvate kinase activity? (Ans - Alanine binds to an allosteric site of the enzyme, changing the shape of the enzyme's active site Different species of bumblebee compete for flower nectar in their ecosystem. While the flowers vary in the length of their petals, bumblebees vary in the length of a mouth part called a proboscis. Bumblebees demonstrate a preference for flowers that correspond to the length of the proboscis. Species with proboscises of similar length tend to occupy different areas. Species that live in the same area tend to have proboscises of different lengths. which of the following best explains the relationship between the different bumblebee species living in the same area? (Ans - The bumblebees have undergone niche partitioning due to competition Researchers investigated whether time of day affects the rate at which certain mRNAs produced by plants are broken down. At either 1 hour after the start of the light period (morning) or 8 hours after the start of the light period (afternoon), the researchers treated identical plant seedlings with a compound that blocks transcription (time = 0 min). The researchers measured the percent remaining of two mRNAs, mRNA G,and mRNA H over the course of 120 minutes. The data is shown in Figure 1. Based on the data, which of the following best describes the relationship between light and degradation of mRNA G and mRNA H? (Ans – A longer exposure to light increases the rate of mRNA G degradation but not go mRNA H degradation Which of the following observations would best provide the strongest evidence that two plants belong to different biological species? (Ans - They produce viable but sterile offspring Hormones are chemical signals that are released by cells in one part of the body that travel through the bloodstream to signal cells in another part of the body. Insulin is a hormone that is released by the pancreas that induces the uptake of glucose molecules from the bloodstream into cells. In this way, insulin lowers the overall blood glucose levels of the body. Osteoblasts and osteoclasts are two types of bone cells that play a role in regulating blood glucose levels (Figure 1)