AP bio test prep unit 3
the mechanism of action of many common medications involves interfering with the normal pathways that cells use to respond to hormone signals. which of the following best describes a drug interaction that directly interferes with a signal transduction pathway?
A medication enters the target cell and inhibits an enzyme that normally synthesizes a second messenger.
the energy required to run the calvin cycle reactions of photosynthesis comes from which two substances produced during the light dependent reactions
ATP and NADPH
an increase in the rate of oxygen production by algae would be accompanied by a comparable increase in the rate of production of which of the following substances
C6H12O6
process in which carbon from CO2 is incorporated into organic molecules
Calvin cycle (light-independent reactions of photosynthesis)
process in which O2 is released as a by product of oxidation reduction reactions
D. Light-dependent reactions of photosynthesis
Notch is a receptor protein displayed on the surface of certain cells in developing fruit fly embryos. Notch's ligand is a membrane-bound protein called Delta that is displayed on the surface of adjacent cells. When Notch is activated by its ligand, the intracellular tail of the Notch protein becomes separated from the rest of the protein. This allows the intracellular tail to move to the cell's nucleus and alter the expression of specific genes. Which of the following statements best explains Delta's role in regulating cell communication through the Notch signaling pathway?
Delta restricts cell communication to short distances within a developing embryo.
A scientist claims that Elysia chlorotica, a species of sea slug, is capable of photosynthesis. Which of the following observations provides the best evidence to support the claim?
Elysia chlorotica grows when exposed to light in the absence of other food sources.
based on the data shown, changes in the light intensity resulted in changes in the rate of which of the following processes
photosynthesis
which of the following claims is most consistent with the data shown in figure 2
Esp expression is necessary to prevent the overproduction of insulin
Based on Figure 1, which of the following statements best describes the epinephrine signaling pathway?
In involves enzymes activating other enzymes.
The brain coordinates the circulatory and respiratory systems of the human body. The control of breathing, for example, involves neural pathways among the structures represented in the figure above. One important stimulus in the control of breathing is an increase in blood CO2 concentration, which is detected as a decrease in blood pH. Which of the following best describes the physiological response to an overall increase in cellular respiration in the body?
In response to low blood pH, the pH sensors send a signal to the brain, which then sends a signal to the diaphragm, resulting in an increased rate of breathing to help eliminate excess blood CO2 .
Carbohydrate-synthesizing reactions of photosynthesis directly require
products of light reactions
which of the following best describes the effect of insulin binding to the receptor on the osteoblast cells
Insulin binding ultimately increases pancreatic secretion of additional insulin.
which of the following statements best describes the role of adenylyl cyclase in the epinephrine signaling pathway
It accelerates the production of a second messenger.
The rate of oxygen production equaled the rate of oxygen consumption during which of the following time periods?
J to K
Cell communication is critical for the function of both unicellular and multicellular eukaryotes. Which of the following is likely true of cell signaling?
Similar cell signaling pathways in diverse eukaryotes are evidence of conserved evolutionary processes.
which of the following statements provides evidence to support the claim that no ATP will be synthesized in the absence of a proton gradient across the thylakoid membrane
No ATP is synthesized when channel proteins that allow the free passage of protons are inserted into the thylakoid membrane.
What most likely causes the trends in oxygen concentration shown in the graph above?
Photosynthesis produces more oxygen than is consumed by respiration during the day.
Glucocorticoids are steroid hormones that control cellular responses through several different signaling pathways. which of the following statements best predicts the effect of a mutation that results in the loss of the glucocorticoid receptors ligand binding function?
The glucocorticoid receptor will remain associated with the accessory proteins
which of the following is an important difference between light dependent and light independent reactions of photosynthesis
The light-dependent reactions produce ATP and NADPH; the light-independent reactions use energy stored in ATP and NADPH.
based on the information provided, which of the following best justifies the claim that osteocalcin is a hormone?
The osteoblasts in the bone secrete osteocalcin, which causes cells in the pancreas to change their activity.
a researcher observed that mice from the mutant strain experience low blood sugar. which of the following best describes the feedback mechanism in the pathway causing the low blood sugar in the mutant strain?
The positive feedback of insulin production
Vertebrate immune responses involve communication over short and long distances. Which of the following statements best helps explain how cell surface proteins, such as MHC proteins and T cell receptors, mediate cell communication over short distances?
The proteins interact directly with proteins on the surfaces of other cells.
in type 2 diabetes, the cellular response to insulin is disrupted, and individuals with type 2 diabetes cannot properly regulate their blood glucose levels. which of the following is a valid interpretation of the experimental results that explains how individuals with type 2 diabetes differ from individuals without diabetes?
The relatively low levels of glucose uptake in individuals with type 2 diabetes indicate that mobilization of GLUT4 to the cell surface is reduced in muscle cells of those individuals
According to the results of this experiment, germination of tobacco seeds during the first week is
increased by exposure to light
In a certain signal transduction pathway, the binding of an extra cellular molecule to a cell surface protein results in a rapid increase in the concentration of cyclic AMP inside the cell. which of the following statements best describes the role of cyclic AMP in the signal transduction pathway
it acts as a second messenger that helps relay and amplify the signal within the cell
which of the following was a positive control in the experiment
normal strain
in flowering plants, plasmodesmata are narrow channels through cell walls that connect the cytoplasm of adjacent cells. an explanation of how plant cells communicate across cells walls most likely refer to the diffusion through plasmodesmata of which of the following
small, water-soluble molecules
based on the experimental results, which of the following describes the most likely defect in muscle cells of patients with type 2 diabetes
steroid hormone. receptor molecule. hormone receptor complex. transcription.
Additional observations were made on day 21, and no yellow-leaved seedlings were found alive in either dish. This is most likely because
yellow-leaved seedlings were unable to convert light energy to chemical energy