WorksheetsUnit 7 Review (2013 exam)
Total questions: 9
Worksheet time: 18mins
A dog is following the scent of a jackrabbit. Which of the following accurately describes how the dog’s brain integrates information for smell?
Chemoreceptors in the brain send impulses for smell in the nasal cavity.
Chemoreceptor cells in the nasal cavity send impulses to the appropriate area of the brain.
Chemoreceptors on epithelial cells of the tongue send hormones to the appropriate area of the brain.
Receptors originating in the nose send action potentials to the motor regions of the brain.
If ATP breakdown (hydrolysis) is inhibited, which of the following types of movement across cell membranes is also inhibited?
Movement of oxygen into a cell
Movement of water through aquaporins
Passage of a solute against its concentration gradient
Facilitated diffusion of a permeable substance
The equation above shows one of the reversible reactions that occur in blood. After exercise, an athlete’s blood pH has dropped below the normal level. How will normal blood pH be restored?
H+ + HCO3– ↔ H2O + CO2
An increase in O2 concentration in the plasma will lead to an increase in H+ concentration.
An increase in temperature will lead to an increase in H+ concentration.
An increase in sweating will lead to a decrease in OH– and H+ concentration.
An increase in breathing rate will lead to a decrease in blood CO2 and H+ concentration.
Cystic fibrosis is a recessively inherited disorder that results from a mutation in the gene encoding CFTR chloride ion channels located on the surface of many epithelial cells. As shown in the figure, the mutation prevents the normal movement of chloride ions from the cytosol of the cell to the extracellular fluid. As a consequence of the mutation, the mucus layer that is normally present on the surface of the cells becomes exceptionally dehydrated and viscous.
An answer to which of the following questions would provide the most information about the association between the CFTR mutation and the viscous mucus?
Is the mucus also secreted from the cells through the CFTR proteins?
How does the disrupted chloride movement affect the movement of sodium ions and water by the cell?
How does the mutation alter the structure of the CFTR proteins?
What is the change in nucleotide sequence that results in the CFTR mutation?
The diagram above depicts the response to a pinprick (stimulus) on the tip of a human finger. The arrows show the direction of impulse transmission along the labeled axons. If axon II was damaged before the pinprick, which of the following is most likely?
The person will not feel the pinprick.
The person can no longer feel pain.
The person’s finger will not withdraw reflexively.
The person cannot transmit nerve impulses to the brain.
The healthy human immune system responds to pathogens with both specific and nonspecific processes. Which of the following models depicts a nonspecific response?
The diagram above illustrates feedback control as exerted by the hormone thyroxine. Following surgical removal of the thyroid gland, the level of TSH in the blood will increase. Which of the following best explains this increase?
Residual blood thyroxine, from prior to thyroid gland removal, will bind to cells in the anterior pituitary, signaling more TSH secretion.
Thyroxine will remain bound to thyroxine receptors on various body cells, and these body cells will secrete additional hormones that stimulate the anterior pituitary to secrete TSH.
Thyroxine that was stored in the anterior pituitary prior to thyroid gland removal will signal more TSH secretion.
A decrease in thyroxine levels means a loss of inhibition to the hypothalamus and anterior pituitary, leading to increased TSH secretion.
The figure above shows a model of a ligand precursor being cleaved to produce an active ligand that binds to a specific receptor. Which of the following is most likely to reduce the binding of the active ligand to its receptor?
A change in the cytoskeletal attachment of transmembrane proteins
The presence of a large amount of the precursor form of the ligand
An increase in the ratio of the number of unsaturated to the number of saturated fatty acid tails of the membrane lipids
A mutation in the receptor gene that causes a substitution of a charged amino acid for a nonpolar amino acid in the ligand binding site of the receptor
Antidiuretic hormone (ADH) is important in maintaining homeostasis in mammals. ADH is released from the hypothalamus in response to high tissue osmolarity. In response to ADH, the collecting duct and distal tubule in the kidney become more permeable to water, which increases water reabsorption into the capillaries. The amount of hormone released is controlled by a negative feedback loop. Based on the model presented, which of the following statements expresses the proper relationship between osmolarity, ADH release, and urine production?
As tissue osmolarity rises, more ADH is released, causing less water to be excreted as urine.
As tissue osmolarity rises, less ADH is released, causing less water to be excreted as urine.
As tissue osmolarity rises, more ADH is released, causing more water to be excreted as urine.
As tissue osmolarity rises, less ADH is released, causing more water to be excreted as urine.
