AP BIO unit 2 test

Which of the following best describes the numbered areas?

A Areas 1 and 3 are polar, since the membrane molecules are aligned with water molecules.

The investigation is aimed at understanding how molecular size affects movement through a membrane. Which of the following best represents the amount of starch, water, and glucose in the dialysis bag over the course of the investigation?

A.

A model of the plasma membrane showing several biological molecules, including a transmembrane protein, is shown in Figure 1. Figure 1. Phospholipid bilayer with transmembrane protein Which statement best explains why correct protein folding is critical in the transmembrane protein shown above?

A. Interactions of the hydrophobic and hydrophilic amino acids help to anchor the protein in the membrane.

A team of biologists develop a new drug, and one team member hypothesizes that the drug is incapable of freely passing across the plasma membrane and requires the help of membrane proteins to enter cells. Alternatively, another biologist on the team hypothesizes that the drug can diffuse passively across the plasma membrane like O2O2 and CO2CO2 can. Which of the following, if true about the drug, best supports the alternative hypothesis that the new drug will exhibit simple diffusion across plasma membranes?

A. The drug is a small nonpolar molecule.

The following questions refer to the following diagram. For each phrase or sentence, select the labeled part to which it is most closely related. Each option may be used once, more than once, or not at all for each group. Site of glucose synthesis

B. B

Liver cells manufacture glycoproteins, while adipose cells store fat. Which of the following subcellular structures is likely to be more prominent in liver cells than in adipose cells?

B. Golgi apparatus

The function of which of the following organelles directly requires oxygen?

B. Mitochondrion

A pathogenic bacterium has been engulfed by a phagocytic cell as part of the nonspecific (innate) immune response. Which of the following illustrations best represents the response?

C

A prokaryotic cell has which of the following?

C. Plasma membrane

Intravenous (IV) solutions administered to patients are normally isotonic. Which of the following is most likely if an IV of distilled water is administered to a patient?

C. The cells that are exposed to hypotonic solutions will expand as water moves osmotically into the cells from the blood.

Water is constantly diffusing into the cytosol of freshwater single-celled organisms. In order to maintain the proper solute concentrations in the cytosol, contractile vacuoles pump out the excess water. An experimenter placed single-celled organisms into various saline concentrations and recorded the ATPATP used by the contractile vacuole. The data are shown in the graph. Of the following, which additional investigation can be used to determine when the cells are in an isotonic solution?

D. Increasing the salinity of the environment a little at a time until the ATP usage reaches a minimum.

Which of the following statements best supports the claim that certain organelles within eukaryotic cells evolved from free-living prokaryotic cells?

D. Some organelles contain their own DNA that is more similar to prokaryotic DNA in structure and function than to the eukaryotic DNA found in the cell's nucleus.

The manner in which several different ions and molecules move through a cell membrane is shown in the diagram above. For each ion or molecule, the relative concentration on each side of the membrane is indicated. Which of the following accurately describes one of the movements taking place?

Na+ transport out of the cell requires ATP hydrolysis.

Paramecia are unicellular protists that have contractile vacuoles to remove excess intracellular water. In an experimental investigation, paramecia were placed in salt solutions of increasing osmolarity. The rate at which the contractile vacuole contracted to pump out excess water was determined and plotted against osmolarity of the solutions, as shown in the graph. Which of the following is the correct explanation for the data?

The contraction rate increases as the osmolarity decreases because the amount of water entering the paramecia by osmosis increases.

Simple cuboidal epithelial cells line the ducts of certain human exocrine glands. Various materials are transported into or out of the cells by diffusion. (The formula for the surface area of a cube is 6 X S2, and the formula for the volume of a cube is S3, where S = the length of a side of the cube.) Which of the following cube-shaped cells would be most efficient in removing waste by diffusion?

A. 10um

The following questions refer to the following diagram. For each phrase or sentence, select the labeled part to which it is most closely related. Each option may be used once, more than once, or not at all for each group. Site of conversion of chemical energy of glucose to ATP

A. A

For following group of questions first study the description of the situation or data and then choose the one best answer to each question following it and fill in the corresponding oval on the answer sheet. In the first step of an experiment, rat liver cells were exposed for 5 minutes to amino acids labeled with a radioactive isotope. The cells were then washed to stop any further incorporation of radioactive amino acids. The cells were sampled periodically thereafter, and the radioactivity of a certain protein (protein X) was measured in various cell components, as shown below. The same procedure was repeated with a second protein (protein Y). If the function of Y is protein processing and packaging, the most radioactivity would be found in the

A. Golgi apparatus

Which of the following statements best explains the processes of passive and active transport?

B. Passive transport is the net movement of substances down a concentration gradient that does not require metabolic energy. Active transport is the movement of substances up a concentration gradient that requires energy.

The model below shows the structure of a portion of a plasma membrane in an animal cell. Which statement best explains the orientation of the phospholipid molecules in this model?

B. The hydrophilic phosphate groups of the phospholipid molecules are attracted to the aqueous internal and external environments.

The figure shows a process by which a cell might absorb food from its surrounding environment and break it down for use as a source of energy and matter. The process involves lysosomes, which are membrane-bound organelles that contain hydrolytic enzymes. Activation of the hydrolytic enzymes requires an acidic pH, and lysosomes maintain an internal acidic pH by using ion pumps. Which of the following outcomes will most likely result from a loss of ion pump function in the cell's lysosomes?

B. The internal pH of the lysosomes will increase, which will prevent the activation of hydrolytic enzymes and interfere with the intracellular digestion of food.

Which statement best describes the effect on water transport across the cell membrane if the aquaporin in the figure ceases to function?

B. Water molecules will still be able to move across the cell membrane but at a slower rate.

A student formulated a hypothesis that water-soluble pollutants damage living organisms by increasing the permeability of cellular membranes. To test the hypothesis, the student investigated the effect of isopropanol and acetone on beet root cells. The vacuoles of beet root cells contain large amounts of betacyanin, a water-soluble pigment that is released into the extracellular environment as a result of increased membrane permeability. The student prepared identical samples of beet root tissue and incubated each sample for 15 minutes in the specific solution for that group. At the end of the incubation period, the student measured the absorbance of 460 nm light for each sample. A greater concentration of betacyanin in the solution surrounding the beet root cells results in a greater absorbance of 460 nm light. The results of the experiment are shown in the table above. Based on the data from the investigation, which of the following is the best scientific question about organisms living in water that is polluted with organic solvents?

B. Will organisms living in polluted environments exhibit detrimental effects from an increased permeability of their cellular membranes?

Figure 1 shows a model of how a channel protein influences the movement of a particle across a cell's plasma membrane. Figure 1. A section of a cell's plasma membrane, showing a channel protein and a concentration gradient across the membrane An investigator wants to understand whether a newly found membrane protein is involved in membrane transport of a certain particle. Which investigation will help determine whether the new membrane protein is a channel protein involved in membrane transport?

C. Add more of the proteins to the plasma membrane and measure the rate of the particle movement.

The following questions refer to the following diagram. For each phrase or sentence, select the labeled part to which it is most closely related. Each option may be used once, more than once, or not at all for each group. Site of modification and packaging of proteins and lipids prior to export from the cell

C. C

Researchers claimed that a particular organelle originated from a free-living prokaryotic cell that was engulfed by a larger cell, as shown in Figure 1. Figure 1. A model showing a cell engulfing a smaller cell Which of the following provides evidence to best support the researchers' claim?

C. The organelle has a double membrane.

In an experiment, cells were isolated from an aquatic plant and suspended in pond water, a sucrose sugar solution, or distilled water. All of the cells were then viewed under a microscope. Compared with the cell in the pond water, the cell in the sugar solution appeared shriveled, and the cell in the distilled water appeared inflated. The results of the experiment are represented in Figure 1. Figure 1. The results of an experiment using aquatic plant cells Which of the following statements best explains the observations represented in Figure 1 ?

C. There was a net movement of water out of the cell suspended in the sugar solution and a net movement of water into the cell suspended in the distilled water.

A sample of human blood was placed in a test tube containing a physiological saline solution (0.9% sodium chloride). This type of solution is often used intravenously to quickly rehydrate patients. A drop of the blood from the test tube was placed on a slide and red blood cells (RBCs) were observed under a microscope. Three possible outcomes are diagrammed below. Which of the following best predicts which diagrammed microscope view the laboratory worker would see and best explains why?

C. View 2 because the rate of water movement into the RBCs equals the rate of water movement out of the cells

Which of the following scientific questions is most relevant to the model represented in the figure above?

C. Which molecular substance is actively transported across the plasma membrane?

Changing the shape or morphology of the mitochondrial inner membrane can change the efficiency of mitochondrial function. Which of the following outcomes will most likely result from a change in the shape of the mitochondrial inner membrane from a highly folded surface to a smooth, flat surface?

D. Mitochondria will become less efficient because the surface area of the inner mitochondrial membranes will decrease.

Cells contain smaller components called organelles that are necessary for a cell's survival. Organelle functions have often been compared to components of larger systems. Which of the following functional differences between the rough and smooth endoplasmic reticulum (ER)(ER) is explained by the structural differences between them?

D. Rough ER can synthesize and package proteins for export, and smooth ER cannot.

A human kidney filters about 200L of blood each day. Approximately 2L of liquid and nutrient waste are excreted as urine. The remaining fluid and dissolved substances are reabsorbed and continue to circulate throughout the body. Anti diuretic hormone (ADH) is secreted in response to reduced plasma volume. ADH targets the collecting ducts in the kidney, stimulating the insertion of aquaporins into their plasma membranes and an increased reabsorption of water. If ADH secretion is inhibited, which of the following would initially result?

D. The person would produce greater amounts of dilute urine.

Dialysis tubing is permeable to water molecules but not to sucrose. Four dialysis tubes are half filled with 5 percent, 10 percent, 20 percent, and 40 percent sucrose solutions, respectively, and two dialysis tubes are half filled with distilled water. The dialysis tubes are all sealed at both ends, and the initial masses are determined. Five dialysis tubes are placed into beakers containing distilled water, and the sixth dialysis tube, containing distilled water, is placed into a 40 percent sucrose solution. The masses of the dialysis tubes are recorded at 30-minute intervals for 90 minutes, as shown in the table below. A net movement of water into the beaker occurs in which of the following dialysis tubes?

E. 6