AP BIO MT MCQs

Which statement describes how water is pulled up through the xylem to the leaves of the plant? A As water exits the leaf, hydrogen bonding between water molecules pulls more water up from below. B As water exits the leaf, signals are sent to the roots to pump more water up to the leaves through the xylem by adhesion. C Evaporation from the leaf decreases the hydrogen bonds that form between the water molecules in the xylem, which helps the water molecules to be pulled up the xylem. D Evaporation of water from the leaf increases the hydrogen bonds that form between water molecules in the air, providing the energy for transport.

A As water exits the leaf, hydrogen bonding between water molecules pulls more water up from below.

A magnesium sulfate solution taken orally can cause a net movement of water into the large intestine, which results from water molecules diffusing through aquaporins embedded in the cells of the intestinal lining. By which of the following mechanisms do the water molecules most likely move into the large intestine? A By passive transport from an area of low osmolarity to an area of high osmolarity B By passive transport from an area of high osmolarity to an area of low osmolarity C By active transport from an area of low osmolarity to an area of high osmolarity D By active transport from an area of high osmolarity to an area of low osmolarity

A By passive transport from an area of low osmolarity to an area of high osmolarity

Intravenous (IV)(IV) therapy is used for fluid replacement in instances of dehydration in humans and other animals. One type of IVIV fluid is essentially a saltwater solution. To determine the best concentration for therapy in people, a team of students is researching the effects of solutions of different salt concentrations on red blood cells. The following observations were made from three different red blood cell samples viewed under a microscope. The team wants to extend the research project. What should the team of students do next to obtain data that are more conclusive? A Repeat the process with other salt concentrations. B Develop a model to explain why the cells react differently to different salt concentrations. C Repeat the process using red blood cells from other animals. D Develop an experimental procedure that uses a stain that makes the organelles of red blood cells more visible.

A Repeat the process with other salt concentrations.

Lysosomes digest food particles brought into a cell by endocytosis. After a vesicle containing food particles fuses with a lysosome, H+H+ ions are transported into the lysosome from the cytosol. This significantly lowers the pHpH of the lysosome relative to the cytosol and activates the enzymes that digest the particles. Which of the following best predicts what will happen to the lysosomal enzymes if the proteins that transport H+H+ ions from the cytosol into the lysosome are damaged? A The lysosomal enzymes will not become active, since there will be no active transport of H+H+ ions. B The lysosomal enzymes will not become active, since H+H+ ions will diffuse out of the lysosome. C The lysosomal enzymes will become active, since facilitated diffusion will move H+H+ ions into the lysosome. D The lysosomal enzymes will become active, since passive diffusion will move H+H+ ions into the lysosome.

A The lysosomal enzymes will not become active, since there will be no active transport of H+H+ ions.

Which of the following is the most likely cause of the change in mean aspen height from 1998 to 2010 ? A The reintroduction of wolves led to a decrease in the population of elk, allowing aspen trees to grow taller. B The reintroduction of wolves led to a decrease in the population of small mammals, allowing aspen trees to grow taller. C The reintroduction of wolves led to an increase in the number of carcasses that provided fertilizer for young aspen trees. D The reintroduction of wolves led to an increase in the number of carcasses, so coyotes no longer ate young aspen trees.

A The reintroduction of wolves led to a decrease in the population of elk, allowing aspen trees to grow taller.

Which of the following best describes the process that adds a monosaccharide to an existing polysaccharide? A The monosaccharide is completely broken down by a specific enzyme and then the atoms are reorganized and made into a polysaccharide. B Ionic bonds are formed between adjacent carbon atoms of the monosaccharide and the polysaccharide by adding water (H2O)(H2O) and a specific enzyme. C A specific enzyme removes the hydrogen (HH) from the monosaccharide and the hydroxide (OHOH) from the polysaccharide, creating a bond between the two and creating a water (H2OH2O) molecule. D A specific enzyme removes two hydroxides (OH)(OH), one from the monosaccharide, and one from the polysaccharide, creating a bond between the two monosaccharides and creating a hydrogen peroxide (H2O2H2O2) molecule.

C A specific enzyme removes the hydrogen (HH) from the monosaccharide and the hydroxide (OHOH) from the polysaccharide, creating a bond between the two and creating a water (H2OH2O) molecule. D

Researchers investigate the transport of a certain protein into cells by endocytosis. In an experiment, the researchers incubate the cells in the presence of the protein and measure the amount of the protein that is absorbed into the cells over a five-minute period. Based on their observations, what should the researchers do to further clarify how the availability of the protein outside the cells affects the rate of endocytosis of the protein? A Incubate the cells in the absence of the protein. B Incubate the cells in the presence of several different proteins. C Incubate the cells in the presence of several different concentrations of the protein. D Incubate the cells in the presence of the protein for several different lengths of time.

C Incubate the cells in the presence of several different concentrations of the protein.

Gaucher disease is an inherited disorder in which cells of the body are unable to break down a particular type of lipid, resulting in a buildup of the lipid in some tissues and organs. Based on the information provided, Gaucher disease results most directly from a defect in the function of which of the following organelles? A The smooth endoplasmic reticulum B The nucleus C The lysosome D The mitochondrion

C The lysosome

Which of the following is the most likely reason for the difference in leaf growth? A The phosphorus-starved plant was unable to synthesize both the required proteins and lipids, limiting growth. B The phosphorus-starved plant was unable to synthesize both the required proteins and carbohydrates, limiting growth. C The phosphorus-starved plant was unable to synthesize both the required nucleic acids and lipids, limiting growth. D The phosphorus-starved plant was unable to synthesize both the required carbohydrates and nucleic acids, limiting growth.

C The phosphorus-starved plant was unable to synthesize both the required nucleic acids and lipids, limiting growth.

A study recorded changes in the distribution of some commercial marine species off the East Coast of the United States over a period of several decades. The results of the study are summarized in Figure Some researchers link changes in the distribution of these species to warming of the oceans due to climate change. Which of the following pieces of data best supports this alternative hypothesis? A Decreased acidity of ocean water in the more southern latitudes caused a migration of these species northward. B These species evolved new adaptations over time, allowing them to survive in warmer ocean environments. C The prey of these species require colder waters to survive, and owing to warming in the oceans, they are moving farther north, to higher latitudes, where the water is colder. D Diseases devastated the prey of these species, forcing them to move northward as insufficient food was available in their original range.

C The prey of these species require colder waters to survive, and owing to warming in the oceans, they are moving farther north, to higher latitudes, where the water is colder.

Which of the following best describes a structural similarity between the two molecules shown in Figure 1 that is relevant to their function? A Both molecules are composed of the same four nucleotides, which allows each molecule to be produced from the same pool of available nucleotides. B Both molecules are composed of the same type of five-carbon sugar, which allows each molecule to act as a building block for the production of polysaccharides. C Both molecules contain nucleotides that form base pairs with other nucleotides, which allows each molecule to act as a template in the synthesis of other nucleic acid molecules. D Both molecules contain nitrogenous bases and phosphate groups, which allows each molecule to be used as a monomer in the synthesis of proteins and lipids.

D Both molecules contain nitrogenous bases and phosphate groups, which allows each molecule to be used as a monomer in the synthesis of proteins and lipids.

Mammals do not produce digestive enzyme B. However, sheep and cattle are two types of mammals that contain microorganisms in their digestive tract that produce enzyme B. Which of the following would most likely occur if cattle lost the ability to maintain a colony of microorganisms in their digestive tract? A Cattle would no longer be able to synthesize cellulose. B Cattle would have to convert cellulose to starch before digesting it. C Cattle would have to start producing enzyme BB without the help of the bacteria. D Cattle would no longer be able to use cellulose as a primary source of glucose.

D Cattle would no longer be able to use cellulose as a primary source of glucose.

Euglenids are single-cell eukaryotes that live in aquatic environments. The chloroplasts found inside euglenids are enveloped by three membranes, as represented in Figure 1. The inner membrane of euglenid chloroplasts resembles the thylakoid membrane. Which of the following claims about the origin of the euglenid chloroplast is best supported by the three-membrane structure of the envelope? A It originated from the spontaneous assembly of organic molecules into a lipid bilayer inside a free-living prokaryote. B It originated from the fusion of the plasma membranes of two different free-living photosynthetic prokaryotes. C It originated from the incorporation of a photosynthetic prokaryote into a eukaryotic cell by a single endosymbiotic event. D It originated from the incorporation of a photosynthetic prokaryote into a eukaryotic cell by two endosymbiotic events.

D It originated from the incorporation of a photosynthetic prokaryote into a eukaryotic cell by two endosymbiotic events.

In a study of energy flow, the following data were collected: Each human requires 55 grams of protein per day. An acre of soybeans produces 200,000 grams of protein per year. A cow grazing on one acre of land produces 19,000 grams of protein per year. Based on these data, an acre of land would support: 10 humans per year on a diet of soy, or 0.9 human per year on a diet of beef. Which of the following statements best explains these relationships in terms of energy transfer? A Humans are better adapted to make efficient use of soy protein than beef protein, so they can extract more energy from a gram of soy protein than from a gram of beef protein. B A cow can harvest energy only at a certain rate, so adding another cow to the acre of land would double the number of humans supported by the acre. C Preparing meat for human consumption takes more energy per gram of protein than preparing soy for consumption. D Only 10% of the energy on each level of the trophic pyramid is available for use by the next level. The rest is lost as heat or used for growth and repair.

D Only 10% of the energy on each level of the trophic pyramid is available for use by the next level. The rest is lost as heat or used for growth and repair.

Which feature of model 1 best illustrates how biological information is coded in a DNA molecule? A The 5′5′ and 3′3′ labels at the ends of each strand B The labeling of the hydrogen bonds between base pairs C The lines connecting sugars and phosphate groups that represent covalent bonds D The linear sequence of the base pairs

D The linear sequence of the base pairs

Which of the following statements best describes the properties of the molecules indicated in Figure 1 a. Molecule B has hydrophilic properties and molecules A and C have hydrophobic properties b. Molecule B has both hydrophobic + hydrophilic properties + molecules A and C are only hydrophilic c. Molecules B and C have hydrophilic properties and all three molecules have hydrophobic properties d. Molecules B and C have hydrophobic properties and all three molecules have hydrophilic properties

d. Molecules B and C have hydrophobic properties and all three molecules have hydrophilic properties