AP Biology Semester 1 TEST
Human immunodeficiency virus (HIV) is classified as an RNA virus because its genome, or genetic material, consists of a single strand of RNA. Which of the following claims is best supported by the information above? A. The nucleotides of HIV form an antiparallel nucleic acid structure. B. The structure of HIV forms a double-stranded nucleic acid. C. Deoxyribose is a five-carbon sugar within the nucleic acid structure of HIV. D. Uracil nucleotides are present in the HIV genome.
D
Which of the following best explains how modified proteins are transported within a compartmentalized cell? A. Modified proteins are transported in ribosomes that travel between membrane-bound organelles within the cell. B. Modified proteins are transported within contiguous intracellular membranes that connect membrane-bound organelles. C. Modified proteins are transported within contiguous extracellular membranes that connect membrane-bound organelles. D. Modified proteins are transported in vesicles that travel between membrane-bound organelles within the cell.
D
Which of the following is true about the amino acids that make up a transmembrane protein? A. Amino acids with polar side groups are in contact with the fatty acid region of the cell membrane. B. Amino acids with nonpolar side groups are in contact with the phosphate region of the cell membrane. C. Amino acids with charged side groups are in contact with the fatty acid region of the cell membrane. D. Amino acids with nonpolar side groups are in contact with the fatty acid region of the cell membrane.
D
Which of the following describes how phospholipid regions are positioned in the cell membrane? A. Hydrophilic phosphate regions are positioned toward aqueous environments. B. Hydrophilic phosphate regions face each other within the interior of the cell membrane. C. Hydrophobic fatty acid regions face each other within the exterior of the cell membrane. D. Hydrophobic fatty acid regions are positioned toward aqueous environments.
A
A student uses a microscope to compare a human skeletal muscle cell and a human epithelial cell. The student observes that the muscle cell has more mitochondria than the epithelial cell. Which of the following conclusions is best supported by this observation? A. The epithelial cell requires more ATP than the muscle cell. B. The muscle cell requires more ATP than the epithelial cell. C. The muscle cell does not require ATP to function. D. The epithelial cell does not require ATP to function.
B
Given the structure of water, H2O, which of the following must be true? A. Water has an overall negative charge. B. Each water molecule can form four hydrogen bonds. C. Each water molecule will form covalent bonds with its neighbors. D. Water is able to easily dissolve nonpolar substances.
B
Which of the following questions would a researcher most likely ask if they wanted to know whether a hydrolysis reaction or a dehydration synthesis reaction is occurring? A. Are the monomers identical to one another? B. Is water a reactant or product of the reaction? C. Which polymer is involved in the reaction? D. Is an enzyme involved in the reaction?
B
Which of the following statements accurately describes a similarity between the nucleotides of DNA and RNA? A. The nucleotides of DNA and RNA are connected through hydrogen bonds to form the sugar-phosphate backbone. B. The nucleotides of DNA and RNA contain a five-carbon sugar bonded to a phosphate group and a nitrogenous base. C. The nucleotides of DNA and RNA contain the same five-carbon sugar. D. The nucleotides of DNA and RNA contain the same nitrogenous bases.
B
Which of the following statements best describes the selective permeability of the cell membrane? A. The cell membrane regulates the transport of all substances into and out of the cell. B. The cell membrane regulates the transport of specific substances into and out of the cell. C. The cell membrane regulates the transport of intracellular substances out of, but not into the cell. D. The cell membrane regulates the transport of extracellular substances into, but not out of the cell.
B
Chlorophyll a is a pigment that absorbs light energy from the sun and gives plants their green color. Which of the following plant cell structures is most likely to contain chlorophyll a? A. Mitochondria B. Vacuole C. Chloroplast D. Ribosome
C
If ATP hydrolysis is inhibited, which of the following types of movement across a cell membrane would likely also be inhibited? A. Passage of water through aquaporins B. Facilitated diffusion of a substance through channel proteins C. Movement of an ion against its concentration gradient D. Movement of carbon dioxide molecules down their concentration gradient
C
Which of the following best describes how high levels of cholesterol affect the cell membrane at certain temperatures? A. At high temperatures, high amounts of cholesterol increase the fluidity of the cell membrane. B. At low temperatures, high amounts of cholesterol increase the rigidity of the cell membrane. C. At low temperatures, high amounts of cholesterol increase the fluidity of the cell membrane. D. At high temperatures, high amounts of cholesterol decrease the rigidity of the cell membrane.
C
A cytologist uses a microscope to compare a human hepatocyte and a human epithelial cell. She observes that the smooth endoplasmic reticulum (ER) of the hepatocyte is larger and contains more folds than the smooth ER of the epithelial cell. Which of the following is best supported by this observation? A. The hepatocyte is able to produce more proteins than the epithelial cell. B. The epithelial cell is able to detoxify substances more efficiently than the hepatocyte. C. The epithelial cell is able to generate more ATP than the hepatocyte. D. The hepatocyte is able to synthesize lipids more efficiently than the epithelial cell.
D
A damaged cell is unable to properly modify proteins after they are synthesized, which causes the proteins to misfold. Which of the following structures is most likely damaged in the cell? A. Mitochondrion B. Chloroplast C. Ribosome D. Endoplasmic reticulum
D
A biologist develops a simulation of the carbon cycle in a laboratory by setting up a closed ecosystem. The ecosystem consists of a glass container with an Earth-like atmosphere and a body of freshwater. In the water are a fish and an aquatic plant. The container is kept in well-lit and temperature controlled conditions. Which of the following best explains how the fish influences the carbon level in the atmosphere? A. It increases the carbon dioxide levels through cellular respiration. B. It decreases the carbon dioxide levels by consuming the plant. C. It decreases the carbon dioxide levels when it decomposes. D. It increases the carbon dioxide levels through photosynthesis.
A
In order to develop antibiotics, scientists need to understand how bacteria grow, divide, and spread during an infection. An essential part of bacterial growth is RNA synthesis because RNA must be synthesized before proteins can be assembled. If RNA synthesis is blocked, bacteria will not be able to survive and reproduce. Which of the following questions will best direct an investigation on how an antibiotic that inhibits RNA synthesis in bacteria can be developed? A. Which chemical compounds block the 3'3'3'3, ' end of a growing RNA strand? B. Which chemical compounds add a hydroxyl (-OH) group to the growing RNA strand? C. Which chemical compounds block the 5'5'5'5, ' end of the growing RNA strand? D. Which proteins are used to undergo cell division through binary fission?
A
In the cell membrane, carbohydrate chains can be covalently linked to membrane proteins to form glycoproteins. They can also be covalently linked to membrane phospholipids to form glycolipids. During an investigation, researchers discover a new toxin that enters a cell after binding to a carbohydrate on the cell membrane. Which of the following best describes how the toxin attaches to the cell membrane? A. The toxin attaches to specific monosaccharides on the cell membrane. B. The toxin attaches to specific fatty acids on the cell membrane. C. The toxin attaches to specific phospholipids on the cell membrane. D. The toxin attaches to specific amino acids on the cell membrane.
A
Lactose is a dimer sugar composed of two monomeric subunits (galactose and glucose). In an investigation, researchers placed intestinal cells in a nutrient medium containing lactose. The researchers determined that the lactose had broken down to galactose and glucose. he cells were then modified and re-exposed to the lactose medium. The researchers were no longer able to detect the presence of galactose and glucose. Which of the following conclusions best explains an outcome of this modification? A. The cells were unable to hydrolyze the lactose dimer into its monomeric subunits. B. The cells were unable to hydrolyze lactose, resulting in the formation of a covalent bond between galactose and glucose. C. The cells were able to undergo a reverse reaction and build lactose. D. The cells were able to perform dehydration synthesis reactions in order to break down lactose into its monomeric subunits.
A
Nitrogen is found throughout ecosystems in both organic and inorganic forms. Plants cannot use nitrogen directly from the atmosphere. Instead, they often rely on microbes to convert nitrogen into sources they can use through a process called nitrogen fixation. Although nitrogen fixation is common, nitrogen is still a limiting resource in many ecosystems. As a result, many plants have evolved in a way that allows them to survive in ecosystems that have a limited supply of nitrogen for plants. Most plants assimilate nitrogen through their roots. In contrast, there are 600-plus species of carnivorous plants that obtain up to 80%, percent of their nitrogen from trapped prey. These carnivorous plants thrive in environments such as bogs or marshes, where the nitrogen supply is low. These plants obtain what little nutrients are available from the soil, but they are able to best meet their metabolic requirements by supplementing with nutrients obtained from insects. Based on the passage, which of the following statements is true? A. Carnivorous plants use trapped insects as a source of nitrogen. B. Nitrogen in an ecosystem is found only in organic compounds. C. Atmospheric nitrogen is the most readily-available source of nitrogen for plants. D. Carnivorous plants are able to thrive because they typically live in areas with nutrient-rich soil.
A
The endoplasmic reticulum (ER) is a structure found in eukaryotic cells. It is composed of two parts: the smooth ER and the rough ER. Which of the following best describes a difference between the rough ER and the smooth ER? A. The rough ER has ribosomes on its surface, but the smooth ER does not. B. The rough ER processes toxins, but the smooth ER does not. C. The smooth ER is part of the endomembrane system, but the rough ER is not. D. The smooth ER is a site of protein synthesis, but the rough ER is not.
A
Which of the following best describes how organelles within the endomembrane system function together to transport proteins? A. Vesicles bud off from one organelle and then fuse with others to transport proteins through the endomembrane system. B. Contiguous intracellular membranes connect each organelle, allowing proteins to travel through the endomembrane system. C. Contiguous extracellular membranes connect each organelle, allowing for proteins to travel through the endomembrane system. D. Ribosomes bud off from one organelle and then fuse with others to transport proteins through the endomembrane system.
A
Which of the following best describes how the central vacuole helps support the structure of a plant cell? A. When the central vacuole is full of water, it applies pressure to the cell wall and maintains the shape of the cell. B. The central vacuole uses a large, rigid membrane to support the shape of the plant cell. C. When the central vacuole is empty, it expands in order to fill space and maintain the cell's structure. D. The central vacuole uses a network of protein fibers to support the shape of the plant cell.
A
Which of the following best explains why coastal cities like San Diego often have a smaller air temperature range than inland cities? A. The high heat capacity of water allows the ocean to moderate the temperature of nearby air and land. B. The cohesive tendency of water molecules causes high surface tension, so heat is unable to penetrate the top layer of the ocean and escape into the air. C. Because water is less dense as a solid than as a liquid, it easily vaporizes, causing excess heat to escape into the air near coastal cities. D. The adhesive properties of ocean water allow the water molecules to stick to one another, preventing temperature change of the air above it.
A
Which of the following examples explains how a biological activity relies on water's adhesive properties? A. Water travels through vascular tissue from the roots to the leaves of a plant. B. Vacuoles swell as water dilutes the contents of the vacuole. C. Stomata in leaves control transpiration of water out of the leaf as water vapor. D. Feathers retain an oily coating that repels water droplets.
A
Which of the following questions would best help determine if a cell has membrane-bound organelles? A. Are there distinct environments within the cell? B. Does the cell have a selectively permeable membrane? C. Does the cell replicate genetic information? D. Are there ribosomes present within the cell?
A
A neuron stimulates muscle contraction by sending signals across the neuromuscular junction, or the point of contact between a neuron and a muscle cell. The signaling process begins when membrane-bound structures inside the neuron fuse with the cell membrane, releasing signaling molecules into the neuromuscular junction. These molecules then diffuse through the junction and binds to receptors on the surface of the muscle cell, leading to muscle contraction. Botulism is a rare illness caused by a toxin produced by the bacterium Clostridium botulinum. This toxin, called botulinum toxin, inhibits the process by which signaling molecules are released from neurons at the neuromuscular junction. This disrupts the neuron-muscle cell signaling pathway, resulting in temporary paralysis. Based on the information, which of the following cell processes does botulinum toxin most likely inhibit? A. Receptor-mediated endocytosis B. Vesicle fusion during exocytosis C. Facilitated diffusion through membrane channels D. Membrane transport mediated by transmembrane ATPases
B
Most species of shark are strict carnivores. However, bonnethead sharks (Sphyrna tiburo) have been observed consuming seagrass within their natural habitat. Like other plants, seagrasses contain cellulose within their cell walls. Based on the information above, which of the following best supports the claim that bonnethead sharks are capable of hydrolyzing cellulose during digestion? A. Cellulose is consumed as a linear polysaccharide and is converted into branched glucose monosaccharides during digestion. B. Cellulose is consumed as a linear polysaccharide and is broken down into glucose monosaccharides during digestion. C. Cellulose is consumed as glucose monosaccharides and is converted into a linear polysaccharide and during digestion. D. Cellulose is consumed as a linear polysaccharide and remains as a linear polysaccharide during digestion.
B
Nitrogen is found throughout ecosystems in both organic and inorganic forms. Plants cannot use nitrogen directly from the atmosphere. Instead, they often rely on microbes to convert nitrogen into sources they can use through a process called nitrogen fixation. Although nitrogen fixation is common, nitrogen is still a limiting resource in many ecosystems. As a result, many plants have evolved in a way that allows them to survive in ecosystems that have a limited supply of nitrogen for plants. Most plants assimilate nitrogen through their roots. In contrast, there are 600-plus species of carnivorous plants that obtain up to 80%, percent of their nitrogen from trapped prey. These carnivorous plants thrive in environments such as bogs or marshes, where the nitrogen supply is low. These plants obtain what little nutrients are available from the soil, but they are able to best meet their metabolic requirements by supplementing with nutrients obtained from insects. Based on the passage, which of the following statements is true of carnivorous plants? A. Carnivorous plants are able to directly incorporate nitrogen from the atmosphere. B. Carnivorous plants are typically found in areas with nutrient-poor soil. C. Carnivorous plants evolved to capture prey because they cannot absorb nitrogen from the soil. D. Carnivorous plants do not require sunlight because they obtain all their nutrients from insects.
B
Which of the following describes the most likely way in which two water molecules will interact? A. An ionic bond will form between the oxygens in each water molecule. B. A hydrogen bond will form between the hydrogen atom of one water molecule and the oxygen atom of the other water molecule. C. A metallic bond will form between the hydrogens in each water molecule. D. A covalent bond will form between the hydrogen of one water molecule and the oxygen of the other water molecule.
B
A biologist develops a simulation of the carbon cycle in a laboratory by setting up a closed ecosystem. The ecosystem consists of a glass container with an Earth-like atmosphere and a body of freshwater. In the water are a fish and an aquatic plant. The container is kept in well-lit and temperature controlled conditions. Which of the following is likely to happen to the carbon dioxide level in the atmosphere if the plant dies? A. It will increase due to the emission of fossil fuels from the decaying plant. B. It will decrease due to increased cellular respiration in the ecosystem. C. It will increase due to lack of photosynthesis in the ecosystem. D. It would decrease due to decomposition of the plant.
C
A team of virologists has isolated a nucleic acid sample from a newly discovered virus. In order to classify the virus, they need to figure out whether the viral nucleic acid is DNA or RNA. Which of the the following characteristics of the nucleic acid sample would best help classify the viral nucleic acid as DNA or RNA? A. The nucleotides of the virus contain a five-carbon sugar. B. The nucleotides of the virus contain phosphate groups. C. The nucleotides of the virus contain uracil. D. The nucleotides of the virus contain covalent bonds.
C
Bodies of water, such as ponds, freeze from top to bottom, forming a floating sheet of ice. This can help aquatic organisms survive during cold winter months. Which of the following statements explains why the ice floats on the surface of the pond? A. The crystalline structure of solid ice makes it more dense than liquid water. B. The ice molecules have higher kinetic energy than the liquid water molecules, causing them to float. C. The increased number of hydrogen bonds in ice compared to liquid water causes the water molecules in ice to be further apart. D. As water freezes, ionic bonds form between water molecules, preventing the ice from sinking below the surface.
C
Cowpox is classified as a DNA virus because its genome, or genetic material, consists of double-stranded DNA. Which of the following claims is best supported by the information above? A. Thymine nucleotides are not found in the cowpox genome. B. Cowpox has a single-stranded nucleic acid structure. C. Uracil nucleotides are not found in the cowpox genome. D. Cowpox contains a five-carbon sugar called ribose in its nucleic acid structure.
C
Gastric acid is a digestive fluid that is made with the help of parietal cells in the stomach lining. The parietal cell plasma membrane maintains a concentration gradient of potassium ions (K+) between the cell cytoplasm and the extracellular fluid. During the formation of gastric acid, K+ moves down this gradient, passing from the cytoplasm into the extracellular space. Which of the following is the most likely mechanism by which K+ moves across the plasma membrane of a parietal cell during gastric acid formation? A. K+ flows through aquaporins. B. K+ is transported through transmembrane ATPases. C. K+ passes through membrane channel proteins. D. K+ directly diffuses through the membrane bilayer.
C
Which of the following observations could be best explained by water's high surface tension? A. A tree takes up water from its roots. B. A local pond is slow to freeze, despite low air temperature. C. A leaf floats on the surface of a puddle. D. A human sweats in order to cool down.
C
Which of the following statements about cell structures best supports the common ancestry of all living things? A. Eukaryotes have nuclei and prokaryotes do not. B. All plant cells have a cell wall. C. All cells contain ribosomes. D. Both plant and animal cells have mitochondria.
C
An unknown cell is determined to contain a nucleus, a cell wall, mitochondria, chloroplasts, and ribosomes. Which of the following statements about the unknown cell is most likely true? A. The unknown cell is a prokaryote. B. The unknown cell is an animal cell. C. The unknown cell cannot synthesize proteins. D. The unknown cell can perform photosynthesis.
D
Glycogen is a highly branched macromolecule usually stored in liver and muscle cells. If blood glucose levels decrease, glycogen breaks down to release glucose in a process called glycogenolysis. In this process, the glycogen polysaccharide goes through hydrolysis and breaks down into glucose monosaccharides. If a toxin were to inhibit glycogenolysis, which of the following statements best predicts a consequence of this inhibition? A. The covalent bonds within an individual glucose monomer will not be cleaved. B. In response to the detection of low glucose levels, more glucose will be released from stored glycogen. C. In response to the detection of low glucose levels, glycogen will continuously be broken down to release glucose. D. The covalent bonds between individual glucose monomers will not be cleaved.
D
Several botanists are studying the effect of high temperature on chloroplast function in Arabidopsis thaliana, a species of flowering plant. The botanists find that extremely high temperatures damage the membrane of the chloroplasts. This causes the contents of the chloroplasts to leak into the cytosol, which makes them nonfunctional. Which of the following is a likely immediate consequence of this damage? A. ATP production in the cell will decrease B. The chloroplast cannot transcribe DNA for protein synthesis. C. The chloroplast cannot synthesize lipids for the cell membrane. D. Glucose production in the cell will decrease.
D
Tay-Sachs disease is a genetic disorder that causes certain lipids known as gangliosides to accumulate in the neurons of the brain and spinal cord. As the gangliosides build up, neurons rapidly degenerate. Which of the following cell structures is most likely associated with the accumulation of gangliosides? A. Mitochondria B. Endoplasmic reticulum C. Nucleus D. Lysosomes
D
Which of the following best describes the permeability of the cell wall? A. Substances cannot pass across the cell wall because it is an impermeable structural boundary. B. All substances pass across the cell wall because it is a permeable structural boundary. C. Only water passes across the cell wall because it is a semipermeable structural boundary. D. Some substances pass across the cell wall because it is a semipermeable structural boundary.
D
Which of the following best explains why enzymatic reactions within the lysosome are compartmentalized? A. The hydrolytic enzymes of the lysosome function best within an environment that is similar to the cytosol. B. The hydrolytic enzymes of the lysosome function best within an environment that is connected to the Golgi complex. C. The hydrolytic enzymes of the lysosome function best within an environment that is connected to the endoplasmic reticulum (ER D. The hydrolytic enzymes of the lysosome function best within an environment that differs from the cytosol.
D
Which of the following is true about the transportation of substances across the lipid region of the cell membrane? A. Polysaccharides can freely dissolve across the lipid region of the cell membrane. B. Gases such as N2, O2, and CO2 require embedded transport proteins to dissolve across the lipid region of the cell membrane. C. Ions can freely dissolve across the lipid region of the cell membrane. D. Small nonpolar molecules can freely dissolve across the lipid region of the cell membrane.
D
Which statement best describes why water is an effective solvent? A. Water's relatively small size allows it to fit between individual atoms, driving them apart. B. Water is an ionic compound that attracts other like molecules. C. Water's hydrophobic nature separates polar and non-polar substances. D. Water's polarity allows it to dissolve ionic and polar compounds.
D