AP Bio
The rate of oxygen consumption in germinating pea seeds at 26ºC is
0.05
Which of the following best predicts which diagrammed microscope view the laboratory worker would see and best explains why?
View 2 because the rate of water movement into the RBCs equals the rate of water movement out of the cells
Evolved from a photoautotrophic prokaryote
B-chloroplast
A feature of organic compounds NOT found in inorganic compounds is the presence of
carbon atoms covalently bonded to each other
The O2 released during photosynthesis comes from
H2O
Which of the following is most directly responsible for water's unique properties?
It forms hydrogen bonds.
If ATP breakdown (hydrolysis) is inhibited, which of the following types of movement across cell membranes is also inhibited?
Passage of a solute against its concentration gradient
Individuals with an inherited autosomal recessive disorder called primary ciliary dyskinesia (PCD) often have severe respiratory problems due to defective cilia. Males with PCD are often sterile because they produce sperm with defective flagella. Which of the following most likely explains the effect of the recessive allele?
The cells do not produce functional motor proteins in flagella and cilia.
Water and ammonia interact to form hydrogen bonds, as represented in the figure. Which statement best helps explain the formation of the hydrogen bond represented in the figure?
The nitrogen has a partial negative charge, and the hydrogen attached to the oxygen has a partial positive charge.
Which of the following statements is true about the Krebs (citric acid) cycle and the Calvin (light-independent) cycle?
They both are carried out by enzymes located within an organelle matrix.
Which statement best describes the effect on water transport across the cell membrane if the aquaporin in the figure ceases to function?
Water molecules will still be able to move across the cell membrane but at a slower rate.
A prokaryotic cell has which of the following?
plasma membrane
During respiration, most ATP is formed as a direct result of the net movement of
protons down a concentration gradient
The synthesis of protein or carbohydrate polymers always produces which of the following as a byproduct?
water
A net movement of water into the beaker occurs in which of the following dialysis tubes?
6
Researchers propose a model to explain variation in phytoplankton cell sizes in a marine environment. They base their model on the idea that smaller cells absorb nutrients more efficiently. The researchers predict that the mean diameter of phytoplankton cells will change by 50 micrometers for every 5-kilometer increase in distance from the shore because of a gradual decrease in nutrient availability. To test their model, the researchers determine that the phytoplankton cells found closest to shore have a mean diameter of 900 micrometers. Based on the model, what will be the mean diameter of the phytoplankton cells that are found 25 kilometers from shore?
650 micrometers
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
The figure shows a diagram of a portion of a phospholipid bilayer. The upper, middle, and lower areas of the bilayer are labeled 1, 2, and 3, respectively. Areas 1 and 3 show the heads of the phospholipids adjacent to water molecules. Area 2 shows the fatty acid tails of the phospholipids, pointing to the center of the membrane, away from the phospholipid heads at the membrane surfaces. Which of the following best describes the numbered areas?
Areas 1 and 3 are polar, since the membrane molecules are aligned with water molecules.
A researcher claims that only a portion of the light energy captured by green plants is available for growth and repair. Which of the following observations best helps justify the researcher's claim?
As light energy is converted to chemical energy by metabolic processes, some of the energy is lost as heat.
Bacteriophages are viruses that infect bacteria. In an experiment, bacteriophages were labeled with either radioactive phosphorus or radioactive sulfur. The labeled bacteriophages were incubated with bacteria for a brief amount of time and then removed. The infected bacteria cells were found to contain significant amounts of radioactive phosphorus but not radioactive sulfur. Based on the results of the experiment, which of the following types of molecules did the bacteriophages most likely inject into the bacteria cells?
DNA
The chemical reaction for photosynthesis is 6CO2 + 12H2O + light energy → → C6H12O6 + 6O2 + 6H2O If the input water is labeled with a radioactive isotope of oxygen, 18O, then the oxygen gas released as the reaction proceeds is also labeled with 18O. Which of the following is the most likely explanation?
During the light reactions of photosynthesis, water is split, removing electrons and protons, and oxygen gas is released.
Which of the following questions is most relevant to understanding the Calvin cycle?
How is ATP used in the formation of 3-carbon carbohydrates?
Figure 1 is a diagram of water molecules at the air-water interface at the surface of a pond. The figure presents a diagram of the alignment of water molecules at an air-water interface. Four identical water molecules are shown just below the surface of the water, near the air-water interface. Each water molecule consists of one large atom and two smaller ones. A key indicates that the smaller atoms have a partial positive charge, and the larger atom has a partial negative charge. The water molecules are identically aligned at the surface of the water. For each water molecule, one of the smaller atoms with the partial positive change is situated at the bottom of the larger atom, toward the water below. Vertical dotted lines extend downward from these smaller atoms. For each water molecule, the other small atom with the positive partial charge is positioned at the upper right of the larger atom. The upper left side of the larger atom is shown to have a partial negative charge. Horizontal dotted lines are drawn between the upper portions of neighboring water molecules. Figure 1. Alignment of water molecules at air-water interface Based on Figure 1, which of the following best describes how the properties of water at an air-water interface enable an insect to walk on the water's surface?
Hydrogen bonds between molecules at the surface of the water provide surface tension, which allows the water surface to deform but not break under the insect.
Enzymes with their highest activity at an alkaline (basic) pH are represented by which of the following graphs?
II only
Cyanobacteria contain a variety of pigment molecules, as shown in Table 1. As a result, the color of cyanobacteria cultures can vary significantly based on the relative amount of each pigment produced. A researcher placed a culture of cyanobacteria under green lights. Within a few weeks, the appearance of the cyanobacteria changed from green to red. The researcher claimed the color change in the culture was the result of an adaptation allowing greater photosynthesis. Which of the following provides the best reasoning to justify the researcher's claim?
In green light, more phycoerythrin molecules are produced, allowing more green light to be absorbed, thus increasing photosynthesis.
Which of the following questions will best direct an investigation of the mechanism of ATP synthase?
Is the phosphorylation of ADP by ATP synthase dependent on the formation of a proton gradient?
Polypeptides are continuously being formed and degraded. One of these processes is shown. The figure presents the molecular structures of polypeptides. A molecule at the top of the figure has a backbone with six repeats of the following atoms: N, C, C. One R group, of the range R 1 through R 6, is bonded with the first C of each the N, C, C repeats. An arrow that is joined by another arrow labeled H 2 O points to two shorter molecules, each with only three repeats of the atoms: N, C, C. One of the shorter molecules has R groups R 1, R 2, and R 3. The other molecule has R groups R 4, R 5, and R 6. Figure 1. Polypeptide reaction Which statement is the most accurate description of the reaction shown in Figure 1?
It represents a polypeptide chain that is broken down through a hydrolysis reaction.
Which of the following statements best helps justify the inclusion of test tube 5 as a control in the experiment?
It will provide a measurement of product formation in the presence of a denatured enzyme.
Contains hydrolytic enzymes associated with the intracellular digestion of macromolecules
Lysosome
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?
Mitochondria will become less efficient because the surface area of the inner mitochondrial membranes will decrease.
The function of which of the following organelles directly requires oxygen?
Mitochondrion
Membrane-bound organelles have been an important component in the evolution of complex, multicellular organisms. Which of the following best summarizes an advantage of eukaryotic cells having internal membranes?
Organelles isolate specific reactions, increasing metabolic efficiency.
The molecular structures of linoleic acid and palmitic acid, two naturally occurring substances, are shown in the figure. Based on the molecular structures shown in the figure, which molecule is likely to be solid at room temperature?
Palmitic acid, because the absence of carbon-carbon double bonds allows the molecules to pack closely together.
Which of the following statements best describes how organisms such as rabbits obtain the carbon necessary for building biological molecules
Rabbits eat plants and break down plant molecules to obtain carbon and other atoms that they rearrange into new carbon-containing molecules.
Segment one shows 2 rows. Row one, five prime dash A T A T G A G T A G T dash three prime. Row two, three prime das T A T A C T C A T C A das five prime. Segment two shows 2 rows. Row one, five prime dash G C G C A G A C G A C dash three prime. Row two, three prime dash C G C G T C T G C T G dash five prime. The sequences for two short fragments of DNA are shown above. Which of the following is one way in which these two segments would differ?
Segment 1 would become denatured at a lower temperature than would segment 2 because A-T base pairs have two hydrogen bonds whereas G-C base pairs have three.
Which of the following statements best supports the claim that certain organelles within eukaryotic cells evolved from free-living prokaryotic cells?
Some organelles contain their own DNA DNA that is more similar to prokaryotic DNA in structure and function than to the eukaryotic found in the cell's nucleus.
Cholesterol is an important component of animal cell membranes. Cholesterol molecules are often delivered to body cells by the blood, which transports the molecules in the form of cholesterol-protein complexes. The complexes must be moved into the body cells before the cholesterol molecules can be incorporated into the phospholipid bilayers of cell membranes. Based on the information presented, which of the following is the most likely explanation for a buildup of cholesterol molecules in the blood of an animal?
The animal's body cells are defective in endocytosis.
DNA and RNA are nucleic acids that can store biological information based on the sequence of their nucleotide monomers. Figure 1 shows a short segment of each of the two types of nucleic acids. Which of the following best describes a structural difference between DNA and RNA?
The backbone of DNA DNA contains deoxyribose, whereas the backbone of RNA RNA contains ribose.
The carbohydrates glucose, galactose, and fructose have the same chemical formula (C6H12O6) but different structural formulas, as represented in the figure. Which of the following statements about glucose, galactose, and fructose is most likely true?
The carbohydrates have different properties because they have different arrangements of carbon, hydrogen, and oxygen atoms.
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?
The cells that are exposed to hypotonic solutions will expand as water moves osmotically into the cells from the blood.
esearchers compared similar proteins from related organisms in different habitats. They found that the proteins from organisms living in harsh environments had a greater number of cysteine amino acids than did proteins from organisms not living in harsh environments. The structure of cysteine is shown. Bonds can form between the sulfur atom of different cysteine amino acids (S-S bonds). Which of the following best describes the effect of a greater number of cysteine amino acids on the stability of the proteins?
The change leads to increased protein stability because of an increased number of S-S S-S bonds in the tertiary structure of the proteins.
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 O2 and CO2 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?
The drug is a small nonpolar molecule.
A researcher proposes a model of an enzyme-catalyzed reaction in which a reactant is converted to a product. The model is based on the idea that the reactant passes through a transition state within the enzyme-substrate complex before the reactant is converted to the product. Which of the following statements best helps explain how the enzyme speeds up the reaction?
The enzyme's active site binds to and stabilizes the transition state, which decreases the activation energy of the reaction.
Figure 1 represents a common process that occurs in organisms. The figure shows a reaction between two molecules. The top of the figure shows the two molecules. Each molecule has a central C atom that is bonded with four other atoms or groups. One bond of the C atom is with an N atom that is also bonded with two H atoms. A second bond of the C atom is with a C atom that is also bonded with an O H group and double bonded with an O atom. In each molecule, the central C atom is also bonded with an H atom. In one of the molecules, the fourth bond of the C atom is with an H atom. In the other molecule, the fourth bond of the C atom is with a C H 3 group. An arrow points to a new molecule that is formed when the two molecules join with a byproduct of a water molecule. The new molecule has a six-atom backbone, that from the left to the right is composed of the following atoms: N, C, C, N, C, C. The leftmost N atom is also bonded with two H atoms, the next C atom is also bonded with two H atoms, the next C atom is also double-bonded with an O atom, the next N atom is also bonded with one H atom, the next C atom is also bonded with an H atom and a C H 3 group, and the final C atom is bonded with an O H group and double-bonded with an O atom. Figure 1. Structural formula for a common biological reaction Which of the following is an accurate description of the process shown in Figure 1 ?
The formation of a covalent peptide bond in a dehydration synthesis reaction
Which of the following characteristics of Figure 1 best shows that the fragment is RNA and not DNA?
The identity of each nitrogenous base
A researcher designs an experiment to investigate the effect of environmental temperature on the function of an enzyme. For each trial included in the experiment, the researcher will add the enzyme and its substrate to an aqueous buffer solution and then measure the amount of product formed over 20 minutes. Which of the following must remain the same for all trials of this experiment?
The initial concentration of the substrate
Which of the following best describes how amino acids affect the tertiary structure of a protein?
The interactions of the different R R -groups with other R R -groups and with their environment determine the tertiary structure of the protein.
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.
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 shows a model of one cell engulfing a smaller cell in 3 stages. Stage 1 shows a small cell next to a large cell. Stage 2 shows the large cell beginning to wrap around and engulf the small cell. Stage 3 shows the small cell inside the large cell. Figure 1. A model showing a cell engulfing a smaller cell Which of the following provides evidence to best support the researchers' claim?
The organelle has a double membrane.
From the initial conditions and results described, which of the following is a logical conclusion?
The pores of the bag are larger than the glucose molecules but smaller than the starch molecules.
Which of the following statements best helps explain the reaction specificity of an enzyme?
The shape and charge of the substrates are compatible with the active site of the enzyme.
Organelles such as mitochondria and the endoplasmic reticulum have membranes that compartmentalize reactions and other metabolic processes. To function properly, the organelles must move substances across their membranes. Which of the following statements describes a feature shared by mitochondria and the endoplasmic reticulum that increases the efficiency of their basic functions?
They have highly folded membranes.
Which of the following best describes the structures of carbohydrates?
They occur as monomers, chains of monomers, and branched structures.
Simple diffusion and facilitated diffusion are related in that both
depend on a concentration gradient
According to the chemiosmotic theory (chemiosmotic coupling), the energy required to move protons from the mitochondrial matrix to the intermembrane space against a concentration gradient comes most directly from
electrons flowing along the electron transport chain
The illustration shows the active transport of hydrogen ions through a membrane protein. The illustration shows a cell's plasma membrane. A membrane protein is shown with the label "A T P." Hydrogen ions, H plus, are shown on both sides of the plasma membrane, with only a couple of ions below the membrane and many ions above the membrane. An upward pointing arrow is drawn through the channel in the center of the membrane protein to indicate the active transport of hydrogen ions from the side of the membrane with a low concentration to the side with a high concentration. Which of the following best predicts the effect of not having ATP available to supply energy to this process?
ions will stop moving through the protein.
If, instead of the bag, a potato slice were placed in the beaker of distilled water, which of the following would be true of the potato slice?
it would gain mass
ATP serves as a common energy source for organisms because
its energy can be easily transferred to do cellular work
If the experiment is repeated at pH 11, the observed activity level of the enzyme will most likely be
lower than the level at pH p H 9
Oxygen consumption can be used as a measure of metabolic rate because oxygen is
necessary for ATP synthesis by oxidative phosphorylation
View 2 because the rate of water movement into the RBCs equals the rate of water movement out of the cells
nuclear envelope
Which of the following correctly uses the data to justify the claim that the phosphagen system is an immediate, short-term source of ATP for muscle cells?
production by the phosphagen system increases and decreases rapidly following the start of the exercise period.
