AP Bio Midterm

Which is characteristics of mitochondria and chloroplasts that supports the endosymbiotic theory?

Both contain DNA molecules

(A) Glysolysis(B) Krebs cycle (citric acid cycle)(C) Calvin cycle (light-independent reactions of photosynthesis)(D) Light-dependent reactions of photosynthesis(E) Chemiosmosis Process in which carbon from CO2 is incorporated into organic molecules

C

Which of the following describes the most likely location of cholesterol in an animal cell?

Embedded in the plasma membrane

Students investigated the effect of light on the carbon cycle in aquatic ecosystems by performing the controlled experiment summarized below. Which of the following graphs is the most appropriate representation of the experimental results documented in the table?

x: Mean pH y: Standard Error plot graph with line of best fit

The maximum production rate of acetyl-CoA under condition 1 is closest to which of the following?

1 micromole/sec

If NaF is added to cells undergoing cellular respiration, which of the following will most likely accumulate in the cells?

2-phosphoglycerate

The graph in Figure 1 shows the percent saturation of fetal hemoglobin and maternal hemoglobin in humans as a function of the partial pressure of oxygen. Based on the data, which of the following values is closest to the predicted difference in the percent saturation of fetal hemoglobin and maternal hemoglobin at 40Hg?

20

To model a plant cell, a permeable, nonflexible case is placed around each piece of dialysis tubing. The greatest pressure potential will develop within dialysis tube number

4

The figure shows a model of the exchange of matter between the organisms that live together in an aquarium. The model includes matter exchange between plants, fish, and bacteria. The bacteria are represented as rod-shaped organisms living in the gravel at the bottom of the aquarium. Which of the following statements best describes how molecules released by the fish become nutrients for the plants?

The ammonia molecules released by the fish are converted by the bacteria to nitrates, which are used by the plants to make proteins and nucleic acids.

Figure 1 represents a nucleic acid fragment that is made up of four nucleotides linked together in a chain. Which of the following characteristics of Figure 1 best shows that the fragment is RNA and not DNA?

The identity of each nitrogenous base

All eukaryotic cells contain at least one Golgi complex, typically located in the cytoplasm and near the endoplasmic reticulum. Which of the following best describes a process that occurs within the Golgi complex?

Enzymatic modification of newly synthesized integral membrane proteins.

Pyruvate kinase, a key enzyme in the glycolysis pathway, is inhibited by the amino acid alanine. The ability of alanine to inhibit the enzyme is not affected by increasing the concentration of substrate. Which of the following best explains the mechanism by which alanine inhibits pyruvate kinase activity?

Alanine binds to an allosteric site of the enzyme, changing the shape of the enzyme's active site.

Which of the following accurately describes a model of active transport?

A membrane protein binds a specific molecule outside of the cell and moves the molecule into the cell where there is already a high concentration of the molecule compared with the outside.

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

Which of the following best describes the role of ATP and NADPH in the process of photosynthesis?

ATP and NADPH are carriers of chemical energy that is used in the production of carbohydrates.

Muscle contraction depends on ATP hydrolysis... 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?

ATP production by the phosphagen system increases and decreases rapidly following the start of the exercise period.

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?

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

Amylase is an enzyme that converts carbohydrate polymers into monomers. Glycogen synthase is one of the enzymes involved in converting carbohydrate monomers into polymers. Which of the following best explains the reactions of these enzymes?

Amylase aids in the addition of a water molecule to break covalent bonds whereas glycogen synthase aids in the removal of a water molecule to form covalent bonds.

Mitochondria are found in most eukaryotic cells and contain their own DNA and ribosomes that are similar to those typical of many prokaryotic cells. Which of the following statements is justified by these observations?

An ancestral cell most likely engulfed an aerobic prokaryote in a relationship that proved beneficial for both cells.

Which of the following groups of cellular components are found in eukaryotic cells but not prokaryotic cells?

An endoplasmic reticulum, mitochondria, and a nucleus

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.

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 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

Figure 1. An amino acid The amino acid in Figure 1 is found in a region of a polypeptide that folds away from water. Which part of the amino acid most likely contributes to the hydrophobic behavior of this region of the polypeptide?

Carboxyl (COOH) group

Which two cellular organelles in eukaryotes have both electron transport systems and chemiosmotic mechanisms?

Chloroplasts and mitochondria

The chemical reaction for photosynthesis is... 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 best describes an advantage that eukaryote organisms have over prokaryote organisms?

Eukaryotes have organelles that allow for compartmentalization of cellular processes, which increases the efficiency of those processes.

This group of questions refers to molecules of the following substances. (A) Cytochrome (B) FADH2 (C) NAD+ (D) NADP+ (E) Oxygen (O2) Coenzyme that transfers electrons from the Krebs cycle to the mitochondrial electron-transport chain at a lower energy level than that of electrons entering at the beginning of the chain

FADH2

Glucose diffuses slowly through artificial phospholipid bilayers... Using this information, which transport mechanism is most probably functioning in the intestinal cells?

Facilitated diffusion

When a substance moves across the plasma membrane along a concentration gradient at a rate faster... the process is best described as

Facilitated diffusion

A tissue culture of vertebrate muscle was provided with a constant excess supply of glucose under anaerobic conditions starting at time zero and the amounts of pyruvic acid and ATP produced were measured Which of the following is most likely to result if oxygen is added to the tissue culture?

For each glucose molecule consumed, more ATP will be formed.

Which of the following describes why a glucose transporter is needed to move glucose into the cell?

Glucose is large and polar and cannot pass through the phospholipid bilayer.

Which metabolic process is common to both aerobic cellular respiration and alcoholic fermentation?

Glycolysis

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?

Golgi apparatus

Which of the following best explains why a cell's plasma membrane is composed of two layers of phospholipids rather than just a single layer?

Having two oppositely oriented layers of phospholipids allows only the hydrophilic heads to interact with water inside and outside of the cell.

Which of the following types of bonds is most likely responsible for the unusual base pairing shown in Figure 3 that results in the formation of a triplex DNA structure?

Hydrogen

Figure 1 is a diagram of water molecules at the air-water interface at the surface of a pond. 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.

Which of the following is responsible for the cohesive property of water?

Hydrogen bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule.

Enzymes with their highest activity at an alkaline (basic) pH are represented by which of the following graphs?

II only

Polypeptides are continuously being formed and degraded. One of these processes is shown. 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.

The CFTR protein is made up of amino acids linked together in a chain. Some humans produce a version of the CFTR protein in which phenylalanine (an amino acid) has been deleted from position 508 of the amino acid chain. Which of the following best predicts how the amino acid deletion will affect the structure of the CFTR protein?

It will affect the primary, secondary, and tertiary structures of the CFTR protein.

A researcher claims that increasing the environmental temperature by 10C will double the rate of an enzyme-catalyzed reaction. To test the claim, the researcher designs an experiment that uses a particular enzyme isolated from plants. The design of the experiment is presented in Table 1. For each test tube in the experiment, the researcher will measure the rate of product formation. 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.

Based on the data in Figure 1, which of the following most likely represents the change in energy that occurs when ATP hydrolysis is coupled with the phosphorylation of a substrate?

Line 1 represents ATP hydrolysis, and line 4 represents phosphorylation of a substrate.

Which of the following processes is most likely to occur as a result of an animal cell receiving a signal to initiate apoptosis?

Lysosomes will release digestive enzymes into the cytosol

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.

For following group of questions first study the description of the data and then choose the one best answer to each question following it and fill in the corresponding oval on the answer sheet. If the potato solution was boiled for 10 minutes and cooled for 10 minutes before being tested, the average time for the disks to float to the surface of the hydrogen peroxide solution would be

More than 30 seconds

Based on Figure 1, the amino acids in region A are most likely to have which of the following characteristics?

Most amino acids will be hydrophobic because they interact most favorably with the phospholipid tails.

This group of questions refers to molecules of the following substances. (A) Cytochrome (B) FADH2 (C) NAD+ (D) NADP+ (E) Oxygen (O2) An intermediate electron acceptor for oxidations that occur in both glycolysis and in Krebs cycle reactions

NAD+

The manner in which several different ions and molecules move through a cell membrane is shown in the diagram above. Which of the following accurately describes one of the movements taking place?

Na+ transport out of the cell requires ATP hydrolysis

A typical bag of fertilizer contains high levels of nitrogen, phosphorus, and potassium but trace amounts of magnesium and calcium. Which of the following best matches the fertilizer component with the molecule in which it will be incorporated by organisms in the area?

Nitrogen will be incorporated into nucleic acids.

Scientists examined the folded structure of a purified protein resuspended in water and found that amino acids with nonpolar R groups were primarily buried in the middle of the protein, whereas amino acids with polar R groups were primarily on the surface of the protein. Which of the following best explains the location of the amino acids in the folded protein?

Nonpolar R groups that cannot form hydrogen bonds with water are pushed into the middle of the protein.

Which of the following conclusions is most clearly supported by the representations of nucleic acid #1 and nucleic acid #2?

Nucleic acid #1 contains adenine-thymine base pairs, whereas nucleic acid #2 does not.

The illustration above is a model of a typical beet root cell. Based on the experimental results, which of the following best represents the effect of acetone on the permeability of cellular membranes?

Particles in circle in organelle > particles entirely outside organelle

Protein digestion in humans is primarily carried out by three enzymes... Which of the following best predicts how the structure and function of pepsin will change as it enters the small intestine?

Pepsin will change in shape because of the basic environment of the small intestine; therefore, its enzymatic activity will decrease.

For following group of questions first study the description of the data and then choose the one best answer to each question following it and fill in the corresponding oval on the answer sheet. Which of the following experimental designs should the students use as a control for the experiment?

Place a catalase-soaked disk in a beaker of water.

Which of the following correctly illustrates a dipeptide and an amino acid in the optimal position to form a tripeptide?

R O R O H R O | || | || | | || H-N-C-C-N-C-C H-N-C-C | | | | | | || H H H H OH H OH

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.

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 contains deoxyribose, whereas the backbone of RNA contains ribose.

The carbohydrates glucose, galactose, and fructose have the same chemical formula 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.

In an experiment, the efficiency of oxygen exchange across plasma membrane is being assessed in four artificial blood cells. Which artificial cell is predicted to be the most efficient in exchanging oxygen with the environment by diffusion?

The cuboidal cell

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.

Mercurial sulfhydryl is an inhibitor of aquaporins. Which of the following is the most likely effect of adding mercurial sulfhydryl to the distilled water solution?

The grape cells will gain water more slowly because of a lack of facilitated diffusion.

The figure above shows an organelle typically found in eukaryotic cells. Which of the following best describes the function of the double membrane system of this organelle?

The inner membrane has specialized proteins that create a hydrogen ion concentration gradient between the intermembrane space and the matrix.

A cell's membrane potential is maintained by the movement of ions into and out of the cell. A model showing the influence of membrane proteins on the movement of sodium (Na+) and potassium (K+) ions across the plasma membrane is presented in Figure 1. Based on the model presented in Figure 1, which of the following outcomes will most likely result from a loss of protein X function?

The membrane potential will be disrupted by an increase in K+ concentration inside the cell.

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.

Researchers claimed that a particular organelle originated from a free-living eukaryotic cell... Which of the following provides evidence to best support the researchers' claim?

The organelle has a double membrane

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.

A mutation in the gene coding for a single-polypeptide enzyme results in the substitution of the amino acid serine, which has a polar R group, by the amino acid phenylalanine, which has a nonpolar R group. When researchers test the catalysis of the normal enzyme and the mutated enzyme, they find that the mutated enzyme has much lower activity than the normal enzyme does. Which of the following most likely explains how the amino acid substitution has resulted in decreased catalytic activity by the mutated enzyme?

The substitution altered the secondary and tertiary structure of the enzyme so that the mutated enzyme folds into a different shape than the normal enzyme does.

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. Which of the following statements best explains the observations represented in Figure 1 ?

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 scientist is developing a mathematical model of cells of different shapes. To construct the model, the scientist has specified that the width of each cell at its widest point must be 30μ and the height of each cell must be 90μ. Table 1 shows the three-dimensional shapes that the scientist is considering for the model cells. Which of the proposed shapes for the model cells will allow the most efficient exchange of materials with the surrounding environment?

Triangular prism

The diagram shows how water can adhere to the xylem in the stems of plants, which contributes to water movement in the plant. Which of the following best explains how water is able to move upward from the roots of a plant, through its xylem in the stem, and out to the leaves?

Water and the xylem are both polar. Water molecules have the ability to form hydrogen bonds with each other and with the walls of the xylem.

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

Which molecular substance is actively transported across the plasma membrane?

Figure 1 represents a common process that occurs in organisms. Figure 1. Structural formula for a common biological reaction Which of the following is an accurate description of the process shown in Figure 1 ?

he formation of a covalent peptide bond in a dehydration synthesis reaction

Oxygen consumption can be used as a measure of metabolic rate because oxygen is

necessary for ATP synthesis by oxidative phosphorylation