AP Biology final

AP biology final

Vertebrate immune responses involve communication over short and long distances. Which of the following statements best helps explain how cell surface proteins, such as MHC proteins and T cell receptors, mediate cell communication over short distances?

The proteins interact directly with proteins on the surfaces of other cells.

Notch is a receptor protein displayed on the surface of certain cells in developing fruit fly embryos. Notch's ligand is a membrane-bound protein called Delta that is displayed on the surface of adjacent cells. When Notch is activated by its ligand, the intracellular tail of the Notch protein becomes separated from the rest of the protein. This allows the intracellular tail to move to the cell's nucleus and alter the expression of specific genes.

Delta restricts cell communication to short distances within a developing embryo.

In flowering plants, plasmodesmata are narrow channels through cell walls that connect the cytoplasms of adjacent cells. An explanation of how plant cells communicate across cell walls will most likely refer to the diffusion through plasmodesmata of which of the following?

Small, water-soluble molecules

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 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.

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 of the following statements best predicts the effect of increasing the permeability of the mitochondrial membranes to large molecules?

ATP production will decrease because of an increase in the occurrence of uncontrolled chemical reactions.

Which of the following best describes how the amount of DNA in the cell changes during M phase?

The amount of DNA is halved as the cell divides into two daughter cells.

Which of the following patterns is shown by the data?

In mutant 3 cells, more time is spent in prophase/prometaphase than in the later stages of mitosis.

What is the expected percent change in the DNA content of a typical eukaryotic cell as it progresses through the cell cycle from the start of the G1 phase to the end of the G2 phase?

+100%

Which of the following presents a correct interpretation of the changes in chromosome number depicted in Figure 1 ?

Chromosomes enter metaphase containing two chromatids attached by a centromere. During anaphase, the chromatids are separated, each becoming a chromosome. Cytokinesis distributes the chromosomes into two separate cells.

Based on Figure 1, what percent of the time required to complete a full cycle do the cells typically spend in interphase?

95%

he cell cycle of yeast cells grown in the nutrient-poor environment is approximately what percent of the cell cycle of yeast cells grown in the nutrient-rich environment?

168

Which of the following best describes how the amount of DNA in the cell changes during M phase?

The amount of DNA is halved as the cell divides into two daughter cells.

Based on the model, what will be the mean diameter of the phytoplankton cells that are found 25 kilometers from shore?

650 micrometers

Which statement correctly indicates the cell that is able to more efficiently exchange materials with the external environment and provides a correct explanation?

The bacterial cell, because it has the largest surface-to-volume ratio.

Of the two cells represented in the figure, which would likely be more efficient at exchanging substances with the surrounding environment?

Cell A, because it has the larger surface-area-to-volume ratio.

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 a process that occurs within the Golgi complex?

Enzymatic modification of newly synthesized integral membrane proteins

Which of the following functional differences between the rough and smooth endoplasmic reticulum (ER) is explained by the structural differences between them?

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

Which of the following claims is scientifically accurate and consistent with an observation that a decrease in lysosome production within a cell leads to a decline in mitochondrial activity?

Fewer lysosomes will be available to break down macromolecules to provide the necessary nutrients for cellular respiration.

Muscle cells have high ATP demands. Which of the following is a scientific claim about how the structure of the mitochondria in muscle cells should be different than it is in other cells because of the high energy demands of mitochondria?

The inner membrane of the mitochondria in muscle cells should have more folds to increase the surface area, allowing more ATP to be synthesized.

Based on the model, the newly synthesized protein is transported directly from the endoplasmic reticulum to which of the following?

The Golgi complex

A researcher claims that the synthesis of ATP from ADP and inorganic phosphate (Pi) is essential to cellular function.

Which of the following statements best helps justify the researcher's claim?

ATP hydrolysis is an energy-releasing reaction that is often coupled with reactions that require an input of energy.

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.

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.

Which of the following outcomes will most likely result from the irreversible binding of GDP to the G protein?

The intracellular concentration of glycogen will increase.

Which of the following statements best predicts the effect of a mutation that results in a loss of the glucocorticoid receptor's ligand binding function?

The glucocorticoid receptor will remain associated with the accessory proteins.

A DNA mutation changes the shape of the extracellular domain of transmembrane receptor protein A produced by the cell. Which of the following predictions is the most likely consequence of the mutation?

The molecule that normally binds to protein A will no longer attach, deactivating the cellular response.

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.

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.

The observed differences between the groups most likely resulted from differences in the ability of the seedlings to produce which of the following monomers?

Which of the following statements best predicts the effect of increasing the concentration of substrate (ethyl alcohol), while keeping the concentration of the inhibitor (methyl alcohol) constant?

Competitive inhibition will decrease because the proportion of the active sites occupied by substrate will increase.

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 9

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.

Which of the following statements best justifies the inclusion of test tube V as a control in the experiment?

It will show the color change that occurs in the absence of enzyme activity.

Which of the following statements best justifies the inclusion of test tubes 3 and 7 in the experiment?

They will show whether the isolated cellular contents have enzymatic activity.

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 would be the most appropriate control for this experiment?

A test tube containing a piece of exposed camera film submerged in water

Which of the following actions will provide the most appropriate negative control for the experiment?

Repeating the experiment with denatured enzymes

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.

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.

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.

Which of the following statements best helps explain the reaction specificity of hexokinase?

Glucose has the right shape and charge to cause hexokinase to undergo a structural change needed for catalysis, whereas water does not.

Which of the following best predicts the effect of not having ATP available to supply energy to this process?

H+ ions will stop moving through the protein.

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.

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.

Cyclic AMP phosphodiesterase is an enzyme that catalyzes the conversion of cyclic AMP to a different molecule. Which of the following best predicts the effect of inhibiting cyclic AMP phosphodiesterase in a muscle cell stimulated by epinephrine?

Phosphorylase kinase will remain active because protein kinase A will no longer be deactivated.

Air is less dense at very high elevations, so less oxygen is available than in the denser air at sea level. Based on the model in Figure 1, if a person travels from sea level to a high elevation location, which of the following correctly predicts the response to the decreased blood oxygen level?

Responses

More erythropoietin will be secreted from the kidneys, increasing production of erythrocytes.

Argatroban is a competitive inhibitor of thrombin. Which of the following effects on the coagulation cascade is most likely to result from inhibiting thrombin activity with argatroban?

The rate of fibrin formation will decrease.

A researcher claims that different metabolic pathways allow bacteria to use different molecules as sources of matter and energy.

Which of the following statements best helps justify the researcher's claim by providing a relevant example?

E. coli bacteria reproduce in liquid media containing either glucose or galactose.

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 best supports the claim that this species is better adapted to environmental changes than other photosynthetic species are?

The additional pigments allow the species containing them to harvest energy from wavelengths of light that the other photosynthetic species cannot use.

Which of the following best describes the formation of the bond shown in Figure 1 ?

A covalent bond is formed between a carbon atom and a nitrogen atom along with the formation of H2O

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 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.

Based on Figure 1, which of the following statements best describes the epinephrine signaling pathway?

In involves enzymes activating other enzymes.

Which of the following statements best describes the role of adenylyl cyclase in the epinephrine signaling pathway?

It accelerates the production of a second messenger.

Which of the following statements best describes the role of cyclic AMP in the signal transduction pathway?

Responses

It acts as a second messenger that helps relay and amplify the signal within the cell.

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.

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

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.

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.

Aquaporins are channel proteins that facilitate the transport of water across the cell membrane. One group of researchers hypothesizes that without functional aquaporins, no water will be able to enter the cell. A different group proposes an alternative hypothesis, stating that even with nonfunctional aquaporins, a small amount of water will still cross the cell membrane. An experiment is set up in which plant cells with mutated (nonfunctional) aquaporins and plant cells with normally functioning aquaporins are both placed in distilled water.

Which of the following data would support the alternative hypothesis?

Cells with mutated aquaporins exhibit moderate turgor pressure and are hypertonic.

Plant cell walls are composed of cellulose, while fungal cell walls are composed of chitin. A group of scientists hypothesize that this difference means the cell wall has largely different functions in plant cells and fungal cells. Alternatively, another group of scientists hypothesize that despite their biochemical differences, plant and fungal cell walls serve similar functions.

Which of the following observations would best support the alternative hypothesis described above?

In both plant cells and fungal cells, the cell wall surrounds the outside of the cell membrane.

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.

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.

Of the following, which additional investigation can be used to determine when the cells are in an isotonic solution?

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

Which procedure should be done next to gather data needed to meet the scientist's objective?

Incubate samples containing 1.0μm/mL of ATP at four temperatures other than 25°C.

Which of the following best describes a structural difference between DNA and RNA?

Responses

The backbone of DNA contains deoxyribose, whereas the backbone of RNA contains ribose.

Which of the following characteristics of Figure 1 best shows that the fragment is RNA and not DNA?

The identity of each nitrogenous base

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.

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.

Which of the following provides evidence to best support the researchers' claim?

Responses

The organelle has a double membrane.

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 that is more similar to prokaryotic DNA in structure and function than to the eukaryotic DNA found in the cell's nucleus.

The endosymbiont theory proposes a model for the evolution of mitochondria. According to the model, an ancestral eukaryote engulfed a small, free-living prokaryotic organism. The engulfed prokaryote then formed an endosymbiotic relationship with the eukaryotic host.

Which of the following observations best supports the model?

Mitochondria and some prokaryotes share similar metabolic reactions that produce ATP.

A researcher claims that increased atmospheric carbon dioxide levels cause increased growth rates in plants.

Which of the following statements best supports the researcher's claim?

Atmospheric carbon dioxide is the raw material for photosynthesis, which plants rely on for producing sugars and other organic compounds.

Which of the following statements provides evidence to support the claim that no ATP will be synthesized in the absence of a proton gradient across the thylakoid membrane?

No ATP is synthesized when channel proteins that allow the free passage of protons are inserted into the thylakoid membrane.

A scientist claims that Elysia chlorotica, a species of sea slug, is capable of photosynthesis.

Which of the following observations provides the best evidence to support the claim?

Elysia chlorotica grows when exposed to light in the absence of other food sources.

Which of the following best describes the numbered areas?

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

Which statement best explains the orientation of the phospholipid molecules in this model?

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

Which statement best explains why correct protein folding is critical in the transmembrane protein shown above?

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

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 best describes the structures of carbohydrates?

They occur as monomers, chains of monomers, and branched structures.

Which of the following best describes how amino acids affect the tertiary structure of a protein?

The interactions of the different R-groups with other R-groups and with their environment determine the tertiary structure of the protein.

Glycogen synthetase kinase 3 beta is a protein kinase that has been implicated in many types of cancer. Depending on the cell type, the gene for glycogen synthetase kinase 3 beta (GSK3β) can act either as an oncogene or as a tumor suppressor.

Which of the following best predicts how GSK3β mutations can lead to the development of cancer?

Cells with inactive GSK3β fail to trigger apoptosis.