AP Bio Units 1-3

A common laboratory investigation involves putting a solution of starch and glucose into a dialysis bag and suspending the bag in a beaker of water, as shown in the figure below. The investigation is aimed at understanding how molecular size affects movement through a membrane. Which of the following best represents the amount of starch, water, and glucose in the dialysis bag over the course of the investigation?

A)

The following questions refer to an experiment that is set up to determine the relative volume of O2 consumed by germinating and nongerminating (dry) pea seeds at two different temperatures. The change in volume is detected by using a respirometer over a given period of time. The data are given below. The rate of oxygen consumption in germinating pea seeds at 26ºC is

A) 0.05 mL / min

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

A) Amino Acid has a NH2 group on the left and a COOH group on the right

For following group of questions first study the description of the situation or data and then choose the one best answer to each question following it and fill in the corresponding oval on the answer sheet. In the first step of an experiment, rat liver cells were exposed for 5 minutes to amino acids labeled with a radioactive isotope. The cells were then washed to stop any further incorporation of radioactive amino acids. The cells were sampled periodically thereafter, and the radioactivity of a certain protein (protein X) was measured in various cell components, as shown below. Which of the following correctly shows the order in which protein X moves through the cell?

A) Endoplasmic Reticulum --> Golgi Apparatus --> Lysosomes

Process in which sugar is oxidized to pyruvic acid

A) Glysolysis

Students in a class measured the mass of various living organisms. They then kept the organisms in the dark for 24 hours before remeasuring them. None of the organisms were provided with nutrients during the 24-hour period. The data are as follows. Which of the following is the best explanation for the pattern of change in mass of the organisms over time?

B) Cellular respiration

A culture of Spirogyra (an autotrophic alga) is maintained in a water solution containing dissolved carbon dioxide and a source of phosphates but lacking nitrogen compounds. A researcher determines the rates of synthesis of several organic compounds found in the Spirogyra before and after several weeks in the water solution. Which of the following graphs best illustrates a likely result of the experiment?

B) Graph be shows proteins and nucleic acids decreasing with carbohydrates and lipids staying the same with time. Without a source of nitrogen, the Spirogyra cannot synthesize proteins or nucleic acids, both of which contain nitrogen. This answer reflects that the student is able to represent graphically the exchange of molecules between an organism and its environment and the use of these molecules in synthesis.

Process in which CO2, is released as a by-product of oxidation-reduction reactions

B) Krebs cycle (citric acid cycle)

The salinity of a small inland lake has recently started to increase. Researchers are planning to study the lake over several decades to investigate how freshwater organisms survive significant changes in their natural habitat. Which of the following physiological mechanisms will the researchers most likely observe among the surviving organisms in the lake?

B) Single-celled organisms will use various mechanisms to counteract the increased flow of water from cells to the environment.

A student analyzed a viral genome and found that the genome had the following nucleotide composition. • 28% adenine • 20% thymine • 35% cytosine • 17% guanine Which of the following best describes the structure of the viral genome?

B) Single-stranded DNA

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. The solid line in the graph above represents the pyruvic acid produced in moles per liter per minute. ATP levels were also found to be highest at points A and C, lowest at B and D. A second culture was set up under the same conditions, except that substance X was added, and the results are indicated by the dotted line. It is most reasonable to hypothesize that, in the breakdown of glucose, substance X is

B) an inhibitor

Simple diffusion and facilitated diffusion are related in that both

B) depend on a concentration gradient

During respiration, most ATP is formed as a direct result of the net movement of

B) protons down a concentration gradient

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. The solid line in the graph above represents the pyruvic acid produced in moles per liter per minute. ATP levels were also found to be highest at points A and C, lowest at B and D. A second culture was set up under the same conditions, except that substance X was added, and the results are indicated by the dotted line. Which of the following best accounts for the shape of the solid line between points A and D?

C) ATP acted as an allosteric inhibitor on one or more of the enzymes.

Process in which carbon from CO2 is incorporated into organic molecules

C) Calvin cycle (light-independent reactions of photosynthesis)

A feature of organic compounds NOT found in inorganic compounds is the presence of

C) Carbon atoms covalently bonded to each other

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?

C) DNA

An intermediate electron acceptor for oxidations that occur in both glycolysis and in Krebs cycle reactions

C) NAD+

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?

C) Organelles isolate specific reactions, increasing metabolic efficiency.

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

C) Which molecular substance is actively transported across the plasma membrane?

A student placed 20 tobacco seeds of the same species on moist paper towels in each of two petri dishes. Dish A was wrapped completely in an opaque cover to exclude all light. Dish B was not wrapped. The dishes were placed equidistant from a light source set to a cycle of 14 hours of light and 10 hours of dark. All other conditions were the same for both dishes. The dishes were examined after 7 days, and the opaque cover was permanently removed from dish A. Both dishes were returned to the light and examined again at 14 days. The following data were obtained. Additional observations were made on day 21, and no yellow-leaved seedlings were found alive in either dish. This is most likely because

C) yellow-leaved seedlings were unable to convert light energy to chemical energy

For following group of questions first study the description of the situation or data and then choose the one best answer to each question following it and fill in the corresponding oval on the answer sheet. In the first step of an experiment, rat liver cells were exposed for 5 minutes to amino acids labeled with a radioactive isotope. The cells were then washed to stop any further incorporation of radioactive amino acids. The cells were sampled periodically thereafter, and the radioactivity of a certain protein (protein X) was measured in various cell components, as shown below. What is the most likely identity of protein X ?

D) An enzyme that participates in the degradation and recycling of cell components

The enzyme hexokinase catalyzes the conversion of glucose to glucose-6-phosphate, which is an important step in glycolysis. The reaction involves the transfer of a phosphate group from ATP to glucose. Either a glucose molecule or a water molecule can fit in the active site of hexokinase. The presence of a water molecule in hexokinase's active site would result in the hydrolysis of ATP to ADP instead of the conversion of glucose to glucose-6-phosphate. Which of the following statements best helps explain the reaction specificity of hexokinase?

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

A cell is treated with a drug that prevents the formation of new lysosomes. The cell continues to transcribe the genes that code for the hydrolytic enzymes that are normally found in lysosomes and continues to translate the mRNAs for those proteins on membrane-bound ribosomes. The hydrolytic enzymes are most likely to accumulate in which of the following cellular structures?

D) Golgi Complex

Which of the following is most directly responsible for water's unique properties?

D) It forms hydrogen

Process in which O2 is released as a by-product of oxidation-reduction reactions

D) Light-dependent reactions of photosynthesis

What most likely causes the trends in oxygen concentration shown in the graph above?

Photosynthesis produces more oxygen than is consumed by respiration during the day.

Process found in both photosynthesis and cellular respiration

E) Chemiosmosis

The following questions refer to an experiment that is set up to determine the relative volume of O2 consumed by germinating and nongerminating (dry) pea seeds at two different temperatures. The change in volume is detected by using a respirometer over a given period of time. The data are given below. Which of the following conclusions is best supported by the data?

E) In pea seeds an increase in temperature results in an increase in oxygen consumption.

The synthesis of protein or carbohydrate polymers always produces which of the following as a byproduct?

E) Water