AP Biology Unit 3

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

protons down a concentration gradient

The rate of oxygen consumption in germinating pea seeds at 26ºC is

0.05 mL / min

Figure 1. Accumulation of acetyl-CoA under different conditions The maximum production rate of acetyl-CoA under condition 1 is closest to which of the following?

1 micromole/sec

Based on Figure 1, the net number of ATP molecules produced during glycolysis from the metabolism of a single glucose molecule is closest to which of the following?

2

Certain chemicals, including sodium fluoride (NaF), are capable of inhibiting specific steps of glycolysis. Figure 1 shows the steps of the glycolysis pathway, indicating where various macromolecules enter the pathway as well as the specific reaction inhibited by NaF. If NaF is added to cells undergoing cellular respiration, which of the following will most likely accumulate in the cells?

2 Phosphoglycerate

A scientist determined the rate of an enzyme-catalyzed reaction by measuring the amount of product formed over time. The following curve was generated from the data collected. During which time interval is the reaction rate lowest?

4-5 minutes

Based on the data, which of the following is the best approximation of the rate of growth per week in section II from day 14 to day 21 ?

4.5 grams/week

(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 sugar is oxidized to pyruvic acid

A

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

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.

(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 CO2, is released as a by-product of oxidation-reduction reactions

B

(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 found in both photosynthesis and cellular respiration

E

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

Figure 1. Absorbance readings of four prepared tubes with various solutions over a 60-minute period. Which of the following best justifies the use of tube 2 as a control treatment?

It was a positive control for measuring the effect of DCMU on the reaction.

The student decreased the intensity of the light hourly and recorded the corresponding changes in oxygen concentration. The graph below shows the results from the recording device. An increase in the rate of oxygen production by algae would be accompanied by a comparable increase in the rate of production of which of the following substances?

C6H12O6

(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 O2 is released as a by-product of oxidation-reduction reactions

D

Which of the following best explains how DCMU affected the reaction?

DCMU acts as an inhibitor to the movement of electrons within the light reaction of photosynthesis.

The diagram below shows energy changes in a specific chemical reaction with and without the addition of an enzyme to the reaction. Which of the following questions can best be answered by the diagram?

Does the addition of an enzyme reduce the activation energy required for a reaction?

Which of the following questions best addresses whether a particular inhibitor is competitive or noncompetitive?

Does the inhibitor bind to an allosteric site or the active site of the enzyme?

Which of the following best explains the connection between energy, growth, and the maintenance of an ordered system in the experiment?

Energy input from light is required for the grass to grow and maintain an ordered structure.

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

Graphs representing enzymes sensitive to changes in pH include which of the following?

I, II, and III only

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 conclusions is best supported by the data?

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

The student decreased the intensity of the light hourly and recorded the corresponding changes in oxygen concentration. The graph below shows the results from the recording device. The rate of oxygen production equaled the rate of oxygen consumption during which of the following time periods?

J to K

Figure 1. Absorbance readings of four prepared tubes with various solutions over a 60-minute period. Which of the following claims is best supported by the experimental results?

Light is required for the electron transport chain to transfer electrons.

Which of the following best explains the observed difference in mass between the grass in section I after 14 days and the grass in section III after 21 days?

Mass lost by cell respiration in section III was not replaced by photosynthesis.

Which of the following experimental designs would best allow researchers to investigate the effect of pH on the rate of the enzyme-catalyzed reaction?

Measure reaction rates at different pH levels when the enzyme concentration remains the same and the substrate concentration is μ100μM.

The student decreased the intensity of the light hourly and recorded the corresponding changes in oxygen concentration. The graph below shows the results from the recording device. Based on the data shown, changes in the light intensity resulted in changes in the rate of which of the following processes?

Photosynthesis

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 can be used to determine the rate of enzyme-catalyzed reactions?

Rate of disappearance of the substrate

Figure 1. Diagram of the electron transport chain and ATP synthase in the membrane of mitochondria On average, more ATP can be produced from an NADH molecule than can be produced from a molecule of FADH2. Based on Figure 1, which of the following best explains the difference in ATP production between these two molecules?

The electrons of FADH2 are transferred through three complexes of the electron transport chain whereas those of NADH are transferred through all four complexes.

Which of the following best describes how an increase in the concentration of substrate in the reaction mixture affected the frequency of enzyme‑substrate interactions?

The frequency of enzyme-substrate interactions increased until all of the active sites were interacting with substrate.

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.

Which of the following is an appropriate null hypothesis for the student's experiment?

The presence of light has no effect on the mass of the grass.

Based on the data, which of the following is the most likely effect of a period of increased volcanic activity that significantly decreases the amount of sunlight reaching a particular ecosystem for several years?

There will be a decrease in the population sizes of most species and a decrease in the number of trophic levels.

Which of the following best describes the functionof the coenzymes NAD+ and FAD in eukaryoticcellular respiration?

They serve as final electron acceptors in theelectron transport chain.

Which of the following best describes why ice was used during this experiment?

To retard the breakdown of the catalase

In which of the following tubes did the greatest reduction of DCPIP occur after 60 minutes?

Tube 2

The carbon 'that makes up organic molecules in plants is derived directly from

carbon fixed in photosynthesis

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 transportchain

According to the results of this experiment, germination of tobacco seeds during the first week is

increased by exposure to light

A scientist determined the rate of an enzyme-catalyzed reaction by measuring the amount of product formed over time. The following curve was generated from the data collected. The rate of the reaction could also be determined by

measuring the change in the amount of substrate

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

The most likely explanation for the results shown in Graph I is that

pH affects the shape of the active site of the enzyme