Archive for June 2018

A drug designed to inhibit the response of cells to testosterone would almost certainly result in which of the following?

Naim 04:58

A drug designed to inhibit the response of cells to testosterone would almost certainly result in which of the following?




A) lower cytoplasmic levels of cAMP
B) an increase in receptor tyrosine kinase activity
C) a decrease in transcriptional activity of certain genes
D) an increase in cytosolic calcium concentration
E) a decrease in G-protein activity


Answer: C

Which of the following is not true of cell communication systems?

Naim 04:57

Which of the following is not true of cell communication systems?




A) Cell signaling was an early event in the evolution of life.
B) Communicating cells may be far apart or close together.
C) Most signal receptors are bound to the outer membrane of the nuclear envelope.
D) Protein phosphorylation is a major mechanism of signal transduction.
E) In response to a signal, the cell may alter activities by changes in cytosol activity or in transcription of RNA.


Answer: C

Which of the following is (are) true regarding the activity of a protein regulated by phosphorylation?

Naim 04:57

Which of the following is (are) true regarding the activity of a protein regulated by phosphorylation?




A) It depends mostly on the concentration of inorganic phosphate inside the cell.
B) It depends on the balance in the cell between active kinase and active phosphatase molecules.
C) It is dependent on the site of attachment of the protein to the plasma membrane.
D) Only A and B are true.
E) A, B, and C are true.


Answer: B

In general, a signal transmitted via phosphorylation of a series of proteins

Naim 04:57

In general, a signal transmitted via phosphorylation of a series of proteins




A) brings a conformational change to each protein.
B) requires binding of a hormone to a cytosol receptor.
C) cannot occur in yeasts because they lack protein phosphatases.
D) involves only the tyrosine-kinase receptor pathways and no G-protein linked pathways.
E) allows target cells to change their shape and therefore their activity.


Answer: A

Testosterone functions inside a cell by

Naim 04:56

Testosterone functions inside a cell by




A) acting as a signal receptor that activates ion-channel proteins.
B) binding with a receptor protein that enters the nucleus and activates specific genes.
C) acting as a steroid signal receptor that activates ion-channel proteins.
D) becoming a second messenger that inhibits adenylyl cyclase.
E) coordinating a phosphorylation cascade that increases glycogen metabolism.


Answer: B

G proteins and G-protein-linked receptors

Naim 04:55

G proteins and G-protein-linked receptors




A) are found only in animal cells.
B) are found only in bacterial cells.
C) are thought to have evolved very early, because of their similar structure and function in a wide variety of modern organisms whose common ancestors diverged billions of years ago.
D) probably evolved from an adaptation of the citric acid cycle.
E) are not widespread in nature and were unimportant in the evolution of eukaryotes.


Answer: C

What would be true for the signaling system in an animal cell that lacks the ability to produce GTP?

Naim 04:55

What would be true for the signaling system in an animal cell that lacks the ability to produce GTP?




A) It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
B) It could activate only the epinephrine system.
C) It would be able to carry out reception and transduction, but would not be able to respond to a signal.
D) Only A and C are true.
E) A, B, and C are true.


Answer: A

Most signal molecules

Naim 04:54

Most signal molecules




A) bind to specific sites on receptor proteins in a membrane.
B) are water-soluble.
C) are able to pass through the plasma membrane by active transport.
D) A and B only
E) A, B, and C



Answer: D

Which of the following is (are) true of ligand-gated ion channels?

Naim 04:54

Which of the following is (are) true of ligand-gated ion channels?




A) They are important in the nervous system.
B) They lead to changes in sodium and calcium concentrations in cells.
C) They open or close in response to a chemical signal.
D) Only A and B are true.
E) A, B, and C are true.


Answer: E

The process of transduction usually begins

Naim 04:53

The process of transduction usually begins




A) when the chemical signal is released from the alpha cell.
B) when the signal molecule changes the receptor protein in some way.
C) after the target cell divides.
D) after the third stage of cell signaling is completed.
E) when the hormone is released from the gland into the blood.


Answer: B

From the perspective of the cell receiving the message, the three stages of cell signaling are

Naim 04:53

From the perspective of the cell receiving the message, the three stages of cell signaling are




A) the paracrine, local, and synaptic stages.
B) signal reception, signal transduction, and cellular response.
C) signal reception, nucleus disintegration, and new cell generation.
D) the alpha, beta, and gamma stages.
E) signal reception, cellular response, and cell division.


Answer: B

The old saying "one rotten apple spoils the whole barrel" is due to chemical signaling in plants via

Naim 04:53

The old saying "one rotten apple spoils the whole barrel" is due to chemical signaling in plants via




A) an increased uptake of carbon dioxide during respiration in target cells.
B) a local regulator for apple development.
C) a release of ethylene gas, a plant hormone for ripening.
D) an a/a cell signal system in the rotten apple.
E) a signal transduction pathway involving glycogen phosphorylase.


Answer: C

Which of the following is true of synaptic signaling and hormonal signaling?

Naim 04:53

Which of the following is true of synaptic signaling and hormonal signaling?




A) Hormonal signaling occurs in animals only.
B) Hormonal signaling is important between cells that are at greater distances apart than in synaptic signaling.
C) Both always act on target cells by a G-protein-signaling pathway.
D) Only A and B are true.
E) A , B, and C are true.


Answer: B

What could happen to the target cells that lack receptor proteins for ligands from local regulators?

Naim 04:52

What could happen to the target cells that lack receptor proteins for ligands from local regulators?




A) They could compensate by receiving nutrients via an a factor.
B) They could develop normally in response to neurotransmitters instead.
C) They could divide but never reach full size.
D) They would not be able to multiply in response to growth factors from nearby cells.
E) Hormones would not be able to interact with target cells.


Answer: D

Where is the electron transport chain found in plant cells?

Naim 04:51

Where is the electron transport chain found in plant cells?




A) thylakoid membranes of chloroplasts
B) stroma of chloroplasts
C) inner membrane of mitochondria
D) matrix of mitochondria
E) cytoplasm
F) two of the above are correct



Answer: F

Which of the following statements best describes the relationship between photosynthesis and respiration?

Naim 04:51

Which of the following statements best describes the relationship between photosynthesis and respiration?



A) Respiration is the reversal of the biochemical pathways of photosynthesis.
B) Photosynthesis stores energy in complex organic molecules, while respiration releases it.
C) Photosynthesis occurs only in plants and respiration occurs only in animals.
D) ATP molecules are produced in photosynthesis and used up in respiration.
E) Respiration is anabolic and photosynthesis is catabolic.



Answer: B

In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from

Naim 04:50

In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from




A) the stroma to the photosystem II.
B) the matrix to the stroma.
C) the stroma to the thylakoid space.
D) the intermembrane space to the matrix.
E) ATP synthase to NADP+ reductase.


Answer: C

Suppose the interior of the thylakoids of isolated chloroplasts were made acidic and then transferred in the dark to a pH-8 solution. What would be likely to happen?

Naim 04:50

Suppose the interior of the thylakoids of isolated chloroplasts were made acidic and then transferred in the dark to a pH-8 solution. What would be likely to happen?




A) The isolated chloroplasts will make ATP.
B) The Calvin cycle will be activated.
C) Cyclic photophosphorylation will occur.
D) Only A and B will occur.
E) A, B, and C will occur.


Answer: A

As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find 30,000 molecules of ATP consumed, but only 20,000 molecules of NADPH. Where did the extra ATP molecules come from?

Naim 04:49

As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find 30,000 molecules of ATP consumed, but only 20,000 molecules of NADPH. Where did the extra ATP molecules come from?




A) photosystem II
B) photosystem I
C) cyclic electron flow
D) noncyclic electron flow
E) chlorophyll


Answer: C

Which of the following statements about the light reactions of photosynthesis are true?

Naim 04:42

Which of the following statements about the light reactions of photosynthesis are true?



A) The splitting of water molecules provides a source of electrons.
B) Chlorophyll (and other pigments) absorb light energy, which excites electrons.
C) ATP is generated by photophosphorylation.
D) Only A and C are true.
E) A, B, and C are true.


Answer: E

An outcome of this experiment was to help determine

Naim 04:42
Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He noted that the largest groups were found in the areas illuminated by the red and blue light.

An outcome of this experiment was to help determine




A) the relationship between heterotrophic and autotrophic organisms.
B) the relationship between wavelengths of light and the rate of aerobic respiration.
C) the relationship between wavelengths of light and the amount of heat released.
D) the relationship between wavelengths of light and the oxygen released during photosynthesis.
E) the relationship between the concentration of carbon dioxide and the rate of photosynthesis.



Answer: D

What did Engelmann conclude about the congregation of bacteria in the red and blue areas?

Naim 04:42
Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He noted that the largest groups were found in the areas illuminated by the red and blue light.

What did Engelmann conclude about the congregation of bacteria in the red and blue areas?



A) Bacteria released excess carbon dioxide in these areas.
B) Bacteria congregated in these areas due to an increase in the temperature of the red and blue light.
C) Bacteria congregated in these areas because these areas had the most oxygen being released.
D) Bacteria are attracted to red and blue light and thus these wavelengths are more reactive than other wavelengths.
E) Bacteria congregated in these areas due to an increase in the temperature caused by an increase in photosynthesis.


Answer: C

During photosynthesis, visible light has enough energy to

Naim 04:41

During photosynthesis, visible light has enough energy to




A) force electrons closer to the nucleus.
B) excite electrons.
C) split a water molecule into hydrogen and oxygen.
D) B and C only.
E) A, B, and C.



Answer: D

A plant has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are not being absorbed by this pigment?

Naim 04:40

A plant has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are not being absorbed by this pigment?



A) red and yellow
B) blue and violet
C) green and yellow
D) blue, green, and red
E) green, blue, and violet


Answer: A

Where does the Calvin cycle take place?

Naim 04:40

Where does the Calvin cycle take place?



A) stroma of the chloroplast
B) thylakoid membrane
C) cytoplasm surrounding the chloroplast
D) chlorophyll molecule
E) outer membrane of the chloroplast


Answer: A

If photosynthesizing green algae are provided with CO2 synthesized with heavy oxygen (18O), later analysis will show that all but one of the following compounds produced by the algae contain the 18O label. That one exception is

Naim 04:39

If photosynthesizing green algae are provided with CO2 synthesized with heavy oxygen (18O), later analysis will show that all but one of the following compounds produced by the algae contain the 18O label. That one exception is




A) PGA.
B) PGAL.
C) glucose.
D) RuBP.
E) O2.


Answer: E

If photosynthesizing green algae are provided with CO2 synthesized with heavy oxygen (18O), later analysis will show that all but one of the following compounds produced by the algae contain the 18O label. That one exception is

Naim 04:39

If photosynthesizing green algae are provided with CO2 synthesized with heavy oxygen (18O), later analysis will show that all but one of the following compounds produced by the algae contain the 18O label. That one exception is




A) PGA.
B) PGAL.
C) glucose.
D) RuBP.
E) O2.



Answer: E

The early suggestion that the oxygen (O2) liberated from plants during photosynthesis comes from water was

Naim 04:38

The early suggestion that the oxygen (O2) liberated from plants during photosynthesis comes from water was




A) first proposed by C.B. van Niel of Stanford University.
B) confirmed by experiments using oxygen-18 (18O).
C) made following the discovery of photorespiration because of rubisco's sensitivity to oxygen.
D) A and B
E) A, B, and C


Answer: B

What happens at the end of the chain in Figure 7.2?

Naim 04:28

What happens at the end of the chain in Figure 7.2? 



A) Two electrons combine with a molecule of oxygen and two hydrogen atoms.
B) Two electrons combine with a proton and a molecule of NAD+.
C) Four electrons combine with a molecule of oxygen and 4 protons.
D) Four electrons combine with four hydrogen and two oxygen atoms.
E) One electron combines with a molecule of oxygen and a hydrogen atom.



Answer: C

A young dog has never had much energy. He is brought to a veterinarian for help and she decides to conduct several diagnostic tests. She discovers that the dog's mitochondria can use only fatty acids and amino acids for respiration, and his cells produce more lactate than normal. Of the following, which is the best explanation of the dog's condition?

Naim 04:27

A young dog has never had much energy. He is brought to a veterinarian for help and she decides to conduct several diagnostic tests. She discovers that the dog's mitochondria can use only fatty acids and amino acids for respiration, and his cells produce more lactate than normal. Of the following, which is the best explanation of the dog's condition?




A) His cells contain something that inhibits oxygen use in his mitochondria.
B) His cells cannot move NADH from glycolysis into the mitochondria.
C) His cells lack the enzyme in glycolysis that forms pyruvate.
D) His cells have a defective electron transport chain, so glucose goes to lactate instead of to acetyl CoA.
E) His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane.



Answer: E
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