Bio Quizzes (Chapters 6-11)

Which of the following would likely diffuse through the lipid bilayer of a plasma membrane most rapidly? a. an amino acid b. O2 c. Na+ d. sucrose

O2

Which of the following statements correctly describes some aspect of protein secretion from prokaryotic cells? Prokaryotes cannot secrete proteins because they lack rough endoplasmic reticulum. Proteins secreted by prokaryotes are likely synthesized on ribosomes bound to the cytoplasmic surface of the plasma membrane. The mechanism of protein secretion in prokaryotes is probably the same as that in eukaryotes. Prokaryotes cannot secrete proteins because they lack an endomembrane system

Proteins that are secreted by prokaryotes are synthesized on ribosomes that are bound to the cytoplasmic surface of the plasma membrane

Gaucher disease is the most common of lipid storage diseases in humans. It is caused by a deficiency of an enzyme necessary for the breakdown of lipids. This leads to the accumulation of fatty material in organs of the body including the spleen, liver, kidneys, lungs, brain, and bone marrow. Using your knowledge of the structure of eukaryotic cells, identify the statement below that best explains how internal membranes and the organelles of cells may be involved in Gaucher disease. The mitochondria are most likely defective and do not produce adequate amounts of ATP needed for cellular energy. The Golgi apparatus produces vesicles with faulty membranes, which fail to be transported to the plasma membrane for secretion. The lysosomes lack sufficient amounts of enzymes necessary for the metabolism of lipids. The rough endoplasmic reticulum contains too many ribosomes, which results in an overproduction of the enzyme involved in lipid breakdown.

The lysosomes lack sufficient amounts of enzymes necessary for the metabolism of lipids.

Starting with one molecule of glucose, glycolysis results in the net production of which of the following sets of energy-containing products? a. 2 NADH, 2 pyruvate, and 2 ATP b. 2 NAD+, 2 pyruvate, and 2 ATP c. 4 NADH, 2 pyruvate, and 4 ATP d. 6 CO2, 2 pyruvate, and 2 ATP

a. 2 NADH, 2 pyruvate, and 2 ATP

A cell has enough available ATP to meet its needs for about 30 seconds. What is likely to happen when an athlete exhausts his or her ATP supply? a. Catabolic processes are activated that generate more ATP b. He or she has to sit down and rest c. Other cells take over, and the muscle cells that have used up their ATP cease to function. d. ATP is transported into the cell from the circulatory system

a. Catabolic processes are activated that generate more ATP

If an animal cell suddenly lost the ability to produce GTP, what might happen to its signaling system? a. It would not be able to activate G proteins on the cytoplasmic side of the plasma membrane b. It would be able to carry out reception and transduction but would not be able to respond to a signal. c. It would use ATP instead of GTP to activate G proteins on the cytoplasmic side of the plasma membrane. d. It would not be able to activate receptor tyrosine kinases

a. It would not be able to activate G proteins on the cytoplasmic side of the plasma membrane

In a metabolic pathway, succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, a substance that resembles succinate but cannot be acted upon by succinate dehydrogenase. Increasing the amount of succinate molecules to those of malonic acid reduces the inhibitory effect of malonic acid. What role does malonic acid play with respect to succinate dehydrogenase? a. Malonic acid is a competitive inhibitor b. Malonic acid blocks the binding of fumarate. c. Malonic acid is an allosteric regulator. d. Malonic acid is a noncompetitive inhibitor

a. Malonic acid is a competitive inhibitor

A patient was involved a serious accident and lost a large quantity of blood. In an attempt to replenish body fluids, distilled water—equal to the volume of blood lost—is added to the blood directly via one of his veins. What will be the most probable result of this transfusion? a. The patient's red blood cells will swell and possibly burst because the blood has become hypotonic compared to the cells. b. The patient's red blood cells will shrivel up because the blood has become hypertonic compared to the cells. c. The patient's red blood cells will burst because the blood has become hypertonic compared to the cells. d. The patient's red blood cells will shrivel up because the blood has become hypotonic compared to the cells

a. The patient's red blood cells will swell and possibly burst because the blood has become hypotonic compared to the cells.

Cell membranes have distinct inside and outside faces. Which of the following statements is the most likely explanation for the membrane's asymmetrical nature? a. The two sides of a cell membrane face different environments and carry out different functions. b. Proteins only function on the cytoplasmic side of the cell membrane, which results in the membrane's asymmetrical nature. c. Since cell membranes communicate signals from one organism to another, the cell membranes must be asymmetrical.. d. Since the cell membrane forms a border between one cell and another in tightly packed tissues such as epithelium, the membrane must be asymmetrical.

a. The two sides of a cell membrane face different environments and carry out different functions.

Which of the following processes generally requires protein phosphorylation? a. activation of receptor tyrosine kinases b. activation of steroid hormone receptors c. activation of G protein-coupled receptors d. activation ligand-gated ion channels

a. activation of receptor tyrosine kinases

An animal cell lacking carbohydrates on the external surface of its plasma membrane would likely be impaired in which function? a. cell-cell recognition b. transporting ions against an electrochemical gradient c. establishing a diffusion barrier to charged molecules d. attaching the plasma membrane to the cytoskeleton

a. cell-cell recognition

Even though plants cells carry out photosynthesis, they still use their mitochondria for oxidation of pyruvate. Under what conditions will plant cell mitochondria be active in this process? a. in all cells, with or without light b. only in photosynthetic cells in the light, while photosynthesis occurs concurrently c. in photosynthesizing cells in the light, and in other cells in the dark d. only in cells that store glucose in the form of starch and only in the dark

a. in all cells, with or without light

Which of the following processes is directly associated with photosystem I? a. receiving electrons from the thylakoid membrane electron transport chain b. generation of molecular oxygen c. extraction of hydrogen electrons from the splitting of water d. passing electrons to NADP

a. receiving electrons from the thylakoid membrane electron transport chain

A research team is working on the design of a new drug for the treatment of lung cancer. To be most effective, this drug must specifically enter the cytoplasm of lung cells while not entering the cells of other tissues. Which of the following characteristics would likely enhance the specificity of this drug? a. similarity of the drug molecule to other molecules normally transported lung cells b. specificity of the drug molecule for binding to the extracellular matrix of lung cells c. phospholipid composition of lung cell plasma membranes d. the relative hydrophobicity of the drug molecule

a. similarity of the drug molecule to other molecules normally transported lung cells

In a plant, which of the following reactions produce molecular oxygen (O2)? a. the light reactions alone b. the Calvin cycle alone c. the light reactions and the Calvin cycle d. neither the light reactions nor the Calvin cycle

a. the light reactions alone

Approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose (C6H12O6) in aerobic cellular respiration? a. 18-24 b. 30-32 c. 4 d. 2

b. 30-32

Particular receptor tyrosine kinases (RTKs) that promote excessive cell division are found at high levels in various cancer cells. HER2 is an RTK that is present at excessively high levels in some breast cancer cells. Herceptin is a protein that binds to HER2 and inhibits cell division. Herceptin may be an effective treatment for breast cancer treatment under which of the following conditions? a. If injection of HER2 in the patient's cancer cells stimulates cell division. b. If the patient's cancer cells have excessive levels of HER2. c. If the patient's genome codes for the HER2. d. If the patient has excessive levels of other RTKs in cancer cells

b. If the patient's cancer cells have excessive levels of HER2.

Why is glycolysis considered to be one of the first metabolic pathways to have evolved? a. It is present in prokaryotic cells but not in eukaryotic cells. b. It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms. c. It produces much less ATP than does oxidative phosphorylation. d. It requires the presence of membrane-enclosed cell organelles found only in eukaryotic cells

b. It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms.

Which of the following statements about diffusion is true? a. It is an active process in which molecules move from a region of lower concentration to a region of higher concentration. b. It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration. c. It requires an expenditure of energy by the cell. d. It is very rapid over long distances.

b. It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.

Which of the following statements best describes the relationship between photosynthesis and cellular respiration? a. Cellular respiration runs the biochemical pathways of photosynthesis in reverse b. Photosynthesis stores energy in complex organic molecules; cellular respiration releases energy from complex organic molecules. c. Photosynthesis occurs only in plants; cellular respiration occurs only in animals. d. Photosynthesis is catabolic; cellular respiration is anabolic

b. Photosynthesis stores energy in complex organic molecules; cellular respiration releases energy from complex organic molecules.

When a plant cell, such as one from a tulip leaf, is submerged in a hypertonic solution, what is likely to occur? a. The cell will become turgid. b. Plasmolysis will shrink the interior of the cell. c. The cell will burst. d. The cell will become flaccid

b. Plasmolysis will shrink the interior of the cell.

What will happen to a red blood cell (RBC), which has an internal ion content of about 0.9%, if it is placed into a beaker of pure water? a. The cell would shrink because the water in the beaker is hypertonic relative to the cytoplasm of the RBC. b. The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC. c. The cell will remain the same size because the solution outside the cell is isotonic. d. The cell would shrink because the water in the beaker is hypotonic relative to the cytoplasm of the RBC

b. The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC

What does it mean to say that a signal is transduced? a. The signal enters the cell directly and binds to a receptor inside. b. The physical form of the signal changes as it passes from the cell membrane to the ultimate intracellular target c. The signal is amplified, such that even one signal molecule evokes a large response. d. The signal triggers a sequence of phosphorylation events inside the cell

b. The physical form of the signal changes as it passes from the cell membrane to the ultimate intracellular target

Which of the following statements is true of steroid receptors? a. The receptor molecules are themselves lipids or glycolipids. b. The receptor may be inside the nucleus of a target cell c. The unbound steroid receptors are quickly recycled by lysosomes. d. Steroid receptors are typically bound to the external surface of the nuclear membrane

b. The receptor may be inside the nucleus of a target cell

Which of the following statements about anabolic pathways is true? a. They decrease the entropy of the organism and its environment. b. They consume energy to build up polymers from monomers. c. They are usually spontaneous chemical reactions. d. They release energy by degrading polymers to monomers

b. They consume energy to build up polymers from monomers.

HIV is the virus that causes AIDS. In the mid-1990s, researchers discovered an enzyme in HIV called protease. Once the enzyme's structure was known, researchers began looking for drugs that would fit into the active site and block it. If this strategy for stopping HIV infections were successful, it would be an example of what phenomenon? a. noncompetitive inhibition b. competitive inhibition c. allosteric regulation d. denaturation

b. competitive inhibition

The mechanism of photophosphorylation is most similar to which of the following processes? a. substrate-level phosphorylation in glycolysis b. oxidative phosphorylation in cellular respiration c. the Calvin cycle d. reduction of NADP+

b. oxidative phosphorylation in cellular respiration

What are the products of linear electron flow during the light reactions of photosynthesis? a. heat and fluorescence b. ATP and P700 c. ATP and NADPH d. ADP and NADP+

c. ATP and NADPH

In the absence of oxygen, yeast cells can obtain energy by fermentation, which results in the production of which of the following sets of molecules? a. ATP, NADH, and ethanol b. ATP, CO2, and acetyl CoA c. ATP, CO2, and ethanol (ethyl alcohol) d. ATP, CO2, and lactate

c. ATP, CO2, and ethanol (ethyl alcohol)

Some photosynthetic organisms contain chloroplasts that lack photosystem II, yet are able to survive. Which of the following approaches would be the best way to detect the lack of photosystem II in these organisms? a. Determine whether they have thylakoid membranes. b. Determine whether they consume CO2 in the dark. c. Determine whether they produce O2 in the light. d. Determine the action spectrum for photosynthesis in these organisms.

c. Determine whether they produce O2 in the light.

The receptors for steroid hormones are located inside the cell instead of the membrane surface like most other signal receptors. How do steroids gain access to their receptors? a. Steroid hormone receptors undergo conformational changes that relocate them on the membrane surface. b. Both steroid hormones and their receptors are produced by the same cells. c. Steroid hormones are lipid soluble, so they can readily diffuse through the lipid bilayer of the cell membrane. d. Steroid hormones first bind to a steroid activator and this complex is transported across the cell membrane by a steroid transport protein

c. Steroid hormones are lipid soluble, so they can readily diffuse through the lipid bilayer of the cell membrane.

Biological systems use free energy based on empirical data that all organisms require a constant energy input. The first law of thermodynamics states that energy can be neither created nor destroyed. For living organisms, which of the following statements is an important consequence of this first law? a. The entropy of an organism decreases with time as the organism grows in complexity. b. The energy content of an organism is constant except for when its cells are dividing. c. The organism must ultimately obtain all the necessary energy for life from its environment. d. Organisms are unable to transform energy from the different states in which it can exist

c. The organism must ultimately obtain all the necessary energy for life from its environment.

Which of the following factors would tend to increase membrane fluidity? a. a relatively high protein content in the membrane b. a lower temperature c. a greater proportion of unsaturated phospholipids d. a greater proportion of saturated phospholipids

c. a greater proportion of unsaturated phospholipids

As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in one hour. You find that 30,000 molecules of ATP were consumed, but only 20,000 molecules of NADPH were consumed. What is the source of the extra ATP molecules? a. photosystem II b. photosystem I c. cyclic electron flow d. linear electron flow

c. cyclic electron flow

Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as ________ is to ________. a. work; energy b. exergonic; spontaneous c. exergonic; endergonic d. free energy; entropy

c. exergonic; endergonic

Which of the following metabolic processes normally occurs regardless of whether or not oxygen (O2) is present? a. lactate fermentation b. oxidative phosphorylation c. glycolysis d. citric acid cycle

c. glycolysis

Celery stalks that are immersed in fresh water for several hours become stiff. Similar stalks left in a 0.15 M salt solution become limp. From this we can deduce that the fresh water ________. a. is hypertonic and the salt solution is hypotonic to the cells of the celery stalks b. and the salt solution are both hypertonic to the cells of the celery stalks c. is hypotonic and the salt solution is hypertonic to the cells of the celery stalks d. is isotonic and the salt solution is hypertonic to the cells of the celery stalks

c. is hypotonic and the salt solution is hypertonic to the cells of the celery stalks

In the initial step in carbon fixation, a molecule of CO2 is attached to RuBP to produce a six-carbon molecule, which is immediately split to produce two molecules of 3-phosphoglycerate. After phosphorylation and reduction produces glyceraldehyde 3-phosphate (G3P), what more needs to occur to complete the Calvin cycle? a. addition of a pair of electrons from NADPH b. regeneration of ATP from ADP c. regeneration of RuBP d. regeneration of NADP+

c. regeneration of RuBP

Which structure is not part of the endomembrane system? Responses Golgi apparatus nuclear envelope chloroplast plasma membrane

chloroplast

Which of the following statements is an important consequence of the first law of thermodynamics for a living organism? a. Organisms grow by converting energy into organic matter. b. The energy content of an organism is constant. c. The entropy of an organism decreases with time as the organism grows in complexity. d. An organism ultimately must obtain all of the necessary energy for life from its environment

d. An organism ultimately must obtain all of the necessary energy for life from its environment

How do cells use the ATP cycle illustrated in the figure? a. Cells use the cycle primarily to generate heat. b. Cells use the cycle to recycle ADP, phosphate, and the energy released by ATP hydrolysis. c. Cells use the cycle to recycle energy released by ATP hydrolysis. d. Cells use the cycle to recycle ADP and phosphate

d. Cells use the cycle to recycle ADP and phosphate

At puberty, an adolescent female body changes in both structure and function of several organ systems, primarily under the influence of changing concentrations of estrogen and other steroid hormones. How can one hormone, such as estrogen, mediate so many effects? a. Estrogen is produced in very large concentration by nearly every tissue of the body. b. Each cell responds in the same way when steroids bind to the cell surface. c. Estrogen is kept away from the surface of any cells, not able to bind it at the surface. d. Estrogen binds to specific receptors inside many kinds of cells, each with different responses

d. Estrogen binds to specific receptors inside many kinds of cells, each with different responses

The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the a. oxidation of glucose and other organic compounds. b. transfer of phosphate to ADP. c. flow of electrons down the electron transport chain. d. H+ concentration gradient across the membrane holding ATP synthase.

d. H+ concentration gradient across the membrane holding ATP synthase.

In autumn, chlorophyll is degraded in the leaves of deciduous trees. Why do the leaves change color to shades of yellow, orange, or red? a. Sugars from sap fill the leaves prior to winter. b. Degraded chlorophyll changes into many other colors. c. In the absence of photosynthesis, the leaves produce energy exclusively by aerobic cellular respiration. d. Other pigments such as carotenoids are still present in the leaves

d. Other pigments such as carotenoids are still present in the leaves

Hormones are chemical substances produced in one organ that are released into the bloodstream and affect the function of a target organ. Which of the following conditions is required for the target organ to respond to a particular hormone? a. Cells in the target organ must modify their plasma membranes to allow the hormone to enter the cytoplasm. b. The target organ must be the same as the organ that produced the hormone. c. The target organ must have the opposite mating type of the organ that produced the hormone. :d. The target organ must have receptors that recognize and bind the hormone molecule

d. The target organ must have receptors that recognize and bind the hormone molecule

What role do phosphatases play in signal transduction pathways? a. They transfer a phosphate group from one protein in the pathway to the next molecule in the series. b. They activate protein kinases by phosphorylation. c. They amplify the second messenger cAMP. d. They inactivate protein kinases to turn off signal transduction.

d. They inactivate protein kinases to turn off signal transduction.

If an enzyme in solution is saturated with substrate, the most effective way to obtain a faster yield of products is to :a. add more substrate. b. heat the solution to 90°C. c. add a noncompetitive inhibitor. d. add more of the enzyme.

d. add more of the enzyme.

Which of the following metabolic processes take place in the cytosol of a eukaryotic cell? a. oxidation of pyruvate to acetyl CoA b. fermentation and chemiosmosis c. citric acid cycle d. glycolysis and fermentation

d. glycolysis and fermentation

Which of the following activities would be inhibited by a drug that specifically blocks the addition of phosphate groups to proteins? a. binding of G proteins to G protein-coupled receptors b. ligand-gated ion channel signaling pathways c. adenylyl cyclase activity d. receptor tyrosine kinase activity

d. receptor tyrosine kinase activity

Which of the following aspects of enzyme structure is best described by a clasping handshake analogy? a. the specific manner in which an enzyme folds to form secondary and tertiary structures b. the specific manner in which an enzyme interacts with water c. the specific manner in which an enzyme is denatured by low pH d. the specific manner in which an enzyme binds substrate

d. the specific manner in which an enzyme binds substrate

Is the reaction endergonic or exergonic if change in free energy (G)<0?

exergonic

Cyanide binds with at least one molecule involved in producing ATP. If a cell is exposed to cyanide, most of the bound cyanide is likely to be localized within the ________

mitochondria

Suppose a young boy is always tired and fatigued, suffering from a metabolic disease. Which of the following organelles is most likely malfunctioning in this disease? A) lysosomes B) Golgi apparatus C) mitochondria D) smooth endoplasmic reticulum

mitochondria

A cell with a predominance of rough endoplasmic reticulum is most likely ________ producing large quantities of proteins in the cytosol producing large quantities of proteins for secretion producing large quantities of carbohydrates for storage in the vacuole producing large quantities of carbohydrates to assemble an extensive cell wall matrix

producing large quantities of proteins for secretion

Examination of a cell by transmission electron microscopy reveals a high density of ribosomes in the cytoplasm. This observation suggests that this cell is actively producing large amounts of which of the following molecules?

proteins

Which of the following are found in plant, animal, and bacterial cells?

ribosomes

The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and, therefore, abundant in liver cells? smooth endoplasmic reticulum nuclear envelope rough endoplasmic reticulum Golgi apparatus

smooth ER

A cell with a predominance of smooth endoplasmic reticulum is likely specialized to ________. Responses store large quantities of water actively secrete large quantities of protein synthesize large quantities of lipids import and export large quantities of protein

synthesize large quantities of lipids