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All Textbook Solutions for Biology 2e

Figure 1.6 In the example below, the scientific method is used to solve an everyday problem. Order the scientific method steps (numbered items) with the process of solving the everyday problem (lettered items). Based on the results of the experiment, is the hypothesis correct? If it is incorrect, propose some alternative hypotheses. Observation Question Hypothesis (answer) Prediction Experiment Result There is something wrong with the electrical outlet. If something is wrong with the outlet, my coffeemaker also won’t work when plugged into it. My toaster doesn’t toast my bread. I plug my coffee maker into the outlet. My coffeemaker works. Why doesn't my toaster work?Figure 1.7 Decide if each of the following is an example of inductive or deductive reasoning. All flying birds and insects have wings. Birds and insects flap their wings as they move through the air. Therefore, wings enable flight. Insects generally survive mild winters better than harsh ones. Therefore, insect pests will become more problematic if global temperatures increase. Chromosomes, the carriers of DNAr separate into daughter cells during cell division. Therefore, each daughter cell will have the same chromosome set as the mother cell. Animals as diverse as humans, insects, and wolves all exhibit social behavior. Therefore, social behavior must have an evolutionary advantage.Figure 1.16 Which of the following statements is false? Tissues exist within organs which exist within organ systems. Communities exist within populations which exist within ecosystems Organelles exist within cells which exist within tissues. Communities exist within ecosystems which exist in the biosphere.The first forms of life on Earth were plants microorganisms birds dinosaurs A suggested and testable explanation for an event is called a ________. hypothesis variable theory control Which of the following sciences is not considered a natural science? biology astronomy physics computer science The type of logical thinking that uses related observations to arrive at a general conclusion is called _____________. deductive reasoning the scientific method hypothesis-based science inductive reasoning The process of helps to ensure that a scientist’s research is original, significant, logical, and thorough __________. publication public speaking peer review the scientific method A person notices that her houseplants that are regularly exposed to music seem to grow more quickly than those in rooms with no music. As a result, she determines that plants grow better when exposed to music. This example most closely resembles which type of reasoning? inductive reasoning deductive reasoning neither, because no hypothesis was made both inductive and deductive reasoning The smallest unit of biological structure that meets the functional requirements of “living” is the _______. a. organ b. organelle c. cell d. macromolecule Viruses are not considered living because they ___________ . a. are not made of cells b. lack cell nuclei c. do not contain DNA or RNA d. cannot reproduce The presence of a membrane-enclosed nucleus is a characteristic of ________. prokaryotic cells eukaryotic cells living organisms bacteria A group of individuals of the same species living in the same area is called a(n). family community population ecosystem Which of the following sequences represents the hierarchy of biological organization from the most inclusive to the least complex level? organelle, tissue, biosphere, ecosystem, population organ, organism, tissue, organelle, molecule organism, community, biosphere, molecule, tissue, organ biosphere, ecosystem, community, population, organism Where in a phylogenetic tree would you expect to find the organism that had evolved most recently? at the base within the branches at the nodes at the branch tips Although the scientific method is used by most of the sciences, it can also be applied to everyday situations. Think about a problem that you may have at home, at school, or with your car, and apply the scientific method to solve it.Give an example of how applied science has had a direct effect on your daily life.Name two topics that are likely to be studied by biologists, and two areas of scientific study that would fall outside the realm of biology.Thinking about the topic of cancer, write a basic science question and an applied science question that a researcher interested in this topic might ask.Select two items that biologists agree are necessary in order to consider an organism “alive.” For each, give an example of a nonliving object that otherwise fits the definition of “alive.”Consider the levels of organization of the biological world, and place each of these items in order from smallest level of organization to most encompassing: skin cell, elephant, water molecule, planet Earth, tropical rainforest, hydrogen atom, wolf pack, liver.You go for a long walk on a hot clay. Give an example of a way in which homeostasis keeps your body healthy.Using examples, explain how biology can be studied from a microscopic approach to a global approach.Figure 2.3 How many neutrons do carbon-12 and carbon-13 have, respectively?Figure 2.7 An atom may give, take, or share electrons with another atom to achieve a full valence shell, the most stable electron configuration. Looking at this figure, how many electrons do elements in group 1 need to lose in order to achieve a stable electron configuration? How many electrons do elements in groups 14 and 17 need to gain to achieve a stable configuration?Figure 2.24 Which of the following statements is false? Molecules with the formulas CH3CH2COOH and C3H6O2 could be structural isomers. Molecules must have a double bond to be cis-trans isomers. To be enantiomers, a molecule must have at least three different atoms or groups connected to a central carbon. To be enantiomers, a molecule must have at least four different atoms or groups connected to a central carbon.If xenon has an atomic number of 54 and a mass number of 108, how many neutrons does it have? 54 27 100 108 Atoms that vary in the number of neutrons found in their nuclei are called _____________. ions neutrons neutral atoms isotopes Potassium has an atomic number of 19. What is its electron configuration? shells 1 and 2 are full, and shell 3 has nine electrons shells 1, 2 and 3 are full and shell 4 has three electrons shells 1, 2 and 3 are full and shell 4 has one electron shells 1, 2 and 3 are full and no other electrons are present Which type of bond represents a weak chemical bond? hydrogen bond atomic bond covalent bond nonpolar covalent bond Which of the following statements is not true? Water is polar Water stabilizes temperature Water is essential for life Water is the most abundant molecule in the Earth’s atmosphere.When acids are added to a solution, the pH should ___________ . a. decrease b. increase c. stay the same d. cannot tell without testing We call a molecule that binds up excess hydrogen ions in a solution a(n). acid isotope base donator Which of the following statements is true? Acids and bases cannot mix together Acids and bases will neutralize each other Acids, but not bases, can change the pH of a solution Acids donate hydroxide ions (OH-); bases donate hydrogen ions (H+).Each carbon molecule can bond with as many as other atom(s) or molecule(s). one two six four Which of the following is not a functional group that can bond with carbon? sodium hydroxyl phosphate carbonyl What makes ionic bonds different from covalent bonds?Why are hydrogen bonds and van der Waals interactions necessary for cells?Discuss how buffers help prevent drastic swings in pH.Why can some insects walk on water?What property of carbon makes it essential for organic life?Compare and contrast saturated and unsaturated triglycerides.Figure 3.5 What kind of sugars are these, aldose or ketose?Figure 3.23 Which categories of amino acid would you expect to find on the surface of a soluble protein, and which would you expect to find in the interior? What distribution of amino acids would you expect to find in a protein embedded in a lipid bilayer?Figure 3.33 A mutation occurs, and cytosine is replaced with adenine. What impact do you think this will have on the DNA structure?Dehydration synthesis leads to formation of monomers polymers water and polymers none of the above During the breakdown of polymers, which of the following reactions takes place? hydrolysis dehydration condensation covalent bond The following chemical reactants produce the ester ethyl ethanoate (C4H8O2): C2H6O + CH3COOH What type of reaction occurs to make ethyl ethanoate? condensation hydrolysis combustion acid-base reaction An example of a monosaccharide is fructose glucose galactose all of the above Cellulose and starch are examples of: monosaccharides disaccharides lipids polysaccharides Plant cell walls contain which of the following in abundance? starch cellulose glycogen lactose Lactose is a disaccharide formed by the formation of a bond between glucose and glycosidic; lactose glycosidic; galactose hydrogen; sucrose hydrogen; fructose Which of the following is not an extracellular matrix role of carbohydrates? protect an insect’s internal organs from external trauma prevent plant cells from lysing after the plant is watered maintain the shape of a fungal spore provide energy for muscle movement Saturated fats have all of the following characteristics except: they are solid at room temperature they have single bonds within the carbon chain they are usually obtained from animal sources they tend to dissolve in water easily Phospholipids are important components of ___________ . a. the plasma membrane of cells b. the ring structure of steroids c. the waxy covering on leaves d. the double bond in hydrocarbon chains Cholesterol is an integral part of plasma membranes. Based on its structure, where is it found in the membrane? on the extracellular surface embedded with the phospholipid heads within the tail bilayer attached to the intracellular surface The monomers that make up proteins are called _____ a. nucleotides b. disaccharides c. amino acids d. chaperones The helix and the pleated sheet are part of which protein structure? primary secondary tertiary quaternary Mad cow disease is an infectious disease where one misfolded protein causes all other copies of the protein to being misfolding. This is an example of a disease impacting structure. primary secondary tertiary quaternary A nucleotide of DNA may contain. ribose, uracil, and a phosphate group deoxyribose, uracil, and a phosphate group deoxyribose, thymine, and a phosphate group ribose, thymine, and a phosphate group The building blocks of nucleic acids are ____. a. sugars b. nitrogenous bases c. peptides d. nucleotides How does the double helix structure of DNA support its role in encoding the genome? The sugar-phosphate backbone provides a template for DNA replication tRNA pairing with the template strand creates proteins encoded by the genome Complementary base pairing creates a very stable structure Complementary base pairing allows for easy editing of both strands of DNA.Why are biological macromolecules considered organic?What role do electrons play in dehydration synthesis and hydrolysis?Amino acids have the generic structure seen below, where R represents different carbon-based side chains. Describe how the structure of amino acids allows them to be linked into long peptide chains to form proteins.Describe the similarities and differences between glycogen and starch.Why is it impossible for humans to digest food that contains cellulose?Draw the ketose and aldose forms of a monosaccharide with the chemical formula C3H6O3. How is the structure of the monosaccharide changed from one form to the other in the human body?Explain at least three functions that lipids serve in plants and/or animals.Why have trans fats been banned from some restaurants? How are they created?Why are fatty acids better than glycogen for storing large amounts of chemical energy?Part of cortisol’s role in the body involves passing through the plasma membrane to initiate signaling inside a cell. Describe how the structures of cortisol and the plasma membrane allow this to occur.Explain what happens if even one amino acid is substituted for another in a polypeptide chain. Provide a specific example.Describe the differences in the four protein structures.Aquaporins are proteins embedded in the plasma membrane that allow water molecules to move between the extracellular matrix and the intracellular space. Based on its function and location, describe the key features of the protein’s shape and the chemical characteristics of its amino acids.What are the structural differences between RNA and DNA?What are the four types of RNA and how do they function?Figure 4.7 Prokaryotic cells are much smaller than eukaryotic cells. What advantages might small cell size confer on a cell? What advantages might large cell size have?Figure 4.8 If the nucleolus were not able to carry out its function, what other cellular organelles would be affected?Figure 4.18 If a peripheral membrane protein were synthesized in the lumen (inside) of the ER, would it end up on the inside or outside of the plasma membrane?When viewing a specimen through a light microscope, scientists use to distinguish the individual components of cells. a beam of electrons radioactive isotopes special stains high temperatures The is the basic unit of life organism cell tissue organ Prokaryotes depend on to obtain some materials and to get rid of wastes. ribosomes flagella cell division diffusion Bacteria that lack fimbriae are less likely to ___________ . adhere to cell surfaces swim through bodily fluids synthesize proteins retain the ability to divide Which of the following organisms is a prokaryote? a. amoeba b. influenza A virus c. charophyte algae d. E. coli Which of the following is surrounded by two phospholipid bilayers? the ribosomes the vesicles the cytoplasm the nucleoplasm Peroxisomes got their name because hydrogen peroxide is: used in their detoxification reactions produced during their oxidation reactions incorporated into their membranes a cofactor for the organelles’ enzymes In plant cells, the function of the lysosomes is carried out by. vacuoles peroxisomes ribosomes nuclei Which of the following is both in eukaryotic and prokaryotic cells? nucleus mitochondrion vacuole ribosomes Tay-Sachs disease is a genetic disorder that results in the destruction of neurons due to a buildup of sphingolipids in the cells. Which organelle is malfunctioning in Tay-Sachs? lysosome endoplasmic reticulum peroxisome mitochondria Which of the following is not a component of the endomembrane system? mitochondrion Golgi apparatus endoplasmic reticulum d. Iysosome The process by which a cell engulfs a foreign particle is known as: endosymbiosis phagocytosis hydrolysis membrane synthesis Which of the following is most likely to have the greatest concentration of smooth endoplasmic reticulum? a cell that secretes enzymes a cell that destroys pathogens a cell that makes steroid hormones a cell that engages in photosynthesis Which of the following sequences correctly lists in order the steps involved in the incorporation of a proteinaceous molecule within a cell? protein synthesis of the protein on the ribosome; modification in the Golgi apparatus; packaging in the endoplasmic reticulum; tagging in the vesicle synthesis of the protein on the lysosome; tagging in the Golgi; packaging in the vesicle; distribution in the endoplasmic reticulum synthesis of the protein on the ribosome; modification in the endoplasmic reticulum; tagging in the Golgi; distribution via the vesicle synthesis of the protein on the lysosome; packaging in the vesicle; distribution via the Golgi; tagging in the endoplasmic reticulum Congenital disorders of glycosylation are a growing class of rare diseases. Which organelle would be most commonly involved in the glycoprotein disorder portion of the group? RER ribosomes endosomes Golgi apparatus Which of the following have the ability to disassemble and reform quickly? microfilaments and intermediate filaments microfilaments and microtubules intermediate filaments and microtubules only intermediate filaments Which of the following do not play a role in intracellular movement? microfilaments and intermediate filaments microfilaments and microtubules intermediate filaments and microtubules only intermediate filaments In humans, are used to move a cell within its environment while are used to move the environment relative to the cell. cilia, pseudopodia flagella; cilia microtubules; flagella microfilaments; microtubules Which of the following are only in plant cells? gap junctions desmosomes plasmodesmata tight junctions The key components of desmosomes are cadherins and. actin microfilaments intermediate filaments microtubules Diseased animal cells may produce molecules that activate death cascades to kill the cells in a controlled manner. Why would neighboring healthy cells also die? The death molecule is passed through desmosomes The death molecule is passed through plasmodesmata The death molecule disrupts the extracellular matrix The death molecule passes through gap junctions.In your everyday life, you have probably noticed that certain instruments are ideal for certain situations. For example, you would use a spoon rather than a fork to eat soup because a spoon is shaped for scooping, while soup would slip between the tines of a fork. The use of ideal instruments also applies in science. In what situation(s) would the use of a light microscope be ideal, and why?In what situation(s) would the use of a scanning electron microscope be ideal, and why?In what situation(s) would a transmission electron microscope be ideal, and why?What are the advantages and disadvantages of each of these types of microscopes?Explain how the formation of an adult human follows the cell theory.Antibiotics are medicines that are used to fight bacterial infections. These medicines kill prokaryotic cells without harming human cells. What part or parts of the bacterial cell do you think antibiotics target? Why?Explain why not all microbes are harmful.You already know that ribosomes are abundant in red blood cells. In what other cells of the body would you find them in great abundance? Why?What are the structural and functional similarities and differences between mitochondria and chloroplasts?Why are plasma membranes arranged as a bilayer rather than a monolayer?In the context of cell biology, what do we mean by form follows function? What are at least two examples of this concept?In your opinion, is the nuclear membrane part of the endomembrane system? Why or why not? Defend your answer.What are the similarities and differences between the structures of centrioles and flagella?How do cilia and flagella differ?Describe how microfilaments and microtubules are involved in the phagocytosis and destruction of a pathogen by a macrophage.Compare and contrast the boundaries that plant, animal, and bacteria cells use to separate themselves from their surrounding environment.How does the structure of a plasmodesma differ from that of a gap junction?Explain how the extracellular matrix functions.Pathogenic E. coil have recently been shown to degrade tight junction proteins during infection. How would this provide an advantage to the bacteria?Figure 5.12 A doctor injects a patient with what the doctor thinks is an isotonic saline solution. The patient dies, and an autopsy reveals that many red blood cells have been destroyed. Do you think the solution the doctor injected was really isotonic?Figure 5.16 Injecting a potassium solution into a person’s blood is lethal. Capital punishment and euthanasia utilize this method in their subjects. Why do you think a potassium solution injection is lethal?Figure 5.19 If the pH outside the cell decreases, would you expect the amount of amino acids transported into the cell to increase or decrease?Which plasma membrane component can be either found on its surface or embedded in the membrane structure? protein cholesterol carbohydrate phospholipid Which characteristic of a phospholipid contributes to the fluidity of the membrane? its head cholesterol a saturated fatty acid tail double bonds in the fatty acid tail What is the primary function of carbohydrates attached to the exterior of cell membranes? identification of the cell flexibility of the membrane strengthening the membrane channels through membrane A scientist compares the plasma membrane composition of an animal from the Mediterranean coast with one from the Mojave Desert. Which hypothesis is most likely to be correct? The cells from the Mediterranean coast animal will have more fluid plasma membranes The cells from the Mojave Desert animal will have a higher cholesterol concentration in the plasma membranes The cells’ plasma membranes will be indistinguishable The cells from the Mediterranean coast animal will have a higher glycoprotein content, while the cells from the Mojave Desert animal will have a higher lipoprotein content.Water moves via osmosis. throughout the cytoplasm from an area with a high concentration of other solutes to a lower one from an area with a high concentration of water to one of lower concentration from an area with a low concentration of water to higher concentration The principal force driving movement in diffusion is the. temperature particle size concentration gradient membrane surface area What problem is faced by organisms that live in fresh water? Their bodies tend to take in too much water They have no way of controlling their tonicity Only salt water poses problems for animals that live in it Their bodies tend to lose too much water to their environment.In which situation would passive transport not use a transport protein for entry into a cell? water flowing into a hypertonic environment glucose being absorbed from the blood an ion flowing into a nerve cell to create an electrical potential oxygen moving into a cell after oxygen deprivation Active transport must function continuously because. plasma membranes wear out not all membranes are amphiphilic facilitated transport opposes active transport diffusion is constantly moving solutes in opposite directions How does the sodium-potassium pump make the interior of the cell negatively charged? by expelling anions by pulling in anions by expelling more cations than are taken in by taking in and expelling an equal number of cations What is the combination of an electrical gradient and a concentration gradient called? potential gradient electrical potential concentration potential electrochemical gradient What happens to the membrane of a vesicle after exocytosis? It leaves the cell It is disassembled by the cell It fuses with and becomes part of the plasma membrane It is used again in another exocytosis event.Which transport mechanism can bring whole cells into a cell? pinocytosis phagocytosis facilitated transport primary active transport In what important way does receptor-mediated endocytosis differ from phagocytosis? It transports only small amounts of fluid It does not involve the pinching off of membrane It brings in only a specifically targeted substance It brings substances into the cell, while phagocytosis removes substances.Many viruses enter host cells through receptor- mediated endocytosis, What is an advantage of this entry strategy? The virus directly enters the cytoplasm of the cell The virus is protected from recognition by white blood cells The virus only enters its target host cell type The virus can directly inject its genome into the cell’s nucleus.Which of the following organelles relies on exocytosis to complete its function? Golgi apparatus vacuole mitochondria endoplasmic reticulum Imagine a cell can perform exocytosis, but only minimal endocytosis. What would happen to the cell? The cell would secrete all its intracellular proteins The plasma membrane would increase in size over time The cell would stop expressing integral receptor proteins in its plasma membrane The cell would lyse.Why is it advantageous for the cell membrane to be fluid in nature?Why do phospholipids rend to spontaneously orient themselves into something resembling a membrane?How can a cell use an extracellular peripheral protein as the receptor to transmit a signal into the cell?Discuss why the following affect the rate of diffusion: molecular size, temperature, solution density, and the distance that must be traveled Why does water move through a membrane?Both of the regular intravenous solutions administered in medicine, normal saline and lactated Ringer’s solution, are isotonic. Why is this important?Describe two ways that decreasing temperature would affect the rate of diffusion of molecules across a cell’s plasma membrane.A cell develops a mutation in its potassium channels that prevents the ions from leaving the cell If the cell’s aquaporins are still active, what will happen to the cell? Be sure to describe the tonicity and osmolarity of the cell.Where does the cell get energy for active transport processes?How does the sodium-potassium pump contribute to the net negative charge of the interior of the cell?Glucose from digested food enters intestinal epithelial cells by active transport. Why would intestinal cells use active transport when most body cells use facilitated diffusion?The sodium/calcium exchanger (NCX) transports sodium into and calcium out of cardiac muscle cells. Describe why this transporter is classified as secondary active transport.Why is it important that there are different types of proteins in plasma membranes for the transport of materials into and out of a cell?Why do ions have a difficult time getting through plasma membranes despite their small size?Figure 6.8 Look at each of the processes shown, and decide if it is endergonic or exergonic. In each case, does enthalpy increase or decrease, and does entropy increase or decrease?Figure 6.10 If no activation energy were required to break down sucrose (table sugar), would you be able to store it in a sugar bowl?Figure 6.14 The hydrolysis of one ATP molecule releases 7.3 kcal/mol of energy (?G = -7.3 kcal/mol of energy). If it takes 2.1 kcal/mol of energy to move one Na+ across the membrane (?G = +2.1 kcal/mol of energy), how many sodium ions could be moved by the hydrolysis of one ATP molecule?Energy is stored long-term in the bonds of and used short-term to perform work from a(n) ___________ molecule. ATP : glucose an anabolic molecule : catabolic molecule glucose : ATP a catabolic molecule : anabolic molecule DNA replication involves unwinding two strands of parent DNA, copying each strand to synthesize complementary strands, and releasing the parent and daughter DNA. Which of the following accurately describes this process? This is an anabolic process This is a catabolic process This is both anabolic and catabolic This is a metabolic process hut is neither anabolic nor catabolic.Consider a pendulum swinging. Which type(s) of energy is/are associated with the pendulum in the following instances: i. the moment at which it completes one cycle, just before it begins to fall back towards the other end, ii. the moment that it is in the middle between the two ends, and iii. just before it reaches the end of one cycle (just before instant i.). i. potential and kinetic, ii. potential and kinetic, iii. kinetic i. potential, ii. potential and kinetic, iii. potential and kinetic i. potential, ii. kinetic, iii. potential and kinetic i. potential and kinetic, ii. kinetic iii. kinetic Which of the following comparisons or contrasts between endergonic and exergonic reactions is false? Endergonic reactions have a positive ?G and exergonic reactions have a negative ?G Endergonic reactions consume energy and exergonic reactions release energy Both endergonic and exergonic reactions require a small amount of energy to overcome an activation barrier Endergonic reactions take place slowly and exergonic reactions take place quickly.Which of the following is the best way to judge the relative activation energies between two given chemical reactions? Compare the ?G values between the two reactions Compare their reaction rates Compare their ideal environmental conditions Compare the spontaneity between the two reactions.Which of the following is not an example of an energy transformation? turning on a light switch solar panels at work formation of static electricity none of the above In each of the three systems, determine the state of entropy (low or high) when comparing the first and second: i. the instant that a perfume bottle is sprayed compared with 30 seconds later, ii. an old 1950s car compared with a brand new car, and iii. a living cell compared with a dead cell. a. i. low, ii. high, iii. low b. i. low, ii. high, iii. high c. i. high, ii. low, iii. high d. i. high, ii. low, iii. low The energy released by the hydrolysis of ATP is primarily stored between the alpha and beta phosphates equal to -57 kcal/mol harnessed as heat energy by the cell to perform work providing energy to coupled reactions Which of the following molecules is likely to have the most potential energy? sucrose ATP glucose ADP Which of the following is not true about enzymes They increase ?G of reactions They are usually made of amino acids They lower the activation energy of chemical reactions Each one is specific to the particular substrate(s) to which it hinds.An allosteric inhibitor does which of the following? Binds to an enzyme away from the active site and changes the conformation of the active site, increasing its affinity for substrate binding Binds to the active site and blocks it from binding substrate Binds to an enzyme away from the active site and changes the conformation of the active site, decreasing its affinity for the substrate Binds directly to the active site and mimics the substrate.Which of the following analogies best describes the induced-fit model of enzyme-substrate binding? a hug between two people a key fitting into a lock a square peg fitting through the square bole and a round peg fitting through the round hole of a children’s toy the fitting together of two jigsaw puzzle pieces Does physical exercise involve anabolic and/or catabolic processes? Give evidence for your answer.Name two different cellular functions that require energy that parallel human energy-requiring functions.Explain in your own words the difference between a spontaneous reaction and one that occurs instantaneously, and what causes this difference.Describe the position of the transition state on a vertical energy scale, from low to high, relative to the position of the reactants and products, for both endergonic and exergonic reactions.Imagine an elaborate ant farm with tunnels and passageways through the sand where ants live in a large community. Now imagine that an earthquake shook the ground and demolished the ant farm. In which of these two scenarios, before or after the earthquake, was the ant farm system in a state of higher or lower entropy?Energy transfers take place constantly in everyday activities. Think of two scenarios: cooking on a stove and driving. Explain how the second law of thermodynamics applies to these two scenarios.Do you think that the Ea for ATP hydrolysis is relatively low or high? Explain your reasoning.With regard to enzymes, why are vitamins necessary for good health? Give examples.Explain in your own words how enzyme feedback inhibition benefits a cell.Figure 7.11 Dinitrophenol (DNP) is an "uncoupler" that makes the inner mitochondrial membrane "leaky" to protons. It was used until 1938 as a weight-loss drug. What effect would you expect DNP to have on the change in pH across the inner mitochondrial membrane? Why do you think this might be an effective weight-loss drug?Figure 7.12 Cyanide inhibits cytochrome c oxidase, a component of the electron transport chain. If cyanide poisoning occurs, would you expect the pH of the intermembrane space to increase or decrease? What effect would cyanide have on ATP synthesis?(Figure 7.14) Tremetol, a metabolic poison found in the white snake root plant, prevents the metabolism of lactate. When cows eat this plant, tremetol is concentrated in the milk they produce. Humans who consume the milk can become seriously ill. Symptoms of this disease, which include vomiting, abdominal pain, and tremors, become worse after exercise. Why do you think this is the case?The energy currency used by cells is ATP ADP AMP adenosine A reducing chemical reaction. reduces the compound to a simpler form adds an electron to the substrate removes a hydrogen atom from the substrate is a catabolic reaction During the second half of glycolysis, what occurs? ATP is used up Fructose is split in two ATP is made Glucose becomes fructose.What is removed from pyruvate during its conversion into an acetyl group? oxygen ATP B vitamin carbon dioxide What do the electrons added to NAD+ do? They become part of a fermentation pathway They go to another pathway for ATP production They energize the entry of the acetyl group into the citric acid cycle They are converted to NADP.GTP or ATP is produced during the conversion of isocitrate into ketoglutarate succinyl CoA into succinate fumarate into malate malate into oxaloacetate How many NADU molecules are produced on each turn of the citric acid cycle? one two three four What compound receives elections from NADH? FMN ubiquinone cytochrome c1 oxygen Chemiosmosis involves. the movement of electrons across the cell membrane the movement of hydrogen atoms across a mitochondrial membrane the movement of hydrogen ions across a mitochondrial membrane the movement of glucose through the cell membrane Which of the following fermentation methods can occur in animal skeletal muscles? lactic acid fermentation alcohol fermentation mixed acid fermentation propionic fermentation A major connection for sugars in glycolysis is ____ ___________ . glucose-6-phosphate fructose-l,6-bisphosphate dihydroxyacetone phosphate phosphoenolpyruvate Beta-oxidation is. the breakdown of sugars the assembly of sugars the breakdown of fatty acids the removal of amino groups from amino acids The effect of high levels of ADP is to__inv __ cellular respiration. increase the activity of specific enzymes decrease the activity of specific enzymes have no effect on the activity of specific enzymes slow down the pathway The control of which enzyme exerts the most control on glycolysis? hexokinase phosphofructokinase glucose-6-phosphatase aldolase Why is it beneficial for cells to use ATP rather than energy directly from the bonds of carbohydrates? What are the greatest drawbacks to harnessing energy directly from the bonds of several different compounds?Nearly all organisms on Earth carry out some form of glycolysis. How does this fact support or not support the assertion that glycolysis is one of the oldest metabolic pathways?Because they lose their mitochondria during development, red blood cells cannot perform aerobic respiration; however, they do perform glycolysis in the cytoplasm. Why do all cells need an energy source, and what would happen if glycolysis were blocked in a red blood cell?What is the primary difference between a circular pathway and a linear pathway?How do the roles of ubiquinone and cytochrome c differ from the roles of the other components of the electron transport chain?What accounts for the different number of ATP molecules that are formed through cellular respiration?What is the primary difference between fermentation and anaerobic respiration?Would you describe metabolic pathways as inherently wasteful or inherently economical? Why?How does citrate from the citric acid cycle affect glycolysis?Why might negative feedback mechanisms be more common than positive feedback mechanisms in living cells?Figure 8.6 On a hot, dry day, plants close their stomata to conserve water. What impact will this have on photosynthesis?Figure 8.16 What is the source of electrons for the chloroplast electron transport chain? Water Oxygen Carbon dioxide NADPH Figure 8.18 Which of the following statements is true? In photosynthesis, oxygen, carbon dioxide, ATP, and NADPH are reactants. G3P and water are products. In photosynthesis, chlorophyll, water, and carbon dioxide are reactants. G3P and oxygen are products. In photosynthesis, water, carbon dioxide, ATP, and NADPH are reactants. RuBP and oxygen are products. In photosynthesis, water and carbon dioxide are reactants. G3P and oxygen are products.Which of the following components is nor used by both plants and cyanobacteria to carry out photosynthesis? chloroplasts chlorophyll carbon dioxide water What two main products result from photosynthesis? oxygen and carbon dioxide chlorophyll and oxygen sugars/carbohydrates and oxygen sugars/carbohyd rates and carbon dioxide In which compartment of the plant cell do the light- independent reactions of photosynthesis take place? thylakoid stroma outer membrane mesophyll Which statement about thylakoids in eukaryotes is not correct? Thylakoids are assembled into stacks Thylakoids exist as a maze of folded membranes The space surrounding thylakoids is called stroma Thylakoids contain chlorophyll.Predict the end result if a chloroplast’s light-, independent enzymes developed a mutation that prevented them from activating in response to light GA3P accumulation ATP and NAD PH accumulation Water accumulation Carbon dioxide depletion How are the NADPH and GA3P molecules made during photosynthesis similar? They are both end products of photosynthesis They are both substrates for photosynthesis They are both produced from carbon dioxide They both store energy in chemical bonds.Which of the following structures is not a component of a photosystem? ATP synthase antenna molecule reaction center primary electron acceptor How many photons does it take to fully reduce, one molecule of NADP+ to NADPH? 1 2 4 8 Which complex is not involved in the establishment of conditions for ATP synthesis? photosystem I ATP synthase photosystem II cytochrome complex From which component of the light-dependent reactions does NADPH form most directly? photosystem II photosystem I cytochrome complex ATP synthase Three of the same species of plant are each grown under a different colored light for the same amount of time. Plant A is grown under blue light, Plant B is grown under green light, and Plant C is grown under orange light. Assuming the plants use only chlorophyll a and chlorophyll b for photosynthesis, what would be the predicted order of the plants from most growth to least growth? A, C, B A, B, C C, A, B B, A, C Plants containing only chlorophyll b are exposed to radiation with the following wavelengths: 10nm (x- rays), 450nm (blue light), 670nm (red light), and 800nm (infrared light). Which plants harness the most energy for photosynthesis? X-ray irradiated plants Blue light irradiated plants Red light irradiated plants Infrared irradiated plants Which molecule must enter the Calvin cycle continually for the light-independent reactions to take place? RuBisCO RuBP 3-PGA CO2 Which order of molecular conversions is correct for the Calvin cycle? RuBP + G3P 3-PGA sugar RuBisCO CO2 RuBP G3P RuBP + CO2 [RuBisCO] 3-PGA G3P CO2 3-PGA RuBP G3P Where in eukaryotic cells does the Calvin cycle take place? thylakoid membrane thylakoid lumen chloroplast stroma granum Which statement correctly describes carbon fixation? the conversion of CO2 into an organic compound the use of RuBisCO to form 3-PGA the production of carbohydrate molecules from G3P the formation of RuBP from G3P molecules the use of ATP and NADPH to reduce CO2 If four molecules of carbon dioxide enter the Calvin cycle (four “turns” of the cycle), how many G3P molecules are produced and how many are exported? 4 G3P made, 1 G3P exported 4 G3P made, 2 G3P exported 8 G3P made, 1 G3P exported 8 G3P made, 4 G3P exported What is the overall outcome of the light reactions in photosynthesis?Why are carnivores, such as lions, dependent on photosynthesis to survive?Why are energy carriers thought of as either “full1’ or “empty”?Describe how the grey wolf population would be impacted by a volcanic eruption that spewed a dense ash cloud that blocked sunlight in a section of Yellowstone National Park.How does the closing of the stomata limit photosynthesis?Describe the pathway of electi on transfer from photosystem II to photosystem I in light-dependent reactions.What are the roles of ATP and NADPH in photosynthesis?How and why would the end products of photosynthesis be changed if a plant had a mutation that eliminated its photosystem II complex?Why is the third stage of the Calvin cycle called the regeneration stage?Which part of the light-independent reactions would be affected if a cell could not produce the enzyme RuBisCO?Why does it take three turns of the Calvin cycle to produce G3P, the initial product of photosynthesis?Imagine a sealed terrarium containing a plant and a beetle. How does each organism provide resources for the other? Could each organism survive if it was, the only living thing in the terrarium? Why or why not?Compare the flow of energy with the flow of, nutrients in a closed, sunny ecosystem consisting of a giraffe and a tree.Figure 9.8 HER2 is a receptor tyrosine kinase. In 30 percent of human breast cancers, HER2 is permanently activated, resulting in unregulated cell division. Lapatinib, a drug used to treat breast cancer, inhibits HER2 receptor tyrosine kinase autophosphorylation (the process by which the receptor adds phosphates onto itself), thus reducing tumor growth by 50 percent. Besides autophosphorylation, which of the following steps would be inhibited by Lapatinib? Signaling molecule binding, dimerization, and the downstream cellular response. Dimerization, and the downstream cellular response. The downstream cellular response. Phosphatase activity, dimerization, and the downsteam cellular response.Figure 9.10 In certain cancers, the GTPase activity of the RAS G-protein is inhibited. This means that the RAS protein can no longer hydrolyze GTP into GDP What effect would this have on downstream cellular events?Figure 9.17 Which of the following statements about quorum sensing is false? Autoinducer must bind to receptor to turn on transcription of genes responsible for the production of more autoinducer. The receptor stays in the bacterial cell but the autoinducer diffuses out. Autoinducer can only act on a different cell: it cannot act on the cell in which it is made. Autoinducer turns on genes that enable the bacteria to form a biofilm.Figure 9.18 What advantage might biofilm production confer on the S. aureus inside the What property prevents the ligands of cell-surface receptors from entering the cell? The molecules bind to the extracellular domain. The molecules are hydrophilic and cannot penetrate the hydrophobic inferior of the plasma membrane. The molecules are attached to transport proteins that deliver them through the bloodstream to target cells. The ligands are able to penetrate the membrane and directly influence gene expression upon receptor binding.The secretion of hormones by the pituitary gland is an example of.____ autocrine signaling paracrine signaling endocrine signaling direct signaling across gap junctions Why are ion channels necessary to transport ions into or out of a cell? Ions are too large to diffuse through the membrane. Ions are charged particles and cannot diffuse through the hydrophobic interior of the membrane. Ions do not need ion channels to move through the membrane. Ions bind to carrier proteins in the bloodstream, which must be removed before transport into the cell.Endocrine signals are transmitted more slowly than paracrine signals because.___ the ligands are transported through the bloodstream and travel greater distances the target and signaling cells are close together the ligands are degraded rapidly the ligands don't bind to carrier proteins during transport A scientist notices that when she adds a small, water-soluble molecule to a dish of cells, the cells turn off transcription of a gene. She hypothesizes that the ligand she added binds to a(n)____receptor. Intracellular Hormone Enzyme-linked Gated ion channel-linked Where do DAG and IP3 originate? They are formed by phosphorylation of cAMP.' They are ligands expressed by signaling cells. They are hormones that diffuse through the plasma membrane to stimulate protein production. They are the cleavage products of the inositol phospholipid, PIP2.What property enables the residues of the amino acids serine, threonine, and tyrosine to be phosphorylated? They are polar. They are non-polar. They contain a hydroxyl group. They occur more frequently in the amino acid sequence of signaling proteins.Histamine binds to the H1 G-protein-linked receptor to initiate the itchiness and airway constriction associated with an allergic response. If a mutation in the associated G-protein’s alpha subunit prevented the hydrolysis of GTP how would the allergic response change? More severe allergic response compared to normal G-protein signaling. Less severe allergic response compared to normal G-protein signaling. No allergic response. No change compared to normal G-protein signaling.A scientist observes a mutation in the transmembrane region of EGFR that eliminates its ability to be stabilized by binding interactions during dimerization after ligand binding. Which hypothesis regarding the effect of this mutation on EGF signaling is most likely to be correct? EGF signaling cascades would be active for longer in the cell. EGF signaling cascades would be active for a shorter period of time in the cell. EGF signaling cascades would not occur. EGF signaling would be unaffected.What is the function of a phosphatase? A phosphatase removes phosphorylated amino acids from proteins. A phosphatase removes the phosphate group from phosphorylated amino acid residues in a protein. A phosphatase phosphorylates serine, threonine, and tyrosine residues. A phosphatase degrades second messengers in the cell.How does NF-kB induce gene expression? A small, hydrophobic ligand binds to NF-kB, activating it. Phosphorylation of the inhibitor Ik-B dissociates the complex between it and NF- kB, and allows NF-kB to enter the nucleus and stimulate transcription. NF-kB is phosphorylated and is then free to enter the nucleus and bind DNA. NF-kB is a kinase that phosphorylates a transcription factor that binds DNA and promotes protein production.Apoptosis can occur in a cell when the cell is damaged no longer needed infected by a virus all of the above What is the effect of an inhibitor binding an enzyme? The enzyme is degraded. The enzyme is activated. The enzyme is inactivated. The complex is transported out of the cell How does PKC’s signaling role change in response to growth factor signaling versus an immune response? PKC interacts directly with signaling molecules in both cascades, but only exhibits kinase activity during growth factor signaling. PKC interacts directly with signaling molecules in growth factor cascades, but interacts with signaling inhibitors during immune signaling. PKC amplifies growth factor cascades, but turns off immune cascades. PKC is activated during growth factor cascades, but is inactivated during immune response cascades.A scientist notices that a cancer cell line fails to die when he adds an inducer of apoptosis to his culture of cells. Which hypothesis could explain why the cells fail to die? The cells have a mutation that prevents the initiation of apoptosis signaling. The cells have lost expression of the receptor for the apoptosis-inducing ligand. The cells overexpress a growth factor pathway that inhibits apoptosis. All of the above.Which type of molecule acts as a signaling molecule in yeasts? steroid autoinducer mating factor second messenger Quorum sensing is triggered to begin when treatment with antibiotics occurs bacteria release growth hormones bacterial protein expression is switched on a sufficient number of bacteria are present A doctor is researching new ways to treat biofilms on artificial joints. Which approach would best help prevent bacterial colonization of the medical implants? Increase antibiotic dosing Create implants with rougher surfaces Vaccinate patients against all pathogenic bacteria Inhibit quorum sensing What is the difference between intracellular signaling and intercellular signaling?How are the effects of paracrine signaling limited to an area near the signaling cells?What are the differences between internal receptors and cell-surface receptors?Cells grown in the laboratory are mixed with a dye molecule that is unable to pass through the plasma membrane. If a ligand is added to the cells, observations show that the dye enters the cells. What type of receptor did the ligand bind to on the cell surface?Insulin is a hormone that regulates blood sugar by binding to its receptor, insulin receptor tyrosine kinase. How does insulin's behavior differ from steroid hormone signaling, and what can you infer about its structure?The same second messengers are used in many different cells, but the response to second messengers is different in each cell. How is this possible?What would happen if the intracellular domain of a cell-surface receptor was switched with the domain from another receptor?If a cell developed a mutation in its MAP2K1 gene (encodes the MEK protein) that prevented MIEK from being recognized by phosphatases, how would the EGFR signaling cascade and the cell’s behavior change?What is a possible result of a mutation in a kinase that controls a pathway that stimulates cell growth?How does the extracellular matrix control the growth of cells?A scientist notices that a cancer cell line shows high levels of phosphorylated ERK in the absence of EGF. What are two possible explanations for the increase in phosphorylated ERK? Be specific in which proteins are involved.What characteristics make yeasts a good model for learning about signaling in humans?Why is signaling in multicellular organisms more complicated than signaling in single-celled organisms?Pseudomonas infections are very common in hospital settings. Why would it be important for doctors to determine the bacterial load before treating an infected patient?Figure 10.6 Which of the following is the correct order of events in mitosis? Sister chromatids line up at the metaphase plate. The kinetochore becomes attached to the mitotic spindle. The nucleus reforms and the cell divides. Cohesin proteins break down and the sister chromatids separate. The kinetochore becomes attached to the mitotic spindle. Cohesin proteins break down and the sister chromatids separate. Sister chromatids line up at the metaphase plate. The nucleus reforms and the cell divides. The kinetochore becomes attached to the cohesin proteins. Sister chromatids line up at the metaphase plate. The kinetochore breaks down and the sister chromatids separate. The nucleus reforms and the cell divides. The kinetochore becomes attached to the mitotic spindle. Sister chromatids line up at the metaphase plate. Cohesin proteins break down and the sister chromatids separate. The nucleus reforms and the cell divides.Figure 10.13 Rb and other proteins that negatively regulate the cell cycle are sometimes called tumor suppressors. Why do you think the name tumor suppressor might be appropriate for these proteins?Figure 10.14 Human papillomavirus can cause cervical cancer. The virus encodes E6, a protein that binds p53. Based on this fact and what you know about p53, what effect do you think E6 binding has on p53 activity? E6 activates p53 E6 inactivates p53 E6 mutates p53 E6 binding marks p53 for degradation A diploid cell has ________ the number of chromosomes as a haploid cell. one-fourth half twice four times An organism s traits are determined by the specific combination of inherited. cells. genes. proteins. chromatids.The first level of DNA organization in a eukaryotic cell is maintained by which molecule? cohesin condensin chromatin histone Identical copies of chromatin held together by cohesin at the centromere are called.______ histones nucleosomes chromatin sister chromatids.S. Chromosomes are duplicated during what stage of the cell cycle? G1 phase S phase prophase prometaphase Which of the following events does not occur during some stages of interphase? DNA duplication organelle duplication increase in cell size separation of sister chromatids The mitotic spindles arise from which cell structure? centromere centroscme kinetochore cleavage furrow Attachment of the mitotic spindle fibers to the kinetochores is a characteristic of which stage of mitosis? prophase prometaphase metaphase anaphase Unpacking of chromosomes and the formation of a new nuclear envelope is a characteristic of which stage of mitosis? prometaphase metaphase anaphase telophase Separation of the sister chromatids is a characteristic of which stage of mitosis? prometaphase metaphase anaphase telophase The chromosomes become visible under a light microscope during which stage of mitosis? prophase prometaphase metaphase anaphase The fusing of Golgi vesicles at the metaplhase plate of dividing plant cells forms what structure? cell plate actin ring cleavage furrow mitotic spindle At which of the cell-cycle checkpoints do external forces have the greatest influence? G1 checkpoint G2 checkpoint M checkpoint G0 checkpoint What is the main prerequisite for clearance at the G2 checkpoint? cell has reached a sufficient size an adequate stockpile of nucleotides accurate and complete DNA replication proper attachment of mitotic spindle fibers to kinetochores If the M checkpoint is not cleared, what stage of mitosis will be blocked? prophase prometaphase metaphase anaphase Which protein is a positive regulator that phosphorylates other proteins when activated? p53 retinoblastoma protein (Rb) cyclin cyclin-dependent kinase (Cdk)Many of the negative regulator proteins of the cell cycle were discovered in what type of cells? gametes cells in G0 cancer cells stem cells Which negative regulatory molecule can trigger cell suicide (apoptosis) if vital cell cycle events do not occur? p53 p21 retinoblastoma protein (Rb) cyclin-dependent kinase (Cdk)are changes to the order of nucleotides in a segment of DNA that codes for a protein. Proto-oncogenes Tumor suppressor genes Gene mutations Negative regulators A gene that codes for a positive cell-cycle regulator is called a(n).______ kinase inhibitor tumor suppressor gene proto-oncogene oncogene.A mutated gene that codes for an altered version of Cdk that is active in the absence of cyclin is a(n) ___________ . kinase inhibitor tumor suppressor gene proto-oncogene oncogene.Which molecule is a Cdk inhibitor that is controlled by p53? cyclin anti-kinase Rb p21 Which eukaryotic cell-cycle event is missing in binary fission? cell growth DNA duplication karyokinesis cytokinesis

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