Quiz 5: How Cells Work

The energy required for life processes must be extracted from an organism's A) nucleus. B) environment. C) predators. D) biosynthesis.

The illustration below indicates that photosynthesis and cellular respiration are both complementary and balanced.An excess of sugars produced fossil fuels like coal and petroleum; this suggests that in the past, A) the amount of photosynthesis occurring exceeded the amount of cellular respiration. B) sugars were only one of several products of photosynthesis. C) reduced carbon-rich molecules could be produced independently from the photosynthetic process. D) the energy release from respiration must have exceeded energy use in photosynthesis.

What is the importance of photosynthesis to organisms other than plants? A) All other organisms require carbon dioxide for life processes. B) The sugars made during photosynthesis are building blocks of DNA. C) All cells must have chloroplasts in order to survive. D) Photosynthesis captures energy that other organisms access when they eat either plants or organisms that eat plants.

Photosynthetic organisms capture energy from sunlight and convert it into chemical bonds by forming A) sugars. B) enzymes. C) work. D) substrates.

Photosynthesis and cellular respiration are both complementary and relatively balanced,but early history of life on Earth showed increasing oxygen concentrations.This indicates that A) both photosynthesis and respiration were occurring at approximately the same levels. B) neither photosynthesis nor respiration were occurring. C) the amount of photosynthesis occurring exceeded the amount of cellular respiration. D) the amount of cellular respiration occurring exceeded the amount of photosynthesis.

Each time a person takes a breath,he or she is bringing in the oxygen he or she needs to stay alive.The ultimate source of the oxygen used by all aerobic organisms comes from a reaction that breaks down A) carbon dioxide. B) ATP. C) water. D) NADPH.

What would be the initial outcome of decreasing the number of photosynthetic organisms on Earth with no change in the number of organisms using cellular respiration? A) Oxygen levels would increase. B) Carbon dioxide levels would increase. C) More glucose would be available to animals. D) Animals would access energy directly from sunlight.

What type of reactions release energy by breaking down complex molecules? A) catabolic B) anabolic C) photosynthetic D) dehydration synthesis

A chemical reaction that uses ATP to build cellular components is A) catabolic. B) anabolic. C) photosynthetic. D) respiration.

The capture and use of energy by living organisms involves numerous chemical reactions.Collectively these processes are known as A) metabolism. B) respiration. C) anabolic reactions. D) catabolic reactions.

Chemical reactions that break down lipids are A) catabolic. B) anabolic. C) metabolic. D) respiration.

Some kinds of drain cleaners use enzymes rather than strong,more dangerous chemicals.These enzymes must be able to A) catalyze a catabolic reaction. B) raise the energy of the reaction that clears the clog. C) create energy that can be used to break up the clog. D) catalyze an anabolic reaction.

Plants and animals use different energy storage molecules,yet they both use the same mechanism to "burn" their stored energy.How can plants and animals both be successful,even though they "burn" different energy storage molecules? A) The internal components of plant and animal cells are identical. B) The first law of thermodynamics says that all cells have the same energy transfer system. C) The breaking of the chemical bonds of a storage molecule transfers energy,no matter what molecule is stored. D) All organisms have the same enzymes to catalyze their energy-producing reactions.

A worker is paid every two weeks.She uses some of this money to pay for essentials and puts the remainder of her money in a savings account at a bank.The money the worker saves is analogous to the A) conversion of ADP and phosphate into ATP. B) conversion of ATP into ADP and phosphate. C) way electrons are used to pump protons across a membrane. D) way enzymes catalyze chemical reactions in a cell.

Which of these molecules carries the most energy? A) ADP B) ATP C) NADH D) NAD

Which of the following is either consumed or synthesized in virtually every cellular reaction? A) sugars B) enzymes C) DNA D) ATP

When ATP breaks down into ADP and a phosphate group, A) energy is absorbed by ADP and transferred to enzymes. B) energy is released and can power cellular activities. C) ADP becomes the active site in an enzyme. D) the energy in the broken bond is transferred to the phosphate group.

As an energy carrier,ATP differs from NADPH in that A) ATP transfers energy through phosphorylation,whereas NADPH donates electrons and hydrogen ions. B) ATP transfers energy through redox reactions,whereas NADPH uses phosphorylation. C) NADPH is involved in a larger variety of chemical reactions than ATP. D) NADPH is made by photosystem I,whereas ATP is made by photosystem II.

Cells contain the molecule GTP (guanosine triphosphate).Would this molecule be useful as an energy carrier (similar to ATP)? A) No,because it does not contain the adenosine necessary for storing energy. B) No,because it contains fewer phosphates than ATP. C) Yes,because it contains a nitrogenous base just like ATP. D) Yes,because it contains the same number of phosphates as does ATP.

The first law of thermodynamics states that A) metabolic reactions must be balanced. B) the flow of energy connects living things to their environments. C) energy cannot be created nor destroyed. D) systems tend to become more disorderly.

Which of the following events in a cell would require ATP? A) passive movement of molecules through the cell membrane B) linking together amino acids to form a protein C) breaking a carbohydrate into individual sugar subunits D) splitting a lipid molecule into smaller parts

In a human cell, A) one enzyme usually catalyzes more than five different chemical reactions. B) nearly all chemical reactions are catalyzed by enzymes. C) enzymes must be constantly replaced as they are used up in the reactions that they catalyze. D) some enzymes are specialized to store energy in the form of electrons.

Enzymes can catalyze a reaction only if they A) encounter a molecule of ATP. B) have a phosphate bound to their active site. C) have both products in their active site at the same time. D) encounter a substrate that fits their active site.

A given enzyme A) can be used for many different kinds of chemical reactions. B) is permanently changed during a chemical reaction. C) has a special site where the products bind before the reaction begins. D) increases the rate of a particular reaction.

In the reaction C₆H₁₂O₆  6 O₂  6 CO₂  6 H₂O,the 6 CO₂ molecules are examples of A) substrates. B) products. C) enzymes. D) reactants.

In many organelles,groups of different enzymes are located on membranes in close proximity to each other because A) attaching enzymes to the membrane prevents the cell from losing them to the surrounding environment. B) when enzymes are in close proximity,each one can catalyze more than one type of reaction. C) these enzymes are involved in the same metabolic pathway,and keeping them closer together increases the efficiency of the pathway. D) all enzymes must act in groups to position substrates in the proper orientation to produce the product.

The image below diagrams the action of an enzyme.Notice that the enzyme is depicted as being more tightly wrapped around the substrates in step 2 than it is in step 1.Why is this? A) When a substrate locks into the active site of an enzyme,the enzyme changes shape to mold itself around the substrates. B) Generally,the size of a substrate is larger than the size of the active site into which it must fit.When the substrate enters the active site,the active site must stretch to fit. C) Before catalysis can occur,a substrate must change its shape so that it fits into the active site of the enzyme more precisely. D) Most active sites are only designed to hold one substrate.In this image,two substrates enter the active site,creating a tighter fit.

In the reaction H₂O  CO₂  carbonic anhydrase  H^  HCO₃^ carbonic anhydrase,carbonic anhydrase is a(n) A) reactant. B) product. C) enzyme. D) active site.

After an enzyme catalyzes a reaction there is a(n)________ in the concentration of ________. A) increase; reactants B) increase; the enzyme C) decrease; the enzyme D) increase; products

The enzyme rubisco is important to the process of A) catabolism. B) fermentation. C) glycolysis. D) carbon fixation.

The events of the Calvin cycle A) use ATP and NADPH to produce sugars. B) move electrons from photosystem II to photosystem I. C) move light-energized electrons to photosystem II. D) absorb light from the light reactions.

The role of water in photosynthesis is to A) provide a phosphate group to ATP. B) capture light energy and transfer it to the electron transport chain. C) provide electrons to the chlorophyll. D) combine with carbon dioxide (CO₂)to make glucose.

Which of the following statements describe the function of the light reaction in photosynthesis? A) As electrons move through the light reaction,they release energy that is used to concentrate protons in the thylakoid. B) As electrons move through the light reaction,they catalyze the formation of ATP. C) The light reaction releases CO₂ from glucose. D) The light reaction captures and stores the electrons given off by NADPH.

In photosynthesis,the carbon used to make sugars is A) provided by enzymes. B) provided by carbon dioxide. C) extracted from DNA. D) oxidized to make sugars.

The chemical 3-(3,4-dichloro-phenyl)-1,1-dimethylurea (DCMU)blocks the movement of electrons at the point indicated by the black,downward-pointing arrow in the figure below.Which of the following would be an immediate effect of treating a chloroplast with this drug? A) Water molecules would be split at a faster rate. B) The amount of NADPH produced by the light reactions would increase. C) A proton gradient would not be created,so ATP could not be made. D) The production of water would increase.

Examine the illustration below.Which statement best summarizes the contribution of photosystem I (PS I)during photosynthesis? A) PS I provides the initial energy boost to the electrons on their way to photosystem II (PS II). B) PS I energizes electrons that initially accumulate within the thylakoid space and eventually drive ATP synthesis. C) PS I energizes electrons that are transported by NADPH to the Calvin cycle and will eventually reduce the carbon in CO₂. D) PS I regulates the transmembrane passage of protons through the thylakoid membrane.

Which of the following is a product of the light reactions of photosynthesis? A) water B) carbon dioxide C) oxygen D) glucose

The three stages of cellular respiration (in order)are A) photosynthesis,glycolysis,and oxidative phosphorylation. B) glycolysis,the Krebs cycle,and oxidative phosphorylation. C) glycolysis,fermentation,and the Krebs cycle. D) photosynthesis,the Krebs cycle,and fermentation.

Glycolysis is an anaerobic process,indicating that the glycolytic reactions A) require no oxygen. B) produce molecular oxygen. C) produce ATP. D) produce citric acid.

The Krebs cycle produces A) NADH,ATP,and FADH₂. B) water and carbon dioxide. C) ADP and NADP. D) acetyl CoA and sugars.

Which step of cellular respiration occurs outside the mitochondria? A) glycolysis B) Krebs cycle C) Calvin cycle D) electron transport chain

Which of the following molecules carries electrons to the electron transport chain of oxidative phosphorylation? A) ATP B) NADH C) CO₂ D) ADP

If the mitochondria of a cell did not produce an inner membrane,the mitochondria would be unable to A) maintain the proton gradient required for ATP production. B) capture ATP from the sun. C) perform the Krebs cycle. D) perform glycolysis.

During exercise,the increase in respiration rate and heart rate are driven by the need to replenish the oxygen used to support A) lactic acid fermentation. B) carbon dioxide synthesis in the lungs. C) oxidative phosphorylation in muscle cell mitochondria. D) the Calvin cycle of photosynthesis.

The Krebs cycle functions to A) accept electrons and hydrogen ions from energy carriers. B) transform carbon from carbon dioxide into sugar. C) use energy from sunlight to split water molecules. D) transfer chemical energy from pyruvate to energy carriers.

Which of the following statements comparing photosynthesis and cellular respiration is accurate? A) Photosynthesis is a catabolic pathway,whereas cellular respiration is an anabolic pathway. B) Water is formed during photosynthesis but broken apart during cellular respiration. C) Both photosynthesis and cellular respiration require electron transport chains. D) Both photosynthesis and cellular respiration produce CO₂ as metabolic end products.

A plant cell is mutated so ATP synthase no longer functions.Which process will be affected? A) photosynthesis only B) respiration only C) both photosynthesis and respiration D) neither photosynthesis nor respiration

The energy carriers NADPH and NADH differ structurally.Functionally they are A) quite similar; each is produced in catabolic pathways and is used in anabolic pathways. B) quite similar; each is produced in anabolic pathways and is used in catabolic pathways. C) somewhat different; NADPH is produced from catabolic processes,whereas NADH is used in anabolic processes. D) somewhat different; NADH is produced from catabolic processes,whereas NADPH is used in anabolic processes.

The reaction sugar  oxygen  carbon dioxide  water  ATP is part of A) photosynthesis. B) cellular respiration. C) the Krebs cycle. D) the Calvin cycle.

Which of the following is a similarity between photosynthesis and respiration? A) Neither is a metabolic process. B) They are both metabolic processes. C) Neither is an anabolic process. D) They are both mainly anabolic processes.

Carbon dioxide is one product of a metabolic process,which occurs in both plants and animals.This process is called A) catalysis. B) glycolysis. C) respiration. D) photosynthesis.

Photosynthesis and cellular respiration cycle the element ________ through the environment.When a plant does photosynthesis,it takes this element from the air and produces sugars.When animals conduct cellular respiration,they break down sugars and exhale a gas that contains this element.

Humans store sugars in the form of glycogen.Glycogen is made by linking many glucose molecules together.This process is ________.

A protein in the cell membrane is used to transport molecules against their concentration gradient by active transport.________ is required for this type of transport.

The ________ of an enzyme is an area with a specialized shape and set of chemical properties that allows the enzyme to bind with a particular substrate.

A cell is found that uses sunlight to produce ATP,but it does not produce NADPH.The portion of the light reaction that is not functioning is ________.

The step of cellular respiration that produces a product that will also be used in the Calvin cycle is the ________.

A new bacterial cell is found that is able to grow without food as long as sunlight is available.This cell likely uses ________ to produce its own food.

Two students are debating whether switching energy production from fossil fuels to traditional biomass would reduce carbon dioxide emissions.Explain the role of photosynthesis in storing carbon dioxide in these two energy sources.What is the total energy consumption shown for these two energy sources?

Compare the energy sources shown below that rely on photosynthesis with the energy sources that do not rely directly on photosynthesis.

Defend the following statement by discussing the importance of the products of photosynthesis: "The evolution of photosynthesis was an essential event for the evolution of life as we know it."

Support or refute the following statement: "Cells would not be able to survive unless anabolic and catabolic processes occurred in linked reactions."

Is the burning of wood most representative of anabolism or catabolism? Defend your answer.

A hypothetical chemical forms a permanent bond between the phosphates in ATP.How would this affect the cell?

List the energy carriers in a cell.Which of the energy carriers carries the most energy?

The sequential reaction pathway A  B  C  D is dependent on enzymes for each separate step.The enzyme that has "C" as a substrate becomes nonfunctional.Explain how this affects the metabolic pathway shown.

Explain how an increase in body temperature may affect the activity of enzymes with human cells.

A mutation in a plant cell produces rubisco enzymes,which can only bind O₂ (and not CO₂).What would be the outcome of this mutation?

What products are produced by the light reactions of photosynthesis? Of these products,which are by-products that are released to the atmosphere? Which products are used within the Calvin cycle?

Two students are discussing the importance of glycolysis in human cells.One student states that the main function of glycolysis is to produce ATP.The other states that the main function is to produce NADH.Which student is correct?

List the three stages of cellular respiration.If the mitochondria in a eukaryotic cell are damaged,which of the three stages of cellular respiration would be impacted?

Excess carbon dioxide in the atmosphere is increasing climate change.How do photosynthesis and cellular respiration relate to this issue,and how can we use this knowledge to help decrease this problem?

Photosynthesis and cellular respiration are linked metabolic processes in the sense that the products of one feed into the other.What are the products of each metabolic process that feed into the other?