Skip to ContentGo to accessibility pageKeyboard shortcuts menu
OpenStax Logo
Biology for AP® Courses

Critical Thinking Questions

Biology for AP® CoursesCritical Thinking Questions
Menu
Table of contents
  1. Preface
  2. The Chemistry of Life
    1. 1 The Study of Life
      1. Introduction
      2. 1.1 The Science of Biology
      3. 1.2 Themes and Concepts of Biology
      4. Key Terms
      5. Chapter Summary
      6. Review Questions
      7. Critical Thinking Questions
      8. Test Prep for AP® Courses
    2. 2 The Chemical Foundation of Life
      1. Introduction
      2. 2.1 Atoms, Isotopes, Ions, and Molecules: The Building Blocks
      3. 2.2 Water
      4. 2.3 Carbon
      5. Key Terms
      6. Chapter Summary
      7. Review Questions
      8. Critical Thinking Questions
      9. Test Prep for AP® Courses
      10. Science Practice Challenge Questions
    3. 3 Biological Macromolecules
      1. Introduction
      2. 3.1 Synthesis of Biological Macromolecules
      3. 3.2 Carbohydrates
      4. 3.3 Lipids
      5. 3.4 Proteins
      6. 3.5 Nucleic Acids
      7. Key Terms
      8. Chapter Summary
      9. Review Questions
      10. Critical Thinking Questions
      11. Test Prep for AP® Courses
      12. Science Practice Challenge Questions
  3. The Cell
    1. 4 Cell Structure
      1. Introduction
      2. 4.1 Studying Cells
      3. 4.2 Prokaryotic Cells
      4. 4.3 Eukaryotic Cells
      5. 4.4 The Endomembrane System and Proteins
      6. 4.5 Cytoskeleton
      7. 4.6 Connections between Cells and Cellular Activities
      8. Key Terms
      9. Chapter Summary
      10. Review Questions
      11. Critical Thinking Questions
      12. Test Prep for AP® Courses
      13. Science Practice Challenge Questions
    2. 5 Structure and Function of Plasma Membranes
      1. Introduction
      2. 5.1 Components and Structure
      3. 5.2 Passive Transport
      4. 5.3 Active Transport
      5. 5.4 Bulk Transport
      6. Key Terms
      7. Chapter Summary
      8. Review Questions
      9. Critical Thinking Questions
      10. Test Prep for AP® Courses
      11. Science Practice Challenge Questions
    3. 6 Metabolism
      1. Introduction
      2. 6.1 Energy and Metabolism
      3. 6.2 Potential, Kinetic, Free, and Activation Energy
      4. 6.3 The Laws of Thermodynamics
      5. 6.4 ATP: Adenosine Triphosphate
      6. 6.5 Enzymes
      7. Key Terms
      8. Chapter Summary
      9. Review Questions
      10. Critical Thinking Questions
      11. Test Prep for AP® Courses
      12. Science Practice Challenge Questions
    4. 7 Cellular Respiration
      1. Introduction
      2. 7.1 Energy in Living Systems
      3. 7.2 Glycolysis
      4. 7.3 Oxidation of Pyruvate and the Citric Acid Cycle
      5. 7.4 Oxidative Phosphorylation
      6. 7.5 Metabolism without Oxygen
      7. 7.6 Connections of Carbohydrate, Protein, and Lipid Metabolic Pathways
      8. 7.7 Regulation of Cellular Respiration
      9. Key Terms
      10. Chapter Summary
      11. Review Questions
      12. Critical Thinking Questions
      13. Test Prep for AP® Courses
      14. Science Practice Challenge Questions
    5. 8 Photosynthesis
      1. Introduction
      2. 8.1 Overview of Photosynthesis
      3. 8.2 The Light-Dependent Reaction of Photosynthesis
      4. 8.3 Using Light to Make Organic Molecules
      5. Key Terms
      6. Chapter Summary
      7. Review Questions
      8. Critical Thinking Questions
      9. Test Prep for AP® Courses
      10. Science Practice Challenge Questions
    6. 9 Cell Communication
      1. Introduction
      2. 9.1 Signaling Molecules and Cellular Receptors
      3. 9.2 Propagation of the Signal
      4. 9.3 Response to the Signal
      5. 9.4 Signaling in Single-Celled Organisms
      6. Key Terms
      7. Chapter Summary
      8. Review Questions
      9. Critical Thinking Questions
      10. Test Prep for AP® Courses
      11. Science Practice Challenge Questions
    7. 10 Cell Reproduction
      1. Introduction
      2. 10.1 Cell Division
      3. 10.2 The Cell Cycle
      4. 10.3 Control of the Cell Cycle
      5. 10.4 Cancer and the Cell Cycle
      6. 10.5 Prokaryotic Cell Division
      7. Key Terms
      8. Chapter Summary
      9. Review Questions
      10. Critical Thinking Questions
      11. Test Prep for AP® Courses
      12. Science Practice Challenge Questions
  4. Genetics
    1. 11 Meiosis and Sexual Reproduction
      1. Introduction
      2. 11.1 The Process of Meiosis
      3. 11.2 Sexual Reproduction
      4. Key Terms
      5. Chapter Summary
      6. Review Questions
      7. Critical Thinking Questions
      8. Test Prep for AP® Courses
      9. Science Practice Challenge Questions
    2. 12 Mendel's Experiments and Heredity
      1. Introduction
      2. 12.1 Mendel’s Experiments and the Laws of Probability
      3. 12.2 Characteristics and Traits
      4. 12.3 Laws of Inheritance
      5. Key Terms
      6. Chapter Summary
      7. Review Questions
      8. Critical Thinking Questions
      9. Test Prep for AP® Courses
      10. Science Practice Challenge Questions
    3. 13 Modern Understandings of Inheritance
      1. Introduction
      2. 13.1 Chromosomal Theory and Genetic Linkages
      3. 13.2 Chromosomal Basis of Inherited Disorders
      4. Key Terms
      5. Chapter Summary
      6. Review Questions
      7. Critical Thinking Questions
      8. Test Prep for AP® Courses
      9. Science Practice Challenge Questions
    4. 14 DNA Structure and Function
      1. Introduction
      2. 14.1 Historical Basis of Modern Understanding
      3. 14.2 DNA Structure and Sequencing
      4. 14.3 Basics of DNA Replication
      5. 14.4 DNA Replication in Prokaryotes
      6. 14.5 DNA Replication in Eukaryotes
      7. 14.6 DNA Repair
      8. Key Terms
      9. Chapter Summary
      10. Review Questions
      11. Critical Thinking Questions
      12. Test Prep for AP® Courses
      13. Science Practice Challenge Questions
    5. 15 Genes and Proteins
      1. Introduction
      2. 15.1 The Genetic Code
      3. 15.2 Prokaryotic Transcription
      4. 15.3 Eukaryotic Transcription
      5. 15.4 RNA Processing in Eukaryotes
      6. 15.5 Ribosomes and Protein Synthesis
      7. Key Terms
      8. Chapter Summary
      9. Review Questions
      10. Critical Thinking Questions
      11. Test Prep for AP® Courses
      12. Science Practice Challenge Questions
    6. 16 Gene Regulation
      1. Introduction
      2. 16.1 Regulation of Gene Expression
      3. 16.2 Prokaryotic Gene Regulation
      4. 16.3 Eukaryotic Epigenetic Gene Regulation
      5. 16.4 Eukaryotic Transcriptional Gene Regulation
      6. 16.5 Eukaryotic Post-transcriptional Gene Regulation
      7. 16.6 Eukaryotic Translational and Post-translational Gene Regulation
      8. 16.7 Cancer and Gene Regulation
      9. Key Terms
      10. Chapter Summary
      11. Review Questions
      12. Critical Thinking Questions
      13. Test Prep for AP® Courses
      14. Science Practice Challenge Questions
    7. 17 Biotechnology and Genomics
      1. Introduction
      2. 17.1 Biotechnology
      3. 17.2 Mapping Genomes
      4. 17.3 Whole-Genome Sequencing
      5. 17.4 Applying Genomics
      6. 17.5 Genomics and Proteomics
      7. Key Terms
      8. Chapter Summary
      9. Review Questions
      10. Critical Thinking Questions
      11. Test Prep for AP® Courses
      12. Science Practice Challenge Questions
  5. Evolutionary Processes
    1. 18 Evolution and Origin of Species
      1. Introduction
      2. 18.1 Understanding Evolution
      3. 18.2 Formation of New Species
      4. 18.3 Reconnection and Rates of Speciation
      5. Key Terms
      6. Chapter Summary
      7. Review Questions
      8. Critical Thinking Questions
      9. Test Prep for AP® Courses
      10. Science Practice Challenge Questions
    2. 19 The Evolution of Populations
      1. Introduction
      2. 19.1 Population Evolution
      3. 19.2 Population Genetics
      4. 19.3 Adaptive Evolution
      5. Key Terms
      6. Chapter Summary
      7. Review Questions
      8. Critical Thinking Questions
      9. Test Prep for AP® Courses
      10. Science Practice Challenge Questions
    3. 20 Phylogenies and the History of Life
      1. Introduction
      2. 20.1 Organizing Life on Earth
      3. 20.2 Determining Evolutionary Relationships
      4. 20.3 Perspectives on the Phylogenetic Tree
      5. Key Terms
      6. Chapter Summary
      7. Review Questions
      8. Critical Thinking Questions
      9. Test Prep for AP® Courses
      10. Science Practice Challenge Questions
  6. Biological Diversity
    1. 21 Viruses
      1. Introduction
      2. 21.1 Viral Evolution, Morphology, and Classification
      3. 21.2 Virus Infection and Hosts
      4. 21.3 Prevention and Treatment of Viral Infections
      5. 21.4 Other Acellular Entities: Prions and Viroids
      6. Key Terms
      7. Chapter Summary
      8. Review Questions
      9. Critical Thinking Questions
      10. Test Prep for AP® Courses
      11. Science Practice Challenge Questions
    2. 22 Prokaryotes: Bacteria and Archaea
      1. Introduction
      2. 22.1 Prokaryotic Diversity
      3. 22.2 Structure of Prokaryotes
      4. 22.3 Prokaryotic Metabolism
      5. 22.4 Bacterial Diseases in Humans
      6. 22.5 Beneficial Prokaryotes
      7. Key Terms
      8. Chapter Summary
      9. Review Questions
      10. Critical Thinking Questions
      11. Test Prep for AP® Courses
      12. Science Practice Challenge Questions
  7. Plant Structure and Function
    1. 23 Plant Form and Physiology
      1. Introduction
      2. 23.1 The Plant Body
      3. 23.2 Stems
      4. 23.3 Roots
      5. 23.4 Leaves
      6. 23.5 Transport of Water and Solutes in Plants
      7. 23.6 Plant Sensory Systems and Responses
      8. Key Terms
      9. Chapter Summary
      10. Review Questions
      11. Critical Thinking Questions
      12. Test Prep for AP® Courses
      13. Science Practice Challenge Questions
  8. Animal Structure and Function
    1. 24 The Animal Body: Basic Form and Function
      1. Introduction
      2. 24.1 Animal Form and Function
      3. 24.2 Animal Primary Tissues
      4. 24.3 Homeostasis
      5. Key Terms
      6. Chapter Summary
      7. Review Questions
      8. Critical Thinking Questions
      9. Test Prep for AP® Courses
    2. 25 Animal Nutrition and the Digestive System
      1. Introduction
      2. 25.1 Digestive Systems
      3. 25.2 Nutrition and Energy Production
      4. 25.3 Digestive System Processes
      5. 25.4 Digestive System Regulation
      6. Key Terms
      7. Chapter Summary
      8. Review Questions
      9. Critical Thinking Questions
      10. Test Prep for AP® Courses
      11. Science Practice Challenge Questions
    3. 26 The Nervous System
      1. Introduction
      2. 26.1 Neurons and Glial Cells
      3. 26.2 How Neurons Communicate
      4. 26.3 The Central Nervous System
      5. 26.4 The Peripheral Nervous System
      6. 26.5 Nervous System Disorders
      7. Key Terms
      8. Chapter Summary
      9. Review Questions
      10. Critical Thinking Questions
      11. Test Prep for AP® Courses
      12. Science Practice Challenge Questions
    4. 27 Sensory Systems
      1. Introduction
      2. 27.1 Sensory Processes
      3. 27.2 Somatosensation
      4. 27.3 Taste and Smell
      5. 27.4 Hearing and Vestibular Sensation
      6. 27.5 Vision
      7. Key Terms
      8. Chapter Summary
      9. Review Questions
      10. Critical Thinking Questions
      11. Science Practice Challenge Questions
    5. 28 The Endocrine System
      1. Introduction
      2. 28.1 Types of Hormones
      3. 28.2 How Hormones Work
      4. 28.3 Regulation of Body Processes
      5. 28.4 Regulation of Hormone Production
      6. 28.5 Endocrine Glands
      7. Key Terms
      8. Chapter Summary
      9. Review Questions
      10. Critical Thinking Questions
      11. Test Prep for AP® Courses
      12. Science Practice Challenge Questions
    6. 29 The Musculoskeletal System
      1. Introduction
      2. 29.1 Types of Skeletal Systems
      3. 29.2 Bone
      4. 29.3 Joints and Skeletal Movement
      5. 29.4 Muscle Contraction and Locomotion
      6. Key Terms
      7. Chapter Summary
      8. Review Questions
      9. Critical Thinking Questions
      10. Science Practice Challenge Questions
    7. 30 The Respiratory System
      1. Introduction
      2. 30.1 Systems of Gas Exchange
      3. 30.2 Gas Exchange across Respiratory Surfaces
      4. 30.3 Breathing
      5. 30.4 Transport of Gases in Human Bodily Fluids
      6. Key Terms
      7. Chapter Summary
      8. Review Questions
      9. Critical Thinking Questions
      10. Test Prep for AP® Courses
      11. Science Practice Challenge Questions
    8. 31 The Circulatory System
      1. Introduction
      2. 31.1 Overview of the Circulatory System
      3. 31.2 Components of the Blood
      4. 31.3 Mammalian Heart and Blood Vessels
      5. 31.4 Blood Flow and Blood Pressure Regulation
      6. Key Terms
      7. Chapter Summary
      8. Review Questions
      9. Critical Thinking Questions
      10. Test Prep for AP® Courses
      11. Science Practice Challenge Questions
    9. 32 Osmotic Regulation and Excretion
      1. Introduction
      2. 32.1 Osmoregulation and Osmotic Balance
      3. 32.2 The Kidneys and Osmoregulatory Organs
      4. 32.3 Excretion Systems
      5. 32.4 Nitrogenous Wastes
      6. 32.5 Hormonal Control of Osmoregulatory Functions
      7. Key Terms
      8. Chapter Summary
      9. Review Questions
      10. Critical Thinking Questions
      11. Test Prep for AP® Courses
    10. 33 The Immune System
      1. Introduction
      2. 33.1 Innate Immune Response
      3. 33.2 Adaptive Immune Response
      4. 33.3 Antibodies
      5. 33.4 Disruptions in the Immune System
      6. Key Terms
      7. Chapter Summary
      8. Review Questions
      9. Critical Thinking Questions
      10. Test Prep for AP® Courses
      11. Science Practice Challenge Questions
    11. 34 Animal Reproduction and Development
      1. Introduction
      2. 34.1 Reproduction Methods
      3. 34.2 Fertilization
      4. 34.3 Human Reproductive Anatomy and Gametogenesis
      5. 34.4 Hormonal Control of Human Reproduction
      6. 34.5 Fertilization and Early Embryonic Development
      7. 34.6 Organogenesis and Vertebrate Formation
      8. 34.7 Human Pregnancy and Birth
      9. Key Terms
      10. Chapter Summary
      11. Review Questions
      12. Critical Thinking Questions
      13. Test Prep for AP® Courses
      14. Science Practice Challenge Questions
  9. Ecology
    1. 35 Ecology and the Biosphere
      1. Introduction
      2. 35.1 The Scope of Ecology
      3. 35.2 Biogeography
      4. 35.3 Terrestrial Biomes
      5. 35.4 Aquatic Biomes
      6. 35.5 Climate and the Effects of Global Climate Change
      7. Key Terms
      8. Chapter Summary
      9. Review Questions
      10. Critical Thinking Questions
      11. Test Prep for AP® Courses
      12. Science Practice Challenge Questions
    2. 36 Population and Community Ecology
      1. Introduction
      2. 36.1 Population Demography
      3. 36.2 Life Histories and Natural Selection
      4. 36.3 Environmental Limits to Population Growth
      5. 36.4 Population Dynamics and Regulation
      6. 36.5 Human Population Growth
      7. 36.6 Community Ecology
      8. 36.7 Behavioral Biology: Proximate and Ultimate Causes of Behavior
      9. Key Terms
      10. Chapter Summary
      11. Review Questions
      12. Critical Thinking Questions
      13. Test Prep for AP® Courses
      14. Science Practice Challenge Questions
    3. 37 Ecosystems
      1. Introduction
      2. 37.1 Ecology for Ecosystems
      3. 37.2 Energy Flow through Ecosystems
      4. 37.3 Biogeochemical Cycles
      5. Key Terms
      6. Chapter Summary
      7. Review Questions
      8. Critical Thinking Questions
      9. Test Prep for AP® Courses
      10. Science Practice Challenge Questions
    4. 38 Conservation Biology and Biodiversity
      1. Introduction
      2. 38.1 The Biodiversity Crisis
      3. 38.2 The Importance of Biodiversity to Human Life
      4. 38.3 Threats to Biodiversity
      5. 38.4 Preserving Biodiversity
      6. Key Terms
      7. Chapter Summary
      8. Review Questions
      9. Critical Thinking Questions
      10. Test Prep for AP® Courses
  10. A | The Periodic Table of Elements
  11. B | Geological Time
  12. C | Measurements and the Metric System
  13. Index
29 .
(credit: modification of work by KDS4444/Wikipedia, CC0)

This image shows a U-shaped tube with a semi-permeable membrane separating it into two. The membrane allows small molecules to pass through, but not larger molecules.

Sugar, a large molecule, is added to left arm of the U-shaped tube. Make a claim about what will happen next.

  1. The water level will increase equally in both arms because of the added volume of the sugar.
  2. The water level will increase slightly on the left arm because of the added volume of the sugar.
  3. The water level will increase considerably on the left arm because of the added volume of the sugar, as well as more water going to left arm due to osmotic pressure.
  4. The water level will increase slightly on the right arm because water going to right arm due to osmotic pressure.
30 .
A student measures the osmolality of two aqueous solutions, A and B. The student finds that the osmolality of solution B is much higher than solution A. Based on this result, how do solutions A and B likely differ in the concentration of solutes in their solution, and why?
  1. Solution A likely is the more concentrated solution because osmolality measures the moles of solute per kilogram of solute.
  2. Solution B likely is the more concentrated solution because osmolality measures the moles of solute per kilogram of solvent.
  3. Solution A likely is the more concentrated solution because osmolality measures the moles of solute per kilogram of solvent.
  4. Solution B likely is the more concentrated solution because osmolality measures the moles of solute per kilogram of solute.
31 .
Would an organism that is constantly in a hypertonic environment likely be an osmoregulator or an osmoconformer? Why?
  1. osmoconformer, because it would need to prevent water from leaving its body to remain alive
  2. osmoregulator, because it would need to prevent solutes from leaving its body to remain alive
  3. osmoconformer, because it would need to prevent solutes from leaving its body to remain alive
  4. osmoregulator, because it would need to prevent water from leaving its body to remain alive.
32 .
Why is excretion important in order to achieve osmotic balance?
  1. The body accumulates water within itself when excretion does not occur, which can have dire consequences.
  2. Excretion regulates the movement of water within the membranes, which ultimately maintains osmotic balance.
  3. In the absence of excretion, there is a shift in the concentrations, which disrupts osmotic balance.
  4. The body builds up many chemical compounds that need to be excreted to maintain homeostasis and osmotic balance.
33 .
What is the structure of the nephron?
  1. The nephron consists of three parts: the glomerulus, the renal tubule, and the associated capillary network originating from the cortical radiate arteries.
  2. The nephron consists of three parts: the renal corpuscle, the Bowman’s capsule, and the associated capillary network originating from the cortical radiate arteries.
  3. The nephron consists of three parts: the renal corpuscle, the renal tubule, and the associated capillary network originating from the segmental renal artery.
  4. The nephron consists of three parts: the renal corpuscle, the renal tubule, and the associated capillary network originating from the cortical radiate arteries.
34 .
How does the loop of Henle act as a countercurrent multiplier?
  1. The descending limb of the loop of Henle is water permeable, so the water flows from the filtrate to the interstitial fluid. Osmolality in the limb decreases, and it is lower inside the loop than in the interstitial fluid. As the filtrate enters the ascending limb, Na+ and Cl- ions exit through ion channels present in the cell membrane. Further up, only sodium is passively transported out of the filtrate.
  2. The descending limb of the loop of Henle is water impermeable, so the water flows from the filtrate to the interstitial fluid. Osmolality in the limb increases, and it is higher inside the loop than in the interstitial fluid. As the filtrate enters the ascending limb, Na+ and Cl- ions exit through ion channels present in the cell membrane. Further up, only sodium is passively transported out of the filtrate.
  3. The descending limb of the loop of Henle is water impermeable, so the water flows from the filtrate to the interstitial fluid. Osmolality in the limb increases, and it is higher inside the loop than in the interstitial fluid. As the filtrate enters the ascending limb, Na+ and Cl- ions exit through ion channels present in the cell membrane. Further up, sodium is actively transported out of the filtrate, and chlorine ions follow.
  4. The descending limb of the loop of Henle is water permeable, so the water flows from the filtrate to the interstitial fluid. Osmolality in the limb increases, and it is higher inside the loop than in the interstitial fluid. As the filtrate enters the ascending limb, Na+ and Cl- ions exit through ion channels present in the cell membrane. Further up, sodium is actively transported out of the filtrate, and chlorine ions follows.
35 .
Why might specialized organs have evolved for excretion of wastes?
  1. Specialized organs have evolved to provide a measure of safety for organisms.
  2. Specialized organs have evolved to distinguish different types of organisms.
  3. Specialized organs have evolved for excretion of wastes to conserve metabolic energy.
  4. Specialized organs have evolved for excretion of wastes so that organisms can survive in adverse conditions.
36 .
Explain two different excretory systems other than the kidneys.
  1. (1) An excretory mechanism occurs in annelids through the Malpighian tubules. Metabolic wastes like uric acid freely diffuse into the tubules. Uric acid is excreted as a thick paste or powder. (2) An excretory mechanism occurs in the flatworm, which contains two tubules with cells called flame cells. They have cilia that propel waste matter down the tubules and out of the body.
  2. (1) An excretory mechanism occurs in arthropods through a pore called the nephridiopore. These organisms have a system for tubular reabsorption. (2) An excretory mechanism occurs in annelids through the Malpighian tubules. Metabolic wastes like uric acid freely diffuse into the tubules. Uric acid is excreted as a thick paste or powder.
  3. (1) An excretory mechanism is endocytosis, which occurs when vacuoles merge with the cell membrane and excrete cellular wastes in the environment. (2) An excretory mechanism occurs in annelids through a pore called the nephridiopore. These organisms have a system for tubular reabsorption.
  4. (1) An excretory mechanism is exocytosis, which occurs when vacuoles merge with the cell membrane and excrete cellular wastes in the environment. (2) An excretory mechanism occurs in flatworms which consists of two tubules containing cells called flame cells. They have a cluster of cilia that propel waste matter down the tubules and out of the body.
37 .
How do contractile vacuoles work as excretory systems in microorganisms?
  1. Contractile vacuoles excrete excess water and waste by the process of endocytosis, in which these vacuoles merge with cell membrane and expel wastes into the environment.
  2. Contractile vacuoles excrete uric acid by the process of exocytosis, in which water as well as uric acid is excreted by contraction of a cell when the vacuole merges with the cell membrane.
  3. Contractile vacuoles excrete excess water and uric acid by the process of endocytosis when the vacuole merges with the cell membrane.
  4. Contractile vacuoles excrete excess water and waste by the process of exocytosis, in which the vacuoles merge with the cell membrane and expel wastes into the environment.
38 .
Describe the urea cycle.
  1. The urea cycle is the mechanism of conversion of urea to ammonia involving five intermediate steps catalyzed by five different enzymes. Of the five steps, the first two occur in the mitochondria and the last three in the cytosol.
  2. The urea cycle is the mechanism of conversion of ammonia to urea involving five intermediate steps catalyzed by five different enzymes. Of the five steps, the first two occur in the mitochondria and the last three in the cytosol.
  3. The urea cycle is the mechanism of conversion of ammonia to urea involving five intermediate steps catalyzed by five different enzymes. Of the five steps, the first two occur in the cytosol and the last three in the mitochondria.
  4. The urea cycle is the mechanism of conversion of ammonia to urea involving five intermediate steps all catalyzed by one enzyme. Of the five steps, the first two occur in the mitochondria and the last three in the cytosol.
39 .
How are the formation of urea and uric acid similar and different?
  1. In birds, reptiles, and insects, the urea cycle converts ammonia to urea. In mammals, the uric acid cycle converts ammonia to uric acid. Formation of urea from ammonia requires less energy and is less complex than uric acid formation.
  2. In mammals, the urea cycle converts ammonia to urea. In birds, reptiles, and insects, the uric acid cycle converts ammonia to uric acid. Formation of urea from ammonia requires more energy and is less complex than uric acid formation.
  3. In mammals, the urea cycle converts ammonia to urea. In birds, reptiles, and insects, the uric acid cycle converts ammonia to uric acid. Formation of urea from ammonia requires less energy and is more complex than uric acid formation.
  4. In mammals, the urea cycle converts ammonia to urea. In birds, reptiles, and insects, the uric acid cycle converts ammonia to uric acid. Formation of urea from ammonia requires less energy and is less complex than uric acid formation.
40 .
In terms of evolution, why might the urea cycle have evolved in organisms?
  1. so organisms could adapt to the changing environment when terrestrial life forms evolved
  2. so organisms could evolve the ability to switch between direct ammonia excretion and urea
  3. so organisms could reduce their excretion of ammonia in the form of urea
  4. so organisms could adapt to the changing environment and excrete higher concentrations of uric acid
41 .
(credit: modification of work by Shatoor, Prof. Abdullah et al./African Journal of Pharmacy and Pharmacology)

This graph shows the results of an experiment on some rabbits. The rabbits were injected by increasing amounts of epinephrine, shown in the x-axis. The y-axis shows the heart rate of the rabbit.

What is the independent variable in this experiment?

  1. The concentration of epinephrine injected to the rabbits.
  2. The heart rate of the rabbits.
  3. The time it takes for the injections to be effective.
  4. The number of rabbits used in the experiment.
42 .
How does the renin-angiotensin-aldosterone mechanism function?
  1. Renin, which is secreted by part of the juxtaglomerular complex, acts on angiotensin to form angiotensin I, which is then converted to angiotensin II by ACE. Angiotensin II then stimulates the release of aldosterone and ADH. Angiotensin II acts to destabilize blood pressure and volume.
  2. Renin, which is secreted by part of the juxtaglomerular complex, acts on angiotensin to form angiotensin II, which is then converted to angiotensin I by ACE. Angiotensin II then stimulates the release of aldosterone and ADH. Angiotensin II acts to stabilize blood pressure and volume.
  3. Renin, which is secreted by part of the juxtaglomerular complex, acts on angiotensin to form angiotensin I, which is then converted to angiotensin II and ADH by ACE. ADH then stimulates the release of aldosterone. Angiotensin II acts to stabilize blood pressure and volume.
  4. Renin, which is secreted by part of the juxtaglomerular complex, acts on angiotensin to form angiotensin I, which is then converted to angiotensin II by ACE. Angiotensin II then stimulates the release of aldosterone and ADH. Angiotensin II acts to stabilize blood pressure and volume.
43 .
(credit: modification of work by Shatoor, Prof. Abdullah et al./African Journal of Pharmacy and Pharmacology)

This graph shows the results of an experiment on some rabbits. The rabbits were injected by increasing amounts of epinephrine, shown in the x-axis. The y-axis shows the heart rate of the rabbit.

What is a claim that can be done from this graph?

  1. Even very small amounts of epinephrine trigger a big response.
  2. Epinephrine does not have a lot of effect until its concentration reaches a threshold.
  3. There is no upper limit to the effect of epinephrine.
  4. Increasing epinephrine decreases the rate of the heart beat.
PreviousNext
Order a print copy

As an Amazon Associate we earn from qualifying purchases.

Citation/Attribution

Want to cite, share, or modify this book? This book uses the Creative Commons Attribution License and you must attribute OpenStax.

Attribution information
  • If you are redistributing all or part of this book in a print format, then you must include on every physical page the following attribution:
    Access for free at https://openstax.org/books/biology-ap-courses/pages/1-introduction
  • If you are redistributing all or part of this book in a digital format, then you must include on every digital page view the following attribution:
    Access for free at https://openstax.org/books/biology-ap-courses/pages/1-introduction
Citation information

© Jul 7, 2023 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License . The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.