Chapter 2
Cell Physiology
CHAPTER OUTLINE
OBSERVATIONS OF CELLS
AN OVERVIEW OF CELL STRUCTURE
The plasma membrane bounds the cell.
The nucleus contains the DNA.
The cytoplasm consists of various organelles and the cytosol.
ENDOPLASMIC RETICULUM
The rough endoplasmic reticulum synthesizes proteins for secretion and membrane construction.
The smooth endoplasmic reticulum packages new proteins in transport vesicles.
GOLGI COMPLEX
Transport vesicles carry their cargo to the Golgi complex for further processing.
The Golgi complex packages secretory vesicles for release by exocytosis.
LYSOSOMES AND ENDOCYTOSIS
Lysosomes serve as the intracellular digestive system.
Extracellular material is brought into the cell by endocytosis for attack by lysosomes.
Pinocytosis, receptor-mediated endocytosis and phagocytosis are forms of endocytosis
Lysosomes remove useless but not useful parts of the cell.
PEROXISOMES AND DETOXIFICATION
Peroxisomes house oxidative enzymes that detoxify various wastes. Peroxisomes are small membrane-enclosed sacs containing powerful enzymes.
They are specialized for carrying out particular reactions, including detoxification of various wastes and toxic foreign compounds.
MITOCHONDRIA AND ATP PRODUCTION
Mitochondria, the energy organelles, are enclosed by a double membrane.
Mitochondria play a major role in generating ATP.
Major components of cellular respiration include glycolysis, Citric acid cycle and oxidative phosphorylation
The cell generates more energy in aerobic than in anaerobic conditions.
The energy stored in ATP is used for synthesis, transport, and mechanical work.
CYTOSOL: CELL GELL
The cytosol is important in intermediary metabolism, ribosomal protein synthesis, and nutrient storage.
CYTOSKELETON: CELL “BONE AND MUSCLE”
Microtubules help maintain asymmetrical cell shapes and play a role in complex cell movements.
Microfilaments are important to cellular contractile systems and as mechanical stiffeners.
Intermediate filaments are important in cell regions subject to mechanical stress.
The cytoskeleton functions as an integral whole and links other parts of the cell together.
LIST OF KEY TERMS
actin
adenosine diphosphate (ADP)
adenosine triphosphate (ATP)
adipose tissue
aerobic
amoeboid movement
anaerobic
ATP synthase
cell membrane
cell respiration
chemiosmosis
cilia
citric-acid cycle
cristae
cytoplasm
cytoskeleton
cytosol
deoxyribonucleic acid (DNA)
endocytic vesicles
endoplasm
endoplasmic reticulum
exocytosis
extracellular fluid
flagellum
glycogen
glycolysis
golgi complex
inclusions
intermediary metabolism
intermediate filaments
keratin
kinesin
lysosomes
matrix
messenger RNA (mRNA)
microfilaments
microtrabecular lattice
microtubules
microvilli
mitochondria
myosin
NAD
nucleus
organelles
oxidative enzymes
oxidative phosphorylation
peroxisomes
phagocytosis
pinocytosis
plasma gel
plasma membrane
polyribosome
pseudopod
receptor-mediated endocytosis
ribonucleic acid (RNA)
ribosomal RNA
ribosomes
rough ER
secretory vesicle
signal-recognition protein
smooth ER
transfer RNA
tubulin
LECTURE HINTS AND SUGGESTIONS
1. Slides, transparencies, and electron micrographs are very useful for pointing out the major features of cells and organelles. These can be obtained from Carolina Biological Supply Company, Burlington, NC. Numerous WWW resources are also available such as http://www.cellbio.com.
2. Demonstrate a model of a cell and the different organelles. Encourage students to think of cells as highly dynamic, three dimensional entities.
3. Biology supply houses also furnish charts of cell structures. Display these charts to enhance your lectures on this topic. Also display them in lab when students study cells.
4. Use a video microscope to show living cells or preserved specimens.
5. If you have internet connections in the classroom, a variety of video clips and slides are available at the sites listed below.
6. Students enjoy the "Cell Game" available from Carolina Biological Supply.
7 The importance of ATP in living systems can be easily demonstrated using fireflies. Kits are available from biological supply companies.
8. Use animations to show steps of cellular respiration and how molecules shuttle between the different components of the cytosol and mitochondria.
9. When discussing the energy relationships between glucose and ATP relate to difference between crude oil and gasoline (refined). Glucose is like crude oil, ATP like gasoline.
Answers to Essay Questions
1. A cell’s three major subdivisions are the plasma membrane, which encloses the cell; the nucleus, which contains the genetic material; and the cytoplasm, which is the interior portion of the cell outside the nucleus.
2. An advantage of organelle compartmentalization is that it allows organelles to have a distinct internal compartment that contains specialized chemicals for carrying out particular functions.
3. The five types of organelles include: endoplasmic reticulum, Golgi complex, lysosomes, peroxisomes, and mitochondria.
4. ER is a fluid-filled membranous system distributed throughout the cytosol. Rough ER consists of flattened interconnected sacs, and the outer surface of the rough ER contains ribosomes. These ribosomes synthesize and release proteins into the ER lumen where they undergo transport within or outside the cell. Smooth ER is a meshwork of interconnected tubules and lacks ribosomes, thus the name smooth. The smooth ER collects proteins and lipids from the rough ER and packages them for distribution throughout the cell.
5. Exocytosis is the mechanism by which materials from the inside of the cell are released to the exterior. During exocytosis cells secrete materials into the ECF. Endocytosis is the opposite of exocytosis. It is the internalization of extracellular material by the cell. There are three forms of endocytosis depending on what is being internalized. Pinocytosis is a process by which a droplet of ECF is non-selectively internalized. Phagocytosis is a process by which large multi-molecular particles are internalized. Receptor-mediated endocytosis is a selective process that enables cells to internalize specific large molecules from its environment.
6. Lysosomes serve as the intracellular digestive system. They contain hydrolytic enzymes and, in addition to breaking down raw ingredients, they also remove worn-out organelles.
7. Peroxisomes contain oxidative enzymes and perform detoxifying activities by removing hydrogen atoms from certain organic molecules. Lysosomes serve as the intracellular digestive system. They contain hydrolytic enzymes, and in addition to breaking down raw ingredients, they also remove worn-out organelles.
8. Cellular respiration refers collectively to the intracellular reactions in which energy-rich molecules are broken down to form ATP, using O2 and producing CO2 in the process. Oxidative phosphorylation refers to the process by which ATP is synthesized using the energy released by electrons as they are transferred to O2. Chemiosmosis occurs in the mitochondria and is associated with ATP production tied to the activation of ATP synthase by the flow of H+ Mitochondria are enclosed by a double membrane—an outer membrane that surrounds the organelle itself and an inner membrane that contains numerous folds, called cristae. The innermost cavity formed by the cristae is called the matrix and is filled with a gel-like solution. These organelles play a major role in ATP production. Citric acid cycle reactions occur in the matrix, and oxidative phosphorylation reactions take place on the inner membrane.
9. Mitochondria are enclosed by a double membrane-an outer membrane that surrounds the organelle itself and an inner membrane that contains numerous folds, called cristae. The innermost cavity formed by the cristae is called the matrix and is filled with a gel-like solution. These organelles play a major role in ATP production. Citric acid cycle reactions occur in the matrix, and oxidative phosphorylation reactions take place on the inner membrane.
10. Oxidative enzymes in the peroxisomes utilize oxygen for detoxification. Oxidative enzymes in the mitochondria utilize oxygen in the process of synthesizing ATP.
11. Cells expend energy on synthesis of new chemical compounds, membrane transport processes, and mechanical work.
12. The cytoskeleton is composed of microtubules, microfilaments, and intermediate filaments. Microtubules serve a variety of functions including maintaining the shape of cells, coordinating complex intracellular movements, and serving as the main structural component of cilia and flagella. Microfilaments play a major role in cellular contractile systems, including muscle contraction. Intermediate filaments resist mechanical stress placed on cells.
AUDIOVISUAL AIDS
Videos/Films
The following are films that may be suitable for presentation in your class. The sources for these films, which are coded by abbreviation, are provided in Appendix A.
Anatomy and Physiology Video Tutor, PH
Biological Membranes, PS, 17 min.
Biology Concepts: cellular respiration, CBS, 39 min.
The Building Blocks of Life, CBS, 60 min.
The Cell, CE, 14 min.
The Cell: Basic Unit of Life, EVN, 18 min.
Cell Biology: Life Functions, COR, 20 min.
Cell Biology: Structure and Composition, COR, 13 min.
Cell Motility and Microtubules, FHS, 30 min.
Cell Motility, EI
Cell Organelles and Transport, CE, 14 min.
Cell Structure , (VCR), MG, 24 min.
Cell Structure, PS, 25 min.
The Cell, A Functioning Structure, Parts I and II, CCM, 30 min.
The Cell: Parts I and II, MH, 16 min.
The Cell: Structural Unit of Life, COR, 11 min.
Cell: Unit of Life, PLP, 15 min.
Cells and Energy, CE, 14 min.
Cellular Respiration: Energy for Life. CBS, 22 min.
Concepts in Science: Cellular Respiration, CBS, 60 min.
The Embattled Cell, WFL, 20 min.
Genetics, Stem Cells, and Society: An Interview with Alan Trounson, FMG 37 Min.
Glycolysis 1 and 2, FHS, 10 min. each
Inside the Cell, IM, 45 min.
Inside Cells: Cells and Their Organelles, FMG, 28 Min.
Introduction to Cell Structure, IM, 34 min.
Introduction to Cells, EI, 30 min.
Introduction to Living Cells, PLP, 18 min.
Journey through the Cell - 2 parts, CE, 20 min. each
The Kreb's Cycle, FHS, 10 min.
Learning about Cells, EBE, 16 min.
The Cell, FMG, 150 min.
The Life and Death of a Cell, UC, 27 min.
The Living Cell: An Introduction, EBE, 20 min.
The Magic of Cells, AV, 20 min.
Oxidative Phosphorylation, FHS, 10 min.
Understanding the Cell, EVN, 17 min.
Understanding Cell Membranes, EVN, 32 min.
Visualizing Cell Processes: Cell Movement and Transport, CBS, 13 min.
Visualizing Cell Processes: Photosynthesis and Cellular Respiration, 12 min.
The Unit of Life, MH, 28 min.
Software
Cells Alive!, QG, A CD that explores cell structure in video and animations.
Cell Biology Biodiscs CD, BIO, a series of 13 CDs on cell biology.
Cell Biology Interactive,
Cell City, CE. An innovative CD that explains the operations of a cell.
Cell Structure and Function, EI, presents an overview of the animal cell.
Cell Strucure and Function, CY, an interactive CD.
Cell Structure and Specialization Set, CBS, 5 CDs covering cells.
Cells, CBS, covers the cell theory and differences between plant and animal cells.
Cellular Respiration, CY, an interactive CD.
Cellular Respiration, PLP, an interactive CD.
Energy and the Chemistry of Life, CBS, CD Mac/Win.
Inside the Cell, www.cyber-ed.com.
Learning About Cells and Biology, EDI, an illustrated CD on cell structure and function.
MediaPhys CD-Rom, MH, covers most body systems.
The Plasma Membrane & Cellular Transport, CY, an interactive CD.
The Study of the Cell, PLP, an interactive CD.
Online Software/Animations
http://www.stolaf.edu/people/giannini/biological%20anamations.html (cell biology animation)
http://programs.northlandcollege.edu/biology/Biology1111/animations/flagellum.html
(Northland College Biology)
http://www.dnalc.org/resources/3d/cellsignals.html (cell signals-Dolan DNA learning center)
http://www.sumanasinc.com/webcontent/animations/content/intermediate_filaments.html
(intermediate filaments-Sumanas Inc)
http://www.wisc-online.com/objects/ViewObject.aspx?ID=AP11604
(organelles-Wisc-Online)
http://nhscience.lonestar.edu/biol/glylysis/glylysis.html (glycolysis-lonestar.edu)
http://telstar.ote.cmu.edu/biology/animation/ATPSynthesis/ATPSynthesis_bc.html (ATP synthase-CMU.edu)
http://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/oxidative/oxidativephosphorylation.html (oxidative phosphorylation-Brooks Cole)
Relevant Educational Websites
http://www.cellbioed.org/ (Cell Biology Education journal)
http://ajpcon.physiology.org/ (physiology journal)
http://personal.tmlp.com/Jimr57/textbook/chapter3/chapter3.htm (Virtual cell textbook)
http://www.nrcam.uchc.edu/ (Virtual cell)
http://www.porterendowment.org/ (cell biology educational resources)
http://www.interscience.wiley.com/jpages/0021-9541/ (Journal of Cellular Physiology)
http://www.cellsalive.com (Online videos/animations of cells)
http://link.springer.de/link/service/journals/00418/index.htm (journal)
http://www.cell.com (Cell - online journal; searchable)
http://www.mindquest.net/entrance-educators.html (Cell biology video clips)
http://www.cellbio.com (Cell and Molecular Biology Online)
http://www.biology.arizona.edu/cell_bio/cell_bio.html (The Biology Project: Cell Biology)
http://library.thinkquest.org/3564 (The Cell website)
http://www.med.uc.edu/medware2 (movies and labs)
http://www.sp.uconn.edu/~terry/images/anim/ETS.html (animation of electron transport)
http://www.cellsalive.com/cells/3dcell.htm (cell structure-Cells Alive.com)
http://www.biology.ualberta.ca/facilities/multimedia/index.php?Page=253/ (cell biology-Univ of Alberta)
Relevant Organizations Providing Educational Resources
American Society for Biochemistry and Molecular Biology
9650 Rockville Pike
Rockville, MD 20814
http://www.asbmb.org/ASBMB/site.nsf
American Society for Cell Biology
9650 Rockville Pike
Rockville, MD 20814
http://www.ascb.org/
American Society of Cytopathology
400 West 9th Street, Suite 201
Wilmington, Delaware 19801
http://www.cytopathology.org/
British Society for Cell Biology
http://www.bscb.org
Canadian Society of Biochemistry and Molecular and Cell Biology
The Federation of American Societies for Experimental Biology (FASEB)
9650 Rockville Pike, Bethesda, MD 20814
International Federation for Cell Biology
http://www.ifcbiol.org/
International Society for Analytical Cytology
60 Revere Drive, Suite 500
Northbrook, IL 60062
Teacher’s Domain
WGBH
One Guest Street
Boston, MA 02135
http://www.teachersdomain.org/
Chapter 2—Cell Physiology
MULTIPLE CHOICE
1. Which component below is not always found in a typical human cell?
| a. | cytosol. |
| b. | DNA. |
| c. | flagellum. |
| d. | plasma membrane. |
| e. | water. |
ANS: C PTS: 1
2. A typical human cell is about ____micrometers in diameter.
| a. | 1 to 2 |
| b. | 10 to 20 |
| c. | 80 to 100 |
| d. | 150 to 200 |
| e. | 200 to 300 |
ANS: B PTS: 1
3. Select the structure that is not located in the cytosol of the cell.
| a. | ER. |
| b. | golgi complex. |
| c. | lysosome. |
| d. | mitochondrion. |
| e. | all of the above are located in the cytosol |
ANS: E PTS: 1
4. Which organelle is associated with energy production?
| a. | golgi body. |
| b. | lysosome. |
| c. | mitochondrion. |
| d. | RER. |
| e. | ribosome. |
ANS: C PTS: 1
5. Which of the following statements concerning cells is incorrect?
| a. | cells serve as the living building blocks of the body. |
| b. | the average human cell is about one hundred times smaller than the smallest particle visible by the unaided eye. |
| c. | inanimate chemical molecules are organized within each cell into a living entity. |
| d. | cells are generally colorless and transparent so they must be stained for visualization under a microscope. |
| e. | the three major subdivisions of a cell are the plasma membrane, the nucleus, and the cytoplasm. |
ANS: B PTS: 1
6. The plasma membrane:
| a. | is composed mostly of lipid molecules |
| b. | is composed mostly of protein molecules |
| c. | allows the ICF and ECF to easily exchange materials |
| d. | is a barrier that prevents most molecules from passing through |
| e. | is a very thick structure relative to the size of the cell |
ANS: A PTS: 1
7. The rough endoplasmic reticulum
| a. | is studded with ribosomes. |
| b. | synthesizes proteins for export from the cell or for use in construction of a new cellular membrane. |
| c. | is continuous with the smooth endoplasmic reticulum. |
| d. | is connected to the nucleus. |
| e. | all of these answers. |
ANS: E PTS: 1
8. The rough ER is a membranous system associated with
| a. | chromosomes. |
| b. | lysosomes. |
| c. | microfilaments. |
| d. | ribosomes. |
| e. | vacuoles. |
ANS: D PTS: 1
9. Of the organelles below which occurs in the lowest numbers within a typical human cell?
| a. | mitochondria. |
| b. | ribosomes |
| c. | peroxisomes. |
| d. | lysosomes. |
| e. | nuclei. |
ANS: E PTS: 1
10. Which of the following is contained within the nucleus?
| a. | deoxyribonucleic acid. |
| b. | cytosol. |
| c. | plasma membrane. |
| d. | endoplasmic reticulum. |
| e. | none of these answers. |
ANS: A PTS: 1
11. Select the incorrect statement regarding ribosomes
| a. | they are composed of RNA. |
| b. | they assemble polypeptides. |
| c. | they may be bound to endoplasmic reticulum. |
| d. | they are comprised of 2 parts. |
| e. | they are membrane-bounded. |
ANS: E PTS: 1
12. The smooth endoplasmic reticulum
| a. | is most abundant in cells specialized for protein secretion. |
| b. | gives rise to transport vesicles containing newly synthesized molecules wrapped in a layer of smooth ER membrane. |
| c. | consists of stacks of relatively flattened sacs called cisternae. |
| d. | has many ribosomes. |
| e. | all of these answers. |
ANS: B PTS: 1
13. This molecule carries and delivers amino acids during the process of protein synthesis:
| a. | mRNA |
| b. | rRNA |
| c. | tRNA |
| d. | DNA |
| e. | cDNA |
ANS: C PTS: 1
14. This molecule provides the template for the process of transcription.
| a. | mRNA |
| b. | rRNA |
| c. | tRNA |
| d. | DNA |
| e. | cDNA |
ANS: D PTS: 1
15. Select the incorrect statement about the smooth ER.
| a. | It is abundant in most cell types. |
| b. | It is found in liver cells. |
| c. | It specializes in lipid metabolism. |
| d. | The sarcoplasmic reticulum is a modified form of it. |
| e. | This organelle does not contain ribosomes. |
ANS: A PTS: 1
16. Which structure is not associated with the secretion of proteins produced by ER?
| a. | golgi complex. |
| b. | smooth ER. |
| c. | transport vesicles. |
| d. | lysosomal membrane. |
| e. | plasma membrane. |
ANS: D PTS: 1
17. Polyribosomes
| a. | a unusually large ribosomes. |
| b. | are found on smooth ER. |
| c. | synthesize lipids and nucleic acids. |
| d. | are clusters of ribosomes synthesizing the same protein. |
| e. | none of these answers. |
ANS: D PTS: 1
18. Which characteristic of the golgi complex is incorrect?
| a. | they sort and direct products to their final destination. |
| b. | they modify proteins chemically. |
| c. | they produce secretory vesicles. |
| d. | they produce proteins using ribosome. |
| e. | they receive transport vesicles coming from the ER. |
ANS: D PTS: 1
19. This cytosol:
| a. | is found within the nucleus |
| b. | does not contain organelles or cytoskeleton |
| c. | is found only in plant cells |
| d. | is found outside the cell |
| e. | is part of the ECF |
ANS: B PTS: 1
20. Extrusion of materials to the exterior of the cell through the plasma membrane is called
| a. | endocytosis |
| b. | exocytosis |
| c. | phagocytosis |
| d. | pinocytosis |
| e. | all of these answers. |
ANS: B PTS: 1
21. The form of endocytosis in which whole cells such as bacteria are brought in is
| a. | exocytosis. |
| b. | pinocytosis. |
| c. | receptor-mediated endocytosis. |
| d. | phagocytosis. |
| e. | mitosis. |
ANS: D PTS: 1
22. On average a cell contains how many lysosomes?
| a. | 3 |
| b. | 30 |
| c. | 300 |
| d. | 3,000 |
| e. | 3,000,000 |
ANS: C PTS: 1
23. Select the incorrect characteristic of mitochondria?
| a. | they have an inner fluid filled space called the cristae. |
| b. | they possess their own DNA. |
| c. | they are the site a cell respiration. |
| d. | their inner membranes posses electron carriers. |
| e. | they possess two membranes. |
ANS: A PTS: 1
24. Where do the citric acid cycle reactions occur?
| a. | cytoplasm. |
| b. | cytosol. |
| c. | inner-mitochondrial membrane. |
| d. | outer-mitochondrial membrane. |
| e. | mitochondrial matrix. |
ANS: E PTS: 1
25. What accounts for the most ATP production?
| a. | Kreb's cycle. |
| b. | Citric acid cycle. |
| c. | NADH. |
| d. | oxidative phosphorylation. |
| e. | glycolysis. |
ANS: D PTS: 1
26. Where is CO2 released in the aerobic cellular respiration process?
| a. | glycolysis. |
| b. | electron transport chain. |
| c. | Kreb's cycle. |
| d. | fermentation. |
| e. | none of these answers. |
ANS: C PTS: 1
27. Why do we need to breath in, exchange, and deliver to each cell the oxygen molecule?
| a. | glucose can't be broken down without it. |
| b. | it pulls electrons off the electron transport chains in the last part. of cell respiration. |
| c. | all chemical reactions require it. |
| d. | all of these answers. |
| e. | none of these answers. |
ANS: B PTS: 1
28. What might happen if you did not get enough niacin in your diet?
| a. | glucose would not be able to be cleaved. |
| b. | available FAD would decrease. |
| c. | when the 3-carbon chain is oxidized in glycolysis, electrons would not be able to be captured. |
| d. | only fermentation would be possible |
| e. | all of these answers. |
ANS: C PTS: 1
29. What is the carbon-based end product (chain) of glycolysis?
| a. | NADH. |
| b. | ATP. |
| c. | pyruvate |
| d. | FADH2. |
| e. | CO2. |
ANS: C PTS: 1
30. Why does anaerobic respiration take place when O2 is not available?
| a. | to continue releasing at least some energy from molecules. |
| b. | to continue the glycolysis processes. |
| c. | to generate some ATP. |
| d. | to regenerate the limited NAD. |
| e. | all of these answers. |
ANS: E PTS: 1
31. Chemiosmosis:
| a. | releases CO2. |
| b. | extracts energy from a H+ concentration gradient. |
| c. | to reduce NAD. |
| d. | to ferment pyruvic acid to lactic acid. |
| e. | none of these answers. |
ANS: B PTS: 1
32. Pyruvate derived from glycolysis is transported into which structure to continue the process of cellular respiration?
| a. | mitochondrial matrix |
| b. | mitochondrial cristae |
| c. | cytosol |
| d. | nucleus |
| e. | lysosome |
ANS: A PTS: 1
33. Cristae are found in the
| a. | lysosome. |
| b. | mitochondrion. |
| c. | nucleolus. |
| d. | nucleus. |
| e. | rough ER. |
ANS: B PTS: 1
34. Select the incorrect association.
| a. | ATP/high-energy bonds. |
| b. | electron transport chain/aerobic |
| c. | glycolysis/anaerobic. |
| d. | glycolysis/cytosol. |
| e. | oxidative phosphorylation/low ATP production |
ANS: E PTS: 1
35. In an anaerobic condition,
| a. | oxygen is not present. |
| b. | the degradation of glucose cannot proceed beyond glycolysis. |
| c. | mitochondrial processing of nutrient molecules takes place. |
| d. | both (a) and (b) above. |
| e. | both (a) and (c) above. |
ANS: D PTS: 1
36. The universal energy currency in cells is
| a. | ATP. |
| b. | glucose. |
| c. | glycogen. |
| d. | insulin. |
| e. | myosin. |
ANS: A PTS: 1
37. The gradient of which ion supplies the energy that drive ATP synthesis by ATP synthase?
| a. | Na+ |
| b. | K+ |
| c. | H+ |
| d. | Cl- |
| e. | Ca+2 |
ANS: C PTS: 1
38. Which molecule that directly enters the citric acid cycle.
| a. | acetyl CoA. |
| b. | adenosine diphosphate. |
| c. | citric acid. |
| d. | oxaloacetic acid. |
| e. | pyruvic acid. |
ANS: A PTS: 1
39. ATP synthase
| a. | transports hydrogen ions from the matrix to the intermembrane space of the mitochondrion. |
| b. | is activated by the flow of hydrogen ions from the intermembrane space to the matrix. |
| c. | enzymatically converts ADP + Pi to ATP. |
| d. | both (b) and (c) above. |
| e. | all of these answers. |
ANS: D PTS: 1
40. The function of ATP synthase is to
| a. | act enzymatically. |
| b. | build membranes. |
| c. | carry hydrogen. |
| d. | synthesize ATP. |
| e. | transport oxygen. |
ANS: D PTS: 1
41. NADH
| a. | is an energy carrier. |
| b. | plays a role in cellular respiration. |
| c. | is utilized in glycolysis. |
| d. | is utilized in the citric acid cycle. |
| e. | all of these answers. |
ANS: A PTS: 1
42. Glycolysis
| a. | yields two molecules of ATP for each molecule of glucose processed. |
| b. | requires oxygen. |
| c. | takes place in the mitochondrial matrix. |
| d. | both (a) and (b) above. |
| e. | all of these answers. |
ANS: A PTS: 1
43. The purpose of glycolysis is
| a. | to produce citric acid. |
| b. | to liberate energy from glucose. |
| c. | to produce large numbers of ATP. |
| d. | to trap energy in FADH2. |
| e. | none of these answers. |
ANS: B PTS: 1
44. The term aerobic means
| a. | in the blood. |
| b. | with carbon dioxide. |
| c. | with oxygen. |
| d. | without carbon dioxide. |
| e. | without oxygen. |
ANS: C PTS: 1
45. Select the correct statement about peroxisomes
| a. | they may play a role in drug resistance. |
| b. | their shape resembles hexagonal barrels. |
| c. | they contain oxidative enzymes |
| d. | they are not organelles. |
| e. | they contain hydrolytic enzymes |
ANS: C PTS: 1
46. Select the element that is not a part of the cytoskeleton.
| a. | inclusions. |
| b. | intermediate filaments. |
| c. | microfilaments. |
| d. | microtubular lattice. |
| e. | microtubules. |
ANS: A PTS: 1
47. The bending movements of cilia and flagella
| a. | are accomplished by alternate solation and gelation of the cytosol. |
| b. | involve the alternate assembly and disassembly of actin filaments. |
| c. | are produced by the sliding of adjacent microtubule doublets past each other. |
| d. | are important in providing motility for many organisms but are not of any use in humans. |
| e. | none of these answers. |
ANS: C PTS: 1
48. Microtubules
| a. | serve as a mechanical stiffener for microvilli. |
| b. | are specialized to detect sound and positional changes in the ear. |
| c. | form nonmuscle contractile assemblies. |
| d. | play a structural role in parts of the cell subject to mechanical stress. |
| e. | none of these answers. |
ANS: E PTS: 1
49. Microtubules are composed primarily of:
| a. | phospholipids |
| b. | actin |
| c. | myosin |
| d. | tubulin |
| e. | enzymes |
ANS: D PTS: 1
50. Molecular motors:
| a. | are transporter proteins |
| b. | attach to the particle to be transported |
| c. | do not use energy from ATP to function properly |
| d. | a and b |
| e. | all of the above |
ANS: D PTS: 1
51. Which of the following is the molecular motor that carries secretory vesicles to the ends of the axon?
| a. | kinesin |
| b. | dynein |
| c. | actin |
| d. | NAD |
| e. | microfilaments |
ANS: A PTS: 1
52. The function of the microtrabecular lattice is
| a. | to maintain asymmetrical cell shapes. |
| b. | to suspend and functionally link the largest cytoskeletal elements and organelles. |
| c. | to provide for cellular contractile systems. |
| d. | to serve as mechanical stiffeners. |
| e. | serve as the chief structural units of cilia. |
ANS: B PTS: 1
53. Which of the following is not characteristic of the cytoskeleton?
| a. | the cytoskeleton supports the plasma membrane and is responsible for the particular shape, rigidity, and spatial geometry of each different cell type. |
| b. | the cytoskeleton probably plays a role in regulating cell growth and division. |
| c. | the cytoskeletal elements are all rigid, permanent structures. |
| d. | the cytoskeleton is responsible for cell contraction and cell movements. |
| e. | the cytoskeleton supports and organizes the ribosomes, mitochondria, and lysosomes. |
ANS: C PTS: 1
54. Phagocytosis is a function of which cell type?
| a. | epithelial. |
| b. | muscle. |
| c. | nerve. |
| d. | red blood. |
| e. | white blood. |
ANS: E PTS: 1
55. Which structure is transiently formed from microtubules during cell division?
| a. | flagella |
| b. | cilia |
| c. | mitotic spindle |
| d. | microfilaments |
| e. | none of the above |
ANS: C PTS: 1
56. Intermediate filaments
| a. | comprised mitotic spindles. |
| b. | are important in cell regions subject to mechanical stress. |
| c. | comprise cilia. |
| d. | comprise flagella. |
| e. | form the basal bodies. |
ANS: B PTS: 1
TRUE/FALSE
1. Microtubules serve as mechanical supports or stiffeners.
ANS: T PTS: 1
2. DNA's genetic code is transcribed into messenger RNA.
ANS: T PTS: 1
3. The cytosol is the gel-like mass of the cytoplasm.
ANS: T PTS: 1
4. DNA in the nucleus has the genetic instructions to make enzymatic proteins.
ANS: T PTS: 1
5. mRNA is formed within the nucleus and then moves into the cytoplasm where it is involved in protein synthesis.
ANS: T PTS: 1
6. The rough endoplasmic reticulum is most abundant in cells specialized for protein secretion, whereas smooth endoplasmic reticulum is abundant in cells that specialize in lipid metabolism.
ANS: T PTS: 1
7. Proteins synthesized by the endoplasmic reticulum become permanently separated from the cytosol as soon as they have been synthesized.
ANS: T PTS: 1
8. RER is most abundant in cells specialized for steroid production.
ANS: F PTS: 1
9. The golgi complex is functionally connected to the ER.
ANS: T PTS: 1
10. The endoplasmic reticulum is one continuous organelle consisting of many tubules and cisternae.
ANS: T PTS: 1
11. The lysosomes contain oxidative enzymes.
ANS: F PTS: 1
12. The smooth ER specializes in protein metabolism.
ANS: F PTS: 1
13. Secretory vesicles are released to the exterior of the cell by means of the process of phagocytosis.
ANS: F PTS: 1
14. Pinocytosis is a highly selective process that enables cells to import specific large molecules that it needs from its environment
ANS: F PTS: 1
15. Sorting and directing the finished products to their final destinations is basic function of the . Golgi stack.
ANS: T PTS: 1
16. All cell organelles are renewable.
ANS: T PTS: 1
17. Secretion refers to release to the cell’s exterior, on appropriate stimulation, of a product produced by the cell
ANS: T PTS: 1
18. Endocytosis can be accomplished by phagocytosis and pinocytosis.
ANS: T PTS: 1
19. Phagocytosis is a specialized form of endocytosis used for bringing in liquids.
ANS: F PTS: 1
20. The peroxisomes mainly generates hydrogen peroxide.
ANS: T PTS: 1
21. Glycolysis generates ATP from glucose via aerobic processes.
ANS: F PTS: 1
22. ATP synthase is located in the inner mitochondrial membrane.
ANS: T PTS: 1
23. Most intermediary metabolism is accomplished in the cytosol.
ANS: T PTS: 1
24. Glycolysis reactions generate the most ATP per glucose molecule.
ANS: F PTS: 1
25. Dynein is a mitochondrial enzyme.
ANS: F PTS: 1
26. Keratin is important in the formation of skin cell networks.
ANS: T PTS: 1
27. Amoeboid movement is accomplished by transitions of the cytosol between a gel and a sol state as a result of alternate assembly and disassembly respectively of actin filaments.
ANS: T PTS: 1
28. The protective, waterproof outer layer of skin is formed by the tough skeleton of the microtrabecular lattice that persists after the surface skin cells die.
ANS: F PTS: 1
COMPLETION
1. The three major subdivisions of a cell are the ____________________, the ____________________, and the ____________________.
ANS: plasma membrane, nucleus, cytoplasm
PTS: 1
2. The fluid contained within all of the cells of the body is known collectively as ____________________, and the fluid outside of the cells is referred to as ____________________.
ANS: intracellular fluid, extracellular fluid
PTS: 1
3. The two major parts of the cell's interior are the ____________________ and the ____________________.
ANS: nucleus, cytoplasm
PTS: 1
4. ____________________ RNA carries amino acids to the sites of protein synthesis in the cell.
ANS: transfer
PTS: 1
5. The ____________________ ER is the central packaging and discharge site for molecules to be transported from the ER.
ANS: smooth
PTS: 1
6. The nucleus is surrounded by a double-layered membrane, the ____________________ which is pierced by many nuclear ____________________.
ANS: nuclear envelope, pores
PTS: 1
7. ____________________ are distinct, highly organized structures that perform specialized functions within the cell.
ANS: Organelles
PTS: 1
8. The ribosomes of the rough ER synthesize ____________________, whereas its membranous walls contain enzymes essential for the synthesis of ____________________.
ANS: proteins, lipids
PTS: 1
9. The sarcoplasmic reticulum stores the substance ____________________.
ANS: calcium
PTS: 1
10. Among these so-called storage diseases is ________ disease, which is characterized by abnormal accumulation of complex molecules found in nerve cells.
ANS: Tay-Sachs
PTS: 1
11. ____________________ refers to the process of an intracellular vesicle fusing with the plasma membrane, then opening and emptying its contents to the exterior.
ANS: exocytosis
PTS: 1
12. ____________________ is a protein responsible for pinching off an endocytic vesicle.
ANS: dynamin
PTS: 1
13. Foreign material to be attacked by lysosomal enzymes is brought into the cell by the process of ____________________.
ANS: endocytosis
PTS: 1
14. Lysosomes contain ____________________ enzymes that are capable of digesting and removing unwanted debris from the cell.
ANS: hydrolytic
PTS: 1
15. Lysosomes that have completed their digestive activities are known as ____________________.
ANS: residual bodies
PTS: 1
16. Peroxisomes form ________ from molecular oxygen and the hydrogen atoms stripped from the toxic molecule.
ANS: hydrogen peroxide
PTS: 1
17. When ATP is utilized _________ and ___________ are produced.
ANS: ADP/Pi
PTS: 1
18. ____________________ refers collectively to the large set of intracellular chemical reactions that involve the degradation, synthesis, and transformation of small organic molecules.
ANS: intermediary metabolism
PTS: 1
19. The decomposition of hydrogen peroxide produces the substances ____________________ and ____________________.
ANS: water, oxygen
PTS: 1
20. ____________________ is a peroxisomal enzyme that breaks down hydrogen peroxide.
ANS: catalase
PTS: 1
21. One glucose molecule is converted into two molecules of ____________________ by the end of glycolysis.
ANS: pyruvate
PTS: 1
22. The metabolism of acetyl CoA into the citric acid cycle depends on the presence of ____________________ gas in the cell.
ANS: oxygen
PTS: 1
23. The chemiosmotic mechanism involves the transport of hydrogen across the membranes of the ____________________.
ANS: mitochondrion
PTS: 1
24. Adipose tissue stores the substance ____________________.
ANS: fat
PTS: 1
25. ____________________ are the dominant structural and functional components of cilia and flagella.
ANS: microtubules
PTS: 1
26. Microfilaments are comprised of the protein ____________________.
ANS: actin
PTS: 1
27. One disease caused by neurofilament abnormalities is ____________________.
ANS: amyotropic lateral sclerosis.
PTS: 1
28. A cilium or flagellum originates from the ____________________, a structure in the cell.
ANS: basal body
PTS: 1
MATCHING
Match the following with its characteristics.
| a. | glycolysis |
| b. | citric-acid cycle |
| c. | oxidative phosphorylation |
1. directly uses inspired oxygen
2. does not directly use inspired oxygen
3. takes place in the cytosol
4. takes place in the mitochondrial matrix
5. takes place on the inner mitochondrial membrane
6. low yield of ATP
7. high yield of ATP
1. ANS: C PTS: 1
2. ANS: A PTS: 1 NOT: B is also correct.
3. ANS: A PTS: 1
4. ANS: B PTS: 1
5. ANS: C PTS: 1
6. ANS: A PTS: 1 NOT: B is also correct.
7. ANS: C PTS: 1
Complete the sentences by matching the appropriate vesicle(s) from the following list. More than one answer may apply.
| a. | transport vesicles |
| b. | coated vesicles |
| c. | secretory vesicles |
8. Originate from the Golgi complex.
9. Originate from the endoplasmic reticulum.
10. Contain newly-synthesized molecules
11. Contents emptied to the exterior by exocytosis.
12. Enclosed in a clathrin framework.
13. Fuse with and enter the Golgi complex.
14. Contents become concentrated over time.
15. Contents are unloaded at a specific intracellular compartment.
8. ANS: B PTS: 1 NOT: C is also correct.
9. ANS: A PTS: 1
10. ANS: A PTS: 1
11. ANS: C PTS: 1
12. ANS: B PTS: 1
13. ANS: A PTS: 1
14. ANS: C PTS: 1
15. ANS: B PTS: 1
Match the term to its description.
| a. | plasma membrane |
| b. | nucleus |
| c. | cytoplasm |
| d. | cytosol |
| e. | organelles |
| f. | cytoskeleton |
16. Houses the cell's DNA.
17. Is/are responsible for cell shape and movement.
18. Are highly organized membrane-bound intracellular structures.
19. Selectively controls movement of molecules between the intracellular fluid and the extracellular fluid.
20. Consists of organelles and cytosol.
21. Is/are site of intermediary metabolism.
22. Perform specific functions within the cell.
23. Composed mostly of lipids with variable proteins.
24. Is/are the site of fat and glycogen storage.
16. ANS: B PTS: 1
17. ANS: F PTS: 1
18. ANS: E PTS: 1
19. ANS: A PTS: 1
20. ANS: C PTS: 1
21. ANS: D PTS: 1
22. ANS: E PTS: 1
23. ANS: A PTS: 1
24. ANS: D PTS: 1
Match the term to its description.
| a. | ER |
| b. | Golgi complex |
| c. | Lysosome |
| d. | Peroxisome |
| e. | Mitochondrion |
| f. | Free ribosome |
| g. | Microtubule |
| h. | Microfilament |
25. Contains powerful oxidative enzymes important in detoxifying various wastes.
26. Is/are an important component of cilia and flagella.
27. Is/are one continuous extensive organelle consisting of a network of tubules and flattened filament.
28. Removes unwanted cellular debris and foreign material.
29. Is/are the powerhouse of the cell.
30. Acts as a mechanical stiffener.
31. Synthesizes proteins for use in the cytosol.
32. Consists of stacks of flattened sacs.
33. Is/are shaped like an octagonal barrel.
25. ANS: D PTS: 1
26. ANS: G PTS: 1
27. ANS: A PTS: 1
28. ANS: C PTS: 1
29. ANS: E PTS: 1
30. ANS: H PTS: 1
31. ANS: F PTS: 1
32. ANS: B PTS: 1
33. ANS: F PTS: 1
Match the term to its description.
| a. | flagella |
| b. | cilia |
| c. | microvilli |
34. Are hair-like motile protrusions.
35. Increase the surface area of the small intestine epithelium.
36. Sweep mucus and debris out of respiratory airways.
37. Increase the surface area of the kidney tubules.
38. Enable sperm to move.
39. Are whip-like appendages.
40. Guide egg to oviduct.
34. ANS: B PTS: 1
35. ANS: C PTS: 1
36. ANS: B PTS: 1
37. ANS: C PTS: 1
38. ANS: A PTS: 1
39. ANS: A PTS: 1
40. ANS: B PTS: 1
Match the term to its description.
| a. | microtubules |
| b. | microfilaments |
| c. | intermediate filaments |
| d. | microtrabecular lattice |
41. Are/is the largest of the cytoskeletal elements.
42. Are/is present in parts of the cell subject to mechanical stress.
43. Are/is the smallest element(s) visible with a conventional electron microscope.
44. Consist(s) of actin.
45. Organize(s) the glycolytic enzymes in a sequential alignment.
46. Form(s) the mitotic spindle.
47. Are/is essential for creating and maintaining an asymmetrical cell shape.
48. Are/is composed of tubulin.
49. Provide(s) a pathway for axonal transport.
50. Are/is visible only with a high-voltage electron microscope.
51. Play(s) a key role in muscle contraction.
52. Slide past each other to cause ciliary bending.
41. ANS: A PTS: 1
42. ANS: C PTS: 1
43. ANS: B PTS: 1
44. ANS: B PTS: 1
45. ANS: D PTS: 1
46. ANS: A PTS: 1
47. ANS: A PTS: 1
48. ANS: A PTS: 1
49. ANS: A PTS: 1
50. ANS: D PTS: 1
51. ANS: B PTS: 1
52. ANS: A PTS: 1
Match the cellular protein with its correct characteristic.
| a. | dynamin |
| b. | tubulin |
| c. | kinesin |
| d. | actin |
53. Causes pinching off of endocytic vesicles.
54. Found along with myosin in muscle.
55. Comprises intermediate filaments.
56. Comprises microtubules.
57. Provides for transport of vesicles.
53. ANS: A PTS: 1
54. ANS: D PTS: 1
55. ANS: D PTS: 1
56. ANS: B PTS: 1
57. ANS: C PTS: 1
The accompanying figure relates to the secretion process for proteins by the endoplasmic reticulum. Match the steps highlighted in the figure (steps 1-7) with the statements using the letter key below.
| a. | Step 1 |
| b. | Step 2 |
| c. | Step 3 |
| d. | Step 4 |
| e. | Step 5 |
| f. | Step 6 |
| g. | Step 7 |
58. The transport vessel fuses with the Golgi complex.
59. Secretory vesicle fuses with the plasma membrane and empties content to the cell’s exterior.
60. Lysosome also bud off the Golgi complex.
61. Rough ER synthesizes protein to be secreted.
62. Vesicle move through the Golgi where modification and sorting takes place.
63. Secretory vesicles bud off the Golgi complex and remain in the cytosol.
64. The smooth ER packages the secretory product into transport vesicles.
58. ANS: C PTS: 1 OBJ: ART
59. ANS: F PTS: 1
60. ANS: G PTS: 1
61. ANS: A PTS: 1
62. ANS: D PTS: 1
63. ANS: E PTS: 1
64. ANS: B PTS: 1
ESSAY
1. Compare the structure and function of lysosomes and peroxisomes.
ANS:
Lysosomes serve as the intracellular digestive system. They contain hydrolytic enzymes and, in addition to breaking down raw ingredients, they also remove worn-out organelles.
Peroxisomes contain oxidative enzymes and perform detoxifying activities by removing hydrogen atoms from certain organic molecules. Lysosomes serve as the intracellular digestive system. They contain hydrolytic enzymes, and in addition to breaking down raw ingredients, they also remove worn-out organelles.
PTS: 1
2. Explain the relationship between Golgi complex and exocytosis.
ANS:
Vesicles with their selected cargo destined for different sites are wrapped in membranes containing different surface proteins. These surface proteins allow the vesicles to “dock” and unload their cargo at the proper location within the cell. Once a vesicle has docked at its target it opens and empties its content. Secretory vesicles release their contents out of the cell in a process called exocytosis.
PTS: 1
3. Compare the following terms: cellular respiration, oxidative phosphorylation and chemiosmosis.
ANS:
Cellular respiration refers to the collection of intracellular reactions in which nutrient molecules are broken down to form ATP. During the process, oxygen is utilized and carbon dioxide is produced. Oxidative phosphorylation is the process by which ATP is synthesized using the energy released by electrons as they are transferred to oxygen; it takes place at the mitochondrial inner membrane. Chemiosmosis encompasses the last steps of oxidative phosphorylation and involves the production of ATP via the activation of ATP synthase. This enzyme is activated as H+ moves into the mitochondrial matrix.
PTS: 1
4. Describe the major aspects of the cytoskeleton.
ANS:
The cytoskeleton is composed of microtubules, microfilaments, and intermediate filaments. Microtubules serve a variety of functions including maintaining the shape of cells, coordinating complex intracellular movements, and serving as the main structural component of cilia and flagella. Microfilaments play a major role in cellular contractile systems, including muscle contraction. Intermediate filaments resist mechanical stress placed on cells.
PTS: 1
5. Describe the structure and function of mitochondria.
ANS:
Mitochondria are enclosed by a double membrane—an outer membrane that surrounds the organelle itself and an inner membrane that contains numerous folds, called cristae. The innermost cavity formed by the cristae is called the matrix and is filled with a gel-like solution. These organelles play a major role in ATP production. Citric acid cycle reactions occur in the matrix, and oxidative phosphorylation reactions take place on the inner membrane.
PTS: 1
Fundamentals of Human Physiology, 4th Edition Lauralee Sherwood solutions manual and test bank
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