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A study guide for chapter 1 of the textbook 'pathophysiology: the biological basis for disease in adults and children'. It includes questions and answers related to cellular biology, specifically the process of b lymphocyte maturation and the role of th1 and th2 cells in the immune response. It also covers the topic of tumor markers and their relationship to cancer cells.
Typology: Exams
1 / 680
MULTIPLE CHOICE
ANS: C In metabolic absorption, all cells take in and use nutrients and other substances from their surroundings. The remaining options are not inclusive in their descriptions of cellular metabolic absorption.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: C The nucleus contains the nucleolus , a small dense structure composed largely of RNA, most of the cellular DNA, and the DNA-binding proteins, such as the histones, which regulate its activity. The mitochondria are responsible for cellular respiration and energy production. Ribosomes’ chief function is to provide sites for cellular protein synthesis. Lysosomes function as the intracellular digestive system.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: B
Peroxisomes are so named because they usually contain enzymes that use oxygen to remove hydrogen atoms from specific substrates in an oxidative reaction that produces H 2 O 2 , which is a powerful oxidant and potentially destructive if it accumulates or escapes from peroxisomes. Ribosomes are RNA-protein complexes (nucleoproteins) that are synthesized in the nucleolus and secreted into the cytoplasm through pores in the nuclear envelope called nuclear pore complexes. Lysosomes are saclike structures that originate from the Golgi complex and contain more than 40 digestive enzymes called hydrolases , which catalyze bonds in proteins, lipids, nucleic acids, and carbohydrates. An endosome is a vesical that has been pinched off from the cellular membrane.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: D The lysosomal membrane acts as a protective shield between the powerful digestive enzymes within the lysosome and the cytoplasm, preventing their leakage into the cytoplasmic matrix. Disruption of the membrane by various treatments or cellular injury leads to a release of the lysosomal enzymes, which can then react with their specific substrates, causing cellular self-digestion. The chief function of a ribosome is to provide sites for cellular protein synthesis. The Golgi complex is a network of flattened, smooth vesicles and membranes often located near the cell nucleus. The smooth endoplasmic reticulum is involved in steroid hormone production and removing toxic substances from the cell.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: C Antidiuretic hormone leads to increased retention of water in the body. Epinephrine causes increases in heart rate and force of contraction. Increased cortisol secretion is due to ACTH. Breakdown of fat is due to glucagon.
PTS: 1 DIF: Cognitive Level: Remembering
d. (^) M ANS: B
The four designated phases of the cell cycle are: (1) the G 1 phase (G = gap), which is the period between the M phase (M = mitosis) and the start of DNA synthesis; (2) the S phase (S = synthesis), during which DNA is synthesized in the cell nucleus; (3) the G 2 phase, during which RNA and protein synthesis occurs, the period between the completion of DNA synthesis and the next phase (M); and (4) the M phase, which includes nuclear and cytoplasmic division.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: C Proteins have several functions, including acting as receptors, transport channels for electrolytes, and enzymes to drive active pumps Lipids help act as the “glue” holding cell membranes together. Proteases cause the breakdown of protein. Carbohydrates are involved in cellular protection and lubrication and help produce energy via oxidative phosphorylation.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: B Understanding the various steps involved in this process is crucial for designing drug interventions. Dysregulation of proteases features prominently in many human diseases, including cancer, autoimmunity, and neurodegenerative disorders. Cardiac, vascular, gastrointestinal, renal, and endocrine disorders do not involve this process.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: D
The bilayer’s structure accounts for one of the essential functions of the plasma membrane. It is impermeable to most water-soluble molecules (molecules that dissolve in water) because the water-soluble molecules are insoluble in the oily core region. The bilayer serves as a barrier to the diffusion of water and hydrophilic substances while allowing lipid-soluble molecules, such as oxygen (O 2 ) and carbon dioxide (CO 2 ), to diffuse through it readily. Carbohydrate chains, glycoprotein channels, and membrane channel proteins do not prevent water-soluble molecules from entering cells across the cell membrane.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: B During the absolute refractory state of the action potential, no stimulus is able to evoke another response from the cell. A stronger than normal impulse may generate a response in the relative refractory period. This period of time is not related to the number of stimuli. A hyperpolarized state means a stronger than normal stimulus would be needed to generate a response.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: B Cells communicate in three main ways; they display plasma membrane-bound signaling molecules that affect the cell itself and other cells in direct physical contact with it, they affect receptor proteins inside the target cell, and they form protein channels (gap junctions) that directly coordinate the activities of adjacent cells. Neurotransmitters are released by neurons and cross the synaptic cleft to communicate with the cells they innervate. Ligands are involved in binding processes.
PTS: 1 DIF: Cognitive Level: Remembering
d. (^) Hormonal ANS: D
Chemical signaling can be classified into three categories: (1) local-chemical mediator, (2) hormone, and (3) neurotransmitter. Hormones are released by one set of cells and travel through tissues or the bloodstream to another set of cells where they produce a response by those cells. In paracrine signaling, cells secrete local chemical mediators that are quickly absorbed, destroyed, or immobilized. Paracrine signaling requires close membrane-to-membrane contact. Paracrine signaling usually involves different cell types; however, cells also may produce signals that they, themselves, respond to, which is called autocrine signaling. Neurotransmitters are released by neurons and cross the synaptic cleft to communicate with the cells they innervate.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: A In paracrine signaling , cells secrete local chemical mediators that are quickly taken up, destroyed, or immobilized. Autocrine signaling occurs when the target cells produce signals that they themselves respond to. Neurotransmitters are released by neurons and cross the synaptic cleft to communicate with the cells they innervate. Hormones are released by one set of cells and travel through tissues or the bloodstream to another set of cells where they produce a response by those cells.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: D In each type of chemical signaling, the target cell receives the signal by first attaching to its receptors. The other options do not correctly describe this process.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: D
Signal transduction involves incoming signals or instructions from extracellular chemical messengers (ligands) that are conveyed to the cell’s interior for execution. The other options do not correctly describe how cells receive communication from the surrounding extracellular fluid.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: B The two major second-messenger pathways are cyclic AMP (cAMP) and calcium (Ca++). GTP, ATP, and GDP are not major second-messenger pathways. GTP and GDP are “middlemen” or intermediaries. Nutrients are transformed into energy in the form of ATP.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: B Glycolysis provides energy to the cells when oxygen delivery is insufficient or delayed. Oxidative phosphorylation is the process by which energy produced from nutrients is transferred to ATP. Lactolysis is the breakdown of lactose. Passive transport is the movement of water and small, nonelectrically charge molecules across plasma membranes.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: C Oxidative phosphorylation occurs in the mitochondria and is the mechanism by which the energy produced from carbohydrates, fats, and proteins is transferred to ATP. Glycolysis provides energy to the cells when oxygen delivery is insufficient or delayed. Oxidative cellular metabolism and tricarboxylic acid phosphorylation are not involved in transferring energy to ATP.
PTS: 1 DIF: Cognitive Level: Remembering
a. (^) Being driven by osmosis, hydrostatic pressure, and diffusion b. (^) Involving receptors that can bind with substances being transported c. (^) Being capable of transporting macromolecules d. (^) Requiring energy generated by the cell
ANS: A Water and small electrically uncharged molecules move easily through pores in the plasma membrane’s lipid bilayer. This process, called passive transport , naturally occurs through any semipermeable barrier. It is driven by osmosis, hydrostatic pressure, and diffusion, all of which depend on the laws of physics and do not require life. The other options do not correctly describe passive transport.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: B Active transport requires a life, biologic activity, and the expenditure of metabolic energy. Movement due simply to differences in concentration gradients is called passive transport. Movement of two molecules in the same direction is called symport, while moving two molecules in opposite directions is called antiport.
PTS: 1 DIF: Cognitive Level: Remembering
PTS: 1 DIF: Cognitive Level: Remembering
c. (^) Diffusion d. (^) Active transport
ANS: A
Hydrostatic pressure is the mechanical force of water pushing against cellular membranes. Osmosis is the movement of water “down” a concentration gradient, that is, across a semipermeable membrane from a region of higher water concentration to a region of lower water concentration. Diffusion is the movement of a solute molecule from an area of greater solute concentration to an area of lesser solute concentration. Active transport requires a life, biologic activity, and the expenditure of metabolic energy.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: C Osmolality is a measure of the number of milliosmoles per kilogram (mOsm/kg) of water, or the concentration of molecules per weight of water. Osmolarity is a measure of the number of milliosmoles per liter (mOsm/L) of solution, or the concentration of molecules per volume of solution. Osmolality is a measure of the number of milliosmoles per kilogram (mOsm/kg) of water, or the concentration of molecules per weight of water. Osmolarity is a measure of the number of milliosmoles per liter (mOsm/L) of solution, or the concentration of molecules per volume of solution. In plasma, less of the plasma weight is water; therefore the overall concentration of particles is greater. The osmolality will be greater than the osmolarity because of the smaller proportion of water. Osmolality is thus the preferred measure of osmotic activity in clinical assessment of individuals.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: C A hypertonic solution has a concentration of greater than 285 to 294 mOsm/kg. An example of a hypertonic solution is 3% saline solution. Water can be pulled out of the cells by a hypertonic solution; therefore the cells shrink. An isotonic solution will cause the cells to become more hydrated without disrupting the osmolality of either intracellular or extracellular fluid. Hypotonic solutions can cause cells to swell or burst. No solutions lead to cell division.
PTS: 1 DIF: Cognitive Level: Remembering
a. (^) Hydrostatic pressure b. (^) Active diffusion c. (^) Passive osmosis
d. (^) Mediated transport ANS: D Mediated transport is the means by which glucose is transported from the blood to the cells. This process uses transport proteins. Hydrostatic pressure is the force of water pushing against a cell membrane. Diffusion is a passive process, not active. Osmosis is the movement of water “down” a concentration gradient, that is, across a semipermeable membrane from a region of higher water concentration to a region of lower water concentration and is a passive process.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: C The exact mechanism for the transport of Na+^ and K+^ across the membrane is uncertain. One proposal is that ATPase enzyme induces the transporter protein to undergo several conformational changes, causing Na+^ and K+^ to move short distances (see Figure 1-29). The remaining options do not correctly describe the means by which K+^ and Na+^ are transported.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: A In eukaryotic cells, secretion of macromolecules almost always occurs by exocytosis. The remaining options do not correctly describe exocytosis.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: C The cellular uptake of nutrients, such as cholesterol, for example, depends on receptor-mediated endocytosis. Nutrients are not transported via the other options.
PTS: 1 DIF: Cognitive Level: Remembering
b. (^) Sodium gates open, and sodium rushes into the cell, changing the membrane potential from negative to positive. c. (^) Sodium gates close, allowing potassium into the cell to change the membrane potential from positive to negative. d. (^) Potassium gates close, allowing sodium into the cell to change the membrane potential from positive to negative. ANS: B When a resting cell is stimulated through voltage-regulated channels, the cell membranes become more permeable to Na+. As Na+^ moves into the cell the membrane potential decreases, or moves forward , from a negative value (in millivolts) to zero. The Na+^ gates open, and Na+^ rushes into the cell, causing the membrane potential to reduce to zero and then become positive (depolarization). The remaining options do not correctly describe the change that initiates an action potential.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: C Different types of cells require different factors to stimulate proliferation; for example, platelet-derived growth factor stimulates the production of connective tissue cells. Platelet-derived growth factor does not stimulate production of platelets, epidermal cells, or fibroblasts.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: A Growth factors, also called cytokines , stimulate an increase in cell mass or cell growth by promoting the synthesis of proteins and other macromolecules and inhibiting their degradation.
PTS: 1 DIF: Cognitive Level: Remembering
d. (^) The process involves the interaction of male and female cells. ANS: C
During telophase, the final stage of cellular reproduction, two identical diploid cells, called daughter cells, has been formed from the original cell. The process occurs hundreds of times a second. Interphase is the longest phase of the cell cycle. Male and female cells do not interact in cellular reproduction; each cell is responsible for reproducing itself.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: B Eukaryotic cells have a characteristic set of membrane-bound intracellular compartments called organelles that include a well-defined nucleus encased in a nuclear membrane. Eukaryotic cells are also larger than prokaryotes.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: C Phagocytosis is the engulfment of large particles in phagocytic cells. Phagocytosis is an example of endocytosis, not exocytosis and does not focus on solutes.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: A A cell has the potential to differentiation and to gain the ability to perform one of eight specialized functions. Muscle cells can generate forces that produce motion. Nerves cells are capable of conductivity. Cells of the adrenal gland, testis, and ovary can secrete. Respiration is a function that all cells possess.
PTS: 1 DIF: Cognitive Level: Remembering
a. (^) Excretion b. (^) Metabolic absorption c. (^) Reproduction d. (^) Secretion
ANS: D Certain cells, such as mucous gland cells, can synthesize new substances from substances they absorb and then secrete the new substances to serve elsewhere as needed. Excretion occurs when cells rid themselves of waste products. Reproduction is the process of forming new cells.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: A All cells have the capacity to excrete, thus allowing them to rid themselves of waste products resulting from the metabolic breakdown of nutrients. Muscle cells have the property of movement. Conductivity is a property of nerve cells. Many, but not all, cells are capable of reproduction.
PTS: 1 DIF: Cognitive Level: Remembering
ANS: A The DNA damage response occurs when DNA is damaged and several protein kinases are recruited to the site of damage and start a signaling pathway that stops the progression of the cell cycle, or cell cycle arrest. Cell cycle arrest does not involve suppressing programmed cell death, macromolecule degradation, or growth factor production.
PTS: 1 DIF: Cognitive Level: Remembering
MULTIPLE RESPONSE
1. What are the major chemical components of the cell membranes? (Select all that apply.) a. (^) Lipids b. (^) Sodium ions c. (^) Carbohydrates d. (^) DNA e. (^) Proteins
ANS: A, E The major chemical components of all cell membranes are lipids and proteins. Sodium ions,
carbohydrates, and DNA are not major chemical components of cell membranes.
PTS: 1 DIF: Cognitive Level: Remembering