NUR4125 PrepU Chapter 2

When working with a client who has end-stage renal disease (ESRD) and is receiving peritoneal dialysis, the concept of diffusion can be explained by which statement?

"If your potassium level is high, then K+ particles will move from your peritoneal cavity into the dialysis solution, where the concentration of K+ is lower." Explanation: Diffusion refers to the passive process by which molecules and other particles in a solution become widely dispersed and reach a uniform concentration because of energy created by their spontaneous kinetic movements. In the process of reaching a uniform concentration, these molecules and particles move "downhill" from an area of higher to an area of lower concentration. Lipid-soluble molecules, such as oxygen, carbon dioxide, alcohol, and fatty acids (not K+) become dissolved in the lipid matrix of the cell membrane and diffuse through the membrane in the same manner that diffusion occurs in water. Diuretics are not very effective if a person has ESRD. The rate of diffusion depends on how many particles are available for diffusion, the kinetic movement of the particles, and the number and size of the openings in the membrane through which the molecules or ions can move. The environmental temperature does not play a role in this.

The nurse educates a client with a suspected myocardial infarction (MI) about the blood test to evaluate troponin levels. Which statement by the client indicates the education has been successful?

"This test is specific to components found in my heart muscle." Explanation: Normally, during the noncontracted state of a cardiac or skeletal muscle cell, troponin covers the tropomyosin-binding sites on the actin filament and prevents formation of cross-bridges. During electrical stimulus, calcium binds with troponin to open the binding sites and allow actin-myosin cross-bridges to form. The presence of troponin I or troponin T (specialized troponins found in the heart muscle) in the blood indicates that cardiac muscle damage released troponin into the bloodstream. The damage could arise from MI or other conditions such as ischemia, sepsis, or renal failure. Troponin levels remain elevated for at least 1 week after cardiac injury but take time to elevate and be detected. For this reason, a repeat level needs ot be drawn a few hours after the initial sample and one negative result is not sufficient to rule out MI. Lifestyle modification will not lower troponin levels.

The cytoplasm surrounds the nucleus of the cell and contains organelles. Select the organelles found in the cytoplasm. Select all that apply.

- Endoplasmic reticulum - Golgi apparatus - Mitochondria - Lysosomes Explanation: The cytoplasm surrounds the nucleus, and it is in the cytoplasm that the work of the cell takes place. Embedded in the cytoplasm are various membrane-enclosed organelles (e.g., endoplasmic reticulum, Golgi apparatus, mitochondria, and lysosomes) and complexes without membranes (e.g., ribosomes and proteasomes) that have important functions in cells. In addition to its organelles, the cytoplasm also contains a network of microtubules, actin microfilaments, and intermediate filaments called the cytoskeleton.

Which statements are accurate about mitochondria? Select all that apply.

- Mitochondria in active skeletal muscles increase rapidly. - Mitochondria are self-replicating. - Mitochondria regulate apoptosis. Explanation: Mitochondria are the cell components that convert organic compounds into energy the cells can use. They do not directly manufacture energy. Mitochondrial DNA is inherited from the maternal DNA. Mitochondria are self-replicating and will increase rapidly in skeletal muscles that are in use. Mitochondria regulate cell death, or apoptosis.

What are the three main parts of a typical cell? Select all that apply.

- Nucleus - Cell membrane - Cytoplasm Explanation: When seen under a light microscope, three major components of the cell become evident: the nucleus, the cytoplasm, and the cell membrane. Cell walls and vacuoles are found in plants and bacteria.

The Krebs cycle provides a common pathway for the metabolism of nutrients by the body. The Krebs cycle forms two pyruvate molecules. Each of the two pyruvate molecules formed in the cytoplasm from one molecule of glucose yields another molecule of:

ATP Explanation: Each of the two pyruvate molecules formed in the cytoplasm from one molecule of glucose yields another molecule of ATP, which is a special carrier for cellular energy. FAD, or flavin adenine dinucleotide, is a coenzyme of protein metabolism that accepts electrons and is reduced. NADH + H+ is an end product of glycolysis. The electron transport chain oxidizes NADH + H+ and FADH2 and donates the electrons to oxygen, which is reduced to water.

Which membrane transport mechanism requires the greatest amount of energy?

Active transport Explanation: Active transport encompasses endocytosis and exocytosis, both of which are membrane transport mechanisms that involve the expenditure of energy. Facilitated diffusion, passive transport, and simple diffusion are all processes that do not require metabolic energy.

What is the name of the process during which cells use energy to move ions against an electrical or chemical gradient?

Active transport Explanation: The process that moves ions against an electrical or chemical gradient is called active transport. This process of osmosis occurs when water moves through water channels in a semipermeable membrane along a concentration gradient, moving from an area of higher to one of lower concentration. Passive movement of particles or ions across the cell membrane is directly influenced by chemical or electrical gradients and does not require an expenditure of energy. Diffusion refers to the process by which molecules and other particles in a solution become widely dispersed and reach a uniform concentration because of energy created by their spontaneous kinetic movements.

The cells of the client's epithelial tissue are tightly bound together by specialized junctions. Select the junctions primarily responsible for preventing cell separation.

Adhering junctions Explanation: The primary role of adhering junctions is preventing cell separation. Nexus junctions play a role in cell-to-cell communications. Continuous tight or occluding junctions seal the surface membranes of adjacent cells together.

Select the type of energy production that occurs in the mitochondria with the Krebs cycle.

Aerobic metabolism Explanation: Two types of energy production are present in the cell: (1) the aerobic (i.e., with oxygen) pathway occurring in the mitochondria and involving the citric acid cycle (Krebs cycle), and (2) the anaerobic (i.e., without oxygen) glycolytic pathway, occurring in the cytoplasm. Glycolysis is the anaerobic process by which energy is liberated from glucose. It is an important source of energy for cells that lack mitochondria.

A client experiences burning muscle pain at the peak of high intensity physical training for an athletic competition. What is the best explanation for the cause of this occurrence?

Anaerobic glycolysis creates pyruvate, which converts to lactic acid. Explanation: During aerobic activity, glycolysis occurs in the citric acid cycle and mitochondria oxidize electrons with an increase in ATP. However, during intense activity, the energy need may outstrip the supply of oxygen. Anaerobic glycolysis continues to supply cells with ATP when oxygen is not present. Fatty acids are oxidized to enter the citric acid cycle.

What concept will the nurse need to explain to a client with cancer about the purpose and action of chemotherapy?

Apoptosis Explanation: Cancer is a condition in which cells experience dysregulated apoptosis as the cells fail to age and die. Chemotherapy stimulates these cells to increase their rate of death. Pinocytosis is when a cell engulfs small solid or liquid substances from the surrounding environment. Osmosis is fluid moving across a cell membrane and is not directly related to chemotherapeutic impact on cells. Depolarization has to do with electrical impulse transmission and is not directly correlated with chemotherapy.

A client with a complete tear of the rotator cuff in the right shoulder was given the choice between surgery and stem cell transplant. The client chose to try the stem cell injection. The client asked the health care provider, "How does this work on my shoulder?" The best response would be:

Bone marrow stem cells have been shown to generate cartilage, bone, and muscle when injected directly into the injured site. Explanation: Whether adult stem cells have a differentiation capacity similar to that of embryonic stem cells remains the subject of current debate and research. Thus far, bone marrow stem cells have been shown to have very broad differentiation capabilities, being able to generate not only blood cells but also fat, cartilage, bone, endothelial, and muscle cells.

Cadherins, selectins, and some integrins, which are adhesion molecules, depend on which of the following to function in cell adhesion?

Calcium Explanation: Important classes of extracellular macromolecules are the adhesion molecules that maintain intercellular contacts. There are three classes of adhesion molecules that depend on extracellular calcium to function in cell adhesion: cadherins, selectins, and integrins (some of which are magnesium dependent).

The cell surface is surrounded by a cell coat (glycocalyx.). Select the most important function of the cell coat.

Cell-to-cell recognition and adhesion Explanation: The cell coat participates in cell-to-cell recognition and adhesion, and it contains tissue transplant antigens. Ribosomes serve as sites for protein synthesis in the cell; the Golgi apparatus modifies materials synthesized in the ER. DNA provides the information necessary for the synthesis of the various proteins.

Select the main function of nervous tissue.

Communication Explanation: Nervous tissue is designed for communication purposes and includes the neurons, the supporting neural structures, and the ependymal cells that line the ventricles of the brain and the spinal canal. Muscle tissue is a specialized tissue designed for contractility. Connective tissue supports and connects body structures.

Select the option that best describes the nucleus of the cell.

Contains the site for RNA synthesis that ultimately is essential for protein synthesis. Explanation: The nucleus is the site for the synthesis of the three main types of RNA. These RNA molecules move from the nucleus to the cytoplasm and carry out the synthesis of proteins that is essential for the cell to stay alive. The messenger RNA copies and carries the DNA instructions. The mitochondria transform compounds into energy. The lysosomes break down excess and worn-out cell parts as well as foreign substances that are taken into the cell.

Although energy is not made in mitochondria, they are known as the "power plants" of the cell. Why are they thought of this way?

Extract energy from organic compounds Explanation: Mitochondria contain the enzymes that can change carbon-containing nutrients into energy that is easily accessible to the cell. Mitochondria contain their own DNA. Glycolysis is anaerobic metabolism and unrelated to oxidative energy. Mitochondria store phosphate bonds (such as in ATP) to power cellular functions.

Exocytosis allows granular content to be released into extracellular fluid by which process?

Creating an opening in the cell membrane, allowing contents of the vesicle to be released into ECF. Explanation: In exocytosis, a secretory granule fuses to the inner cell membrane to form an opening, allowing granule contents to be released. The granule contains cellular debris and synthesized substances such as peptide hormones, which it releases into the extracellular fluid. Phagocytosis and pinocytosis—types of endocytosis—function to engulf, kill, and present particles to lysosomal enzymes for degradation.

When exercising outside on an extremely warm day, the client can feel his heart pounding very rapidly. Thinking in terms of the ability of the aorta to stretch to accommodate more blood circulating during exercise and the warm environment, this is an example of the function of which fibrous protein?

Elastin Explanation: Three types of fibers are found in the extracellular space: collagen, elastin, and reticular fibers. Elastin acts like a rubber band; it can be stretched and then returns to its original form. Elastin fibers are abundant in structures subjected to frequent stretching, such as the aorta and some ligaments. Collagen is the most common protein in the body. It is a tough, nonliving, white fiber that serves as the structural framework for skin, ligaments, tendons, and many other structures. Reticular fibers are extremely thin fibers that create a flexible network in organs subjected to changes in form or volume, such as the spleen, liver, uterus, or intestinal muscle layer.

Which form of signal transduction resulting from ligand-receptor binding has the potential to produce effects in the entire body system?

Endocrine Explanation: Cells communicate in several ways. In endocrine signaling, the cells release chemical mediators (hormones) that enter the bloodstream, then bind to cell receptors throughout the body. A ligand is a substance with a high affinity for the receptor. In autocrine signaling, a cell releases a chemical to the extracellular fluid, which changes its own activity. In paracrine signaling, a cell releases a chemical to the extracellular fluid, but enzymes rapidly metabolize the chemicals so they only act on nearby cells.

A client with type 1 diabetes mellitus is experiencing hyperglycemia. Consequently, the client's cells lack intracellular glucose, resulting in glucose accumulating in the blood. Which process would best allow glucose to cross into the cell membranes?

Facilitated diffusion Explanation: Transport molecules perform facilitated diffusion, in which one substance carries another substance across a cell membrane. Simple diffusion does not require a transport molecule. Glucose does not cross the cell membrane by secondary active transport or endocytosis.

Tissues are composed primarily of cells in the M phase. T/F?

False Explanation: Tissues may be composed primarily of quiescent cells in the G0 phase. The M phase is the phase during which cell mitosis occurs.

Which statement regarding cell metabolism is most accurate?

Glycolysis also provides energy in situations when delivery of oxygen to the cells is delayed. Explanation: Glycolysis provides energy in situations when delivery of oxygen to the cells is delayed or impaired. Anabolism is a constructive process, in which more complex molecules are formed from simpler ones. Energy from foodstuffs is used to convert ADP to ATP. The aerobic pathway occurs in the mitochondria.

Some messengers, such as thyroid hormone and steroid hormones, do not bind to membrane receptors but move directly across the lipid layer of the cell membrane and are carried to the cell nucleus. What do they do at the cell nucleus?

Influence DNA activity Explanation: At the membrane of the cell nucleus, both thyroid and steroid hormones cross into the cell nucleus itself, where they influence DNA activity. Ion channel-linked receptors transiently open or close ion channels. Thyroid and steroid hormones act within the cell nucleus to increase transcription of mRNA to alter cell function.

The nucleus is called the center of the cell because it has the ability to do which of the following?

It contains the DNA that is essential for protein synthesis to keep the cell alive. Explanation: The nucleus contains the DNA that is essential to the cell because its genes contain the information necessary for the synthesis of proteins that the cell must produce to stay alive. The messenger RNA copies and carries the DNA instructions. The mitochondria transforms compounds into energy.

Select the organelle that is responsible for the breakdown of excess and worn-out cell parts as well as foreign substances that are taken into the cell.

Lysosomes Explanation: Lysosomes break down excess and worn-out cell parts as well as foreign substances that are taken into the cell. Peroxisomes contain enzymes that are used in oxidative reactions. Proteasomes are responsible for proteolysis of malformed and misfolded proteins. Ribosomes serve as sites for protein synthesis in the cell.

Apoptosis (programmed cell death) is regulated by which cellular component?

Mitochondria Explanation: Mitochondria function as key regulators of apoptosis or programmed cell death. Golgi apparatus, protoplasm, and phospholipids exist within the cell. They are not key in the process of programmed cell death.

Which cellular organelle transforms organic compounds into energy that is easily accessible to the cell?

Mitochondria Explanation: The mitochondria are literally the "power plants" of the cell because they transform organic compounds into energy that is easily accessible to the cell. They do not make energy, but extract it from organic compounds.

A school nurse is teaching a class on immunity. Which statement contains an accurate explanation about cellular defenses?

Neutrophils engulf invading organisms where lysosomes break them down. Explanation: Phagocytosis is when a cell, such as macrophages or neutrophils, engulfs an invading organism or damaged cells. Once inside the cell, the encapsulated particle is broken down by lysosomal enzymes.

A nurse practitioner (NP) has been asked to address the local high school basketball team regarding health and nutrition. One player asks how the pizza he ate last night is converted to energy that he can use today when he goes to practice. Which response is the best answer?

Nutrients are converted to ATP, and when ATP undergoes hydrolysis, it transfers energy to molecules in the cells for their use. Explanation: Cellular metabolism (catabolism) of carbohydrates via glycolysis, TCA cycle, and the mitochondrial electron transport chain converts the caloric energy into the chemical energy of ATP. ATP is hydrolyzed by enzymes in the cell to liberate the stored energy.

Which statement is true concerning human cell division?

Parent cell divides and each daughter cell receives chromosomes identical to the parent. Explanation: Cell division, or mitosis, is the process during which a parent cell divides and each daughter cell receives chromosomes identical to the parent. The series of mitotic divisions is called cleavage. Gene activity is needed for cell division and cell replication.

There are two forms of endoplasmic reticulum (ER) found in a cell. They are the rough and the smooth ER. What does the rough ER do in a cell?

Produces proteins Explanation: Rough ER is studded with ribosomes attached to specific binding sites on the membrane. Proteins produced by the rough ER are usually destined for incorporation into cell membranes and lysosomal enzymes or for exportation from the cell. The rough ER segregates (rather than combines) these proteins from other components of the cytoplasm and modifies their structure for a specific function. Rough ER does not transport anything through the cell membrane. Rough ER is studded with ribosomes; it does not destroy them.

The Golgi complex, or Golgi bodies, consists of stacks of thin, flattened vesicles or sacs within the cell. These Golgi bodies are found near the nucleus and function in association with the endoplasmic reticulum (ER). What is one purpose of the Golgi complex?

Receive proteins and other substances from the cell surface by a retrograde transport mechanism Explanation: Recent data suggest that the Golgi apparatus has yet another function: it can receive proteins and other substances from the cell surface by a retrograde transport mechanism. Golgi bodies do not produce bile. They produce secretory, not excretory, granules, and they produce large carbohydrate molecules rather than small ones.

To effectively relay signals, cell-to-cell communication utilizes a chemical messenger system to perform which function?

Release of hormones secreted by neurons into the bloodstream Explanation: Signals are transmitted by releasing chemical secretions into extracellular fluid. In some parts of the body, the same chemical messenger can function as a neurotransmitter, a paracrine mediator, and a hormone secreted by neurons into the bloodstream. Chemical signals move through cell-to-cell junctions to reach other cells and may attach to surface receptor proteins. The cytoplasmic contractile microfilaments are incapable of transmitting communication signals.

Which type of tissue forms the architecture of liver sinusoids and lymphoid tissues such as the spleen?

Reticular connective tissue Explanation: Reticular connective tissue is characterized by a network of fibers interspersed with fibroblasts and macrophages. Reticular tissue forms the architecture of liver sinusoids, adipose tissue, bone marrow, and lymphoid tissues such as the spleen.

A client with a pathophysiologic condition that affects the desmosomes is most likely to exhibit which problem?

Separation at the junctions between epithelial cells Explanation: Desmosomes are a type of cell junction common in epithelium. Failure of epithelial desmosomes results in the inappropriate separation of adjacent cells. Desmosomes do not contribute to muscle contraction, communication between neurons and effector organs, or the structure of collagen and elastin.

Which type of epithelium is found in the lining of blood vessels, lymph nodes, and alveoli of the lungs?

Simple squamous epithelium Explanation: Simple squamous epithelium is adapted for filtration, which works well on the blood vessels, lymph nodes, and alveoli of the lungs. Stratified squamous keratinized epithelium makes up the epidermis of the skin. A pseudostratified ciliated columnar epithelium with goblet cells forms the lining of most of the upper respiratory tract. Transitional epithelium is well adapted for the lining of organs that are constantly changing their volume, such as the urinary bladder.

Some tissues, such as the mucosal surface of the gastrointestinal tract, have cells that are capable of cell division and serve as a reserve source for specialized cells. What term describes these specialized cells?

Stem cells Explanation: Although most cells differentiate into specialized cell types, many tissues contain a few stem cells that apparently are only partially differentiated. These stem cells are still capable of cell division and serve as a reserve source for specialized cells throughout the life of the organism. Simple epithelium cells are adapted for filtration and line the blood vessels, lymph nodes, and alveoli. Stratified squamous keratinized epithelium make up the epidermis of the skin.

What statement is true concerning the use of ATP [adenosine triphosphate] by skeletal muscles?

Skeletal muscles use ATP at a rapid rate during exercise. Explanation: Skeletal muscles use minimal amounts of ATP when relaxed, and use ATP at a rapid rate when exercising.

A nurse practitioner (NP) has been asked to speak with the local high school track team about health, wellness, and nutrition. One of the athletes asks about the differences in the physiology of the energy used in sprinting versus long-distance running. Which response is the best answer?

Sprinters utilize ATP generated via anaerobic glycolysis, and distance runners utilize ATP generated via aerobic metabolism. Explanation: The use of anaerobic glycolysis by sprinters is due to the rapid demand for ATP, which outpaces the ability to produce it. Distance runners utilize ATP as it is synthesized; therefore, they may run for much longer. Diet does not affect muscle function on a cellular level. A reference to "explosive" or "slow, steady" energy does not explain the physiology of the matter.

A nurse on the oncology ward in the hospital is doing some background research to better understand the molecular basis of cancer. She comes to the understanding that transformed cancer cells are very similar to a normal type of cell, with the exception of regulation of division. Which cell type found in the normal state is most similar to a cancer cell?

Stem cells Explanation: Cancer cells and stem cells have very similar characteristics. They both are immortal and undifferentiated, unlike epithelial, muscle, and neural tissue. The primary difference between stem cells and cancer cells is the rate and regulation of division. Cancer cells have lost the ability to regulate the cell cycle.

A young, healthy adult helps lift a sofa to move it 25 feet. The nurse knows that which source of energy will the client most likely use in this process?

Stored ATP Explanation: Stored ATP, creatine phosphate, and muscle glycogen are among the first energy sources utilized during aerobic exercise. Amino acids, fatty acids, and glucose are utilized after prolonged periods of exercise.

The student is examining a tissue sample with a microscope. The student decides that it is squamous keratinized tissue. Which type of epithelial tissue is the student viewing?

Stratified epithelium Explanation: Stratified, squamous keratinized epithelium makes up the epidermis of the skin. Simple epithelium is found in the lining of blood vessels, lymph nodes, and alveoli of the lungs. Glandular epithelium is located in exocrine and endocrine glands. Neuroepithelium is located in in olfactory mucosa, retina, and the tongue.

Each skeletal muscle is a discrete organ made up of hundreds or thousands of muscle fibers. Although muscle fibers predominate, substantial amounts of connective tissue, blood vessels, and nerve fibers are also present. What happens during muscle contraction?

The thick myosin and thin actin filaments slide over each other, causing shortening of the muscle fiber. Explanation: Thin and thick filaments are the two types of muscle fibers that are responsible for muscle contraction. The thin filaments are composed primarily of actin, and the thick filaments are composed of myosin. During muscle contraction, the thick myosin and thin actin filaments slide over each other, causing shortening of the muscle fiber, although the length of the individual thick and thin filaments remains unchanged. When activated by ATP, the cross-bridges swivel in a fixed arc, much like the oars of a boat, as they become attached to the actin filament. During contraction, each cross-bridge undergoes its own cycle of movement, forming a bridge attachment and releasing it, and moving to another site where the same sequence of movement occurs. This pulls the thin and thick filaments past each other. The calcium-calmodulin complex is in smooth muscle. It binds to and activates the myosin-containing thick filaments, which interact with actin.

What determines the number of mitochondria in a given cell type?

The type of activity the cell performs. Explanation: The number of mitochondria in a given cell type is largely determined by the type of activity the cell performs and how much energy is needed to undertake the activity. The nutrition the cell receives, the gender of the organism, and the number of similar cells in the organism do not have any influence on the number of mitochondria present in any individual cell type.

Which explanation identifies correctly how the G protein-linked receptors are similar?

They have a ligand-binding extracellular receptor component, which causes changes that activate the G protein on the cytoplasmic side of the cell membrane. Explanation: Although there are differences among the G protein-linked receptors, all share a number of features. They all have a ligand-binding extracellular receptor component, which recognizes a specific ligand or first messenger. Upon ligand binding, they all undergo conformational changes that activate the G protein found on the cytoplasmic side of the cell membrane. Instead of having a cytosolic domain that associates with a G protein, enzyme-linked receptors have cytosolic domain either that has intrinsic enzyme activity or that associates directly with an enzyme. The binding of the hormone to a special transmembrane receptor results in activation of the enzyme adenylyl cyclase at the intracellular portion of the receptor. This enzyme then catalyzes the formation of the second messenger cAMP, which has multiple effects on cell function. Insulin, for example, acts by binding to an enzyme-linked receptor. Ion channel-linked receptors are involved in the rapid synaptic signaling between electrically excitable cells.

How does facilitated diffusion enable molecules to cross cell membranes?

Transport proteins carry molecules to areas of lower concentration. Explanation: Diffusion is movement of a substance across cell membranes in the direction of a lower concentration. Facilitated diffusion also moves substances to areas of lower concentration, but with the assistance of a carrier molecule. Ion channels are proteins that allow certain electrolyte ions to pass rapidly through the membrane. Active transport occurs when a transport protein carries substances across the cell membrane toward an area of higher concentration.

Smooth muscle contractions are typically characterized as:

involuntary. Explanation: Smooth muscle is often called involuntary muscle because it contracts without the person willing it to contract. Voluntary, motor, and somatic contractions are all under conscious control.

Although the majority of cellular DNA exists in the cell nucleus, the part of the cell DNA from one's mother is located where?

mitochondria Explanation: In addition to nuclear DNA, part of the DNA of a cell resides in the mitochondria. Mitochondrial DNA (mtDNA) is inherited from the mother by her offspring. DNA is not present in the Golgi apparatus, smooth endoplasmic reticulum, or microfilaments.

A client with a history of ischemic heart disease has had a myocardial infarction and gone into cardiac arrest. As a result, the client will:

obtain energy from glycolysis due to the sudden development of anaerobic conditions. Explanation: During anaerobic conditions such as cardiac arrest, glycolysis becomes a major source of cellular energy. Lactic acid is a waste product which does not get converted into ATP. Glycolysis requires the presence of NAD+, but it is not stored in hepatocytes. Pyruvic acid is an important short-term energy source, but it does not bind with oxygen molecules.

While reviewing the basic information related to hemodialysis, the nurse explains that water molecules move through adjacent phospholipid molecules in the cell membrane by:

osmosis. Explanation: Water molecules move through adjacent phospholipid molecules in the cell membrane by osmosis without actually dissolving in the region occupied by the fatty acid side of the chains. Osmosis is regulated by the concentration of nondiffusible particles on either side of the membrane, with water moving from the side with the lower concentration of particles to the side with the higher concentration.

A client with end-stage renal disease has been on peritoneal dialysis at home. Based on the lab work, the client regulates the type of solution to infuse into the abdomen. When there is a high concentration of potassium inside the cell (hyperkalemia), the solution infused has a lower concentration so that the potassium ions will diffuse outward. At this point, the cellular membrane is said to be:

polarized because of the presence of a negative membrane potential. Explanation: Because of the large concentration gradient existing across the cell membrane, potassium ions tend to diffuse outward. As they do so, they carry their positive charges with them, causing the inside to become negative in relation to the outside. This new potential difference repels further outward movement of the positively charged potassium ion. The membrane is said to be polarized.

The organelle responsible for synthesis of proteins by bound ribosomes is called:

rough endoplasmic reticulum. Explanation: The rough endoplasmic reticulum contains bound ribosomes that are responsible for manufacturing proteins such as pancreatic enzymes and plasma proteins.