Module 2: Cellular Adaptation, Injury, and Death

The cellular structure that contains DNA is called the: - cytoplasm - nucleus - ribosome - histone

nucleus

The chief function of the Golgi apparatus is: - enzyme storage and degradation. - lipid synthesis and metabolism. - disposal of phagocytized particles. - packaging proteins into secretory vesicles.

packaging proteins into secretory vesicles.

A white blood cell can ingest bacteria or cellular debris through the process of: - exocytosis - phagocytosis - facilitated diffusion - active transport

phagocytosis Phagocytosis is engulfment of bacteria or cellular debris by cells.

The main principle of the fluid mosaic model is that: - fluids can move easily in and out of cells. - proteins float in a fluid lipid bilayer. - cell membranes consist mainly of fluid. - the body consists mainly of water.

proteins float in a fluid lipid bilayer.

The cellular component that is most susceptible to radiation injury is the - membrane - DNA - RNA - ribosomes

DNA Cellular DNA is particularly susceptible to damage from radiation via breakage of the bonds holding the linear DNA together. Cell membranes, RNA, and ribosomes are not the most susceptible to radiation injury.

The primary effect of aging on all body systems is - decreased functional reserve. - diseased function. - programmed senescence. - senility.

decreased functional reserve. All body systems show age-related changes that can be generally described as a decrease in functional reserve; aging leads to inability to adapt to (internal and external) environmental changes. Not all effects of aging are considered disease; some are considered a normal part of aging. Programmed senescence is currently only a theory of aging that states cells have a preprogrammed number of cell divisions before they will die. Senility is an outdated term used to describe the cognitive changes associated with dementia; dementia is a disease and is not a normal part of aging.

Of the statements below, the accurate statement regarding nutrition and cellular health is - the body can generally produce elements essential for nutritional balance. - obese individuals are generally nutritionally healthy. - deficient cellular uptake by one cell type may contribute to excess nutrient delivery to other cell types. - a normal BMI indicates nutritional health.

deficient cellular uptake by one cell type may contribute to excess nutrient delivery to other cell types. Deficient cellular uptake by one cell type may contribute to excess nutrient delivery to other cell types such as in diabetes mellitus. Most of these essential nutrients must be obtained from external sources, because the cell is unable to manufacture them. Obesity involves an excess of caloric intake. The BMI is a measure for obesity, but does not indicate if a nutritional imbalance is present.

The cellular change that is considered preneoplastic is - anaplasia. - dysplasia. - metaplasia. - hyperplasia

dysplasia. Dysplastic cells have the potential to become cancerous and are therefore referred to as preneoplastic. Anaplasia, metaplasia, and hyperplasia are not considered preneoplastic.

Repolarization of a neuron after a depolarizing action potential is because of - activation of the Na+-K+ pump. - influx of calcium. - efflux of potassium. - influx of sodium.

efflux of potassium - Repolarization is because of efflux of potassium from the cell. - The Na+-K+ pump maintains cellular volume via osmotic pressure and helps to maintain resting membrane potential. - Calcium influx prolongs the action potential. - Influx of sodium initiates depolarization.

An increase in organ size and function caused by increased workload is termed - atrophy. - hypertrophy. - metaplasia - inflammation.

hypertrophy. Increased function of an organ such as the heart or skeletal muscle results in organ hypertrophy because of cellular enlargement. Atrophy refers to reduction in size of an organ because of cellular shrinkage. Metaplasia refers to replacement of one differentiated cell type with another. Inflammation results from immune response rather than workload.

An increase in extracellular potassium ion from 4.0 to 6.0 mEq/L would - hyperpolarize the resting membrane potential. - make it more difficult to reach threshold and produce an action potential. - hypopolarize the resting membrane potential. - alter the threshold potential.

hypopolarize the resting membrane potential. An increase in extracellular potassium hypopolarizes the cell (makes it less negative) because more K+ ions stay inside the cell owing to the reduced concentration gradient. Hyperpolarization of the resting membrane potential (makes it more negative) is caused by a decrease in extracellular potassium. Hyperpolarization resulting from a decrease in extracellular potassium makes it more difficult to reach threshold and produce an action potential. The threshold for action potential does not change with a change in extracellular potassium.

Movement of water through a membrane that separates two compartments with unequal concentration is called: - facilitated diffusion - active transport - osmosis - endocytosis

osmosis Osmosis is movement of water through a membrane into a compartment with a higher particle concentration.

Transport channels, receptors, and cell adhesion molecules all are found in cell membranes and they are made primarily of: - lipids. - carbohydrates. - proteins. - nucleic acids.

proteins.

Carbon monoxide injures cells by - destruction of cellular membranes. - reducing oxygen level on hemoglobin. - promotion of free radicals. - crystallization of cellular organelles.

reducing oxygen level on hemoglobin Carbon monoxide binds tightly to hemoglobin preventing the red blood cell from carrying adequate oxygen, leading to hypoxic injury. Other chemicals such as carbon tetrachloride promote free radicals, which injure cells and destroy cellular membranes. Crystallization of cellular organelles is caused by hypothermia.

Metaplasia is - the replacement of one differentiated cell type with another. - the transformation of a cell type to malignancy. - an irreversible cellular adaptation. - the disorganization of cells into various sizes, shapes, and arrangements.

the replacement of one differentiated cell type with another. Metaplasia is the replacement of one differentiated cell type with another secondary to persistent damage. Dysplasia transforms cells to preneoplastic lesions, which may become malignant. Metaplasia is reversible when the damage is stopped. Disorganization of cells into various sizes, shapes, and arrangements occurs in dysplasia.

Gap junctions are connecting channels that allow passage of small molecules from one cell to the next and are especially important for - distance signaling. - tissues requiring synchronized function. - communication within a cell. - passage of large molecules.

tissues requiring synchronized function. Gap junctions are especially important in tissues in which synchronized functions are required such as in cardiac muscle contraction. Gap junctions are channels between adjacent cells, not distant cells. Gap junctions function to promote communication not within a cell, but between adjacent cells. Gap junctions allow passage of small molecules, but not large molecules.

Excitable cells are able to conduct action potentials because they have - receptors for neurotransmitters - tight junctions - ligand-gated channels - voltage-gated channels

voltage-gated channels - Voltage-gated channels respond to changes in membrane potential and are responsible for conducting action potentials. - Receptors for neurotransmitters allow neurotransmitters to bind to the cell membrane but are not directly responsible for action potentials in excitable cells. - Tight junctions are intercellular connections that help segregate proteins on the cell membrane and are not involved in conducting action potentials. - Ligand-gated channels respond to binding of a signaling molecule such as a neurotransmitter, but are not directly responsible for action potentials in excitable cells.

Viruses differ from most bacteria in that they (Select all that apply.) - enter the host cell. - directly produce free radicals. - use the host's metabolic processes to survive and replicate. - do not induce an immune response. - do not produce toxins.

- enter the host cell. - use the host's metabolic processes to survive and replicate. - do not produce toxins.

Bacteria cause injury to cells by (Select all that apply.) - producing exotoxins. - producing endotoxins. - producing destructive enzymes. - reproducing inside of host cells altering cellular function. -evoking an immune reaction

- producing exotoxins. - producing endotoxins. - producing destructive enzymes. - evoking an immune reaction.

Glycolysis is the metabolic process of breaking down a glucose molecule to form - CO2 and H2O. - 2 ATP and 2 pyruvate. - 30 ATP. - oxygen.

2 ATP and 2 pyruvate - Glycolysis produces a net gain of two ATP molecules and breaks down glucose modules to produce two pyruvate molecules. - Oxidative phosphorylation produces CO2 and H2O. - Oxidative phosphorylation produces 30 ATP molecules. - Oxygen is not produced by glycolysis, but it is necessary for oxidative phosphorylation.

What is a lysosome? - A cell that has ruptured - A degradative enzyme inside a cell - A substance that has been ingested by a phagocytic cell - A membrane-bound bag of degradative enzymes within a cell

A membrane-bound bag of degradative enzymes within a cell

What is a cytoskeleton? - Cellular debris from a dead cell - The proteins in a cell membrane - A protein network inside a cell - The result of phagocytosis

A protein network inside a cell

The phase of cellular metabolism in which energy is released during breakdown of nutrient sources is anabolism. T/F

False Catabolism involves energy release via breakdown of nutrient sources such as glucose to provide ATP to the cell. In contrast, anabolism refers to energy-using processes that result in complex molecules such as fats.

Which one of these cellular processes can operate without oxygen? - Oxidative phosphorylation - Glycolysis - Citric acid cycle - Krebs cycle

Glycolysis Glycolysis degrades glucose to pyruvate without oxygen. This is called anaerobic metabolism.

During conditions of prolonged insufficient oxygen availability (e.g., respiratory or cardiovascular disease) anaerobic glycolysis accumulated pyruvate can lead to lactic acidosis. T/F

True Pyruvate is converted to lactate and released into the blood stream, resulting in lactic acidosis.

Some individuals inherit a gene that results in dangerously high blood cholesterol caused by impaired endocytosis of low-density lipoproteins (LDLs). T/F

True The defective gene inhibits the synthesis of LDL protein receptors on the cell membrane. This impairs endocytosis of LDL. High levels of LDL in the blood predispose to atherosclerosis.

GTP-binding proteins (G-proteins) function to - activate receptors on the extracellular surface. - degrade second-messenger molecules. - activate intracellular enzyme systems. - synthesize ATP.

activate intracellular enzyme systems G-proteins activate specific target enzymes within the cell and these enzymes then produce second-messenger molecules that trigger specific intracellular function. Membrane-bound G-protein channels are a component of the cell membrane; they do not activate other receptors on the extracellular surface. G-proteins do not degrade second messengers, but instead produce these. G-proteins do not synthesize ATP.

Apoptosis is a process that results in cellular - atrophy. - death. - proliferation. - mutation.

death - Apoptosis results in death of a cell when it is no longer needed. - Atrophy refers to reduction in size of an organ because of cellular shrinkage. - Proliferation refers to growth of new cells. - Mutation refers to alteration in the genetic structure of cellular DNA.

Extreme cold injures cells by all the following except - ischemic injury from vasoconstriction. - peripheral nerve damage from rebound vasodilation. - decreased blood viscosity. - crystallization of cellular components.

decreased blood viscosity. Hypothermia causes increased blood viscosity, which can result in ischemic injury. Initial vasoconstriction causes ischemic injury. Rebound vasodilation leads to intense swelling which damages peripheral nerves. Crystallization of cellular components leads to rupture of these components.

The benefit of glycolysis is that this second stage of catabolism supplies - ATP to meet energy needs of the body. - pyruvate to the citric acid cycle. - energy for oxidative phosphorylation. - lactate during anaerobic conditions.

pyruvate to the citric acid cycle The benefit of glycolysis is to supply pyruvate to the citric acid cycle of cellular metabolism, which then produces much ATP. Glycolysis only produces two ATP modules, which is insufficient for energy needs. Glycolysis does not supply energy for oxidative phosphorylation. Lactate produced during prolonged anaerobic conditions builds up and can lead to lactic acidosis, which is an undesirable outcome.

Signaling molecules such as hormones and growth factors influence their target cells by binding to their: - lipids. - organelles. - receptors. - cytoskeleton.

receptors.

Infectious injury often results from (Select all that apply.) - exotoxins. - endotoxins. - self-destruction of cells. - anti-inflammatory reactions. - enzymes from white blood cells.

- exotoxins. - endotoxins. - self-destruction of cells. - enzymes from white blood cells. Exotoxins produced by bacteria interfere with cellular functions. Endotoxins are a component of some bacteria; when the bacteria are lyses, endotoxins are released, causing fever and even circulatory shock. Virally infected cells may trigger their own destruction. Enzymes from white blood cells can harm cells in the area of inflammation. Infectious injury promotes inflammation; inflammation can cause more damage than the infecting agent.

The resting membrane potential in nerve and skeletal muscle is determined primarily by - extracellular sodium ion concentration. - the ratio of intracellular to extracellular potassium ions. - activation of voltage-gated sodium channels. - activity of energy-dependent membrane pumps.

the ratio of intracellular to extracellular potassium ions. The major determinant of the resting membrane potential is the difference in potassium ion concentration across the membrane. Extracellular sodium helps maintain cell volume and resting membrane potential, but it is not the primary determinant. Activation of voltage-gated sodium channels help initiate an action potential. Channels are not linked to an energy source; ions flow passively across the cell membrane.

Why is ongoing synthesis of ATP necessary for cell survival? -ATP is synthesized by mitochondria and released into the cytoplasm. - ATP provides energy for ion pumping and other cellular processes. - ATP is the genetic material of the cell. - ATP is an enzyme necessary for glucose metabolism.

ATP provides energy for ion pumping and other cellular processes.

Which form of molecular transport requires energy in the form of ATP? - Passive transport - Facilitated diffusion - Active transport - Osmosis

Active transport Active transport requires ATP to move molecules against a concentration gradient.

Under aerobic conditions, what process produces most of the energy for the cell? - Oxidative phosphorylation - Glycolysis - Active transport - Passive transport

Oxidative phosphorylation

Phospholipids spontaneously form lipid bilayers, because they are - polar - charged - insoluble - amphipathic

amphipathic Phospholipids have a hydrophilic (water-loving) polar end and a hydrophobic (water-fearing) polar end. This amphipathic nature causes the lipids to form bilayers. It is the water-loving and water-fearing nature of the end rather than simply being polar, charged, or insoluble that forms the bilayers.

Cell-to-cell communication through secretion of chemical signals into the bloodstream to target cells throughout the body is called _____ signaling. - synaptic - paracrine - endocrine - autocrine

endocrine Endocrine signaling is accomplished by specialized endocrine cells that secrete hormones that travel via the bloodstream to target cells throughout the body. Synaptic signaling occurs at specialized junctions between the nerve cell and its target cell; the neuron secretes a chemical neurotransmitter into a small space between the nerve and target cell. In paracrine signaling, chemicals are secreted into a localized area, and only those cells in the immediate area are affected. Autocrine signaling occurs when cells respond to signaling molecules that they secrete and provides feedback to that cell rather than other cells.

The cardiac drug digitalis enhances myocardial contraction, because it - increases intracellular calcium level in cardiac cells. - inhibits sodium from entering cardiac cells. - enhances the sodium-potassium pump. - increases the sodium gradient across the cell membrane.

increases intracellular calcium level in cardiac cells. Digitalis inhibits the sodium-potassium pump and allows the accumulation of intracellular sodium, decreasing the sodium gradient across the cell membrane. This leads to less efficient calcium removal by the sodium-dependent calcium pump. Increased calcium inside the cardiac cell leads to more forceful cardiac muscle contraction to treat congestive heart failure caused by cardiac muscle weakness.

Coagulative necrosis is caused by - dissolving of dead cells and cyst formation. - trauma or pancreatitis. - lung tissue damage. - interrupted blood supply.

interrupted blood supply Coagulative necrosis results from interrupted blood supply leading to ischemic cell injury. Liquefactive necrosis results from dissolving of dead cells and cyst formation. Fat necrosis is caused by trauma or pancreatitis. Caseous necrosis is caused by lung tissue damage such as that caused by tuberculosis.

The cellular response indicative of injury because of faulty metabolism is - hydropic swelling. - lactate production. - metaplasia. - intracellular accumulations.

intracellular accumulations. ntracellular accumulations result from faulty metabolism of lipids, carbohydrates, glycogen, and proteins. Hydropic swelling results from malfunction of the sodium-potassium pump. Lactate production results from anaerobic glycolytic pathway. Metaplasia occurs from persistent cell injury.

Reperfusion injury to cells - results in very little cellular damage. - results from calcium deficiency in cells. - occurs following nutritional injury. - involves formation of free radicals.

involves formation of free radicals. Free radicals are formed when high-energy electrons partially reduce oxygen in reperfusion injury. Reperfusion injury usually causes more cell damage than the original hypoxia. It results from calcium overload in the cells. Reperfusion injury results from hypoxic injury, rather than from nutritional injury.

The chief function of the smooth endoplasmic reticulum is: - enzyme storage and degradation. - lipid synthesis and metabolism. - disposal of phagocytized particles. - packaging proteins into secretory vesicles.

lipid synthesis and metabolism.

Necrotic death of brain tissue usually produces _____ necrosis. - coagulative - caseous - liquefactive - fat

liquefactive Liquefactive necrosis is produced when brain tissue dies, as it is rich in enzymes and has little connective tissue. Coagulative necrosis occurs from ischemic injury in any tissue. Caseous necrosis occurs in lung tissue damaged by tuberculosis. Fat necrosis occurs in adipose (fat) tissue.

The organelle that contains enzymes necessary for oxidative phosphorylation to produce ATP is the - mitochondria. - ribosome. - lysosome. - nucleus.

mitochondria The inner membrane of the mitochondria contains many enzymes that promote oxidative phosphorylation which produces ATP. Ribosomes synthesize proteins. Lysosomes and peroxisomes detoxify substances. The nucleus contains genomic DNA that codes for protein synthesis.

All these cellular responses are potentially reversible except - necrosis. - metaplasia. - atrophy. - hyperplasia.

necrosis - Necrosis refers to death of cells/tissue and is not reversible. - Metaplasia refers to the replacement of one differentiated cell type with another from persistent injury and is reversible when the injury stops. - Atrophy occurs because of lack of use of an organ and is reversible. - Hyperplasia is an increase in the number of cells from increased physiologic demands or hormonal stimulation and is reversible.

Somatic death refers to death - of a body organ. - of the entire organism. - of nerve cells. - secondary to brain damage.

of the entire organism. Somatic death refers to death of an entire organism. Somatic death is not simply death of one body organ. Somatic death involves death of all cells in the body. Brain death refers to death of the brain only, but organ systems can remain living with mechanical assistance.

The chief function of ribosomes is: - synthesis of proteins - synthesis of lipids - disposal of phagocytized particles - packaging proteins into secretory vesicles

synthesis of proteins

Ribosomes are very important organelles within the cell that have the function of - detoxifying substances - synthesizing proteins - converting energy to forms that can be used - coding for protein synthesis

synthesizing proteins - Ribosome's primary function is the synthesis of proteins. - Lysosomes and peroxisomes detoxify substances. - Mitochondria convert energy to forms that can be used to drive cell reactions. - The nucleus contains genomic DNA that codes for protein synthesis.

Ion channels open and close in response to all the following except - mechanical pressure - ligand binding - voltage changes - temperature changes

temperature changes on the cell membrane. Mechanically gated channels respond to mechanical deformation. Ligand-gated channels respond to the binding of a signaling molecule (neurotransmitter or hormone). Voltage-gated channels respond to a change in membrane potential.