NU 545 UNIT #1 EXAM STUDY GUIDE
QUESTIONS AND ANSWERS
Understand the transportation of potassium and sodium across plasma membranes -
Answer-The Na+ -K+ antiport system (Na+ moving out of the cell and K+ moving into
the cell) uses the direct energy of ATP to move these cations. The transporter protein is
the enzyme adenosine triphosphatase (ATPase). Approximately 60% to 70% of the ATP
synthesized by cells is used to maintain the Na+-K+ transport system. 1, three Na+ ions
bind to sodium- binding sites on the carrier's interface. 2, at the same time, an energy-
containing adenosine triphosphate molecule produced by the cell's mitochondria bind to
the carrier. The ATP disassociates, transferring its stored energy to the carrier. 3 and 4,
the carrier then changes shape, releases the three Na+ ions to the outside of the cell,
and attracts two potassium ions to its potassium- binding site. 5, the carrier then returns
to its original shape, releasing the two K+ ions and the remnant of the ATP molecule to
the inside of the cell. The carrier is now ready for another pumping cycle (p.31)
What is active transport? - Answer-requires life, biologic activity, and the cell's
expenditure of metabolic energy. Unlike passive transport, active transport occurs
across only living membranes that have to drive the flow "uphill" by coupling it to an
energy source (p. 28)
What are cytokines? - Answer-Growth factor, 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 (p. 38)
Cytokines constitute a large family of small-molecular-weight soluble intracellular-
signaling molecules that are secreted, bind to a specific cell membrane receptors, and
regulate innate or adaptive immunity; either proinflammatory or anti-inflammatory.
Majority of important cytokines are classified as interleukins or interferons (p. 201)
Do all cells continue to replicate and divide? - Answer-No. For example, most of the
neurons and skeletal muscle cells are in a terminally differentiated G0 state; with their
cell cycle control system disassembled, the molecular regulatory switches become
permanently turned off and cell division rarely occurs (p. 37)
When normal columnar ciliated epithelial cells of the bronchial lining are replaced by
stratified squamous epithelial cells, the process is called? - Answer-Bronchial
metaplasia (p. 49)
What is the relation between ischemia and ATP? - Answer-An anaerobic (without
oxygen) metabolic pathway can synthesize ATP. This process called substrate
phosphorylation, or anaerobic glycolysis, is linked to the breakdown (glycolysis) of
carbohydrates.... The reactions in anaerobic glycolysis involve the conversion of
glucose to pyruvic acid (pyruvate) with the simultaneous production of ATP. If oxygen is
absent, pyruvate is converted to lactic acid, which is released into the extracellular fluid.
,Elevated lactate level is indicative of tissue hypoxia or low oxygen concentration (pp.26
& 27)....As lactic acid increases, oxygen decreases (hypoxia), cell tissues...this is
reversible if oxygen is reintroduced...
When does sodium enter the cell and cause swelling? - Answer-A reduction in ATP
levels causes the plasma membrane's sodium-potassium pump (Na+-K+) and sodium-
calcium exchange to fail, which leads to an intracellular accumulation of sodium and
calcium, resulting in cellular swelling and diffusion of potassium out of the cell (p. 51)
Cellular swelling, the most common degenerative change, is caused by the shift of
extracellular water into the cell. In hypoxic injury, movement of fluid and ions into the
cell is associated with acute failure of metabolism and loss of ATP production. Normally,
the pump that transports sodium ions (Na+) out of the cell is maintained by the
presence of ATP in adenosine triphosphatase (ATPase), the active transport enzyme. In
metabolic failure caused by hypoxia, reduced levels of ATP and ATPase permit sodium
to accumulate in the cell, whereas potassium (K+) diffuses outward. The increase of
intracellular sodium concentration increases osmotic pressure, which draws more water
into the cell. The cisternae of the endoplasmic reticulum become distended, rupture,
and coalesce to form large vacuoles that isolate the water from the cytoplasm, a
process called vacuolation. Progressive vacuolation results in cytoplasmic swelling
called oncosis or vacuolar degeneration. If cellular swelling affects all cells in an organ,
the organ increases in weight and becomes distended and pale. Cellular swelling is
reversible and an early manifestation of almost all types of cellular injury (p.84)
What are free radicals in relation to cell damage? Progression of diseases? - Answer-A
free radical is any molecular species capable of independent existence that contains a
single unpaired electron in an outer orbit. Having one unpaired electron makes the
molecule unstable; The molecule becomes stabilized either by donating or by accepting
an electron from another molecule. When the attacked molecule loses its electron, it
becomes a free radical. Therefore, it is capable of injurious chemical bond formation
with DNA, RNA, proteins, lipids, and carbohydrates- many other key molecules in
membranes and nucleic acids. Free radicals are difficult to control and initiate chain
reactions. With low chemical specificity and high reactivity, free radicals can react with
most molecules in their proximity.
An important mechanism of membrane damage is injury induced by free radicals,
especially by a disturbance in the balance between the production of ROS and
antioxidant defenses called oxidative stress. Oxidative stress can be caused by an
increase of different reactive species or depletion of antioxidant defense, or both, and
result in detrimental oxidation of different molecules including proteins, lipids, nucleic
acids, and others. Oxidative stress can activate several intracellular signaling pathways
because ROS can modulate enzymes and transcription factors. This process is an
important mechanism of cell damage and many conditions, including cell injury, cancer,
certain degenerative diseases (Alzheimer's disease), and aging (p. 54).
Know all about lead poisoning. How does it cause damage within the cell? - Answer-
Lead is a toxic heavy metal. Developing fetuses and young children absorb lead more
easily, susceptibility to brain damage. Organ systems affected: nervous, hematopoietic,
, reproductive, gastrointestinal, cardiovascular, musculoskeletal, as well as kidneys.
Exposure occurs via inhalation, ingestion and skin contact. Lead exposure damages or
destroys the plasma membrane, alters cellular ion status (disruption of divalent cations,
ion transport mechanism and protein function). Lead then disrupts the movement and
storage of calcium inside cells, increasing cell stress, which can lead to the death of
neurons and other brain cells. Lead causes abnormal conformational changes in the
protein structure, altered protein functions. Pg 66
Know about the effects of fetal alcohol syndrome on infants. - Answer-Diagnosis of FAS
requires all three facial abnormalities: short palpebral fissure lengths, smooth philtrum
and thin upper lip. FAS may have abnormal facial features, growth problems, CNS
problems, issues with learning, memory, attention, vision, hearing. Pg 70
How does alcohol affect the nervous system? - Answer-Alcohol causes CNS
depression. sedation, drowsiness, loss of motor, altered mental status. Can possibly
cause respiratory arrest because of medullary center depression. Pg 68
Where do lipids accumulate? - Answer-Although lipids sometimes accumulate in heart
and kidney cells, the most common site of intracellular lipid accumulation, or fatty
change, is liver cells. Pg 84
What is hemosiderosis? - Answer-Hemosiderosis is a condition which excess iron is
stored as hemosiderin (a yellow-brown pigment derived from hemoglobin) in the cells of
many organs and tissues. Common in people that get multiple blood transfusions. pg 86
What causes free calcium in the cytosol? - Answer-Influx of extracellular calcium in
injured mitochondria. Calcium stores in mitochondria and endoplasmic reticulum
pumped into the extracellular space bound to calcium-binding proteins -> released after
cell damage -> free Ca++ (see table on pg 86)
What happens to sodium and water during cell injury? - Answer-A process known as
oncosis hypoxia that leads to ATP production decreases which leads to sodium and
water moving into the cell and potassium moving out of the cell, osmotic pressure
increases more water moves into the cell cisternae of endoplasmic reticulum distend
rupture and form vacuoles causing hydropic degeneration pg 84
During cell injury caused by hypoxia, what happens to osmotic pressure? - Answer-The
increase of intracellular sodium concentration increases osmotic pressure which draws
more water into the cell pg 84
What causes mammary glands to enlarge in pregnancy? - Answer-Prolactin and GH
secreted from anterior pituitary cause glands and ducts to grow
After ovulation what happens to uterine endometrial cells? - Answer-Estrogen
stimulates the endometrium to grow and thicken for reception of the fertilized ovum
QUESTIONS AND ANSWERS
Understand the transportation of potassium and sodium across plasma membranes -
Answer-The Na+ -K+ antiport system (Na+ moving out of the cell and K+ moving into
the cell) uses the direct energy of ATP to move these cations. The transporter protein is
the enzyme adenosine triphosphatase (ATPase). Approximately 60% to 70% of the ATP
synthesized by cells is used to maintain the Na+-K+ transport system. 1, three Na+ ions
bind to sodium- binding sites on the carrier's interface. 2, at the same time, an energy-
containing adenosine triphosphate molecule produced by the cell's mitochondria bind to
the carrier. The ATP disassociates, transferring its stored energy to the carrier. 3 and 4,
the carrier then changes shape, releases the three Na+ ions to the outside of the cell,
and attracts two potassium ions to its potassium- binding site. 5, the carrier then returns
to its original shape, releasing the two K+ ions and the remnant of the ATP molecule to
the inside of the cell. The carrier is now ready for another pumping cycle (p.31)
What is active transport? - Answer-requires life, biologic activity, and the cell's
expenditure of metabolic energy. Unlike passive transport, active transport occurs
across only living membranes that have to drive the flow "uphill" by coupling it to an
energy source (p. 28)
What are cytokines? - Answer-Growth factor, 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 (p. 38)
Cytokines constitute a large family of small-molecular-weight soluble intracellular-
signaling molecules that are secreted, bind to a specific cell membrane receptors, and
regulate innate or adaptive immunity; either proinflammatory or anti-inflammatory.
Majority of important cytokines are classified as interleukins or interferons (p. 201)
Do all cells continue to replicate and divide? - Answer-No. For example, most of the
neurons and skeletal muscle cells are in a terminally differentiated G0 state; with their
cell cycle control system disassembled, the molecular regulatory switches become
permanently turned off and cell division rarely occurs (p. 37)
When normal columnar ciliated epithelial cells of the bronchial lining are replaced by
stratified squamous epithelial cells, the process is called? - Answer-Bronchial
metaplasia (p. 49)
What is the relation between ischemia and ATP? - Answer-An anaerobic (without
oxygen) metabolic pathway can synthesize ATP. This process called substrate
phosphorylation, or anaerobic glycolysis, is linked to the breakdown (glycolysis) of
carbohydrates.... The reactions in anaerobic glycolysis involve the conversion of
glucose to pyruvic acid (pyruvate) with the simultaneous production of ATP. If oxygen is
absent, pyruvate is converted to lactic acid, which is released into the extracellular fluid.
,Elevated lactate level is indicative of tissue hypoxia or low oxygen concentration (pp.26
& 27)....As lactic acid increases, oxygen decreases (hypoxia), cell tissues...this is
reversible if oxygen is reintroduced...
When does sodium enter the cell and cause swelling? - Answer-A reduction in ATP
levels causes the plasma membrane's sodium-potassium pump (Na+-K+) and sodium-
calcium exchange to fail, which leads to an intracellular accumulation of sodium and
calcium, resulting in cellular swelling and diffusion of potassium out of the cell (p. 51)
Cellular swelling, the most common degenerative change, is caused by the shift of
extracellular water into the cell. In hypoxic injury, movement of fluid and ions into the
cell is associated with acute failure of metabolism and loss of ATP production. Normally,
the pump that transports sodium ions (Na+) out of the cell is maintained by the
presence of ATP in adenosine triphosphatase (ATPase), the active transport enzyme. In
metabolic failure caused by hypoxia, reduced levels of ATP and ATPase permit sodium
to accumulate in the cell, whereas potassium (K+) diffuses outward. The increase of
intracellular sodium concentration increases osmotic pressure, which draws more water
into the cell. The cisternae of the endoplasmic reticulum become distended, rupture,
and coalesce to form large vacuoles that isolate the water from the cytoplasm, a
process called vacuolation. Progressive vacuolation results in cytoplasmic swelling
called oncosis or vacuolar degeneration. If cellular swelling affects all cells in an organ,
the organ increases in weight and becomes distended and pale. Cellular swelling is
reversible and an early manifestation of almost all types of cellular injury (p.84)
What are free radicals in relation to cell damage? Progression of diseases? - Answer-A
free radical is any molecular species capable of independent existence that contains a
single unpaired electron in an outer orbit. Having one unpaired electron makes the
molecule unstable; The molecule becomes stabilized either by donating or by accepting
an electron from another molecule. When the attacked molecule loses its electron, it
becomes a free radical. Therefore, it is capable of injurious chemical bond formation
with DNA, RNA, proteins, lipids, and carbohydrates- many other key molecules in
membranes and nucleic acids. Free radicals are difficult to control and initiate chain
reactions. With low chemical specificity and high reactivity, free radicals can react with
most molecules in their proximity.
An important mechanism of membrane damage is injury induced by free radicals,
especially by a disturbance in the balance between the production of ROS and
antioxidant defenses called oxidative stress. Oxidative stress can be caused by an
increase of different reactive species or depletion of antioxidant defense, or both, and
result in detrimental oxidation of different molecules including proteins, lipids, nucleic
acids, and others. Oxidative stress can activate several intracellular signaling pathways
because ROS can modulate enzymes and transcription factors. This process is an
important mechanism of cell damage and many conditions, including cell injury, cancer,
certain degenerative diseases (Alzheimer's disease), and aging (p. 54).
Know all about lead poisoning. How does it cause damage within the cell? - Answer-
Lead is a toxic heavy metal. Developing fetuses and young children absorb lead more
easily, susceptibility to brain damage. Organ systems affected: nervous, hematopoietic,
, reproductive, gastrointestinal, cardiovascular, musculoskeletal, as well as kidneys.
Exposure occurs via inhalation, ingestion and skin contact. Lead exposure damages or
destroys the plasma membrane, alters cellular ion status (disruption of divalent cations,
ion transport mechanism and protein function). Lead then disrupts the movement and
storage of calcium inside cells, increasing cell stress, which can lead to the death of
neurons and other brain cells. Lead causes abnormal conformational changes in the
protein structure, altered protein functions. Pg 66
Know about the effects of fetal alcohol syndrome on infants. - Answer-Diagnosis of FAS
requires all three facial abnormalities: short palpebral fissure lengths, smooth philtrum
and thin upper lip. FAS may have abnormal facial features, growth problems, CNS
problems, issues with learning, memory, attention, vision, hearing. Pg 70
How does alcohol affect the nervous system? - Answer-Alcohol causes CNS
depression. sedation, drowsiness, loss of motor, altered mental status. Can possibly
cause respiratory arrest because of medullary center depression. Pg 68
Where do lipids accumulate? - Answer-Although lipids sometimes accumulate in heart
and kidney cells, the most common site of intracellular lipid accumulation, or fatty
change, is liver cells. Pg 84
What is hemosiderosis? - Answer-Hemosiderosis is a condition which excess iron is
stored as hemosiderin (a yellow-brown pigment derived from hemoglobin) in the cells of
many organs and tissues. Common in people that get multiple blood transfusions. pg 86
What causes free calcium in the cytosol? - Answer-Influx of extracellular calcium in
injured mitochondria. Calcium stores in mitochondria and endoplasmic reticulum
pumped into the extracellular space bound to calcium-binding proteins -> released after
cell damage -> free Ca++ (see table on pg 86)
What happens to sodium and water during cell injury? - Answer-A process known as
oncosis hypoxia that leads to ATP production decreases which leads to sodium and
water moving into the cell and potassium moving out of the cell, osmotic pressure
increases more water moves into the cell cisternae of endoplasmic reticulum distend
rupture and form vacuoles causing hydropic degeneration pg 84
During cell injury caused by hypoxia, what happens to osmotic pressure? - Answer-The
increase of intracellular sodium concentration increases osmotic pressure which draws
more water into the cell pg 84
What causes mammary glands to enlarge in pregnancy? - Answer-Prolactin and GH
secreted from anterior pituitary cause glands and ducts to grow
After ovulation what happens to uterine endometrial cells? - Answer-Estrogen
stimulates the endometrium to grow and thicken for reception of the fertilized ovum
