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NU 545 Unit 1 Exam With Questions And Verified Detailed Answers
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NU 545 Unit 1 Exam With Questions And VerifiedDetailed Answers 2024-2025
What is metabolic absorption? - ANSWER The uptake and utilization of nutrition and
other selected substances from the cells surrounds. (pg. 3).
What uses oxygen to remove hydrogen atoms in an oxidative reaction? - ANSWER
Peroxisomes contain enzymes to use o2 to remove H atoms. This produces hydrogen
peroixide.
During cell injury what is released that is capable of cellular autodigestion? - ANSWER
Lysosomes aid in cellular digestion, seen as "trash cans and recycling agents" "as cells
complete their life span and die, lysosomes digest.the debris. Lysosomes involved in
this process of autodigestion are called autolysosomes or autophagomes (pg 7-8).
Where in the cell is genetic info contained? - ANSWER The nucleus contains the
Nucleolus, a small dense structure composed of RNA, DNA, DNA protein. Pg 3.
Cell membranes contain which major chemical components? - ANSWER "The main
components of cell membranes are lipids and proteins. The basic structure of cell
membranes is the lipid bilayer." pg 12
What permits the movement of potassium in and out of the cells? -ANSWER Diffusion is
the passive transport of a solute molecule from and area of greater solute concentration
to an area of lesser solute concentration. (pg. 29). Active transport of K+ and Na+
requires a Sodium-Potassium Pump (pg. 31).
How does the cell prevent injury? -ANSWER Plasma membrane pg 12 table 1.1
(functions of membrane).
In cirrhosis, what does cholesterol have to do with the erythrocytes? - ANSWER causes
,a decrease in membrane fluidity and affects the cells' ability to transport oxygen
What is platelet-derived growth factor? - ANSWER PDGF stimulates proliferation of
connective tissue cells and neuroglial cells. Can help with creating blood clots. Pg 38.
What is cell communication? How does it occur? - ANSWER Cells need to communicate
w/ each other to maintain a stable internal environment, or homeostasis; to regulate
growth and division. it is done by 3 major ways. 1) they display plasma membrane-bound
signaling molecules (receptors) that affect the cell itself and other cells in direct
physical contact. 2) they act on receptor proteins inside the target cell and the signal
molecule must enter the cell to bind with them. 3) they act by forming protein channels
that directly coordinate activities of the adjacent cells. Pg 19.
Chemical signaling? - ANSWER Primary means of cellto-cell communication. There are
basically 5 forms of signaling mediated by secreted molecules: Contact-dependent
signaling requires cells to be in close membrane-membrane contact; Paracrine
signaling- cells secrete local chemical mediators that are quickly absorbed, destroyed,
or immobilized; Autocrine signaling- cells produce signals that they, themselves,
respond to (cancer cells); Hormonal signaling involves specialized endocrine cells that
secrete chemicals called hormones (TSH). One set of cells releases hormones into the
tissue and blood and then that travels and causes a response in other sets of cells; (5)
Neurohormonal signaling- neurosecretory neurons release hormones into the blood.
(p.19)
How does glucose get transported from the blood to the cell? - ANSWER The pancreatic
cells synthesise and release insulin which sends a signal into the muscle cells to pull
sugar out of the blood for fuel.
explain transport 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
direct energy of ATP to move these cations. The transporter protein is the enzyme
adenosine triphosphatase (ATPase). About 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. An energy-containing adenosine triphosphate
molecule produced by the cell's mitochondria binds concurrently to the carrier. The
bound ATP dissociates, transferring its stored energy to the carrier. 3 and 4, the carrier
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 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? - ANS Growth factor, also known as cytokines, stimulate an
increase in cell mass or cell growth through stimulation of the synthesis of proteins and
other macromolecules and inhibition of its degradation (p. 38)
Cytokines are a large family of small-molecular-weight soluble intracellular-signaling
molecules secreted, which bind to a specific cell membrane receptor that regulates
innate or adaptive immunity; either proinflammatory or anti-inflammatory. Most of the
important cytokines are classified as either interleukins or interferons.
Do all cells in the body constantly replicate and divide? ANSWER No. Most neurons, for
example, and skeletal muscle cells are in a terminally differentiated G0 state; their cell
cycle control system is dismantled and the molecular regulatory switches become
permanently in the off position and cell division rarely or never happens, 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 transformation of
glucose to pyruvic acid (pyruvate) with simultaneous production of ATP. In the case of
oxygen absence, pyruvate is converted to lactic acid, which is released in the
extracellular fluid. An increased level of lactate is a sign of tissue hypoxia or low oxygen
concentration: pp.26 & 27.Where there's an increase in lactic acid, there is a decrease
in oxygen, hypoxia of the cell tissues.this is reversible provided oxygen is reintroduced.
When does sodium enter the cell and cause swelling? -ANSWER A decline in ATP
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