HCS 212 Exam 1 Complete Study Questions And Answers With 2025 Updated Solutions
Extracellular fluid ANS Body fluids located outside of cells; includes plasma and interstitial fluid
What can the cytoplasm be divided into? ANS Cytosol and organelles
Plasma membrane ANS • A cell membrane; ...
HCS 212 Exam 1 Complete Study Questions And
Answers
Extracellular fluid ANS Body fluids located outside of cells; includes plasma and interstitial fluid
What can the cytoplasm be divided into? ANS Cytosol and organelles
Plasma membrane ANS • A cell membrane; also called a *plasmalemma* or cell membrane or
phospholipid bilayer
• Has four important functions:
> 1) Physical isolation
> 2) Regulation of exchange with the environment
> 3) Sensitivity
> 4) Cell-to-cell communication, adhesion, and structural support
• Selectively permeable
What is the plasma membrane composed of? ANS Phospholipids, proteins, glycolipids, and
sterols such as cholesterols
What are the two general types of membrane protein called? ANS • 1) Peripheral proteins --
>Attached to either the inner or outer membrane surface
• 2) Integral proteins (transmembrane proteins) --> Embedded in the membrane; most proteins are
quite ling and folded, and, therefore, span the entire width of the membrane one or more times. Some
integral proteins form channels that let water molecules, ions, and small water-soluble substances
into or our of the cell
Glycocalyx ANS The external surface of a plasma membrane that is important for cell-to-cell
communication; viscous, superficial coating that is formed by the carbohydrate (glyco-) components
,of the glycolopids and glycoproteins that extend away from the outer surface of the plasma
membrane
Sterols ANS • Stabilize the membrane structure and maintain its fluidity
• Cholesterol is the most common sterol
What are the passive processes of transport? ANS • 1) Diffusion --> Passive molecular
movement from an area of relatively *high concentration to* an area of relatively *low
concentration*
• 2) Osmosis --> The movement of *water* across a semipermeable membrane *toward* a solution
containing a relatively *high solute concentration*
• 3) Facilitated diffusion --> Passive movement of a substance across a plasma membrane via a
protein carrier
What are the active processes of transport? ANS • 1) Active transport --> The ATP-dependent
absorption or excretion of solutes across a plasma membrane
• 2) Endocytosis --> The movement of relatively large volumes of extra
• 3) Exocytosis --> The ejection of cytoplasmic materials by fusion of a membranous vesicle with the
plasma membrane
Microvilli ANS • Small, finger-shaped projections of the plasma membrane that absorb materials
from the extracellular fluid
• Promote absorption by increasing the surface area exposed to the extracellular environment. A
network of microfilaments stiffens each microvillus and anchors it to the terminal web, a dense
supporting network within the underlying cytoskeleton
,• Interactions between the microfilaments and the cytoskeleton produce a waving or bending action
• Movement of the microvilli circulate fluids close to the plasma membrane, bringing dissolved
substances into contact with receptors on the membrane surface
Cytoskeleton ANS The cell's internal framework of filaments and fibers; A *network of
microtubules, microfilaments, intermediate filaments, and thick filaments * in the cytoplasm
Cytoplasm ANS The material between the plasma membrane and the nuclear membrane
In a cell, what percentage of weight does protein contribute? ANS 15 - 30%
Cytosol ANS Intracellular fluid; contains dissolves nutrients, ions, soluble and insoluble proteins,
and wastes
Organelles ANS Intracellular structures that have specific functions
How does the composition of the cytosol differs from that of the extracellular fluid? ANS 1) The
*cytosol* contains a high concentration of *potassium ions*, while *extracellular fluid* contains a
high concentration of *sodium ions*. There is a *membrane potential* since *OUTSIDE the plasma
membrane* there is a *net excess of POSITIVE CHARGE* and *INSIDE* there is a *net excess of
NEGATIVE CHARGE*
• 2) The cytosol contains a *relatively high concentration of dissolved and suspended proteins*
• 3) The cytosol contains *small quantities of carbohydrates* and *large amounts of amino acids and
lipids*.
> Carbohydrates --> Energy
> Amino acids --> Manufacture proteins
> Lipids --> Maintain plasma membrane and provide energy when carbohydrates are unavailable
, • 4) Contains masses of insoluble substances known as inclusions or inclusion bodies
Inclusions ANS Also called inclusion bodies; aggregations of insoluble pigments, nutrients, or
other materials in the cytoplasm
Nonmembranous organelles ANS Always in contact with the cytosol; cytoskeleton, centrioles,
cilia, flagella, and ribosomes
Membranous organelles ANS Surrounded by membranes that isolate their contents from the
cytosol; mitochondrion nucleus, endoplasmic reticulum, golgi apparatus, lysosome, and peroxisome
What are the four major components of the cytoskeleton? ANS 1) Microfilaments
Microfilaments ANS • Slender strands composed mainly of the protein *actin*
• Microfilaments are scattered throughout the cytosol and form a dense network deep to the plasma
membrane
• Have two major function:
> 1) Microfilaments *anchor the cytoskeleton to integral proteins* of the plasma membrane. This
stabilizes the position of the membrane proteins, strengthens the cell, and attached the plasma
membrane to the underlying cytoplasm
•2) *Action microfilaments interact* with other *microfilaments or larger structures* *composed of*
the protein *myosin*. This interaction *allows part of the cell to move or changes the shape of the
entire cell*
Intermediate filaments ANS • Larger than microfilaments but smaller than microtubules;
composed of *actin*
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