The document summarizes cellular structures and functions. It identifies the five chief cellular functions as movement, conductivity, metabolic absorption, secretion, and excretion. It then describes the structures and functions of key cellular organelles like the nucleus, ribosomes, endoplasmic reticulum, Golgi apparatus, lysosomes, and mitochondria. It also discusses plasma membrane structure and functions such as transport, protection, and cell communication.

1. Cell Biology-viv
1.Identify the five chief cellular functions.
a. Movement: muscle cells-attached to bones to produce limb movements
b. Conductivity: nerve cells-response to a stimulus by a wave of excitation,
an electrical potential, that passes along the surface of the cell to reach its
other parts
c. Metabolic absorption: All cells take in and use nutrients. For example,
cells of the intestine and the kidney are specialized to carry out absorption.
Cells of the kidney tubules reabsorb fluids and synthesize proteins.
Intestinal epithelial cells reabsorb fluids and synthesize protein enzymes
d. Secretion: mucous gland cells can synthesize new substances from
substances they absorb and then secrete the new substances to serve as
needed elsewhere. Cells of adrenal gland, testis, ovary can secrete
hormonal steroids
e. Excretion: all cells can get rid themselves of waste products resulting
from metabolic breakdown of nutrients
f. Respiration: cells absorb oxygen which is used to transform nutrients into
energy (ATP)-Mitochondria
g. Reproduction: tissue growth occurs as cells enlarge and reproduce
themselves. Not all cells are capable of continuous division, and nerve
cells cannot reproduce.
h. Communication: Constant communication allows the maintenance of a
dynamic steady state. Pancreatic cells secrete and release insulin to tell
muscle cells to take up sugar from the blood for energy.
2.Match the cellular function to the cell type that performs that function.
The five cell types and the five chief cellular functions are:
1. Nerve Cells – Detect changes in internal or external environment. They
transmit nerve impulses from one part of the body to another.
2. Muscle Cells – Contract to allow movement of body parts.
3. Red Blood Cells – Transport Oxygen in the bloodstream (from the lungs to
other body parts of the body).
4. Gland Cells – Release substances such as hormones, enzymes, mucus and
sweat.
5. Immune Cells – Recognize and destroy “non-self” cells such as cancer cells
and invading bacteria.
3. Identify the three components of a typical eukaryotic cell.
Eukaryotic cells - Organization, memb-bound organelles, central nubleus.have a true
nucleus bound by a double membrane that contains the genetic information needed for
transcription, translation and production of proteins. Eukaryotic cells have membrane
bound organelles such as the endoplasmic reticulum, mitochondria, golgi apparatus, and
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2. lysosomes. Eukaryotic cells have ribosomes, which can be free in the cell cytoplasm or
can be bound to the endoplasmic reticulum, which in turn makes it a rough endoplasmic
reticulum. Ribosomes are involved in the translation of mRNA to produce proteins that
are inscribed in the genetic code of the mRNA.
4. Describe the structure and functions of the nucleus.
The nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most
of the cellular genetic material, which is organized into long multiple linear DNA
molecules. The DNA molecules form complexes with a large variety of proteins, such as
histones, to form chromosomes, which make up the nuclear genome. The function of the
nucleus is to act as the control center and regulatory component of the cell by
maintaining the integrity of the chromosomes and by controlling the activity of the cell
by regulation of the genes expressed.
5. Describe the structure and functions of ribosomes.
Ribosomes are complexes of RNA and protein that are found within the cell. Ribosomes
are composed of two subunits a small subunit and a large subunit. The function of
ribosomes is to aid in the translation of mRNA and the production of proteins by
catalyzing the assembly of individual amino acids into polypeptide chains, which are
later folded properly and become functioning proteins within the cell.
6.Compare and contrast smooth and rough endoplasmic reticulum in terms of
structure and function.
The smooth endoplasmic reticulum is a network that consists of tubules and vesicles
that branch out within the cell and forms the golgi apparatus. The rough endoplasmic
reticulum has ribosomes attached to it but shares the same common characteristics with
the smooth endoplasmic reticulum and is thought to be continuous with the nuclear
membrane. When the attached ribosomes make a protein they deposit it into the lumen of
the rough endoplasmic reticulum. The protein can then be processed in the lumen area or
it can be transported in the lumen space to other parts of the cell. The endoplasmic
reticulum has the ability to assemble the lipids needed in making membranes and is also a
part of certain types of reactions such as protein processing, lipid formation, membrane
formation and detoxifying reactions.
7. Describe the structure and function of the golgi apparatus.
The golgi apparatus is an organelle of small sacs stacked on one another near the
nucleus that makes carbohydrate compounds, combines them with protein molecules, and
packages the product for distribution from the cell.
8. Describe the structure and function of the lysosome.
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3. The lysosome is a membranous organelle that pinched off from the golgi apparatus
containing various enzymes that can dissolve most cellular compounds and un-needed
macromolecule into basic reusable compounds such as proteins that are not needed into
amino acids which can then be reused by the cell; called digestive bags or suicide bags of
cell.
9. Identify the contents of lysosomes and explain their normal functions (McCance
pg.6):
a. Contains more than 40 digestive enzymes called hydrolases, which
catalyse bonds in proteins, lipids, nucleic acids and carbohydrates.
b. Function: Lysosomal enzymes are capable of digesting most cellular
constituents down to their basic forms such as amino acids, fatty acids, and
sugars. The decreased pH value of a lysosome assist in the digestive processes
of other cell’s. They are “cellular garbage disposals.
10.Describe the structure and function of the mitochondira (McCance pg. 8):
a. Structure: Mitochondria appear as rods (“sausage shaped”) that are bound
by a double membrane. The outer membrane is smooth and surrounds the
mitochondrion itself; the inner membrane is convoluted in the
mitochondrial matrix to form cristae. The inner membrane contains the
enzymes of the respiratory chain. The outer membrane is permeable to
many substances, but the inner membrane is highly selective and contains
many transmembranous transport system
b. Function: Cellular respiration. It regulates cellular metabolism and
provides 95% of a cell’s energy supply. The mitochondria’s enzymes
catalyze oxidative reactions. Power house of the cell, energy formation
with the production of ATP. ATP: energy currency of cell formed by
oxidative phosphorlyation. It has a DNA molecule, which allows it to
produce its own enzymes and replicate copies of itself.
11. Predict how mitochondrial dysfunction can lead result in cell injury and disease:
a. The mitochondria supply our cells with energy through the production of
ATP. If the mitochondria are not functioning properly then the cells start
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4. breaking themselves down to find energy. Glycolysis and lactic acid only
supply us with a small amount of energy so eventually mitochondrial
dysfunction will cause the cells to self destruct by autophagocytosis.
Dysfunction will lead to cell ischemia, injury or death. Dysfunction may
play a role in things like mental disorders and cardiac dysfunctions.
12. Match the five plasma membrane functions with the underlying purpose or
activity (McCance pg 9-10):
Five plasma membrane functions
a. Structure: usually thicker than intercellular organelle membranes.
Containment of cellular organelles. Maintenance of relationship with
cytoskeleton, ER, and other organelles. The outer surface in many cells are
not smooth but are studded with cilia or even smaller cylindrical
projections called microvilli; both are capable of movement; caveolae are
also outer indentations. Maintenance of fluid and electrolyte balance.
b. Protection: Barrier to toxic molecules and macromolecules (protein,
nucleic acid, polysaccharides). Barrier to foreign organisms and cells.
c. Activation of Cell: Hormones (regulates cellular activity), Mitogens
(cellular division), Antigens (antibody synthesis), and Growth factors
(proliferation and differentiation).
d. Transport: Diffusion and exchange diffusion, Endocytosis (pinocytosis
and phagocytosis); receptor-mediated endocytosis, exocytosis (secretion),
and active transport.
e. Cell to Cell Interaction: Communication and attachment at junctional
complexes, symbiotic nutritive relationships, release of enzymes and
antibodies to extracellular environment, and relationship with exracellular
matrix.
13.Explain the anatomical basis for the plasma membrane’s ability to act as a
barrier to water soluble molecule while allowing lipid soluble molecules easy access:
a. The plasma membrane is a phospholipids bilayer arranged with their
nonpolar tails pointing toward each other. The membrane spontaneously
organizes itself into a bilayer because these two incompatible solubilities.
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5. The hydrophobic region (tail) of each lipid molecule is protected from
water, whereas the hydrophilic region (head) is immersed in it. The
bilayer’s structure accounts for one of the essential functions of the plasma
membrane: it is impermeable to most water soluble molecules because
they are insoluble in the oily core region. The bilayer serves as a barrier to
the diffusion of water and hydrophilic substances while allowing lipid-
soluble molecules (O, CO2), to diffuse through.
b. The anatomical basis of the membrane is so that it can have selective
impermeability.
14.Identify four functions of plasma membrane proteins (McCance pg 12):
a. Proteins facilitate transport across membranes by serving as receptors,
enzymes, or transporters. Proteins act as:
i) Transporters other molecules into and out of the cell
ii) Facilitates (catalyzes) membrane reactions
iii) Receives messages, thus acting as receptors for extracellular and
intracellular signals.
iv) Create structural linkages between the external and internal cellular
environments.
15.Explain the role of cell receptors in normal cell function (McCance 14-15):
a. Receptors are protein molecules on the plasma membrane, in the
cytoplasm, or in the nucleus that are capable of recognizing and binding
with specific smaller molecules called ligands. I.e.: Hormones are ligands.
b. Recognition and binding depend on the chemical configuration of the
receptor and its smaller ligand, which must fit together like jigsaw puzzle.
c. Plasma membrane receptors: bind with hormones, neurotransmitters,
antigens, infectious agents, drugs, and metabolites.
16.Compare and contrast endocytosis, pinocytosis, passive transport, active
transport, osmosis, diffusion, and facilitated diffusion:
a. Endocytosis and pinocytosis: involves the ingestion of fluids and solute
molecules through formation of small vesicles (McCance pg 30).
b. Passive transport or facilitated diffusion: the protein transporter moves
solute molecules through cellular membranes without expending
metabolic energy via simple diffusion (down the gradient concentration)
(McCance pg 25).
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6. c. Active transport: the protein transporter moves molecules against, or up
the concentration gradient and required expenditure of energy (ATP)
(McCance pg. 25).
d. Osmosis: the movement of water down a concentration gradient across a
semipermeable membrane from a region of higher water concentration to a
lower concentration. The membrane must be more permeable to water
than to solutes and the concentration of solutes must be greater so that
water moves more easily (McCance pg. 26).
e. Diffusion: the movement of a solute molecule from an area of greater
solute concentration to an area of lesser solute concentration. The
difference in concentration is known as a concentration gradient. The
higher concentration on one side, the greater the diffusion rate. (McCance
25).
17. Describe the Fluid Mosaic Model:
i. Transport other molecules into and out of the cell
j. Facilitate membrane reactions
k. Receive messages, thus acting as receptors for extracellular and
intracellular signals
l. Create structural linkages between external and internal cellular
environment.
m. It accounts for the flexibility of cellular membranes, their self-sealing
properties, and their impermeability to many substances
18. Define the term membrane potential and explain how the membrane potential is
generated:
a. Membrane potential: slight excess of positively charged ions on the
outside of the membrane and slight deficiency of positively charged ions
on the inside of the membrane.
b. When a membrane potential is maintained by a cell, opposite ions are held
on opposite sides of the membrane like water behind a dam-ready to rush
through with force when the proper membrane channels open.
c. Types of membrane potentials:
i. Resting membrane potential: polarized at -70mV
ii. Local potential: depolarized (excitatory) at higher than -70mV and
hyperpolarized (inhibitory) at lower than -70mV
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7. iii. Threshold potential: depolarized at -59mV
iv. Action potential: depolarized at +30mV
19 Describe the role of ATP in cellular metabolism:
a. The energy transferred by ATP is used in doing he body’s work-the work of
muscle contraction and movement, of active transport, and biosynthesis.
b. Because ATP is the form of energy that cells generally use, it is an
especially important organic molecule. ATP is a mole that can pick up
energy and give it to another chemical process; therefore, it is often called
the energy currency of cells.
20. Define oxidative phosphorlyation and describe its role in cellular metabolism:
a. Oxidative phosphorlyation: refer to this oxygen-requiring joining of a
phosphate group to ADP to form ATP.
b. Glycolytic enzymes in the cytoplasm catalyze the production of pyruvic
acid, which diffuses into mitochondria. The enzymes of this critic acid
cycle have been localized mostly to the matter (matrix) inside the inner
mitochondrial membrane. The high-energy electrons and their
accompanying protons are then carried to the cristae of the inner
membrane, where the electron transport carriers and mechanism for
phosphorylation is found. Because so many of the cell’s energy releasing
enzymes are located within the mitochrondria, these tiny structures are
aptly the power plants of the cell.
21. Predict the effect of an ATP deficit on membrane potentials and action
potentials:
a. Both membrane potentials and action potentials require ATP to conduct
impulse. If ATP is deficit, generating impulse will be very difficult.
22. ID three major mechanisms of cell-cell (intracellular) communication:
a. They form protein channels (gap junction) that directly coordinate the
activities of adjacent cells
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8. b. They display plasma membrane-bound signaling molecules (receptors)
that affect the cell itself and other cells in direct physical contact
c. They secrete chemicals that signal to cells some distance away
23. Differentiate between desmosomes, tight functions, and gap junctions:
a. Desmosomes: holds cell together by forming either continuous bands or
belts of epithelial sheets or button-like points of contact and maintain
structural stability.
b. Tight junction: serve as a barrier to diffusion, prevent the movement of
substances through transport proteins in the plasma membrane, and prevent
leakage of small molecules between the plasma membranes of adjacent cells
c. Gap junctions: clusters of communicating tunnels, connexons, that allow
small ions and molecules to pass directly from the inside of one cell to the
inside of another.. It coordinates the activities of adjacent cell. Important for
synchronizing contractions of heart muscle cells through ionic coupling and in
permitting action potentials to spread rapidly from cell to cell neural tissues.
24. Match the type of intercellular junction to the function of cell. See #23
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