Anatomy & Physiology 34A Lecture
Chapter 3 – Cell Structure & Function
I.
Overview
A. Cell Theory Development
B. Overview of the Cellular Basis of Life
C. Plasma Membrane Structure
D. Cytoplasm & Cellular Organelles
II. Cell Theory Development
A. Leeuwenhoek (17th century) – invented a crude microscope and was the first to document
_______organisms (“animicules”)
B. Hooke (17th century) – developed a compound microscope and viewed plant structures he
called “______”
C. Schleiden (botanist) and Schwann (zoologist) (18th century) concluded that all
___________ things were composed of cells.
D. Virchow (19th century pathologist) demonstrated that living cells arise only from other cells,
refuting the theory of _____________ generation.
E. ___________ microscopy (20th century) allowed us to see and study tiny organelles within
cells
F. Cell ____________ concepts:
1. All living things are composed of _______
2. The cell is the basic unit of ________
3. An organism’s structure and ____________ are due to its cells
4. Cells come only from preexisting ________
III. Overview of the Cellular Basis of Life
A. _______ are the basic functional units of life, in which metabolism and replication take
place
B. ______________ is the total of all chemical reactions within a cell
1. _____________ reactions build molecules in cells (e.g.: protein synthesis)
2. _____________ reactions break down molecules (e.g.: cellular respiration)
3. ______________ for metabolism include:
a. Cells must have access to nutrients and ___________ and be able to eliminate
wastes
b.
A relatively constant internal environment (_____________) must be maintained
C. Cellular _______________ processes include mitosis and meiosis
D. About ____ cell types in the human differ in size, shape, enzymes, and membrane
proteins; these differences determine their functions
1. Cell _________ include squamous (flat), cuboidal, to columnar, spherical, fibrous, etc.
2. Cell sizes vary, but most are very __________
a. Cells range from ____-___ m in diameter to 1 m long.
b. Small cells allow for _____________ of nutrients and wastes better than large cells
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E. Most cells have 3 main ___________
1. Plasma _____________ - semipermeable barrier around the cell
2. ____________ - everything (including most organelles) between the plasma and
nuclear membranes. The _______ is the gel-like material in which the other
cytoplasmic elements are suspended
3.
________ - contains the cell’s genetic material in chromosomes.
IV. Plasma Membrane Structure
A. Plasma ______________ (plasmalemma): separates intracellular (internal) contents
from the extracellular (external) environment; regulates passage of materials into and out
of the cell (__________ permeability). Described as a fluid _________ model
composed of fluid lipids studded with proteins
1. ___________________ bilayer
a. ___________ (hydrophilic) ______________ heads interact with intracellular and
extracellular aqueous environments
b. ______________ (hydrophobic) ________ tails interact with each other in
membrane interior
c.
__________ are membrane lipids with attached sugar groups that extend into the
extracellular fluid (part of the glycol___)
d. _______________ in the membrane stabilizes it and makes it more fluid
e. ________ uncharged molecules (O2, CO2), H2O, and ______ can move directly
through the phospholipid bilayer
2.
Membrane Proteins determine cell function; different proteins in different cell
types. Types of membrane _________ include
a.
____________ proteins - mostly glycoproteins embedded in the phospholipid
bilayer; these include
1) ____________ (“gates”) - water-filled pores that open and close to allow
specific substances, such as water or _____ (e. g.: K+, Cl-, Na+), to cross.
Channels include
a) ______________ gated – triggered to open or close by chemical ligands
that bind to them
b) Voltage gated – triggered by _____________ changes
c) _____________ gated – triggered by a physical change (e.g.: temperature
or pressure)
2) ____________ (carriers) - move specific small molecules or ions across via
shape changes in the transporter
3) ____________ - bind a specific substance (_________), such as a hormone
or neurotransmitter, needed for cellular function
4) ____________ - catalysts with an active site that binds specific substances
(___________) to speed up chemical reactions
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5) __________ Markers - major histocompatibility complex (______)
glycoproteins (and glycolipids) that allow cells to recognize what is “self”
and “nonself.”
b.
____________ proteins - found attached to the inner or outer membrane surface,
include
1) ____________ that speed up chemical reactions
2) Second _____________ that transmit an extracellular message to the
intracellular environment
3) _________ proteins on microtubules that promote cellular movement
4) ___________ proteins that support the cell’s shape
5) Cell-adhesion molecules (______s) – surface proteins that bind cells to other
cells.
B. Specializations of the Plasma Membrane
1. Cell surface ____________ include microvilli, cilia, and flagella
a. __________ are microscopic extensions of the cell membrane that increase the
cell’s surface area (e.g., in small intestine)
b. _________ are short, hair-like protein extensions from the cell membrane that move
substances across the cell surface (e.g., in lung passageways)
c. _______________ is a longer, whiplike extension from a cell membrane that moves
the cell itself (e.g., on ________). Both cilia & flagella are cylinders of 9 + 2
________________
2. Membrane Junctions - cells are attached to other cells and to underlying membranes
via _______________:
a.
___________ junctions – plasma membranes fuse to form fluid-tight _______
between cells; found in epithelial cells that line the digestive and urinary tracts
b.
______________ are rivet-like anchoring junctions that fasten cells to each other
or to an extracellular material; found in tissues subjected to friction and
__________ (e.g., skin, heart)
3.
V.
______ junctions are protein ____________ between cells that allow small
molecules and ions to flow freely between cardiac muscle cells and smooth muscle
cells.
Cytoplasm & Cellular ______________ - specialized intracellular structures with
specific functions.
A. ____________ (control center) - largest organelle; controls cellular activities and is
composed of the following
1. Enclosed by a porous, double membrane nuclear ___________
2.
3.
Contains hereditary units (genes) in DNA in _______________
____________ – a dense structure within the nucleus composed of proteins, DNA,
and ______. Function: ribosome assembly.
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B. _____________ (“clamps” on protein assembly line) – granules of rRNA and proteins;
found free in cytoplasm or on ER. Function: sites of _____________ synthesis
C. Endoplasmic Reticulum (____) - (protein and lipid assembly line) network of
___________-enclosed channels (cisternae) continuous with the nuclear envelope. Two
types of ER are:
1.
________ ER - has ribosomes attached. Functions: _________ synthesis, stores
newly formed proteins, glycosylation of some proteins forms glycoproteins, vesicle
formation
2.
________ ER - no ribosomes attached. Functions: _______ synthesis (fatty acids,
steroids), detoxification of toxins, and Ca2+ release
3.
D. __________ Apparatus (packaging and shipping) - stack of flattened, membranous sacs
that work with the ER. Functions:
1. ___________, sort, and deliver proteins and lipids made in the ER to the plasma
membrane for export or incorporation into the membrane
2. Form lysosomes and secretory ___________ (membranous sacs)
E. ______________ (garbage recycler) - membrane enclosed vesicles that contain acidic
__________ enzymes used to digest foreign proteins, and damaged organelles
(autophagy) and whole cells (autolysis)
F. ____________ (detoxification) -smaller than lysosomes. Contain ________ enzymes that
detoxify harmful chemicals (e.g.: alcohol).
G. _______________ (powerhouse) - has a smooth outer membrane and folded inner
membrane (__________) surrounding an inner matrix. Function: enzymes in cristae and
matrix catalyze reactions of aerobic cellular respiration to form ______ energy.
H. Cyto___________ (cell infrastructure & movement) - proteins that maintain cell shape
and coordinate cellular movement.
1.
Micro___________ - thin, filamentous proteins (e.g., _______) that support the
plasma membrane; also interact with myosin in endocytosis, exocytosis and muscle
contraction.
2.
______________ filaments - medium-sized protein filaments, such as keratin and
_____________; strengthen cells.
3.
Micro____________ - thick, filamentous proteins made of _________. Function:
cellular movement. Compose centrioles, cilia, flagella.
a.
____________ - pair of microtubular structures found within a ____________;
cylinders composed of nine tubulin triplets (9+0). Function: formation of mitotic
______, cilia, flagella.
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b.
I.
________ & Flagella - both have 9+2 tubulin arrangement. Cilia function:
____________ of particles out of trachea and ova in fallopian tubes. Flagella
propel _________.
Cell ___________ - non-membrane bound cell products. Include: ____________
(glycosomes) stored in liver, uterine, & muscle cells and triglycerides in lipid droplets
stored in adipocytes (_____ cells).