Download CHAPTER 3: CELLS

UNIT 1 - CHAPTER 3: CELLS
LEARNING OUTCOMES:
3.1
Introduction
1.
3.2
3.3
A Composite Cell
2.
Describe the general characteristics of a composite cell.
3.
Explain how the components of a cell’s membrane provide its functions.
4.
Describe each kind of cytoplasmic organelle and explain its function.
5.
Describe the cell nucleus and its parts.
Movements Into and Out of the Cell
6.
3.4
3.5
3.7
Explain how substances move into and out of cells.
The Cell Cycle
7.
Describe the cell cycle.
8.
Explain how a cell divides.
Control of Cell Division
9.
3.6
Explain how cells differ from one another.
Describe several controls of cell division.
Stem and Progenitor Cells
10.
Explain how stem cells and progenitor cells make possible growth and repair of
tissues.
11.
Explain how two differentiated cell types can have the same genetic information,
but different appearances and functions.
Cell Death
12.
Discuss apoptosis.
13.
Describe the relationship between apoptosis and necrosis.
3-1
UNIT 1 - CHAPTER 3: CELLS
3.1
INTRODUCTION
The cell is the basic unit of structure and function in living things. Cells vary in their
shape, size, and arrangement (See Fig 3.1 & Fig 3.2, page 85), but all cells have similar
components, each with a particular function. As cells divide they differentiate or become
specialized.
3.2.
A COMPOSITE CELL
A.
Introduction: A COMPOSITE CELL or typical animal cell contains three major
cell parts including the CELL (or plasma) MEMBRANE, which is the outer
boundary of the cell, the CYTOPLASM, which holds the cellular organelles
which perform specific functions of the cell, and the NUCLEUS, or control center
of the cell. See Fig 3.3, page 86.
B.
Cell Membrane
1.
2.
General Characteristics: The cell membrane forms the outermost
boundary of the cell and allows the cell to receive and respond to incoming
messages = signal transduction (discussed in greater detail in Chapter 13).
Membrane Structure = Fluid Mosaic Model
See Fig 3.6, page 88 and Fig 3.7, page 89.
The cell membrane is composed of a double layer (bilayer) of
phospholipid molecules with many protein molecules dispersed within it.
a.
The surfaces of the membrane are "hydrophilic" due to the polar
phosphate heads;
b.
The internal portion of the membrane is "hydrophobic" due to
the non-polar fatty acid tails;
c.
The membrane proteins also have both hydrophilic and
hydrophobic properties. There are five types:
See Table 3.1, page 89.
o
Integral proteins are firmly inserted into and extend across
the lipid bilayer. They serve as either channels (pores),
transporters (carriers), receptors (recognition sites) or
enzymes.
1.
See Clinical Application 3.1, Faulty Ion Channels
Cause Disease, page 90.
2.
See Table 3A: Drugs that Affect Ion Channels,
page 90.
o
Receptor proteins
o
Enzymes
o
Cell Adhesion Molecules – guide cellular movements. See
Fig 3.8 page 89.
o
Cell Surface Proteins
3-2
UNIT 1 - CHAPTER 3: CELLS
3.2.
A COMPOSITE CELL
C.
Cytoplasm (cytosol) = the jelly-like fluid (70% water) that holds the cellular
organelles and occupies the space between the nucleus and cell membrane. It
contains abundant protein rods and tubules that form a supportive framework (i.e.
cytoskeleton, see below).
D.
Ribosomes:
1.
2.
3.
4.
E.
small granules dispersed throughout the cytoplasm and on the membranes
of some endoplasmic reticulum (as rough endoplasmic reticulum); See Fig
3.9a and b, page 91.
composed of RNA and protein
Function = protein synthesis.
Not bound by a membrane
Endoplasmic Reticulum (ER):
See Fig 3.9, page 91.
1.
F.
G.
A network of interconnected parallel membranes (maze), that is
continuous with the nuclear membrane.
2.
Two types:
a.
Rough Endoplasmic Reticulum (RER): Fig 3.9a & b, page 91.
o
ER studded with ribosomes.
o
Function = protein synthesis.
b.
Smooth Endoplasmic Reticulum (SER): Fig 3.9c, page 91.
o
lacks ribosomes
o
Function = lipid & cholesterol synthesis.
o
Stores calcium ions
o
Abundant in liver cells (hepatocytes)
Vesicles
1.
membrane transport sacs
2.
made by ER and Golgi (see G. below).
Golgi Apparatus (Complex):
1.
2.
3.
See Fig 3.10, page 92.
flattened membranous sacs ("cisternae") arranged in stacks ("stack of
pancakes") associated with many vesicles (membrane bound sacs
containing proteins).
Function = modification, packaging, and transport of proteins.
Vesicles pinch off as "secretory vesicles", which are transported out of the
cell. See Fig 3.10b, page 92 and Fig 3.11, page 93.
3-3
UNIT 1 - CHAPTER 3: CELLS
3.2
A COMPOSITE CELL
H.
I.

Mitochondria (pl); Mitochondrion (s): See Fig 3.12, page 93.
1.
kidney-shaped organelle whose inner membrane is folded into shelf-like
partitions called cristae.
2.
"Powerhouse" of the cell = site of cellular respiration, where energy is
released from glucose.
3.
See box on page 94 re: mitochondrial DNA.
4.
See Clinical Application 3.2, Disease at the Organelle Level, page 95,
MELAS.
Lysosomes: See Fig 3.13, page 94.
1.
spherical membranous sacs containing digestive enzymes (proteins)
2.
"suicide sacs" which destroy anything the cell no longer wants or needs.
3.
Autolysis is the process by which worn cell parts are digested by
autophagy.
4.
See Clinical Application 3.2, Disease at the Organelle Level, page 95,
Krabbe Disease.
See Fig 3.10b, page 92, which summarizes the close relationship between RER
and GA and lysosomes in protein transport.
J.
Peroxisomes:
1.
membranous sacs containing oxidase enzymes
2.
Function = detoxification of harmful or toxic substances (i.e. alcohol,
formaldehyde, oxygen free radicals).
3.
H2O2 (peroxide) → water.
4.
See Clinical Application 3.2, Disease at the Organelle Level, page 95,
Adrenoleukodystropy (ALD).
K.
Centrosome: See Fig 3.14, page 96.
1.
pair of microtubules located near the nucleus
2.
aid in movement of chromosomes during mitosis.
Cilia and Flagella and Microvilli
1.
Cilia (pl)/ Cilium (s): See Fig 3.15, page 96.
a.
short, hair-like cellular extensions (eyelashes)
b.
help move substances through passageways
c.
located in lining of trachea and fallopian tube
2.
Flagella (pl)/ Flagellum (s): See Fig 3.16, page 97.
a.
tail-like projection
b.
only one flagellum per cell in humans
c.
aid(s) in cell locomotion
d.
Example is sperm cell
3.
Microvilli:
See Fig 3.3, page 86.
a.
small finger-like extensions of the external surface of the cell
membrane
b.
Function = to increase surface area.
L.
3-4
UNIT 1 - CHAPTER 3: CELLS
3.2
A COMPOSITE CELL
M.
N.
O.
Microfilaments and Microtubules: See Fig 3.17, page 97 and Fig 3.18, page 98.
1.
protein structures called microfilaments, microtubules, and intermediate
filaments
2.
form "muscles and bones" of the cell
3.
allow for intracellular transport and movement
*
See box on page 97 re: epidermolysis bullosa.
Other structures
1.
inclusions
a.
temporary storage
b.
pigments (melanin), lipids, and glycogen
Cell Nucleus = the central core, control center or "brain" of the cell.
See Fig 3.19, page 99.
1.
2.
3.
the largest organelle of the cell
filled with nucleoplasm
contains three distinct regions:
a.
Nuclear envelope is a double membrane that separates the
contents of the nucleus from the cytoplasm.
o
At various points, these two membranes fuse = nuclear
pore(s).
o
The nuclear membrane is "selectively permeable"; pores
serve as sites where mRNA can pass out of the nucleus
during protein synthesis, and how ribosomes exit the
nucleus.
b.
Nucleolus = dense spherical body(ies) within the nucleus; pl =
nucleoli
o
o
c.
composed of RNA and proteins;
Function = synthesis of ribosomes.
Chromatin = loosely coiled fibers of DNA and histone proteins
present in the nucleus.
o
o
Nucleosome = fundamental unit of chromatin; spherical
clusters of eight histone proteins connected like beads on
DNA string.
These fibers of chromatin would be condensed into tightly
coiled chromosomes if the cell were preparing to divide.
3-5
UNIT 1 - CHAPTER 3: CELLS
3.2
A COMPOSITE CELL: SUMMARY TABLE OF CELL PARTS
See Table 3.2, page 99 in text and key at the end of the outline.
CELL COMPONENT
DESCRIPTION/
STRUCTURE
FUNCTION(S)
CELL MEMBRANE
CYTOPLASM
RIBOSOMES
ROUGH ENDOPLASMIC
RETICULUM (ER)
SMOOTH ER
GOLGI
VESICLES
MITOCHONDRIA
LYSOSOMES
PEROXISOMES
CENTROSOMES
CILIA
FLAGELLA
MICROVILLI
CYTOSKELETON
OTHER STRUCTURES
NUCLEUS
NUCLEOLUS
CHROMATIN
3-6
UNIT 1 - CHAPTER 3: CELLS
3.3
MOVEMENTS INTO AND OUT OF THE CELL (Membrane Transport)
A.
Introduction: The passage of a substance through the cell membrane may be
physical (passive, requires no energy expenditure) or physiologic (active process,
requires energy expenditure).
1.
2.
B.
In physical (passive) transport processes, substances move from where
they are in high concentration to where they are in low concentration.
Passive transport processes include simple diffusion, facilitated diffusion,
osmosis, and filtration.
In physiologic (active) transport mechanisms, substances move from
where they are in low concentration to where they are in high
concentration at the expense of cellular energy (ATP). Active processes
include active transport, endocytosis, exocytosis and transcytosis.
Physical (Passive) Transport Processes (require no energy expenditure):
1.
Simple Diffusion
a.
b.
c.
d.
2.
Molecules or ions spread spontaneously down a concentration
gradient.
A state of equilibrium is produced.
Examples:
o
A sugar cube dissolving in water; See Fig 3.20, page 100.
o
A drop of dye diffusing in water.
o
An odor diffusing throughout the air in a room.
o
The diffusion of oxygen and carbon dioxide through the
cell membrane. See Fig 3.22, page 101.
Significance in human metabolism: Cellular respiration.
Facilitated Diffusion:
a.
b.
c.
d.
See Fig 3.23, page 101.
a special case of diffusion.
Concentration gradient is high to low.
Special carrier protein molecules within the cell membrane act as
shuttle buses to transport a molecule into/out of a cell.
Significant because this is the process by which most glucose
enters (and leaves) human cells; Cellular respiration.
3-7
UNIT 1 - CHAPTER 3: CELLS
3.3
MOVEMENTS INTO AND OUT OF THE CELL (Membrane Transport)
B.
Physical (Passive) Transport Processes (require no energy expenditure):
3.
Osmosis:
a.
b.
c.
d.
See Fig 3.24, page 102.
Diffusion of WATER molecules through a SELECTIVELY
PERMEABLE MEMBRANE (i.e. cell membrane), in an attempt
to dilute a particular solute.
Remember that water can pass through the membrane, but the
solute cannot!!!
Osmosis is significant in maintaining the osmotic pressure of our
cells at 0.9%.
o
The solutes dissolved in the water of our cells, tissue fluid,
and blood, measure 0.9% (saline).
o
When solutions are infused into our blood or tissues, the
solute concentration of the solution must be equal to that of
our cells and tissues (isotonic = 0.9%), or our cells will
either:
1.
lose water and shrink, or
2.
gain water and swell; perhaps burst or lyse.
Osmosis is demonstrated nicely with red blood cells (rbc's) being
placed in solutions of varying tonicity. See Fig 3.25, page 103.
o
Three (3) conditions may exist:
1.
Isotonic
2.
Hypertonic
3.
Hypotonic
3-8
UNIT 1 - CHAPTER 3: CELLS
3.3
MOVEMENTS INTO AND OUT OF THE CELL (Membrane Transport)
B.
Physical (Passive) Transport Processes (require no energy expenditure):
4.
C.
Filtration:
See Fig 3.26 and Fig 3.27, page 103.
a.
Water and solutes are forced through a body membrane by the
hydrostatic pressure of blood (i.e. blood pressure).
b.
Concentration gradient is high to low.
c.
Solutes include glucose, gases, ions, hormones, and vitamins.
d.
Example is excretion: blood being filtered through the capillaries
(glomerulus) of the kidney to remove wastes.
Physiologic (Active) Transport Processes (require energy expenditure)
1.
Active Transport: See Fig 3.28, page 104.
a.
Molecules or ions move from an area where they are in low
concentration toward an area where they are in higher
concentration at the expense of cellular energy (i.e. ATP).
o
substances include many ions, amino acids, and
monosaccharides.
o
The Na+- K+- ATPase pump (which maintains the Resting
Membrane Potential, RMP in many cells) is an example.
2.
Endocytosis
a.
Molecules or particles that are too large to enter the cell by passive
transport or active transport (above) are brought into the cell within
a vesicle formed from a section of the cell membrane.
b.
Examples:
o
Pinocytosis = cell drinking; the cell brings in liquid
droplets which may contain dissolved substances. See Fig
3.29, page 104.
o
Phagocytosis = cell eating; the cell engulfs and brings in a
solid particle. See Fig 3.30 – 3.31, page 105.
1.
Phagocytes (or macrophages) are very important
scavenger white blood cells in humans.
2.
They will bring in foreign particles, bacteria, etc.,
a.
that then fuses with a lysosome in their
cytoplasm to digest the foreign particles.
o
Receptor-Mediated Endocytosis
See Fig 3.32, page 106.
*
See box on page 106 re: LDL receptors and statin
drugs.
3-9
UNIT 1 - CHAPTER 3: CELLS
3.3
MOVEMENTS INTO AND OUT OF THE CELL (Membrane Transport)
C.
Physiologic (Active) Transport Processes (require energy expenditure)
3.
Exocytosis:
a.
b.
4.
Is the process by which cells transport secretory proteins out? Also
see Fig 3.11, page 92 and Fig 3.12, page 93.
allows cells to get rid of debris by dumping it to the outside (i.e.
into the extracellular fluid).
Transcytosis: See Fig 3.34, page 107.
a.
b.
c.
d.
*
See Fig 3.33, page 107.
combines endocytosis with exocytosis.
Particles travel across cell from apical to basal surfaces.
enables the immune system to monitor pathogens in small intestine
preventing food poisoning.
The HIV virus passes through mucous membranes in this fashion.
See Table 3.3, page 108 for a Summary of Transport Processes.
3-10
UNIT 1 - CHAPTER 3: CELLS
MEMBRANE TRANSPORT SUMMARY TABLE (Keyed at the end of the outline)
TRANSPORT
PROCESS
IS ENERGY
REQUIRED?
[ ]
Gradient
GENERAL
DESCRIPTION
EXAMPLE
IN
HUMANS
SIGNIFICANCE
SIMPLE
DIFFUSION
FACILITATED
DIFFUSION
OSMOSIS
FILTRATION
ACTIVE
TRANSPORT
ENDOCYTOSIS
EXOCYTOSIS
TRANSCYTOSIS
3-11
UNIT 1 - CHAPTER 3: CELLS
3.4
THE CELL CYCLE
The life cycle of a cell is divided into two major portions that include interphase and a
mitotic phase. Remember that the process of cell division is continuous. It is only
divided into stages for convenience and to help you learn.
See Fig 3.35, page 108, which illustrates the cell cycle as a continuum.
A.
Interphase = cell growth and DNA replication.
See Fig 3.36a, page110.
B.
1.
2.
not considered part of mitosis
represents the majority of a cell's life and includes:
a.
cell growth and
b.
duplication of DNA prior to prophase
3.
Interphase is divided into 3 parts:
a.
G1 = rapid growth and replication of centrioles.
b.
S = growth and DNA replication.
c.
G2 = growth and final preparations for cell division.
MITOTIC PHASE (M):
1.
The mitotic phase (M) is divided into 2 parts that include mitosis and
cytoplasmic division (cytokinesis).
a.
Mitosis = division of nuclear parts includes four parts:
o
Prophase:
1.
See Fig 3.36b, page 110.
Distinct pairs of chromosomes become apparent
(tightly coiled DNA and histone proteins).
a.
Chromosomes pairs are composed of
identical sister chromatids, held together by
centromeres.
2.
Centriole pairs migrate to opposite ends of cell, and
spindle fibers form between them.
3.
Nuclear envelope and nucleolus disintegrate.
3-12
UNIT 1 - CHAPTER 3: CELLS
3.4
THE CELL CYCLE
B.
Mitotic (M) phase (continued)
a.
Mitosis (continued)
2.
Metaphase: See Fig 3.36c, page110.
o
o
3.
Anaphase:
o
o
o
4.
o
o
o
See Fig 3.36d, page 110.
Centromere holding chromosome pair together splits/
separates.
Individual chromosomes migrate in opposite directions on
spindle fibers toward polar centrioles.
cytokinesis begins.
Telophase:
o
o
b.
Chromosomes line up in an orderly fashion midway
between the centrioles (i.e. along equatorial plate).
Centromere holding chromosome together attaches to
spindle fiber between centrioles.
See Fig 3.36e, page 110.
Chromosomes complete migration toward centrioles.
Nuclear envelope develops around each set
chromosomes.
Nucleoli develop and reappear.
Spindle fibers disintegrate.
Cleavage furrow is nearly complete.
of
Cytoplasmic Division (Cytokinesis; forming of 2 daughter cells)
1.
begins during anaphase, when the cell membrane begins to
constrict (pinch) around daughter cells.
2.
is completed at the end of telophase when nuclei and cytoplasm of
two newly formed daughter cells (in interphase) are completely
separated by cleavage furrow.
See Fig 3.37c, page 111.
3.
* See Table 3.4, page 109, Major Events in Mitosis.
* See Figure 3.37, page 111, to observe scanning electron micrographs of cell division.
3-13
UNIT 1 - CHAPTER 3: CELLS
3.4
THE CELL CYCLE: See Table 3.4, page 109 and key at end of this outline.
NAME OF PHASE
DESCRIPTION OF
EVENTS
TYPICAL SKETCH
INTERPHASE
PROPHASE
METAPHASE
ANAPHASE
TELOPHASE
3-14
UNIT 1 - CHAPTER 3: CELLS
3.5
CONTROL OF CELL DIVISION
A.
Significance
1.
2.
3.
B.
Length of the Cell Cycle
1.
2.
3.
C.
D.
to form a multi-celled organism from one original cell
growth of organism
tissue repair
varies with cell type, location, and temperature
Average times are 19-26 hrs.
Neurons, skeletal muscle, and red blood cells do not reproduce.
Details of Cell Signaling
1.
Maturation promoting factor (MPF) induces cell division when it becomes
activated.
2.
cdc2 proteins are a group of enzymes that participate in the cell division
cycle.
a.
They transfer a phosphate group from ATP to proteins to help
regulate cell activities.
3.
Cyclin is a protein whose level rises and falls during the cell cycle.
a.
It builds up during interphase and activates the cdc2 proteins of
MPF above.
Abnormal Cell Division (CANCER) See Table 3.5 page 112.
1.
When cell division occurs with no control (goes awry), a tumor, growth,
or neoplasm results.
2.
A malignant tumor is a cancerous growth; a non-cancerous tumor is a
benign tumor;
a.
Malignant tumors may spread by metastasis to other tissues by
direct invasion, or through the bloodstream or lymphatic system.
3.
Oncology is the study of tumors; an oncologist is a physician who treats
patients with tumors.
4.
5.
See Figure 3.38, page 112, an SEM of normal vs. cancer cells.
See box on page 112 re: Granulocyte Colony Stimulating Factor (G-CSF)
used in chemotherapy patients to boost white cell counts.
3-15
UNIT 1 - CHAPTER 3: CELLS
3.6
STEM AND PROGENITOR CELLS: See Fig 3.40, page 114.
Allow for continued growth and renewal of cells
A.
B.
C.
D.
E.
3.7
A Stem cell
1.
divides by mitosis to yield another stem cell and
2.
a partially differentiated progenitor cell.
Progenitor cell
See Fig 3.40 page 114.
1.
committed to a specific cell line
a. epithelial
b. connective
c. muscle
d. nervous
Totipotent cells – can become any cell type.
Pluripotent cells – can become many cell types, but not all.
Differentiation is the process of specializing cell types. It occurs due to gene
activation
*
Figure 3.41 page 115 illustrates how a totipotent stem cell becomes pluripotent
progenitor cells, which further differentiate into specific cells.
*
See From Science to Technology 3.1 on page 116, Stem Cells to Study and Treat
Disease.
CELL DEATH
A.
B.
Apoptosis = programmed cell death; a fast, orderly contained destruction that
packages cellular remnants into membrane-enclosed pieces that are then removed.
1.
is a normal part of development
2.
sculpts organs from tissues that naturally overgrow – important in fetal
development
3.
is protective – peeling skin after sunburn to prevent possible cancer
4.
is continuous and step-wise, like mitosis:
a. “Death receptor” on doomed cell cell’s membrane receives a signal to
die.
b. Enzymes called caspases are activated and destroy the various cell
components.
c. The dying cell’s shape becomes round as it is cut-off from other cells.
d. Its cell membrane undulates forming bulges or blebs.
e. The nucleus bursts and mitochondria decompose.
f. The cell shatters (within one hour of caspases release).
g. Inflammation is prevented because fragments are membrane
encapsulated.
5.
See Figure 3.42, page 117.
Necrosis = disordered form of cell death associated with inflammation and injury.
3-16
UNIT 1 - CHAPTER 3: CELLS
OTHER INTERESTING TOPICS:
A Disease in a Dish re: Rett Syndrome, see Introduction on page 84.
CHAPTER SUMMARY – see pages 117-119.
CHAPTER ASSESSMENTS – see pages 119-120.
INTEGRATIVE ASSESSMENTS/CRITICAL THINKING – see page 121.
3-17
UNIT 1 - CHAPTER 3: CELLS
SUMMARY TABLE OF CELL COMPONENTS:
CELL COMPONENT
DESCRIPTION/
STRUCTURE
FUNCTION(S)
CELL MEMBRANE
Bilayer of phospholipids
with proteins dispersed
throughout
cell boundary; selectively
permeable (i.e. controls
what enters and leaves
cell; membrane transport)
CYTOPLASM
jelly-like fluid (70% water)
suspends organelles in cell
RIBOSOMES
RNA & protein; dispersed
throughout cytoplasm or
studded on ER
protein synthesis
ROUGH ER
Membranous network
studded with ribosomes
protein synthesis
SMOOTH ER
Membranous network
lacking ribosomes
lipid & cholesterol
synthesis
GOLGI
“Stack of Pancakes”;
cisternae
modification, transport,
and packaging of proteins
VESICLE
Cylindrical membrane sacs
Storage and transport
MITOCHONDRIA
Kidney shaped organelles
whose inner membrane is
folded into “cristae”.
Site of Cellular
Respiration;
“Powerhouse”
LYSOSOMES
Membranous sac of
digestive enzymes
destruction of worn cell
parts (autolysis) and
foreign particles
PEROXISOMES
Membranous sacs filled
with oxidase enzymes
(catalase)
detoxification of harmful
substances (i.e. ethanol,
drugs, etc.)
paired cylinders of
microtubules at right
angles near nucleus
aid in chromosome
movement during mitosis
CENTROSOMES
3-18
UNIT 1 - CHAPTER 3: CELLS
CILIA
short, eyelash-like
extensions; human trachea
& fallopian tube
help move substances
through passageways
FLAGELLA
long, tail-like extension;
human sperm
locomotion
MICROVILLI
microscopic ruffling of cell
membrane; duodenum
increase surface area
CYTOSKELETON
Protein strands
(microtubules,
microfilaments,
intermediate filaments)
that makeup cellular
frame
Provide shape of cell,
locomotion; intracellular
movement
OTHER STRUCTURES
Accumulations of
substances
storage
NUCLEUS
Central control center of
cell; bound by lipid bilayer
membrane; contains
chromatin (loosely coiled
DNA and proteins)
controls cellular activity by
directing protein synthesis
(i.e. instructing the cell
what proteins/enzymes to
make).
NUCLEOLUS
dense spherical body(ies)
within nucleus; RNA &
protein
Ribosome synthesis
CHROMATIN
DNA wrapped in protein
forming nucleosomes
Protection of genetic
material
3-19
UNIT 1 - CHAPTER 3: CELLS
MEMBRANE TRANSPORT SUMMARY TABLE
TRANSPORT
PROCESS
IS ENERGY
REQUIRED?
[ ]
Gradient
GENERAL
DESCRIPTION
EXAMPLE
IN
HUMANS
SIGNIFICANCE
SIMPLE
DIFFUSION
NO
[HIGH]
TO
[LOW]
spreading out of
molecules to
equilibrium
O2 into
cells; CO2
out of cells.
Cellular
Respiration
FACILITATED
DIFFUSION
NO
[HIGH]
TO
[LOW]
Process by
which
glucose
enters cells
Gaining
necessary
material; cellular
respiration
OSMOSIS
NO
[HIGH]
TO
[LOW]
Using a special
cm carrier
protein to move
something
through the cell
membrane (cm)
water moving
through the cm
to dilute a
solute
Regulation of
cell size
FILTRATION
NO
[HIGH]
TO
[LOW]
using pressure to
push something
through a cm
ACTIVE
TRANSPORT
YES
[LOW]
TO
[HIGH]
ENDOCYTOSIS
YES
[LOW]
TO
[HIGH]
EXOCYTOSIS
YES
[LOW]
TO
[HIGH]
TRANSCYTOSIS
YES
[LOW]
TO
[HIGH]
opposite of
diffusion at the
expense of
energy
bringing a
substance into
the cell that is
too large to enter
by any of the
above ways;
Phagocytosis:
cell eating;
Pinocytosis: cell
drinking.
expelling a
substance from
the cell into
ECF
Endocytosis
followed by
exocytosis
Maintenance
of osmotic
pressure of
0.9%.
manner in
which the
kidney
filters
things from
blood
K+-Na+ATPase
pump
Phagocytos
ed (foreign)
particles
fuse with
lysosomes
to be
destroyed
Exporting
proteins;
dumping
waste
Immune
system
monitors
pathogens
in sm int;
HIV
removal of
metabolic wastes
maintenance of
the resting
membrane
potential
help fight
infection; control
disease
Excretion of
waste
Protects against
food poisoning;
manner in which
HIV crosses
mucous
membranes
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UNIT 1 - CHAPTER 3: CELLS
Cell Cycle Summary
NAME OF PHASE
INTERPHASE
PROPHASE
METAPHASE
ANAPHASE
TELOPHASE
DESCRIPTION OF EVENTS
TYPICAL SKETCH
DNA appears as chromatin in
nucleus. Cell is growing and
duplicates (replicates) centrioles
during G1, replicates DNA
during S phase; prepares for
division in G2.
Fig 3.36a, page 110.
Distinct chromosomes become
apparent (i.e. sister chromatids
held together by centromere);
Centrioles migrate to opposite
poles of cell and spindle fibers
form between them;
nucleolus disintegrates;
nuclear envelope disintegrates.
Fig 3.36b, page 110.
Chromosomes line up in an
orderly fashion in the middle of
the cell (on metaphase plate);
Each centromere holding
chromatids of the chromosome
together attaches to a spindle
fiber.
Fig 3.36c, page 110.
The centromere holding the
chromosome together splits;
Resulting chromosomes migrate
toward opposite poles of cell
being pulled by spindle fibers;
Cytokinesis begins.
Fig 3.36d, page 110.
Cleavage furrow between
daughter cells is apparent (i.e.
dumb-bell shaped);
Chromosomes complete
migration to poles;
Nuclear envelope & nucleolus
reappear;
Cytokinesis is completed
Fig 3.36e, page 110.
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