Cellular Transport And The Cell
Cycle
Chapter 8
Cellular Transport
Cellular transport~ the “highway”of the
cell. How substances move from one
place to another throughout cells.
Osmosis~ net movement of a solvent
(H2O) through a selectively permeable
membrane.
Selectively permeable membrane~ a
cell membrane that has control over what
can enter and exit the cell.
Concentration level Isotonic
of the substance
outside =
concentration level
of substances
within the cell
Allows Red Blood
Cells to maintain
shape.
water in or out of
cell at the same
rate.
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Solution
Concentration
of the
substance
outside the cell
is higher than
the
concentration
inside the cell.
Cell shrivels
Water moves
out of a cell
Hypertonic solution
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Hypotonic solution
Concentration
level of substance
outside the cell
< concentration
level of
substances within
the cell.
Cells burst if
hypotonic
Water moves
into a cell
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Cell Transport…
Passive transport~ solvent moves from high to low across
concentration gradient under its own power, passive transport is
a form of diffusion. NO ENERGY USED
Forms of passive transport include facilitated diffusion, diffusion,
osmosis.
Water, lipids (fats) and lipid soluble substances are some
compounds that can be diffused through the plasma membrane
by diffusion.
Cell Transport…
Facilitated diffusion – Cell exerts no energy
Proteins help to move substances through plasma
membrane. ( figure 8-5)
o The most common solvents moved by F.D. are sugars and
amino acids. F.D. uses the concentration gradient.
Proteins provide needed paths and openings to allow particles
to pass through.
o
Cell transport…
Active transport- The cell exerts all the energy to produce the
transport. And move it across its concentration gradient
In order for active transport to occur a special transport protein called
a carrier protein must attach to a particle from the substance. (figure
8-6)
Active transport allows movement into and out of the cell, against the
concentration gradient.
Cell transport…
Endocytosis~ engulfs
materials and than moves
them into cell for
processing. Material
doesn’t pass directly
through membrane.
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Exocytosis~ removes
waste by merging with
cells and kicking waste
out to extra cellular fluid.
(Figure 8.7)8.78-7)
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Cell Growth and Reproduction.
Cell size is influenced by:
1. Diffusion affects cell size because as the cell is larger it takes longer
for the process to be finished.
2. DNA affects cell size because some cells have an increased amount of
cytoplasm
3. SA-VR affects the cell size because a cells volume increases faster
than the surface area.
Cell Reproduction…
Cell reproduction occurs from a pre-existing cell.The Process
that this occurs is cell division.
Cell division results in two cells that are identical to the
original cell. The most prevalent cells to regenerate are skin
cells. All worn tissue gets replaced with new cells or repaired.
( pg.209)
Cell Growth and Reproduction
The cell cycle is the sequence of growth and
division of a cell. The cell goes through two
general phases, growth and division.
Interphase~ longest phase ,a cell grows in
size and carries out metabolism, also this is
when chromosomes (DNA material) are
duplicated.
Mitosis is the phase following interphase.
During mitosis two daughter cells are formed,
each having all of its chromosomes, these two
phases are the main phases of the cell cycle.
Why do cells divide by
Mitosis?
Growth &Repair
Reproduction of
single celled
organisms
constant
environment
Amobea
Reproducing
Cells dividing by Mitosis…….
Skin
Identical to
original cell
Same
chromosome #
Identical
chromosome
makeup
Cell Cycle
“G” or Growth
1 phase
“S” or DNA
Synthesis
24 hours
Growth 2
/
/
/
“M” or
Mitosis
phase
Where is DNA located?
1. Nucleus
2. Chromosomes
DNA
Duplicated Chromosome
(Late Interphase):
Sister
Chromatids
Centromere
Spindle & spindle fibers: Pull
apart the sister chromatids
Spindle
fibers
Interphase
Intermission
Normal
metabolic
activities
Major state
DNA=
chromatin
Late Interphase
Prepares for
mitosis
DNA doubles=
Sister
chromatids
Centrioles
double in
animals
Stages of Mitotic Cell Division
Prophase
Metaphase
Anaphase
Telophase
“1st”
“middle”
“apart”
“far” or
separate
Prophase
Nuclear
membrane
disappears
Doubled DNA
= condensed
“chromosomes”
Spindle fibers
Metaphase
Chromosomes line
up mid- cell
Facing
inward
Anaphase
Chromosomes
move to opposite
poles at
Centrioles in
animals
Spindle apparatus
in plants
Telophase
Cells divide
Chromosomes
unwind
Cell plate or
membranes
form
Nucleus
reappears
Animal Telophase
Interphase
Returns to Interphase
“Intermission”
Normal metabolic
activities
Major state
DNA=chromatin
Plant versus Animal Mitosis
Plant:
Cell wall form
cell plate in
telophase
Spindles
Animal:
No cell wall
membrane
cytokinesis
Centrioles
Cell Growth and Reproduction…
Cytokinesis- process in which cytoplasm divides.
I- Interphase
P- Prophase
M- Mitosis
A- Anaphase
T- Telephase
a good way to remember the phases of cell cycle is
CIPMAT.ICIPPMAT.
Control of Cell Cycle
Enzymes control the cell cycle. Certain enzymes are important to
begin and keep the cell cycle going, while certain enzymes only
control certain phases.
Cancer is the result of uncontrolled cell division. During uncontrolled
cell division certain enzymes are not present or were not produced or
environmental changes.
Enzymes are directed by genes located on chromosomes.
Cancerous cells……...
1.Divide too many
times
2.Divide into more
than two cells!
Masses of cells =
“tumors”
 benign
 malignant
Mitosis Flip Book
Make two index cards for each phase of mitosis –
ex. Early and late prophase, early and late
metaphase etc….
Color and Label each part of the cell: Chromatin,
sister chromatids, centromere, spindle, cell
membrane
Make one index card for interphase
Describe each phase on the back of each index
card