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C8-Cellular Transport
And the Cell Cycle
Contents
Section 1- Cellular Transport & the
Cell Cycle
Section 2- Cell Growth &
Reproduction
Section 3- Control of the Cell Cycle
Cellular Transport & Cell Cycle
Three types of
cell transport
Osmosis diffusion
of water across a
selectively
permeable
membrane
Passive Transport
Active Transport
Osmosis- What controls it?
Concentration
gradient
Water diffuses until
it is in equal
concentration on
both sides of a
membrane.
Random
movement due to
kinetic energy
Osmosis- Cells in Isotonic Solution
retain normal shape
Cells in Hypotonic Solution
Cells in Hypertonic Solution
Effects on Animal or Plant Cells
Passive Transport
PT does not require energy
Either simple diffusion or facilitated
diffusion across a membrane through a
transport or carrier protein.
Active Transport
Contrast passive & active
Passive transport acts with the
concentration gradient and requires
no energy to move from higher to
lower concentration.
Active transport acts against the
concentration gradient and requires
energy to move from lower to higher
concentration.
Transport of Large Particles
Endocytosis
cell process to
engulf material &
create vacuole
Exocytosis
expulsion or
secretion of
waste or
hormones from
the cell
Both processes require energy.
8.2 Cell Growth & Reproduction
Diffusion limits cell size.
It’s fast & efficient over short distance.
Slow rate over longer distance.
Amount of DNA must support protein
needs of the cell.
Surface area to volume ratio- volume
increases faster than surface area i.e.
double area = 8X volume
8.2 Cell Growth & Reproduction
Cells divide
before they
become too
large to
function
properly.
Cell Reproduction
Cell division results
in two cells identical
to the parent cell.
Chromosomes
carry genetic
information &
usually exist as
chromatin except
during reproduction.
The Cell Cycle
Sequence of
growth & division
Majority of cycle is
growth phase
called Interphase.
Protein production
Chromosome
duplication
Mitosis period of
nuclear division
Phases of Mitosis
Prophase
Metaphase
Anaphase
Telophase
Phases of Mitosis
Prophase- chromatin coils to form
visible chromosomes
Metaphase- chromosomes move to
the equator of spindle
Anaphase- centromeres split and
sister chromatids move to opposite
poles.
Telophase- Two distinct daughter
cells are formed
Phases of Mitosis
Cytokinesis
After telophase the
cell’s cytoplasm
divides.
In animals the
plasma membrane
pinches in, but in
plants a cell plate
with membranes
forms until a new
cell wall can form.
Results of Mitosis
Guarantees genetic continuity
Cellular organization-> tissues->
organs-> organ systems
Organ systems work together for the
survival of the organism
8.3 Control of the Cell Cycle
Proteins &
Enzymes control
the cell cycle.
Checkpoints within
the cycle are
controlled by
proteins called
cyclins and by
kinase enzyme.
Cancer
Unrestrained cell
division causing
malignant growth
Can be caused by
environmental
factors or by
changes in enzyme
production
Control of the Cell Cycle
Enzyme production
is controlled by
genes located on
the chromosomes.
Key checkpoint
during interphase
just before DNA
replicates.
Cancer: Mistake in Cell Cycle
Cancerous cells form masses of
tissues called tumors.
Later cancer cells enter the
bloodstream and metastasize to other
parts of the body.
A healthy lifestyle can reduce the
incidence of cancer. Low-fat high-fiber
diet, exercise, avoid tobacco use.
Cancer Prevention
Healthy Lifestyle
Diet low in fat & high in fiber from
fruits, vegetables and grains
Vitamins A, C, E and mineral calcium
Daily exercise
Avoiding tobacco use