Slide 1
Cellular Transport and
the Cell Cycle
Slide 2
Diffusion—Movement of
particles from an area of
higher concentration to an
area of lower concentration
Slide 3
Net Movement
movement which changes
concentration
Slide 4
Slide 5
Factors that affect diffusion
Particle size and shape
 Temperature
 Concentration gradient—Difference in
concentration.
 Cytoplasmic streaming—Continuous
movement of materials in cytoplasm.

Slide 6
Diffuse in Membranes
1.
Passive Transport
Moving of materials across cell membrane
without using cellular energy.
• Diffusion (phospholipids)
• Facilitated Diffusion (transport proteins)
Uses Channel Proteins
Active Transport
Moving of materials across cell membrane
using cellular energy
Uses Carrier Proteins
Slide 7
Osmosis
•
•
Diffusion of WATER across a
selectively permeable
membrane.
Water moves from an area of
HIGH water concentration (low
solute) to an area of LOW
water concentration (high
solute)
Slide 8
Osmosis
Slide 9
Osmotic Pressure
Force produced by the net movement of
water out of or into cell.
Result:
Turgid pressure-plants straight up
Water purification (reverse osmosis)
Desalinates Salt Water
Slide 10
Osmotic Condition—Cell
concentrations versus
environmental solution
concentrations.
Isotonic
Hypotonic
Hypertonic
Slide 11
Solution concentrations inside is the same as
outside.
No net movement of water.
Animal cells: Normal
Plant Cells: Flaccid
Isotonic
“Iso” means same
Slide 12
Solute concentrations outside is
less than cell concentration.
Animal Cell : Lysed
Plant Cell: Turgid
“Hypo” - under
Slide 13
Slide 14
Solute concentration outside is
greater than cell concentration.
Animal Cell: Shrink
Plant Cell: Plasmolyzed
“Hyper” - above
Slide 15
This is why it is dangerous to drink sea water - its a myth that
drinking sea water will cause you to go insane, but people marooned
at sea will speed up dehydration (and death) by drinking sea water.
This is also why "salting fields" was a common tactic during war, it
would kill the crops in the field, thus causing food shortages.
Slide 16
Slide 17
Hypertonic, Isotonic and
Hypotonic
Slide 18
Slide 19
Slide 20
Active TransPort
Using a protein molecule to move
particles up the concentration
gradient.
Requires ATP (Adenosine
Triphosphate)
Slide 21
Example of how the cell
uses Active Transport
Pump—Proteins that use active
transport to move particles
between the interior and exterior
of the cell.
e.g. Sodium/Potassium pump:
Used to move sodium and
potassium ions across nerve
membranes.
Slide 22
Active Transport Versus
Passive Transport
Slide 23
Large Molecules
Slide 24
Endocytosis: Cell membrane
indents around molecule and
forms a vesicle.
Pinocytosis—Uptaking fluid molecules
 Phagocytosis—Uptaking solid molecules

Slide 25
Pinocytosis and Phagocytosis
Slide 26
Exocytosis
Vesicles fuse with cell membrane
to release materials.
Slide 27
Endocytosis and Exocytosis
Slide 28
Slide 29
Cell Size
 Cell
size range from 8 micrometers in
diameter to 1 meter with small
diameters.
 Most cells are between 2 and 200
micrometers in diameter.
Slide 30
Comparison of Cell sizes
Slide 31
Cell Size Limitations

Cell must be small

Rate of Diffusion

DNA—Cell cannot survive unless
– larger cells find it difficult to bring in enough food
– export enough waste to keep the cell alive.
– Size :diffusion slower and less efficient.
– enough DNA to support protein needs of cell
– cell activities are carried out quickly and
efficiently
Slide 32
Surface area-to-volume ratio
Another size limiting factor is the
cell’s surface area-to-volume ratio.
As cell’s size increases, its
volume increases much faster
than its surface area.
Slide 33
Cell Surface area-to-volume ratio
As cell size increases, the ratio of cell volume to cell
surface area decreases.
Cells increase in size, there isn't enough cell membrane
to adequately supply the cell interior with enough
oxygen, water, and food.
When this happens, the cell dies.
Slide 34
Slide 35
Cell Growth and Reproduction
Slide 36
Cell Theory
All cells come from pre-existing
cells!
Cell division results in two cells
that are identical to the original
parent cell.
Slide 37
Chromosomes
Chroma (Greek) “colored”
Soma “body”
Dark-staining structures that contain
genetic information that is crucial to
the identity of the cell.
Slide 38
Structure of the Eukaryotic
Chromosome
Exist as CHROMATIN—Long strands of
DNA wrapped around proteins.
 Microscope—Plate of spaghetti

Slide 39
Cell Cycle
The cell cycle
– Interphase (most of the cell’s metabolic
functions are carried out and the chromosomes
are replicated) LONGEST of Cell Cycle
– Mitosis when nuclear division occurs, leading to
the formation of two daughter cells.
– The division of the cytoplasm, called
cytokinesis, follows mitosis.
Slide 40
Cell Cycle: Sequence of growth
and cell division of a cell
Slide 41
Interphase
Cell grows in size
 Carry on metabolism
 Chromosomes are duplicated for cell
division.

Slide 42
Interphase:Cell Prepares for
Mitosis
G1: Chromosomes are not visible under
light (uncoiled); Protein synthesis is
rapidly occurring.
S Stage: Chromosomes replicated in the
nucleus; Chromosomes divide to form
identical sister chromatids connected by a
centromere.
G2: Chromosomes begin to shorten and
coil, and protein synthesis is in high gear;
In animals, the centriole pair replicates
and prepares to form mitotic spindle
Slide 43
Mitosis: A period of nuclear
division

The process by which two daughter cells are
formed, each containing a complete set of
chromosomes.
Slide 44
Mitosis
Prophase
 Metaphase
 Anaphase
 Telophase

Slide 45
Prophase
1st / longest phase of mitosis.
 Chromatin coils up-chromosomes.
 Two halves of the double structure are called
sister chromatids. (Exact Copies of each
other)
 Centromere—holds together sister
chromatids.

Slide 46
Prophase continued…
Nucleus disappears
 Nuclear envelope and nucleolus disintegrate.
 Animals—centrioles migrate to opposite end
of the cell.
 Centriole—Small, dark, cylindrical structures
that are made of microtubules and are
located just outside the nucleus.

Slide 47
Prophase continued…

Spindle—A football shaped, cage-like
structure consisting of thin fibers made of
microtubules.
Slide 48
Metaphase: Second stage of
mitosis

Chromosomes

One sister chromatid’s spindle fiber extends to one
pole, and the other extends to the opposite poles
(ensures a complete set of chromosomes)
– Attach to the spindle fibers via centromeres.
– Pulled by spindle fibers and line up on the midline
(equator).
Slide 49
Anaphase: Third Phase of Mitosis
 Separation
of sister chromosomes
– Centromeres split apart and chromatid pair
separate
– Pulled apart by the shortening of the
microtubules in the spindle fiber.
Slide 50
Telophase: 4th phase of mitosis
Chromosomes reach opposite poles of cell.
 Prophase changes are reversed
(independent existence).
 Chromosomes unwind; Spindle breaks down;
nucleolus reappears; new nuclear envelope
forms each set of chromosomes; new double
membrane begins to form.

Slide 51
Cytokinesis


Cytoplasm division
Animal Cells—towards the end of telophase the
plasma membrane pinches in along the equator

Plant Cells—plants have rigid cell wall, so cell plate
is laid down across cell’s equator. Cell membrane
forms around each cell, and new cell walls form on
each side of the cell plate until separation is
complete.
Slide 52
Result of Mitosis

Two new cells with chromosome
sets identical to those of the
parents; Carry out same function of
parent cells; Grow and divide like
parent cells.
 Tissues: group of cells that work
together to do a specific function.
 Organs: group of two or more
tissues organized to perform
complex activities within an
organism.
 Organ Systems: Multiple organs
that work together to perform
specific life function.
Slide 53
Slide 54
Cell Cycle
Slide 55
Control of Cell Cycle
Cell cycle
 24 to 48 hours
 less then an hour
 never divide only mature
A mistake in the cell cycle can
lead to cancer.
Slide 56
Control of the Cell Cycle
 Enzymes
– Begin and drive the cell cycle
– Control the cycle through its phases.
 Cell can lose control (uncontrolled
dividing)
– failure to produce certain enzymes
– production of other enzymes at the wrong time.
 Cancer
is the result of uncontrolled cell
division.
Slide 57
Causes of loss of control of cell
cycle
Environmental Factors
 Changes in enzyme production

– Enzyme production is directed by genes located
on the chromosome.
– A gene is a segment of DNA that controls the
production of a protein.

Many studies point to portion of interphase
just before DNA replication as being a key
control period.
Slide 58
Cancer: A mistake in the
Cell Cycle
Expressed as cancer when
something prompts the damaged
genes into action.
Slide 59
Cancer
Cancerous cells form masses of tissue called
tumors that deprive normal cells of nutrients.
 Late Stages: Cancer cells enter the
circulatory system and spread throughout the
body (Metastasis), forming new tumors that
disrupt the function of organs, organ
systems, and ultimately the organism.

Slide 60
In Cancer Cells
•There is no awareness of surroundings.
•Cells do not stop dividing when crowded.
•Cells do not stop after a set number of divisions.
•Cells do not enter a resting state.
•Cells divide faster and take less time to complete
the cycle.
Slide 61
Slide 62
Cancer: 2nd Leading Cause of
death in the United States
Environmental and Genetic Factors
 Cigarette smoke
 Air
 Water pollution
 Exposure to UV Radiation
 Viral Infections
 MySpace, Facebook and Twitter
Slide 63
Cancer Prevention
Link between healthy lifestyle and the
incidence of cancer.
 Diets low in fat and high in fiber.
 Minimal amounts of fat.
 Vitamins and minerals; carotenoids, vitamins
A, C, and E and calcium.
 Daily exercise
 No smoking
 Don’t use MySpace,
 Face Book and Twitter

Slide 64
Slide 65
Surface Area and Volume
Surface Area: 6 (# of sides) x A x A
Volume: A x A X A
•Cube doubled
•Outside Grows by 4 x
•Inside grows by 8 x
Slide 66
Slide 67