Title: Cellular%20Transport%20And%20the%20Cell%20Cycle
1Cellular Transport And the Cell Cycle
2Diffusion
- At all temperatures above absolute zero, the
individual atoms that constitute any substance
are always in movement. Indeed, the amount of
this movement is what constitutes temperature
itself. - Simply put, diffusion is the movement of
particles from a region of high concentration to
an area of lower concentration
3Diffusion Cont.
- Particles of a substance will move from a region
of high concentration to a region of lower
concentration. - The difference in concentration of atoms is know
as a concentration gradient
- As particles move in a given area, an equilibrium
is reached where the space between the particles
becomes fairly uniform. - This equal distribution of atoms is called
dynamic equilibrium
4Diffusion Cont.
- Follow link to animation of diffusion
- The Diffusion Applet
- Follow link to tutorial of diffusion and osmosis
- Diffusion and osmosis tutorial
5Plasma Membrane
- Made up of two layers of phospholipids
- Controls what moves into and out of the cell
- Selectively permeable
6Passive Transport
- Transport (diffusion) of particles across the
membrane without the use of energy by the cell - Particles move from a region of high
concentration to a region of low concentration
across the concentration gradient
7Passive transport by proteins
Facilitated Diffusion - Transport of materials
across the plasma membrane with the aid of
channel proteins
- Common method for moving sugars and amino acids
across membranes - Driven by a concentration gradient (substances on
both sides of the membrane are trying to reach
equal concentration)
8Passive Transport
9What is Osmosis?
- Osmosis Diffusion of water across a selectively
permeable membrane - The plasma membrane does not limit the diffusion
of water - In a cell, water always tries to reach an equal
concentration on both sides of the membrane - Regulation of water flow through the membrane is
important in maintaining homeostasis
10What Controls Osmosis?
- Concentration gradient - Unequal distribution of
particles
11Cells in an Isotonic Solution
- Isotonic Solution when the concentration of
dissolved substances in the solution is the same
as the concentration of dissolved substances
inside of the cell - Equal movement of water into and out of the cell,
cell stays the same size
12Cells in a hypotonic solution
- Hypotonic solution when the concentration of
dissolved substances is lower in the solution
outside the cell than the concentration inside
the cell - Water is pulled into the cell, the cell swells
and the internal pressure increases
13Cells in a hypertonic solution
- Hypertonic Solution where the concentration of
dissolved substances outside the cell is higher
than the concentration inside the cell. - Water moves out of the cell, the cell shrinks,
and internal pressure decreases
14- Water moves into a cell placed in a
___________________ solution. - Osmotic
- Hypertonic
- Isotonic
- Hypotonic
15- Water moves out of a cell if it is placed in a
_______________ solution - Hypotonic
- Hypertonic
- Isotonic
- Passive
16- A cell moves particles from a region of lesser
concentration to a region of greater
concentration by _________________. - Facilitated Diffusion
- Passive Transport
- Osmosis
- Active Transport
17- If a cell is placed in salt water, water leaves
the cell by _____________. - Osmosis
- Diffusion
- Active transport
- Phagocytosis
18After viewing the recipe above, explain the role
of osmosis in making pickles. Be ready to share
your answers!
19Active Transport
- Cells can move particles from a region of low
concentration to a region of high concentration,
but it takes ! - Active Transport movement of materials through
a membrane against the concentration gradient
energy
20Active Transport Cont.
- Proteins in the cell membrane (Carrier proteins)
bind with particles of the substance. When the
right molecule binds to the right carrier
protein, chemical energy allows the carrier
protein to change shape so that the particle can
be moved to the other side of the membrane
21(No Transcript)
22Transport of Large Particles
- Some cells can take in large molecules, groups of
molecules, or even whole cells - Endocytosis process by which a cell engulfs a
material and forms a vacuole inside of the cell - Exocytosis expulsion or secretion of materials
from the cell - Used to get rid of waste, secrete hormones
- Both endocytosis and exocytosis require cellular
energy (Active transport)
23 Endocytosis
24Exocytosis
25Endocytosis and Exotytosis
- Use the play dough to model the processes of
endocytosis and exocytosis. Be able to explain
the process. When you have finished, wait for
Mrs. Johnson to come and check your work and hear
your explanation.
26Active Transport
27- Release of waste or large cell products from
inside to outside of cell _____________________. - Endocytosis
- Exocytosis
- Osmosis
- Facilitated Diffusion
28- Type of cell transport which requires energy from
the cell. - Osmosis
- Facilitated Diffusion
- Active Transport
- Passive Transport
29- Active Transport is to carrier protein as
_____________ is to channel protein. - Osmosis
- Endocytosis
- Exocytosis
- Facilitated Diffusion
30- When cell engulfs a large particle
- and forms a vacuole inside the cell
- _____________________.
- Endocytosis
- Exocytosis
- Osmosis
- Facilitated Diffusion
31- Term for cell eating
- Osmosis
- Exocytosis
- Pinocytosis
- Phagocytosis
32Cell Growth
33Cells come in different sizes
- Red blood Cells 8 µm
- Some nerve cells can be up to 1mm in length
- The yolk of an Ostrich egg measures 8cm
- Most living cells are between 2 and 200 µm
- Given the wide range of cell sizes, why cant
most organisms be just one giant cell?
34What limits cell size?
- Diffusion
- Diffusion is fast and efficient over short
distances but slow and inefficient over larger
distances - a mitochondrion at the center of a hypothetical
cell with a diameter of 20 cm would have to wait
months before receiving molecules entering the
cell
35What limits cell size? cont.
- DNA
- The nucleus contains blueprints for the cells
proteins (proteins are used throughout the cell
by the organelles) - There is a limit as to how quickly the DNA
(blueprints) can be copied - The cell cant survive unless there is enough DNA
to support the protein needs of the cell - Some large single celled organisms have developed
more than 1 nucleus
36What limits cell size? Cont.
- Surface area to volume ratio
- As cell size increases, its volume increases
faster than its surface area - If cell size doubles, the cell would require
eight times more nutrients and would have eight
times more waste to excrete. The surface area
would increase only by a factor of four. The
plasma membrane would not have enough surface
area for nutrients, waste and oxygen to diffuse
through
37Surface area to volume ratio
Surface area 6mm2 Volume 1mm3
Surface area 24mm2 Volume 8mm3
Surface area ?? Volume ??
Refer to PS lab 8.1 pg 209
38Cell Size
39To summarize.
- Substances move into and out of cells
- Passive transport
- Diffusion
- Osmosis
- Facilitated diffusion
- Active transport
- Carrier proteins
- Endocytosis/Exocytosis
- Cell size must be limited in order for a cell to
function effectively - Video
40- The structure most responsible for maintaining
cell homeostasis is the ___________. - Cytoplasm
- Mitochondria
- Cell Wall
- Plasma Membrane
41- Which of the following explain why a cells size
is limited? - Volume increases faster than surface area
- Surface area increases faster than volume
- Homeostasis is disrupted by a cell that is too
large - Both a and c
42- As a cell grows, its ___________ increases more
than its ___________. - Length, volume
- Width, surface area
- Volume, surface area
- None of these
43Cell Reproduction
44Cell Reproduction (video clip)
- The cell theory states all cells come from
preexisting cells - We know that all organisms grow and change
- Throughout our lives, worn-out tissues are
repaired or replace by new cells - All of this occurs through Cell Division
- The process by which new cells are produced from
one cell - Results in two cells that are identical to the
parent cell
45What are Chromosomes?
- Chromosomes dark staining structures that
contain genetic material (DNA) - Made up of DNA and protein
- Chromatin long strands of DNA wrapped around
protein (resembles a tangled plate of spaghetti) - Before a cell can divide,
- the long strands of chromatin
- must be organized into a
- chromosome
http//www.sirinet.net/jgjohnso/modchromosome.jpg
46Chromosomes
http//www.uic.edu/classes/bios/bios100/labs/realc
hromo.jpeg
47Video clip
http//lhs.lps.org/staff/sputnam/Biology/U3Cell/ch
romosome_1.png
48The Cell Cycle
- The sequence of growth and division of a cell
- 2 phases
- Growth
- Division
49The Growth Phase Interphase
- The majority of a cells life is spent growing
and making more DNA, this period is called
Interphase - During interphase, cell grows in size and the
chromosomes are duplicated - G1 phase - rapid growth
- S phase DNA synthesis and replication
- G2 phase Centrioles replicate and cell prepares
for division
50The Division PhaseMitosis
- Cells undergo mitosis as they approach the
maximum cell size at which the nucleus can
provide blue-prints for proteins and the plasma
membrane can efficiently transport nutrients and
waste into and out of the cell - 4 phases of Mitosis
- Prophase
- Metaphase
- Anaphase
- Telophase
51The Cell Cycle
http//lhs.lps.org/staff/sputnam/Biology/U3Cell/ce
llcycle_1.png
52Mitosis Prophase
- 1st stage of mitosis (longest stage)
- Chromatin coils up into visible chromosomes
- Each duplicated chromosome is made of 2 sister
chromatids held together by a centromere - The nucleus begins to disappear
- Centrioles migrate to opposite ends of cell
- Spindle fibers become visible
53Mitosis Metaphase
- 2nd stage of mitosis (short stage)
- Chromosomes become attached to the spindle fibers
by their centromeres - Chromosomes line up on the midline
54Mitosis Anaphase
- 3rd stage of mitosis
- Sister chromatids are pulled apart
- the spindle fibers attached to the centromere and
the centriole begin to shorten pulling the
chromatids from each other
55Mitosis Telophase
- 4th stage of mitosis
- Chromatids reach the opposite poles of the cell
- Chromosomes unwind, spindle begins to break down,
nucleolus reappears and nuclear envelop forms
around each set of new chromosomes
56Mitosis
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57 58Division of Cytoplasm
- Cytokinesis division of cytoplasm between the
two newly formed cells - Different for plant and animal cells
59Life Cycle of a Cell and Cell Division
Video clip
60- Among the following, the term that includes the
others is ___________. - Interphase
- Nuclear division
- Mitosis
- Cell Cycle
61- By the end of prophase, each of the following has
occurred except ______________. - Tighter coiling of the chromosomes
- Breaking down of the nuclear envelope
- Disappearing of the nucleolus
- Lining up of chromosomes in the cell
62- The longest phase of the cell cycle is
________________. - Prophase
- Interphase
- Metaphase
- Mitosis
63- A chromatid is attached to a spindle fiber by the
________________. - Nucleolus
- Deep furrow
- Centromere
- Centriole
64- The sequence of growth and division of a cell
makes up ______________ - Mitosis
- The Cell Cycle
- Chromosomes
- Cytoplasmic Division
65- Identify the stage of mitosis
- Anaphase
- Metaphase
- Prophase
- Telephase
66- Identify the stage of mitosis
- Anaphase
- Metaphase
- Prophase
- Telephase
67Results of Mitosis
68So whats the point?
- Mitosis guarantees that the two new cells that
are produced are genetically identical. The two
new daughter cells will carry out the same
cellular processes and functions as those of the
parent cell and will grow and divide just as the
parent cell did.
69Control of the Cell Cycle
- The full story of how the cell cycle is
controlled is not fully understood - Scientist do agree on some aspects of what causes
cells to divide -
- Enzymes
70Enzymes Control the Cell Cycle
- Different enzymes control different parts of the
cell cycle - Interphase
- growth (G1 phase)
- synthesis (S phase)
- getting ready (G2 phase)
- mitosis (prophase, metaphase, anaphase,
telophase)
71Sometimes cells lose control of the cell cycle
- Can result from
- Not enough enzyme
- Too much enzyme
- Production of enzymes at the wrong time
- Enzyme production is controlled by genes
72Cancer
- Uncontrolled cell division can result in cancer
- Cancer is a mistake in the cell cycle
- Cancerous cells form tumors
- Tumors deprive normal cells of nutrients
- Cancer cells can enter the blood stream and
spread throughout the body (metastasis)
73Causes of Cancer
- Genetic factors (Heredity)
- Viruses that cause damage to genes
- Environmental Factors that damage genes
- Cigarette smoke
- Air pollution
- Water pollution
- UV exposure
- Radiation
74Incidence of Cancer
- People of different countries develop different
types of cancer - Ex. Breast cancer is high in the U.S, Stomach
cancer is high in China - When people move from one country to another,
cancer rates follow the pattern of the country in
which they are currently living
75Cancer Prevention
- There is a clear link between a health lifestyle
and incidence of cancer - Diet
- Low fat, high fiber
- Fruits, vegetables, grains
- Vitamins Minerals
- Caratenoids
- Vitamins A, C E
- Calcium
- Exercise
- No tobacco use
76Cell Aging and Cancer
77Growth and Development in Multicellular Organisms
- Cells
- Tissues
- Organs
- Organ systems
- Organism
- Video clip
- No matter how complex the organism, the cell is
still the basic unit of organization