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The Cell
Standard 5: Identify cells, tissues, organs, organ systems,
organisms, populations, communities, and ecosystems as levels or
organization in the biosphere.
Standard 4: Describe similarities and differences of cell
organelles, using diagrams and tables.
Standard 2: Describe the cell process necessary for achieving
homeostasis, including active and passive transport, osmosis,
diffusion, exocytosis, and endocytosis.
Introduction to the Cell
• You have been taught that
Biology is the study of life or
that which was once living. So
how does life actually begin? It
begins with molecules. Those
molecules are going to form tiny
structures called cells.
Introduction to the Cell
• The cell is the smallest unit of
life. It is the basic structure and
function of living things.
• The living parts of the universe
starts off as tiny cells and
grows to form our biosphere.
The Cell
The cell is the basic building block of life. It it responsible
for the many levels of organization that we come in
contact with. It is organized as follows:
MoleculesCellsTissuesOrgansOrgan Systems>
Organisms>Populations>Communities>EcosystemsBisosphere
This means that molecules make up cells. Cells make up
tissues. Tissues make up organs and organ make up organ
systems. Organ systems are going to make up organisms.
Organisms will make up populations. Populations will make up
communities and the communities will make up the
ecosystems. The ecosystems will make up the biospehere.
The Cell Discovery and
Theory
• There are several scientist that
are noted as making
contributions to either the
discovery of the cell or to
making of the cell theory.
The Cell Discovery and
Theory
•
•
•
•
•
Notable Scientists
Robert Hooke- first viewed the cell under a
microscope that he built using a piece of
cork.
Anton van Leeuwenhoek-microscope
maker and was first to view living cells
under the microscope.
Matthias Schleiden-studied plant cells.
Theodore Schwann-studied animal cells.
Rudolph Virchow-studied how diseases
affected cells.
Cell Theory
The cell theory states that:
• All living things are made of one
or more cells.
• The cell is the basic unit of
structure and function in living
organisms.
• All cells arise from pre-existing
cells.
Two Type of Cells
• Prokaryotes- organism that
does not contain a nucleus or
membrane bound organelles.
Ex. Bacteria (Monera Kingdom)
• Eukaryotes- organisms that
contain a membrane bound
nucleus and organelles. Ex.
plant and animal cells
Eukaryotes
There are 4 types of eukaryotes.
• Plant Cells
• Animal Cells
• Protist Cells
• Fungal Cells
Plant Cells
Animal Cells
Cell Organelles
•
•
•
Cytoplasm-the liquid inside the cell
Cell/Plasma membrane-made of
lipids and proteins, it is the
boundary of the cell and control
what enters and leaves the cell.
Nucleus-control center of the cell
where the genetic material is found
Cell Organelles
•
•
•
Cell wall-surrounds the plant cell
and is made of cellulose
*Ribosomes-very small organelles
that are the sites of protein
synthesis.
Endoplasmic reticulum- system of
tubes in the cytoplasm involved in
transporting materials
Cell Organelles
• Golgi Apparatus (Golgi Body or
Golgi Complex)-involved in
packaging and distribution
• *Mitochondria-site of cellular
respiration and is the
powerhouse of the cell (where
ATP is made)
Cell Organelles
• Lysosomes-stores digestive
enzymes
• *Chloroplast-site of
photosynthesis (where
chlorophyll is made)
• Vacuole-involved in food
storage
Cell Organelles
The plant and animal cells share
the same organelles except that
plant cells have a cell wall,
chloroplasts, and central (large)
vacuole.
Cell Locomotion
• Cells can either use cilia or
flagella to aid in locomotion
(movement)
• Cilia- short hair-like particles
found on some cells to help aid in
movement and food gathering ex.
on the paramecium
• Flagella – long whip-like
projections that aids in movement
Cilia and Flagella
Cilia
Cell Survival
• In order for cells to survive,
they must take in nutrients and
get rid of waste products, the
cells move these substances in
and out by either active or
passive transport.
Active Transport
•
Active Transport: the cell requires
energy to move substances across
the cell membrane in the opposite
direction of concentration. It is not
spontaneous. Active transport
moves substances from an area of
low concentration to an area of
high concentration.
Active Transport
2 Types of Active Transport
•
•
Endocytosis-a form of active
transport in which a cell moves
substances into the cell.
Exocytosis- a form of active
transport in which a cell moves
substances out of the cell.
Active Transport
• Endocytosis
Exocytosis
Passive Transport
• Passive Transport-transport
that is spontaneous and does
not require energy. Molecules
move through the plasma/cell
membrane from an area of high
concentration to an area of
low concentration.
2 Types of Passive
Transport
•
•
Diffusion- the process by which substances
move from an area high concentration to an
area of low concentration.
Facilitated diffusion-occurs when carrier
proteins in the plasma membrane assist in
the passage of materials into or out of the
cell.
Osmosis- the movement of water through a
semi-permeable membrane from an area of
high concentration to an area of low
concentration.
Osmosis
• There are 3 types of osmotic
solutions
• Isotonic Solutions-has equal
concentration of substances both
inside the cell and outside. The cell
will not gain or lose water.
• Hypotonic Solutions-causes the cell to
swell, moves water into the cell.
• Hypertonic Solutions--causes the cell
to shrink, moves water out of the cell.
Isotonic Solutions
If the concentration of
solute (salt) is equal on
both sides, the water will
move back and forth but it
won't have any result on
the overall amount of
water on either side.
"ISO" means the same
Hypotonic Solutions
The word "HYPO" means less, in this
case there are less solute (salt)
molecules outside the cell, since salt
sucks, water will move into the cell.
The cell will gain water and grow larger.
In plant cells, the central vacuoles will fill
and the plant becomes stiff and rigid, the
cell wall keeps the plant from bursting
In animal cells, the cell may be in
danger of bursting, organelles called
CONTRACTILE VACUOLES will pump
water out of the cell to prevent this.
Hypertonic Solutions
The word "HYPER" means more, in this
case there are more solute (salt) molecules
outside the cell, which causes the water to
be sucked in that direction.
In plant cells, the central vacuole loses
water and the cells shrink, causing wilting.
In animal cells, the cells also shrink.
In both cases, the cell may die.
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
Cell Division, Mitosis, &
Meiosis
Reproduction In Cells
Cells can reproduce either by sexual
or asexual reproduction.
• Sexual Reproduction- reproduction using
a sperm and an egg cell.
• Asexual Reproduction- reproduction in
which and organism produces another
organism identical to itself or without
the use of a sperm and egg cell.
Cell Division
(Reproduction)
There are two types of cell division:
Mitosis and Meiosis
•
Mitosis- a type or reproduction in
which the cell divides and produces 2
daughter cells that are identical to the
parent cell. (asexual reproduction)
•
Meiosis- a type of cell division in which
the parent cell will divide twice and
produce 4 gametes (sex cells) (sexual
reproduction)
Meiosis and Mitosis
Stages of Mitosis
Interphase
Prophase
Metaphase
Anaphase
Telophase & Cytokinesis
Animated Mitosis Cycle
http://www.cellsalive.com/mitosis.htm
• Interphase
• Prophase
• Metaphase
• Anaphase
• Telophase & Cytokinesis
Interphase
occurs before mitosis begins
• Chromosomes are copied (# doubles)
• Chromosomes appear as threadlike coils
(chromatin) at the start, but each
chromosome and its copy(sister
chromosome) change to sister chromatids
at end of this phase
Nucleus
CELL
MEMBRANE
Cytoplasm
Interphase
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Prophase
1st step in Mitosis
• Mitosis begins (cell begins to divide)
• Centrioles (or poles) appear and begin
to move to opposite end of the cell.
• Spindle fibers form between the poles.
Sister chromatids
Centrioles
Spindle fibers
Prophase
Animal Cell
Plant Cell
Spindle fibers
Centrioles
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Metaphase
2nd step in Mitosis
• Chromatids (or pairs of chromosomes)
attach to the spindle fibers.
Centrioles
Spindle fibers
Metaphase
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Anaphase
3rd step in Mitosis
• Chromatids (or pairs of chromosomes)
separate and begin to move to
opposite ends of the cell.
Centrioles
Spindle fibers
Anaphase
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Telophase
4th step in Mitosis
• Two new nuclei form.
• Chromosomes appear as chromatin
(threads rather than rods).
• Mitosis ends.
Nuclei
Chromatin
Nuclei
Telophase
Animal Cell
Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Cytokinesis
occurs after mitosis
• Cell membrane moves inward to
create two daughter cells – each with
its own nucleus with identical
chromosomes.
Animal Mitosis -- Review
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
Plant Mitosis -- Review
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interphase
Cell Cycle
49
- Cell Division
The Cell Cycle
2
1
3
6
4
5
50
50
Asexual Reproduction
Mitosis is asexual reproduction.
Asexual reproduction is
reproduction without the use of
a sperm and an egg cell.
How do little elephants grow up to be
BIG elephants?
Why do animals shed their
skin?
How does skin repair
itself?
The process of asexual
reproduction begins after a
sperm fertilizes an egg.
Three reasons why cells
reproduce by asexual
reproduction:
1. Growth
2. Repair
3. Replacement
Skin cancer - the abnormal
growth of skin cells - most
often develops on skin exposed
to the sun.
Cells that reproduce by asexual
reproduction reproduce
constantly.
Forms of Asexual
Reproduction
• 4 Types of Asexual
Reproduction
• Fission- asexual reproduction in
which a organism splits into two
equal parts.
• Budding- asexual reproduction in
which an organism can grow
another organism from the top,
bottom, or sides of the organisms
body.
Forms of Asexual
Reproduction
• Regeneration- asexual
reproduction in which an organism
can re-grow missing body parts
• Fragmentation- asexual
reproduction in which an organism
can be broken or cut up and those
parts will grow into a totally new
but identical organism.
Stages of Meiosis
•
•
•
•
•
•
•
Interphase
Prophase
Metaphase
Anaphase
Telophase
Interkenesis
Prophase II
Metaphase II
Anaphase II
Telophase II
Diploid and Haploid
Cells
• Haploid- having a single set or (n)
number of chromosomes
• Diploid- having two sets or two times
the (n) number of chromosomes
EX. Humans have 23 pair of
chromosomes or 46 total (diploid)
chromosomes. n=23 (haploid)
Sex Cells
Sex Cells are also referred to as
gametes.
• Sperm cells and egg cells are called
gametes and contains one set of
chromosomes “n or haploid”.
• Once the sperm fertilizes the egg it
becomes a zygote (somatic cell)
with double the number of
chromosomes (diploid).
Crossing Over - variation
Sex Chromosomes
XX chromosome – female
XY chromosome - male
Meiosis
• Meiosis is sexual reproduction.
• The purpose of meiosis is to produce gametes
(4) in preparation for reproduction. (These
gametes may sometimes referred to as the
daughter cells of Meiosis.)
• Meiosis causes variation which means that no
organism produced during meiosis will be
identical.
Meiosis Animation
• http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter28/animation__stages_of_
meiosis.html