BIOTECHNOLOGY
Chapter 4 Cells: The Foundation of Life
Troy Area High School
Mr. Schanbacher
Essential Questions
• Why are cells the foundation of life?
• What are the different types of cells?
• What are the differences between prokaryotic and
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eukaryotic cells?
What are the different components of cells?
How do cells reproduce by mitosis?
What is the process of meiosis?
What are stem cells?
The Importance of Cells!
• The most basic life processes take place at the cellular
level:
• Reproduction
• Growth
• Immunity
• Nutrient Utilization
• Almost all modern BT is based on the functions and
interactions of plant and animal cells.
Electron Microscope
• Invented in the 1940’s
• Has allowed us to understand cellular funtions
What are the different types of cells?
• Cells come in all shapes and sizes
Prokaryotic
VS Eukaryotic
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Prokaryotic Cells
• Contain genetic material but it is not confined to the
nucleus.
• DNA is contained within a single molecule and is in
contact with the cytoplasm.
• Smallest of all cells and generally considered neither plant
nor animal.
• Bacteria and Archaea
What is the importance of prokaryotic cells
in biotechnology?
• Wine, cheese, yogurt, etc.
• Genetically engineered bacteria produce certain proteins:
• Insulin
• Hepatitis B vaccine
• Tissue plasminogen activator
• Human growth hormone
• Ice-minus bacteria
• Interferon
• bt corn
• rBST
Eukaryotic Cells
• Plants and Animals
• Larger than PC’s
• Have a (or more than one) nucleus made mostly of
nucleic acid (Capital Building)
• Contains DNA
• DNA contains all genetic info responsible for giving an organism its
characteristics (we will look at this more in depth next chapter)
• Surrounding the nucleus is a clear fluid called cytoplasm
• Contain all the material needed to conduct life processes.
• Contains membrane-enclosed structures called organelles
• Organelles perform specialized structures within the cell.
• Both the nucleus and cytoplasm are contained within a
cell membrane and are made of proteins and lipids.
What are the components of eukaryotic
cells?
• Cell Membrane
• Cell Walls
• Organelles
• Mitochondria
• Vacuoles
• Microtubules
• Microfilaments
• Ribosomes
• Golgi apparatus
• Endoplasmatic reticulum
• Lysosomes
• Plastids
• Chloroplasts
• Leucoplasts
• Chromoplasts
What is the purpose of the cell
membrane?
• Cell membrane=Plasma membrane (Gate)
• Phospholipid bilayer
• Three Purposes
• 1. Encloses and protects the cell’s contents from external
environment
• 2. Regulates the movement of materials into and out of the cell
(nutrients and waste)
• 3. Allows for interaction between other cells
• Plants: Cell Wall
• Animals: Plasma Membrane
Diffusion (video)
• The cell membrane is selective or semipermeable
• Only certain substances can pass
• Small or charged molecules and ions (charged molecules)
• Water and other nutrients in….Waste Out
• This process is called diffusion (Passive Transport)
• Molecules in solution pass through the membrane from a region of
higher concentration of molecules to an area of lower concentration
• Example: Animal cells have fewer molecules of oxygen inside the
cell than outside and have more carbon dioxide molecules inside
than out….diffusion is needed to take in oxygen and release CO2!
Osmosis
• The movement of water in and out of the cell
Egg Experiment
• Materials Needed:
• 2 eggs per group
• 2 Containers
• Vinegar
• Scale
• Tap Water
• Food Coloring
• Corn Syrup
• Directions and Worksheet
Homeostasis
• The ability of an organism to remain stable when
conditions around it are changing.
• When cells are filled with water they build up internal
pressure that is called turgor.
• Turgor keeps the cells membranes taut.
• What are some examples of cells lacking turgor pressure?
Cell Walls
• ONLY FOUND IN PLANTS!!!
• Cell Walls give the plant cell its shape and provides protection
for the plant
• Made of cellulose
• We utilize cellulose found in hard plant cells (lumber, paper, cotton,
etc.)
• Pectin
• Found in softer plant tissues such as leaves and fruit
• Used to make jelly to give it a thick consistency
• Plant Cells are held together by contact of individual cell walls.
Cell Wall
Organelles
• Within the cytoplasm of cells are small structures that
serve different roles.
• Mitochondria
• Vacuoles
• Microtubules
• Microfilaments
• Ribosomes
• Golgi apparatus
• Endoplasmatic reticulum
• Lysosomes
• Plastids
• Chloroplasts
• Leucoplasts
• Chromoplasts
Mitochondria
• Peanut Shaped
• Functions to break down food nutrients and supply the
cell with energy (ATP=currency of cell).
• The more energy a cell needs (muscle cells) the more
mitochondria they contain.
• The POWER HOUSE of the cell
Vacuoles
• Plant cells usually have one large vacuole and animal
cells have many smaller ones.
Vacuole
• Serve as storage compartments for the cell
• Store water, nutrients and waste
Microtubules
• Contained in some animal cells
• Thin hollow tubes that act as the “bones” for the cell.
• Supports the cell and gives the cell its shape.
Microfilaments
• Fine fiberlike structures composed of proteins that help
the cell move by waving back and forth.
Ribosomes
• Site where protein molecules are assembled in the cell.
• Act as FACTORIES which translate DNA from the nucleus
to useable proteins molecules.
• Proteins are needed by all cells for growth and other
important functions.
Golgi Apparatus
• Shaped like a bunch of flat sacks
• Function to remove water from proteins and prepare them
(package) for export from the cell.
• THE POST OFFICE.
Endoplasmic Reticulum
• Interconnected tubules and vesicles to transport proteins
throughout the cell.
• THE HIGHWAY
Lysosome
• Digestive unit of cell
• Break down
• Proteins
• Carbs
• Bacteria
• Other foreign material that enters cell
• Worn out and nonfunctional cell parts
• TRASH MAN
Plastids
• Found only in plant cells
• 1. Chloroplasts
• 2. Leucoplasts
• 3. Chromoplasts
Chloroplasts
• Use energy from the sun to make carbs.
• Contain chlorophyll
Cell Reproduction
Meiosis and Mitosis!
What is Meiosis?
• Cells are divided into cells that contain only one-half of
chromosomes needed for the formation of the young animals.
(Humans n=23)
• This is a haploid cell
• These cells are called sex cells or gametes (sperm and egg)
• The process is spermatogenesis in male and oogenesis in
females
• Figure 4-15
• When the two gametes combine all the chromosomes needed
are there (Humans n=46)
• This is a diploid cell.
What is Mitosis?
• All growth that takes place in living organisms comes
about as a result of cells increasing in size or number.
• The process by which cells multiply is MITOSIS!!!!
• When a cell grows it reaches a maximum size and then it
divides into two cells.
• The original cell is the parent cell and the new cells are
called the daughter cells.
Phases of Mitosis
• Interphase
• Prophase
• Metaphase
• Anaphase
• Telephase
Interphase
• The period when the cell is not actually dividing
• G1=Growth One=Cellular contents except chromosomes
are duplicated
• S=DNA or Chromosome replication
• G2=Growth Two=Cell double checks its chromosomes
and grows to its maximum size…cell is now ready to
divide!
Prophase
• First True Phase of Mitosis
• Chromatin appears in the form of shortened rodlike structures
• Chromosomes are formed of two strands called chromatids
that are attached at the center by a structure called the
cetromere (kinetichore)
• Nucleus dissolves
• Spindle forms in place of nucleus and centrioles move to
opposite sides of the cell
Metaphase
• Chromatids move toward the center (equator) of the
spindle
• When they reach the center, the center of the centromere
of chromatids connect themselves to the fibers of the
spindle
Anaphase
• Chromatids separate into an equal number of
chromosomes
• Centromeres duplicate
• When separation occurs, the chromosomes move to
opposite ends of the cell
Telophase
• The chromosomes continue to migrate to the opposite
ends of the cell (called poles)
• The spindle disappears and new membranes are formed
around the chromosomes
• This forms two new nuclei
• This completes MITOSIS (but wait there is more!!!)
Cytokinesis
• This step completes cell division
• Division of the cytoplasm
• Animal Cells
• Cleavage furrow deepens until the cell membrane divides along
with the cytoplasm
• Plant Cells
• Cell plate forms in the middle of the spindle and grows outward
until the cell is split
Daughter Cells (watch again)
• The newly created cells are called daughter cells
• They are genetically identical to each other and the
parent cell that formed them
Animal Stem Cells
• These cells are essentially cells that can become anything
(muscle, brain, blood, heart, etc.)
• They are undifferentiated or unspecialized
• They are extremely important and controversial
• READ MORE
Essential Questions
• Why are cells the foundation of life?
• What are the different types of cells?
• What are the differences between prokaryotic and
•
•
•
•
eukaryotic cells?
What are the different components of cells?
How do cells reproduce by mitosis?
What is the process of meiosis?
What are stem cells?