Transcript THE CELL - TeacherWeb

THE CELL
 Breaks down macromolecules
 Releases energy from food
 Synthesis of cell parts
 Produces proteins
1st Cells Examined
 1600’s Anton van Leeuwenhoek
 1665 Robert Hooke
 1830’s Schleiden & Schwann
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CELL THEORY
17TH Century to 1830’s
3 Main Ideas
1.
2.
3.
All organisms are composed of 1
or more cells.
Cell is basic unit of organization.
All cells come from pre-existing
cells.
TWO BASIC CELL TYPES
DEPENDING ON THEIR
INTERNAL ORGANIZATION
PROKARYOTIC
Organism with a cell that
lacks internal structures
surrounded by membranes.
 Most are single celled
organisms.
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EUKARYOTIC
Organism that has cells
containing internal
membrane-bound
structures/organelles.
 Single or many cells.
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ORGANELLES
Enclosed by a membrane
isolating it from the rest of
the cell.
 Largest = Nucleus
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EUKARYOTIC CELL
STRUCTURES
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Boundaries and Control
Plasma Membrane-Boundary
between cell and the external
environment.
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2 layers: Lipid and Protein
Controls movement of materials
in and out of cell.
Helps chemical balance.
Flexible
Cell Wall-External boundary
outside the plasma membrane.
Relatively inflexible structure
 Plants, Fungi, and most
Bacteria
 Plant cell walls contain
cellulose molecules
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Nucleus- Organelle that
manages cell functions.
Contains DNA
 Surrounded by a Nuclear
Envelope
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Nuclear Envelope
Attachment sites for DNA
organization
 Outer surface has Ribosomes
 Large pores for materials
transportation
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Chromatin- Long tangled
strands of DNA
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Forms chromosomes
Nucleolus-Region that
produces tiny cell particles
involved in protein synthesis.
Contains RNA
 Produces ribosomes
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RIBOSOMES:
Site where the cell assembles
enzymes and other proteins.
 Considered organelles but
are not bounded by a
membrane.
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Assembly, Transport, and Storage
 A major function of most cells
is to make proteins and other
materials.
 Many cells are involved in
protein synthesis.
 Also involved in storage of
materials.
Cytoplasm: Material that lies
outside the nucleus and surrounds
the organelles.
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Most of assembly and storage
takes place (protein assembly)
Clear, gel-like fluid
Makes up more than half the
volume of a typical animal cell
Endoplasmic Reticulum:folded
membrane that forms a network
of interconnected compartments.
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Occupies most of the cytoplasm
Provide a large surface area where
chemical reactions take place
Contains enzyme for lipid synthesis
Rough ER vs. Smooth ER
Functions as cell’s delivery system
Protein Assembly (ribosomes)
Structures for Storage
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Golgi apparatus- A series of closely
stacked, flattened membrane sacs that
receives newly synthesized proteins and
lipids from the ER and distributes them
to the plasma membrane and other cell
organelles.
Vesicles- Small membrane bound
transport packages that transfer protein
from ER to Golgi apparatus.
Structures for Storage (cont.)
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Vacuole- Sac of fluid surrounded by
a membrane used for temporary
storage.
Single celled organisms = specialized
 Plants = 1 large vacuole
 Animals = many smaller vacuoles
(store food, enzymes, & sometimes
waste products)
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Structures for Storage (cont)
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Lysosomes-Organelles that contain
digestive enzymes
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Digest excess or worn out cell parts
Digest food particles
Invade viruses and bacteria
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Organelles that
Transform Energy
Mitochondria – organelle in which
food molecules are broken down to
release energy. (Powerhouse of the cell)
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Found in every cell in varying numbers
(Liver = 2500/cell)
Rod shaped
Inner membrane forms Cristae (long
narrow folds) where energy storing
molecules are produced.
LYSOSOME
RICH DIGESTIVE ENZYME
USED TO BREAKDOWN
FOOD AND MATERIAL.
Clean up crew
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VACUOLE
Storage bubble. Holds food,
materials, and waste.
Enters through ENDOCYTOSIS
Exits through EXOCYTOSIS
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PLASTIDS-Plant organelles
used for storage.
 Storage of:
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Starches
Lipids
Pigments
 Named
according to their color or
pigment they contain.
 Green of leaves
 Bright colors of flowers and fruits
Chloroplasts- organelles of
green plants that transform
light energy directly into usable
chemical energy and store that
energy in food molecules.
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Chlorophyll- A green pigment that
traps the energy from sunlight.
Structures for Support
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Cytoskeleton- A network of thin,
fibrous elements that provide
support for organelles.
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Microtubules- thin, hollow cylinders
made of protein
Microfilaments- thin, solid protein
fibers
Structures for Movement
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Cilia- short, numerous, hairlike
projections out of the plasma
membrane.
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Occur in large numbers on cell’s
surface
Found in upper respiratory tract
Structures for Movement cont.
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Flagella – Long, threadlike
structures that move with a
whiplike motion.
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Sperm cells
Cellular Organization
Unicellular = Single-celled
organisms
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All metabolic functions
preformed by a single
Cellular Organization cont.
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Multicellular = Many celled
organisms.
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Specialized to perform distinct
metabolic functions.
Cell depend on each other to
carry out life functions
Multicellular Organization
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TISSUE = Group of cells function
together to perform an activity
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Cell junctions = contact sites
between adjacent cells
 Anchor
cells together
 Allow cells to communicate
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Muscle and nerve tissues
Stems and roots
Cellular Organization cont.
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Organs = Groups of two or more
tissues that function together.
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Stomach
Leaves
Cellular Organization cont.
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Organ System = A group of
organs that work together to
carry out major life functions.
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Nervous system
Flower of a plant