Transcript Chapter 7 Cell Powerpoint

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1. Definition: a thin, flexible barrier between the cell
and its environment
2. Function: regulates what enters and leaves the
cell; is selectively or semi-permeable; known as the
“gate keeper”
3. Is a lipid bilayer; contains “hydrophobic” (waterfearing) and “hydrophilic” (water-loving) ends
4. Known as the “fluid-mosaic model”
 1. Definition: outer boundary of a
plant cell, bacterial cell and fungal
cell; not present in animal cells
 2. Function: provides support,
strength, and rigidity to the cell;
composed of cellulose
• Is a double-membrane structure that
is the genetic control center of a
eukaryotic cell
• Known as the control center, brain,
or boss of the cell
• Surrounded by a nuclear envelope or
membrane
• Contains DNA in the form of
chromatin
Mass of fibers and granules, dark structure
inside the nucleus; composed of chromatin
DNA plus RNA and protein
Function: produces ribosome
Organelles which manufactures protein
Interprets the code from RNA
Are made of RNA and protein
Are not bound by a membrane
 Is the area between the nucleus and the
cell membrane
 Houses the organelles
 Site of most chemical reactions
 Breaks down molecules to release
energy
 Gel-like fluid or substance
Endoplasmic Reticululm(ER)
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Inter-related series of membranes
forming a network of connected tubules
Provides a delivery system for the cell
Attached to the outer membrane of the
nuclear envelope
Endoplasmic
Reticululm(ER)
► RER
(Rough) is studded (covered) with
ribosomes
► Function: makes proteins and more
membranes
► SER (Smooth) does not have ribosomes;
breaks down drugs and toxins in the liver
► Function: synthesizes lipids, fatty acids,
phospholipids, and steroids
A series of closely stacked, flattened
membrane sacs
 Function: packages, collects, modifies,
and secretes proteins and distributes them
to other parts of the cell
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• Sacs of fluid-filled compartments surrounded by a
membrane in plant and animal cells
• Function: stores food, enzymes, and some waste
• Contractile vacuole-collects excess water and
pumps it out of the cell in some unicellular
organisms
• Central vacuole- a single, large vacuole in the
plant cell that stores water and other substances
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“Clean-up Crew”; membrane bound
organelles
Contain digestive enzymes
Destroy old, worn out cell parts, food
particles, or invading viruses or bacteria
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Microtubules-straight, hollow tubes
composed of tubulin
Intermediate filaments-made of fibrous
protein and have a rope-like structure
Microfilaments-solid, helical rods
composed mainly of actin (globular
protein) important in amoeboid movement
• Short, hair-like projections
• Lines the trachea
• Moves liquid over the surface of the cell
and sweeps mucus with trapped debris out
of our throat; aids in locomotion (movement)
• Also found in kidney tubules and other
structures in the body
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Long, whip-like structures used for locomotion
Propels protists, most animals, and some plant
cells
Typically cilia and flagella have a core
composed of microtubules connected to the
plasma membrane arranged in what is known
as a 9 + 2 pattern. The pattern is so named
because a ring of nine microtubule "doubles"
has in its center two singular microtubules.
 Known as the “powerhouse” of the
cell
 Organelle in which food molecules are
broken down to release energy
 Site of cellular respiration
 Produces large amounts of ATP
(adenosine triphosphate); a high
energy storing molecule
 Growing cells in areas of repair utilize
energy (muscle cells)
 Cilia and flagella require large
amounts of ATP
 Becomes ADP (adenosine
diphosphate), when one phosphate
(PO4-3), group breaks off during
respiration
 ADP is a low energy storing molecule
Found only in plant cells and some protists
Contains the pigment, chlorophyll, which
aids in the process of photosynthesis
Consists of stacks of grana composed of
single disc shaped structures called
thylakoids
Differences Between
Plant and Animal Cells
• Plant Cells
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Chloroplast
Cell Wall
Rectangular Shape
Plastids
Central Vacuole
Nucleus location is
off center
• Animal Cells
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Centrioles
Flagellum
Circular Shape
Lysosomes
Nucleus location is
in the center
Chapter 7 Cellular
Structure & Function
Cell Types
• Prokaryotes-unicellular, cells that do not
contain a nucleus or membrane-bound
organelles (internal structures) but do
have ribosomes (non-membranous
structures). Ex. bacteria
• Eukaryotes-unicellular or multicellular
organisms that have a “true” nucleus and
membrane-bound organelles; plants and
animals
• Eukaryotic cells evolved from prokaryotic
cells (Endosymbiotic Theory)
Light Microscopes
• Most commonly used microscope;
allows light to pass through the
specimen and use two lenses to form
an image; It produces magnified
images by focusing visible light rays.
Electron
Microscopes
Focus beams of electrons on
specimens.
- TEM(Transmission)shine a beam
of electrons through a thick
specimen; studies internal cell
structure.
- SEM(Scanning) runs a pencil-like
beam of electrons back and forth
Electron
Microscopes
- Produce 3D images of the
surface of objects.
- Cannot be used to study live
specimen.
Electron Microscope
Cell Theory
In the 1600’s, early investigators
were curious about the quality of
cloth. They used magnifying lens to
observe this. The telescope was
developed to view objects at a
distance.
Scientists
• Anton Van Leeuwenhoek: credited with
developing the 1st single lens microscope
was the 1st to describe protozoa and
bacteria that are in drops of water
(Dutch scientist)
• Robert Hooke: Coined the term “Cell”;
viewed cork, wood, and plant stems.
(Dutch Biologist)
• Matthias Schleiden: 1838-all plants are
made of cells (German Botanist).
Scientists
• Robert Brown: Observed what is now
known as the nucleus (Scottish
scientist).
• Theodor Schwann: 1839, all animals
are made of cells.
• Rudolph Virchow: 1855, all cells arise
from the division of pre-existing
cells.
Cell Theory
1. All living things are made of cells
2. Cells are the basic unit of structure
and function
3. All cells arise from pre-existing
cells
• Anton Van
Leeuwenhoek
• Robert Hooke
• Matthias Schleiden
• Robert Brown
• Theodor Schwann
• Rudolph Virchow
Cell Transport
Membrane functions
Membrane structure
How molecules cross membranes
Two mechanisms of Transport
Transportation of Molecules
• Passive Transport
Movement of molecules across a
semi-permeable membrane
no energy required
• Active Transport
Movement of molecules across a
semi-permeable membrane against a
concentration gradient with a
protein
ENERGY – ATP
• Facilitated Diffusion
Movement of molecules across a
semi-permeable membrane with a
protein
no energy required
How Molecule Cross Membranes
 Diffusion
Osmosis
Osmosis
Osmotic Effects on Cells
Cellulose in
cell wall
Osmosis in Red Blood Cells
Isotonic
Hypertonic
Hypotonic
Effect of Water on RBC
Osmosis in Plant Cells
Plasmolysis
Hypertonic
Hypotonic
Facilitated Diffusion
Channel proteins
help small polar
or charged
molecules cross
membranes.
Active Transport
Proteins use energy to move
solutes against gradient.
Active Transport: Na+/K+ Pump
ATPase pump protein
gets phosphorylated by
ATP.
Protein’s conformation
changes...
causing binding & then
release of ions.
Active (vesicular) Transport
3 Kinds of
Endocytosis
Vesicular Transport: Exocytosis
How Substances Move Across Membranes
 Passive Transport
Simple diffusion
Osmosis
Facilitated diffusion
 Active transport
Endocytosis
Phagocytosis
Pinocytosis
Receptor-mediated endocytosis
Exocytosis