Transcript Cell Organelles and Features

CELL ORGANELLES AND
FEATURES
THE PLASMA MEMBRANE
• Also called the cell membrane
• Selectively permeable
• The cell structure that encloses the cell and
regulates the passage of materials between the cell
and its environment
• Allows nutrients into the cell
• Allows waste to leave the cell
• Also aids in protection and support of the cell.
STRUCTURE OF CELL MEMBRANE
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Made primarily of phospholipids
Have polar, hydrophilic “water-loving” head
Have a nonpolar, hydrophobic “water-fearing” tail
Water molecule surround the cell membrane
The phospholipids form into a phospholipid bilayer
Cholesterol is found in the membrane to make it
more rigid and prevent it from freezing at low
temperatures
MEMBRANE PROTEINS
• Cell membranes contain specific proteins
• Integral proteins are embedded within the bilayer
• Peripheral proteins are on the only one side of the
bilayer and are not embedded into it
FLUID MOSAIC MODEL
• The phospholipid bilayer behaves like a fluid, more
than a solid.
• The phospholipid bilayer allows other molecules to
“float” in the membrane.
CYTOPLASM
 Gel-like material that fills
the cell.
 In prokaryotic cells all
the processes that keep
the cell alive happen
right in the cytoplasm.
 Eukaryotic cells have
organelles in which
those processes
happen.
Cytoplasm video clip.
CYTOSKELETON
 It is a supporting network of
long, thin protein fibers that
also provide an anchor for
organelles.
 Microtubules - long
hollow protein cylinders
 Microfilaments – thin
protein threads
Still
images
THE NUCLEUS
• Most of the functions of a eukaryotic cell are
controlled by the nucleus
• Contains the chromosomes which are composed of
DNA (deoxyribonucleic acid)
• Surrounded by a double membrane called the
nuclear envelope
• Nuclear envelop contains
proteins lined nuclear pores
that are passage ways for
RNA and other materials to
enter/exit the cell
NUCLEOLUS
• A denser area of the nucleus
• Site where DNA is concentrated
MITOCHONDRIA
• The “power house” of the cell
• Has its own DNA
• Sites of cellular respiration, a process which supplies
the cell with ATP (Adenosine triphosphate)
• Bound by a double membrane
• The inner membrane had many folds called cristae
that carry out cellular respiration
RIBOSOMES
• Small, roughly spherical organelles that are responsible
for making proteins.
• Ribosomes do not have a membrane
• Some are found freely floating in the cytosol
• Others are attached to the rough endoplasmic reticulum
ENDOPLASMIC RETICULUM (ER)
• A complex, extensive network that transports materials
throughout the inside of a cell.
• Two Types:
• Rough ER has ribosomes attached to the surface is
ribosome-studded.
• Produces proteins and phospholipids
• Smooth ER has no attached ribosomes.
• Builds lipids like cholesterol
GOLGI APPARATUS
• Contains sacs that receive materials from the ER.
• Modifies, collects, packages, and distributes
molecules within the cell or outside the cell.
VESICLES
• Small, round sacs that are surrounded by a single
membrane
LYSOSOMES
• Contain chemicals called enzymes necessary for
digesting certain materials in the cell
• Break down old worn out cell parts
• Can break down macromolecules
• Responsible for breaking
down cells when it is time
for the cell to die
• Play an important role in
maintaining the overall
health of an organisms
by destroying cells that
are no longer functioning
correctly
CENTRIOLES
 A small group of
microtubules that
help in cell division
Video clip
VACUOLE
 “Storage” spaces
 A sac to store food, water
,carbohydrates, enzymes,
salts and other materials
needed by the cell.
 Vacuoles in animal
cells (if they are
present) are much
smaller than those in
plant cells.
Video clip
ORGANELLES FOUND IN PLANT CELLS
CELL WALL
 Found in plants, fungi
and some bacteria
 Cell structure that
surrounds the cell
membrane for
protection and
support
 Allows for specific
substances to pass in
and out of the cell.
 Made of cellulose
Video clip
WHY DO PLANTS NEED CELL WALLS?
Cell walls provide structural support for plants like a
Skelton provides structural support for your. Without
cell walls, plants would not be able to stand up
What is important about cellulose?
• It is a macromolecule that humans cannot digest
because they do not have the necessary enzymes;
therefore, it passes through your digestive system as
“fiber,” cleaning out the intestines.
CHLOROPLAST
 Contain the green
pigment, chlorophyll,
which absorbs energy
from the Sun to convert
carbon dioxide and
water into sugar through
the process of
photosynthesis.
MOVEMENT STRUCTURES
Cilia
 Short, numerous
projections that look
like hairs
Flagella
 Longer and less
numerous than cilia
 Create movement
with a whiplike
motion
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THE CHARACTERISTICS OF FUNGI
• Fungi are NOT plants
• Nonphotosynthetic
• Eukaryotes
• Nonmotile
• Most are saprobes
(live on dead organisms)
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THE CHARACTERISTICS OF FUNGI
• Absorptive heterotrophs
(digest food first & then absorb it into
their bodies)
• Release digestive enzymes to break
down organic material or their host
• Store food energy as glycogen
BREAD MOLD
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THE CHARACTERISTICS OF FUNGI
• Important decomposers &
recyclers of nutrients in
the environment
• Most are multicellular,
except unicellular yeast
• Lack true roots or leaves
MULTICELLULA
R MUSHROOM
UNICELLULAR YEAST
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THE CHARACTERISTICS OF FUNGI
• Cell walls are made of chitin
(complex polysaccharide)
• Body is called the Thallus
• They may have several nuclei
within a single cell.
• Grow as microscopic tubes or
filaments called hyphae
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THE CHARACTERISTICS OF FUNGI
• Some are edible, while others are
poisonous
EDIBLE
POISONOUS
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THE CHARACTERISTICS OF FUNGI
• Produce both
sexual and
asexual spores
• Classified by their
sexual
reproductive
structures
Spores come in
various shapes
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THE CHARACTERISTICS OF FUNGI
• Grow best in warm, moist
environments
• Mycology is the study of fungi
• Mycologists study fungi
• A fungicide is a chemical used to
kill fungi
Fungicide kills
leaf fungus
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THE CHARACTERISTICS OF FUNGI
• Fungi include puffballs,
yeasts, mushrooms,
toadstools, rusts, smuts,
ringworm, and molds
• The antibiotic penicillin
is made by the
Penicillium mold
Penicillium mold
Puffball
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DIFFERENCES BETWEEN PLANT CELLS
AND ANIMAL CELLS
Animal cells
Plant cells
Vacuole small or absent
Large central vacuole
Glycogen as food
storage
Starch as food storage
Nucleus at the center
Nucleus near cell wall
SIMILARITIES BETWEEN PLANT
CELLS AND ANIMAL CELLS
Both have a cell membrane surrounding
the cytoplasm
Both have a nucleus
Both contain mitochondria
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DIFFERENCES BETWEEN PLANT
CELLS AND ANIMAL CELLS
Animal cells
Plant cells
Relatively smaller
in size
Relatively larger in
size
Irregular shape
Regular shape
No cell wall
Cell wall present
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