Transcript Vacuoles - SCHOOLinSITES

Section 7.3
Structures
and
Organelles
An internal skeleton supports the cell
and enables movement.
The Cytoskeleton
The Cytoskeleton
Prior to 1970’s cytosol thought to be
unorganized mix of organic molecules.
Later found that cytosol was organized
and protein fibers were identified.
Functions of The Cytoskeleton
 Maintains cell shape
 Allows organelles to move
Microtubules
•
•
•
Hollow, protein cylinders
Maintain shape of cells
Tracks for vesicle and organelle
movement
Microfilaments
•
•
Solid rods of protein (thinner than
tubules)
Enable cell movement.
Flagella
Flagella (L. flagello, whip)
Cilia
Cilia (L. cilium, eyelash, hair)
Short, usually numerous hair like projections
that can move in an undulating fashion.
Differences
Flagella longer than cilia, usually
fewer
Flagella are whip-like projections
Flagella move whip-like (e.g. Sperm
cells), cilia move swimmer-like/oarlike
The Cell as a Coordinated Unit
No organelle or part works alone.
Concept 6.4
The Cell Builds
a
Diversity of Products
Concept 6.4 Objectives
• Identify the role of the nucleus
• Describe how the function of ribosomes, the ER
and the Golgi are related.
• Compare and contrast the functions of vacuoles
and lysosomes.
• Summarize the path of cellular products through
membranes.
Nuclear Envelope
Double membrane
Separates nucleoplasm from cytoplasm
The Nucleolus
Dark-stained spherical body in nucleus
where rRNA and proteins join to form
ribosomal subunits.
Nuclear Pores
(100 nm)
protein
ribosomal subunits
Ribosomes
Cooridinate assembly of amino acids into
polypeptide chains (i.e. protein synthesis).
Ribosomes
Eukaryotic slightly larger
than prokaryotic
Composed of a large
and a small subunit.
Each subunit has its
own mix of protein and
rRNA.
Ribosomes
Endoplasmic Reticulum
Main manufacturing and transport
facility in the cell factory.
Rough ER is:
Contiguous with the outer membrane
of the nuclear envelope.
Studded with ribosomes
cytoplasm side.
on
the
Smooth ER
Continuous with rough ER
No ribosomes (hence smooth)
Function of smooth ER
1. Synthetic processes
Phospholipids
Steroids
Fatty acids
2. Forms transport vesicles
Golgi Apparatus
Delivery System Of the Cell
Discovered in 1898
Named
For
Camillo Golgi
Golgi Apparatus
Stack of 3-20 slightly
curved saccules.
Golgi Apparatus
Receives protein-filled vesicles that bud from the
ER.
Vesicles fuse with membrane of Golgi apparatus.
Golgi Apparatus
• Proteins modified as they
pass through
• Move to outer face after
modification.
• Vesicles form & move to
different locations in cell
Vesicles
Enzyme Storehouses
Lysosomes
Intracellular digestion centers
Produced by Golgi
Membrane-enclosed
vesicles
Contains
digestive
enzymes (function best
in acidic environment)
Break down organelles
Vacuoles
• Large membranous sac
• Larger than vesicles
• Store substances
• Vacuoles in protozoans
include digestive
vacuoles and waterregulating contractile
vacuoles.
Vacuoles
In protozoans include digestive vacuoles
and water-regulating contractile vacuoles.
Vacuoles
Plant cell vacuoles (usually
one or two) more prominent;
water-filled and give support
to cell.
Plant vacuoles store water,
sugars, salt, pigments, and
toxic substances to protect
plant from herbivores.
Chloroplasts & Mitochondra
Energize Cells
Energy-related Organelles
Mitochondria
(Plants & animals)
Chloroplasts
(Plants)
Plastids
• General name for plant cell organelle
• Enclosed by a double membrane
• Contains a series of internal membranes and
vesicles.
Chloroplasts
“Packages” light energy from the sun
(site for photosythesis).
Double membraned organelle.
Flattened sacs (thylakoids) piled into
stacks of grana with a fluid-filled
space around thylakoids called the
stroma.
Chlorophyll located with the thylakoid
membrane.
Mitochondria
• “Unpacks” captured solar
energy (cellular respiration).
• Double-membrane organelle
• ATP production occurs here.
• Found in all organisms except
bacteria.