CHAPTER 3.2
Cell Organelles
EUKARYOTIC CELLS
• Highly organized
• Surrounded by a protective membrane
• Contain membrane-bound organelles that have
specific functions
• The internal structure is anchored to maintain its
framework
CYTOSKELETON
• A network of proteins that can change to meet the needs
of the cell.
• Made of 3 types of fibers:
1. Microtubules: long hollow tubes that give the cell its
shape and act as “tracks” so organelles can move
2. Intermediate filaments: give the cell strength
3. Microfilaments: tiny threads that enable cells to
move and divide
CYTOSKELETON
PROTEIN MAKERS
• Nucleus: Stores DNA (blueprints for protein)
• Ribosomes: Link amino acids to form proteins
• Endoplasmic reticulum (ER): protein & lipid
production
• Golgi apparatus: process, sort & deliver proteins
• Vesicles: isolate and transport specific molecules,
including proteins
PROTEIN MAKERS
NUCLEUS
• Stores DNA
• Nuclear envelope – double membrane of the
nucleus
• Nucleolus – special region where ribosomes
are made
NUCLEUS
ENDOPLASMIC RETICULUM
(ER)
• Interconnected network of folded membranes that
produce proteins and lipids
• Lumen: interior of the ER
• Rough ER: Studded with ribosomes, proteins are made
on the surface and modified in the lumen.
• Smooth ER: No ribosomes, it makes lipids and breaks
down drugs & alcohol.
ENDOPLASMIC RETICULUM
(ER)
RIBOSOMES
• Tiny organelles that link amino acids together
to form proteins
• Made of proteins and RNA
• Exist on the ER and freely in the cytoplasm
RIBOSOMES
GOLGI APPARATUS
• Closely layered stacks of membrane-enclosed spaces
that process, sort, and deliver proteins
• Proteins processed here are:
1. Stored
2. Transported to other organelles
3. Secreted outside the cell
GOLGI APPARATUS
VESICLES
• Temporary membrane-bound sacs that
transport materials through the cell as
needed.
VESICLES
MITOCHONDRIA
• Bean-shaped organelle that provide energy
for the cell
• UNIQUE – they contain their own DNA and
ribosomes!
• What can be inferred from this?????
MITOCHONDRIA
LYSOSOMES
• Membrane-bound organelles that contain
enzymes
• Defend cells from bacteria and viruses
• Break-down damaged cell parts
• More common in animal cells
LYSOSOMES
CENTRIOLES
• Cylinder-shaped organelles made of microtubules
arranged in a circle.
• Help build spindle fibers to divide DNA during cell
division
• Produce and organize microtubules to form cilia
and flagella.
CENTRIOLES
VACUOLES
• Fluid-filled sac used for storage of materials
needed by the cell.
• CENTRAL VACUOLE
• Unique to plant cells
• Strengthens a plant cell and helps support the
entire plant.
VACUOLES
CELL WALL
• Rigid layer that gives protection, support and
shape to plant, algae, fungi & bacterial cells
• NOT present in animal cells
• In plants – made of cellulose, a polysaccharide
CELL WALL
CHLOROPLASTS
• Organelles that contain chlorophyll and carry out
photosynthesis
• Chlorophyll: a light-absorbing molecule that gives
plants their green color
• Like mitochondria:
• Have their own ribosomes and DNA
CHLOROPLASTS