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The Cell’s Machinery
Main Idea
 Eukaryotic cells have specialized internal structures
called organelles that are surrounded by a membrane
(membrane bound)
 Organelles have specific jobs that
 Keep cells alive
 Allow cell to do its special job
Cell Membrane/ Plasma membrane
 Semipermeable outer covering of cell
 Selectively permeable
 Provides support and protection
 Allows for different internal environment
•Made of double layer of phospholipid
molecules
Phosphate molecule head
Hydrophilic – water loving
Fatty acid molecule “tails”
Hydrophobic –water avoiding
Cytoplasm
 Space between nucleus and cell membrane
 Filled with fluid (cytosol) and organelles
Cytoplasm
 Space between nucleus and cell membrane
 Filled with fluid (cytosol) and organelles
Cytoskeleton
 Cell’s framework
 Made of protein fibers:
1. Microtubules
2. Intermediate filaments
3. Microfilaments
Cytoskeleton
 Provides shape and strength
 Helps cells move and divide
Nucleus
 Found only in Eukaryotic cells
 Location of DNA
 Surrounded by nuclear envelope/membrane
Nuclear envelope/membrane
 Surrounds nucleus
 Contains small holes called nuclear pores
 Pores let molecules move between cytoplasm and nucleus
Nucleolus
 Located inside nucleus
 Manufactures ribosomes
Ribosomes
 Site of protein synthesis
 Link amino acids together to form proteins
Ribosomes
 Found in 2 locations:
1. Attached to ER “Rough ER”
2. Free floating in cytoplasm
Endoplasmic Reticulum “ER”
 Network of folded membranes where chemical rxns occur
Endoplasmic Reticulum
 Rough ER – ribosomes attached
 Smooth ER – no ribosomes attached
Golgi Apparatus / Golgi Bodies
 Stack of membrane–enclosed spaces
 Put “finishing touches” on newly made proteins
 Package proteins inside vesicles for shipment
Vesicles
 Small membrane-enclosed sac
 Stores and transports substances
Types of Vesicles
Vacuoles – contain water
Lysosomes – store digestive enzymes
Transport – carry molecules within cell
Secretory – carry molecules outside cell
Vacuoles
 Stores
 Food
 Water
 Waste
Lysosomes
 Contain digestive enzymes used to destroy
 Viruses and Bacteria
 Worn out cell parts
Lysosome ACTION!
Vesicle movement
Endocytosis (move into the cell)
and
Exocytosis (movement out of cell)
Cilia
 Short hair-like protein fiber on outside of
cell membrane
 Move the cell
 Move things past cell
 Gather food
 The protist Vorticelli feeding with cilia
 Movement of substances like mucus
 Cilia moving mucus
Flagella
 Long whip-like tail fiber
 Used for movement
Ex. Sperm tail
A Sperm’s Journey
Comparison of Cilia and Flagella
Mitochondria
 “Powerhouse of the Cell”
 Site of Cell Respiration rxns - energy stored in food
molecules is converted into E the body can use
 Made of two membranes – inner and outer
 Inner membrane has many folds - increases surface area
How Mighty Mitochondria Works
Chloroplast
 Found in plant cells
 Site of photosynthesis rxns.
 Contain the green pigment chlorophyll
Centrosomes and Centrioles
 Centrosomes make microtubules
 In animal cells, centrosomes contain centriole fibers
 Form spindle fibers used in cell division