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Cell Organelles
Structures and Functions
Provincial exam diagram
Cell Membrane
STRUCTURE• Phospholipid bilayer• Contains cholesterol, glycoprotiensFUNCTIONS• Provides protection• Selective permeability• Cell recognition & receptor proteins• Import & Export (endo/exocytosis)
Cytoskeleton
STRUCTURE:protein filaments & microtubules found throughout the cytoplasm
FUNCTIONS:maintains cell shape
transport within the cell - movement of vesicles and organelles
Mitochondria
STRUCTURE:double membrane bound organellematrix (inner space) & cristae (convolutions of inner membrane)
FUNCTIONS:production of ATP (site of cellular respiration)
Mitochondria Structure
Provincial exam diagram!
Smooth Endoplasmic Reticulum
STRUCTURE:• Network of tubules, extension of
nuclear membranes• Lack ribosomes
Smooth Endoplasmic Reticulum
FUNCTIONS• Package proteins for transport within cell• Synthesis of membrane phospholipids• Synthesize lipids, triglycerides, steroids• Large surface area for chemical reactions• Detoxify drugs in liver cells
Diagram: Smooth ER
Rough Endoplasmic Reticulum
STRUCTURE:
• Network of tubules (membranous)• Ribosomes on surface
Rough Endoplasmic Reticulum
• Production of proteins at ribosomes- enzymes & hormones
• Transport to smooth ER for modifications & packaging
Provincial Exam Diagram!
RIBOSOMESMade of rRNA & protein - 2 subunitsFound free (floating in cytoplasm) or
bound (attached to ER)FUNCTIONS:Site of protein synthesis –
polypeptides, enzymesReads RNA code, translates into
amino acid sequence - protein
Ribosome Structure
Liver Cell Polyribosomes
Polyribosomes
Structure:
Many ribosomes grouped together, ribosome cluster
Functions:
Work together to read one strand of RNA - increases speed & # of proteins produced
Polyribosomes
GOLGI BODIES• Stacked flat sacs• Accept vesicles on one side and
produce vesicles on the otherFUNCTION:Modification of proteins and lipidsStorage and packaging of moleculesPOST OFFICE OF CELL
Golgi Apparatus
Vesicles
• Membrane bound sac, liquid filled• Formed from pinching off of membrane of ER, Golgi body, cell membrane
• Can contain proteins, lipids
FUNCTION:
Shipping containers – transport of materials around or out of cell
Vacuoles
• Membrane bound sac• Contains liquids or solids• Larger than vesicles
Vacuole
FUNCTION:Plant cells – large fluid filled vacuoles maintain structure
Storage within cellFood & Contractile vacuoles
Lysosomes
• Membrane bound sacs • Contain digestive enzymes• Manufactured by the Golgi apparatusFUNCTION:Garbage disposalBreakdown bacteria entering cell,
worn out organelles, intracellular digestion
Nucleus
STRUCTURE• Bound by a double porous
membrane• Contains chromatin: DNA &
proteins wound together• Contains RNA
Nucleus
FUNCTION• Stores genetic information• Controls cell division• Directs functioning of cell (provides
template for RNA - protein synthesis)
Nucleolus
• Found within the nucleus• Cluster of RNA
• Produces ribosomes
Nuclear Envelope
• Double membrane (4 phospholipid layers)
• Contains nuclear poresFUNCTION:Protection of nuclear contentsAllows communication with cell via
RNA molecules (through nuclear pores)
Chromosomes
• Double stranded DNA molecules• Found in nucleus
Genetic blueprint in basesCell division (mitosis), RNA
transcription
Plant Cells
Cell Wall
Structure:
Composed of cellulose
Located outside of cell membrane
Function:
Provides structure, protection, rigidity to plant cells (not found in animal cells)
Permeable
Cell Wall
Chloroplast
Structure:
Double membrane bound organelle
Stroma: space within chloroplast
Thylakoid stacks: where reactions occur - contain chlorophyll
Function:
Site of PHOTOSYNTHESIS within plant cells (produces glucose)
Chloroplast
Chloroplast