Lysosomes
• A sac of hydrolytic enzymes
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–
–
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made in the rough ER & modified in the golgi
Acidic in nature
Special inner membrane that resists auto (self) digestion
Can carry out intracellular digestion via phagocytosis
(enfolding of membrane around an object) of membrane
bound food vacuoles
• Digestion products (simple sugars, amino acids, & other
monomers) pass back to the cytosol via exocytosis
Vacuoles
• Food storage structures in plants, protist, and fungal cells.
• Contain hydrolytic enzymes much like lysosomes
• Can be specialized in different animals to perform specific functions
– Contractile vacuole
• protists use this structure to maintain salinity by adding and removing water
– Central vacuole
• found in mature plants
– enclosed in a specialized membrane called a tonoplast
– can be used to store molecules, ions, waste, pigments, or anything needed for growth
– plays a major growth role
• transform energy from their environment
to be used by the host organism. They
Mitochondria
produce their own energy, are mobile, and
divide (bud) to create new structures.
– found in all Eukaryotes
• Transferred from the maternal egg
– site of cellular respiration
• produces ATP through reactions in the
mitochondrial membranes
– the # of mitochondria present is based on the
cell's (organism's) need for energy
– has a smooth outer membrane and a folded
inner membrane called cristae
– contains its own DNA & ribosomes
Chloroplasts
• Converts energy from the sun to into chemical energy
– contain the green pigment chlorophyll
• function in the photosynthetic production of sugar
– consists of many flattened sacks called thalokoids (stacks
are called granum)
– fluid outside is called the stroma
• contains the DNA & ribosomes
Peroxisomes
• Structures is much like lysosomes.
– Produce peroxide (H2O2) for the breakdown of fatty acids by
oxidation for use in the mitochondria.
– Also found in the liver as sites of detoxification.
– Glycoxysomes are specialized structures in plant seeds that
convert fatty acids to sugar used as a source of energy
• Cannot self replicate - product of lipids from the ER,
proteins from the cytosol, & lipids made in the peroxisomes
– they may split (bud) once the necessary parts are assembled
and the size is sufficient
Microfilaments
• Threadlike structures that form a support
structure for the cell and are used in
movement
– Composed of Actin
• a double twisted rod
• Muscle motor unit
– long actin filaments bridged with myosin, a protein
that "walks" the fiber causing contraction
• Pseudopodia (fake foot)
– actin network that converts the solution into gel in
ameoboid organisms
• Cytoplasmic streaming
– a process in large plant cells where cytoplasm is
directed to other parts of the cell to speed delivery of
needed materials
• Hollow tubes made of tubulin
(globular protein)
Microtubules
– Centrosomes
• located near the nucleus in plants
• grow tubules outward resisting
compression forces
– Centrioles
• a set of 9 tubes set in a ring
• Help organize replication in animals
– Flagella & Cilia
• 9 + 2 arrangement
• propel using a whip-like motion in
flagella & oar-like motion in cilia