Post on 24-Feb-2016
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ORGANELLES:CENTROSOME
• Function: Microtubule formation- Two centrioles and
pericentriolar area- Microtubule organizing
center- Cilia and flagella are
composed of microtubules
Figure: 3.17
ORGANELLES:CILIA
• Many per cell• Short hairlike projections• Bundles of microtubules in PM
projections• Function: Move substances along
the outer cell boundary (one way)
Figure 3.15
ORGANELLES:FLAGELLUM
• One per cell• Long bundle of microtubules
enclosed in PM• Propels the entire cell (sperm)
Figure 3.15
ORGANELLES:RIBOSOMES
• Non-membrane bound• Site of protein synthesis
- Composed mainly of RNA (rRNA)• Formed in the nucleolus• Located in the cytosol, or attached
to the nucleus or ER
Figure 3.19 http://www2.prs.k12.nj.us/Schools/PHS/Science_Dept/APBio/Ribosome.html
ORGANELLES:ENDOPLASMIC RETICULUM
(ER)Rough ER• Long, interconnected
flattened sacs of membrane
• Studded with ribosomes for protein synthesis
• Produces secretory & membrane proteins, plus phospholipids
Figure: 3.17
ORGANELLES:ENDOPLASMIC RETICULUM
(ER)Smooth ER • More tubular• No ribosomes• Produces
phospholipids, fats, steroids
• May perform vastly different functions depending on cell type (i.e., muscle vs. liver) Figure: 3.17
Figure: 3.18
ORGANELLES:GOLGI COMPLEX• Flattened sacs (cisternae)• All secretory proteins pass
through GC• More protein modifications (carb,
lipid additions)
Figure: 3.19
ORGANELLES:GOLGI COMPLEX
• Proteins are packaged into vesicles with one of three possible destinations:- Secretory
vesiclessecretion- Membrane
vesiclesplasma membrane
- Transport vesiclesother organelles
ORGANELLES:LYSOSOMES
• Storage/digestive vesicles formed by GC- Contain a variety of
digestive enzymes• Slightly acidic - pH 5
- Proton pumps for H+• Main functions –
- Digestion of substances that enter the cell• Transport byproducts to
cytosol- Digest old organelles
(autophagy)Figure: 3.20
http://bioweb.wku.edu/courses/biol22000/11Organelles/Fig.html
ORGANELLES:PEROXISOMES
• Protect cell from harmful effects of oxidation products
• Contain oxidizing enzymes (oxidases) for detoxifying substances- Hydrogen peroxide (toxic) is a
byproduct of oxidations- Peroxisomes contain catalases to
convert hydrogen peroxide to water
http://bioweb.wku.edu/courses/biol22000/11Organelles/Fig.html
ORGANELLES:MITOCHONDRIA
• Function: ATP production (cellular respiration)- Number of mitochondria in a cell depends
on its ATP demands• Double-membraned organelle
- Outer mt membrane- Inner mt membrane with folds (cristae)
• Large surface area for cellular respiration- Matrix
Figure: 3.21
Cell Overview
• Plasma Membrane – phospholipid bilayer
• Cytoplasm • Cytosol = intracellular fluid• Organelles = “cell’s organs”
• Nucleus – contains chromatin
NUCLEUS• Typically one per
cell• Stores DNA
http://www.nimr.mrc.ac.uk/virology/doorbar/function/fig2/
Figure 3.22
NUCLEUS
• Nuclear envelope: double membrane that encloses the nucleus- Nuclear pores control
entrance/exit of substances• Active transport of large
molecules• Diffusion of small
molecules• Nucleoli: areas within
the nucleus where ribosome assembly occurs