organelle review protein synthesis and secretion ribosomes attach to the e.r. and make protein...
TRANSCRIPT
Organelle Review
Golgi A pparatus M itochondr ia Ribosom es N ucleus
C ytoplasmWhich con tains
Plasm a M em brane Su rrounds T he
Protein Synthesis and Secretion• Ribosomes attach to the E.R. and make
protein • Protein is then sent to the Golgi
Apparatus• The G.A. packages it up and sends it off
to the Plasma Membrane where it can be released from the cell.
Ribosomes –> E.R. –> Golgi A. –> Plasma Membrane
Why do Organelles have Folded Membranes?
• Provides a larger surface area
• Allows for cell processes to be more efficient and effective
• Forms interconnected compartments
Basically it gives the organelle more space to do work!
Are all Cells Created Even?
“How come plant cells have chloroplasts, I want one of
those! That’s Booty!”
Only in Animal Cells
• Lysosomes – contains enzymes that digest proteins, food, and other such things.
• Centrioles – paired structure that assists during cell reproduction
Only in Plant Cells• Plastids –produces food for the cell
through a process called photosynthesis (chloroplast, chromoplast, leucoplast)
• Cell Wall – protection and support–Also found in algae, fungi, and bacteria
• Dictysomes – responsible for cell wall formation (collection and packaging center)
Bacterial Cells (prokaryotic)
• Single Celled Organisms
• Lack a nucleus and other membrane bound organelles
Copy picture from board
Membrane Properties
• Gate Keeper – controls what enters and leaves the cell (outer boundary)
• Selective Permeability – only certain substances can cross the membrane– Small vs. Large
– Neutral vs. Charged
Membrane Structure• Lipid Bilayer – two layers of
phospholipids
acts as barrier and boundary• Phospholipid – 2 fatty acid tails and a
phosphate head
• Tails are non polar, don’t like water
• Heads are polar, face inside and outside of cell where water is
Membrane Structure Continued
• Cholesterol – bind and restrict movement of lipid bilayer; allows for strength and flexibility
• Proteins – some pass through bilayer, while some are only on surfaces–Function regulation, enzymes,
markers for chemicals, infection, and recognition
DIFFUSION
• Random movement of particles from high concentration to low concentration
• [high] to [low]• Diffusion occurs across membranes
until equilibrium (homeostasis) is reached
• Dynamic equilibrium – particles are evenly spread, equal [ ] , but still moving
OSMOSIS• Diffusion of H2O across a selectively
permeable membrane
• Osmotic conditions have 3 options:
Isotonic, Hypotonic, Hypertonic
How many of you have every killed a plant? How?
Over watering or Under watering?
• Isotonic – same [ ] of solutes inside as outside cell, not net change
• Hypotonic – low solutes/ high H2O outside cell; H2O moves in
(Animal cells burst; Plant cells swell)
• Hypertonic – high solutes/ low H2O outside cell; H2O moves out
• Animal cell shrinks
• Plant cell contents shrink (loss of turgor pressure)Think… when you are hyper, you
want to move out of your seat!
Osmosis
State
H2O
Movement
[H2O]
Inside cell
[H2O]
Outside cell
Isotonic [same] [same]
Hypotonic [Low] [High]
Hypertonic[High] [Low]
none
Into the cell
Out ofthe cell
Osmosis
State
H2O
Movement
Solute [ ]
Inside cell
Solute [ ]
Outside Cell
Isotonic[Same] [Same]
Hypotonic [High] [Low]
Hypertonic [Low] [High]
none
Into the cell
Out ofthe cell
PASSIVE TRANSPORT• No energy is required to move particles
through the cell’s plasma membrane• Facilitated Diffusion
–Protein required to move particles through membrane
–Move down [ concentration] gradient by random movement
–Channel proteins vs. carrier proteins–How glucose (sugar) enters the cell
ACTIVE TRANSPORT• Move substances from [low] to [high]• Requires:
–Cell to use energy–Transport protein (pump) = each pump
is specific for a certain substance• 2/3 of your energy used to actively
transport Sodium and Potassium across membranes
ENDOCYTOSIS (endo = in)• Process in which the plasma membrane
engulfs substances from the environment• Pinocytosis – “cell drinking” large drops of
liquid.• Phagocytosis – “cell eating” large particles
are engulfed into a vesicle for digestion–Ex: Amoeba’s and White Blood Cells
(Immunity)