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The Cell
http://www.youtube.com/watch?v=-zafJKbMPA8
http://www.youtube.com/watch?v=rABKB5aS2Zg&feature=fvw
p&NR=1
The Nucleus
“Command center”
 Nucleolus: Ribosome parts
(subunits) are made here.
 Nuclear Envelope:
Phospholipid bilayer surrounds
nucleus.
 Nuclear Pores: Holes in the
nuclear envelope that let
molecules in and out. Very
selective.
 Chromatin: Uncondensed DNA
& proteins (“open book”)
 Chromosomes: Condensed DNA
& proteins (“closed book”).
Condense for cell division
Ribosomes
 Structure: Made of the
large and small subunits
that are made in the
nucleolus.
 Bound ribosomes are found
on the Rough ER or FREE
RIBOSOMES are found in the
cytosol.
 Function: MAKE PROTEINS
 “Assembly line”
Endoplasmic Reticulum—
”manufacturer”
 Structure: Internal membrane system connected to the
nucleus.
 Function:
 Rough ER: has ribosomes on its surface; proteins are made
directly into ER where they can then be modified.
 Smooth ER: Lipids are produced (steroids, phospholipids)
Golgi Apparatus—”Post office”
 Structure: Stacks of membranes called cisternae that
have enzymes in them.
 Function: To modify the proteins/lipids that arrived in
vesicles from the ER, and to attach carb/lipid mailing
labels on the outside of the vesicle to deliver to their
final destination.
How do the nucleus,
ribosomes, ER, and golgi
apparatus work together to
help the cell function?
Lysosomes—”Garbage disposal”
 Structure: small sac like organelle that is filled with
enzymes.
 Functions:
 Break down food macromolecules, which are _________,
__________, and ____________.
 Break down old or failing organelles to prevent cluttering
of cells.
 Destroy the cell from the inside out (programmed cell
death)
 http://www.biochemweb.org/neutrophil.shtml
Vacuoles—”the closet”
 Central vacuole in plants help:
 Store essential nutrients (salts, proteins, and carbs)
 Holds plants upright by having vacuole full of water
 Contractile vacuole pumps water out of organism
 Food vacuole stores macromolecules
Chloroplasts
“Solar Panel”
 Structure:
 Light is absorbed by
chlorophyll in thylakoid
membranes
 Function:
 Use energy from sunlight to
make macromolecules,
especially glucose.
Mitochondria—”Powerplant”
 Structure:
 Enzymes on cristae of inner
membranes convert glucose
and other food molecules to
ATP.
 Cristae are folds of the
inner membrane that
increase surface area to
have more space to make
ATP.
 Function: ATP powers
everything in our bodies.
Cytoskeleton—”Highway”
 Structure:
 Made of different sizes of
tubes/filaments.
 Microfilaments (smallest)
Intermediate filaments,
Microtubules (biggest)
 Functions:
 Microtubules help with cell
division and transporting
vesicles/organelles around
cell.
 Microfilaments help with cell
movement & communication
 Intermediate filaments help
with cell shape
Cell Membrane—”Bouncer”
 Structure: phospholipid
bilayer with proteins and
steroids mixed in.
 Function:
 Boundary that regulates
what comes in and out of
cell. SELECTIVELY
PERMEABLE.
 Proteins and steroids are
involved in transporting
substances across and
communicating with other
cells.
Cell Wall
“Castle Wall”
 Algae, some fungi, plants
and prokaryotes have these
 Structure:
 Located outside cell
membrane
 Made of cellulose in plants,
as well as pectins (sticky)
 Function:
 Provide support and
protection for the cell
Cell Transport
 Without moving nutrients in and waste out, cells would
quickly die. So how do cell membranes do it?
 Types:
 Passive
 Diffusion
 Osmosis
 Facilitated Diffusion
 Active Transport
 Endocytosis
 Exocytosis
Diffusion
 The movement of a solute from an area of high solute
concentration (hypertonic) to an area of low solute
concentration (hypotonic)
 Moves down a concentration gradient
 Every solute has its own gradient
Osmosis
 The movement of water from an area of high water
concentration (hypotonic) to an area of low water
concentration (hypertonic)
Facilitated Diffusion
 NO ENERGY NEEDED
 Proteins help a solute cross the cell membrane
 Moves according to concentration gradient
 http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/ani
mation__how_facilitated_diffusion_works.html
Active Transport
 REQUIRES ENERGY. What kind of energy??
 Moves materials from a low to a high concentration.
 Three types of active transport:
 Pumps
 Endocytosis
 Exocytosis
Sodium-Potassium Pump
 Pumps Sodium (Na+) ions out of cell and potassium (K+)
ions into cell against concentration gradient.
 What does this use?
Endocytosis
 Brings large molecules into cells by cell membrane
surrounding molecules and creating food vacuoles.
 What attaches to the food vacuoles to break food down?
 Pinocytosis = cell drinking
 Phagocytosis is a type of endocytosis.
http://www.biochemweb.org/neutrophil.shtml
Exocytosis
 Removal of large amounts of material from cell by
vesicle fusing with cell membrane.
 Could be waste or materials used somewhere else in
body.
 Where did the vesicle probably come from?
Endo/Exo animation
 http://highered.mcgrawhill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/si
tes/dl/free/0072437316/120068/bio02.swf::Endocytosis
%20and%20Exocytosis