Transcript Cell membranes MOVE!

Chapter 7
Cell Structure and Function
Nucleolus
Nucleus
Nuclear envelope
Rough
endoplasmic
reticulum
Golgi apparatus
Ribosome (attached)
Ribosome (free)
Cell Membrane
Mitochondrion
Smooth
endoplasmic
reticulum
Centrioles
Image from: © Pearson Education Inc, Publishing as Pearson Prentice Hall; All rights reserved
The cell
• The cell is smallest unit of life that can
carry out all the functions of a living thing
• I. History
– A. 1660’s Robert Hooke looked at cork
• Saw and named cell
– B. Improved microscopes
– C. 1830’s – cell theory
• 1. every organism is made of cells
• 2. the cell is the basic unit of life
• 3. all cells come from other living cells
• II. Sizes and shapes
• A. Size – varies from microscopic to
small
• B. Shape – many varieties
III. Comparing cells
• Prokaryote cells – simple organisms –
bacteria, single cell, primitive, no
nucleus
• Can have:
–
–
–
–
–
Cell wall - peptidoglycan
Cell membrane
Ribosomes – makes protein
May have cilia or flagella
DNA is a single ring
• Eukaryote cells –
more complex cell
contain nucleus &
organelles
• May be unicellular
or multicellular
• Variety of shapes &
functions
• Ex; protists, fungi,
plants, animals
No membrane
bound organelles
Organelles with membranes
BACTERIA are
PROKARYOTES
PLANTS & ANIMALS
are EUKARYOTES
IV. Parts of cells – organelles
• Cytoplasm – clear fluid that holds all
cell’s parts (organelles) found
between nucleus & cell membrane
• Cell membrane
– A. protects cell
(surrounds)
– B. allows some
materials to pass
in/out of cell =
semi-permeable
(selectively
permeable)
– C. Made of
phospholipids &
proteins
Cell membrane
Outside
of cell
Proteins
Carbohydrate
chains
Cell
membrane
Inside
of cell
(cytoplasm)
Protein
channel
Lipid bilayer
LIPID TAILS ARE
HYDROPHOBIC
HYDROPHILIC 
HYDROPHOBIC 
Image by Riedell
PHOSPHOLIPID BILAYER
SEE HOW MEMBRANES FORM
Scroll down to animation
Image from: http://employees.csbsju.edu/hjakubowski/classes/ch112/lipids/micbilayer.gif
Cell membranes MOVE!
Animation from: http://www.sp.uconn.edu/~terry/images/anim/fluidmem.gif
Click here to see
Fluidity
Animation
Molecules in cell membranes are
constantly moving and changing
• Nuclear membrane
(envelope)
– A. protects nucleus
– B. has pores = semipermeable – lets some
things in and out
• Nucleus
– Controls all cell activities
– Code tells cell parts what to do
– Contains DNA
• Scrunched up = chromosomes (cell’s dividing)
• Spread out = chromatin (cell’s not dividing)
Identify the pictures
• Nucleolus – makes ribosomes
• Endoplasmic reticulum (ER)- highway
system by which materials are
transported throughout the cell
• 2 kinds
ER con’t
– Smooth
• make lipids
(steroids)
• Destroy toxic
substances
(liver)
– Rough
• has ribosomes
• Make protein &
inserted into ER
to be
transported &
modified
• Cytoskeleton
– Helps maintain shape
– Helps move organelles around
– Can extend out of cell & allow movement
• Cilia – short hairs (like oars)
• Flagella – long tail-like
– 2 kinds:
• Microfilaments
• Microtubules
FLAGELLA
Help in cell
movement
CILIA
Animation from: http://web.jjay.cuny.edu/~acarpi/NSC/13-cells.htm
Move cell itself
WHAT’S THE DIFFERENCE?
CILIA
• Many
• short
Animation from: http://web.jjay.cuny.edu/~acarpi/NSC/13-cells.htm
FLAGELLA
•Few
•Long
• Ribosome
– Made of proteins & RNA
– Protein factory
• Joins a.a.’s to make protein
– Can be free or attached to ER
Ribosomes
• Mitochondria – “powerhouse”
– 2 membranes – inner mem called cristae
– Folded inner membrane increases surface
area for more chemical reactions
– Has own DNA
– Burns glucose  energy called respiration
– Stores energy as ATP
mitochondria
MITOCHONDRIA
Come from
cytoplasm in EGG
You inherit your
mitochondria from
your mother!
http://www.wappingersschools.org/RCK/staff/teacherhp/johnson/visualvocab/p14%5b1%5d.jpg
• Golgi apparatus
– Pancake like membrane stacks
– Modify, sort, & packages proteins so
they can be stored or exported from cell
“exporter”
It’s ALL connected!
Animation from: http://www.franklincollege.edu/bioweb/A&Pfiles/week04.html
See a Golgi movie
Animal cells only
• Centriole – appear during cell division to
pull chromosomes apart
CENTRIOLES/MITOTIC SPINDLE
Made of MICROTUBULES (Tubulin)
Image from: http://www.coleharbourhigh.ednet.ns.ca/library/organelle_worksheet.htm
• Lysosome –
– Contain digestive enzymes “janitor”
– Digests bacteria, food, old organelles
– Self-destruct “dying” cell
• Vesicles – (small vacuole) storage of h2o,
food, waste, in simple animal cells
LYSOSOMES
See
lysosomes
in action:
Image modified from: http://www.people.virginia.edu/~rjh9u/lysosome.html
LYSOSOMES
See LYSOSOME
MOVIE
Image from: http://www.people.virginia.edu/~rjh9u/lysosome.html
“PROGRAMMED CELL DEATH”
APOPTOSIS
= ______________________
Lysosomes help
digest unwanted
cells
See animation
http://www.mgm.ufl.edu/images/bharfe/image3.jpg
http://research.yale.edu/ysm/images/78.3/articles-apoptosis-cells.jpg
Plant cells only
• Cell wall - protects, supports cell
– Shape – square
– Rigid, non – living cellulose
– Outside cell membrane
• Vacuole – storage
– Large- H2O, salt, enzymes, food, waste
Contractile vacuoles control excess
water in cells
(HOMEOSTASIS)
http://www.microscopy-uk.org.uk/mag/imgjun99/vidjun1.gif
1
• Chloroplast – store & make food (sugar, starch)
– Chlorophyll – green pigment that traps and absorbs
sunlight energy
– Thylakoid = membrane sacs do photosynthesis
– Has its own DNA
• Leukoplast – store food (white)
chloroplasts
Similarities of plant & animal
cells
•
•
•
•
Cell membrane
Nucleus
Chromosomes
ribosomes
•
•
•
•
•
ER
Golgi
Mitochondria
Cytoplasm
cytoskeleton
Differences of plant & animal
cells
• Plant
• Cell wall
• Large central
vacuole
• Plastids– Chloroplasts
– Leukoplasts
Rectangular – square
shape
•
•
•
•
Animal
Lysosome
Centrioles
May have cilia or
flagella
• Circular shape
USE WORDS FROM THE WORD BANKS TO COMPLETE THE VENN DIAGRAM COMPARISON