Transcript Ch. 7 - Cells

Do Now
What are cells?
Why do we need them?
List different types of cells that you
know of…
Ch. 7: Cellular Structure and Function
Objectives
 Describe how cells were
discovered and named.
 Compare and contrast light
microscopes vs. electron
microscopes.
 Explain what is found in a basic
cell.
What are cells?
 Basic structural and functional unit of all living
organisms!
 They come in all shapes and sizes
 Lets take a look…
http://www.cellsalive.com/howbig.htm
Cells!
Egg cell
How did we figure out cells
even existed, what they
looked like, what they do?...
Nerve cell
Bacteria cell
Robert Hooke
 1665- saw dead plant cells
from cork, tree stems, roots
and ferns using a light
microscope
 Called them “cellulae”
(small rooms) - reminded
him of the cubicles or cells
where monks live
Anton Van Leeuwenhoek
 First person to observe living cells
 Made microscope with a magnification 10X that of
Hooke’s- “Father of microscopes”
 Observed spirogyra and protists
The “Cell Theory”
Scientists expressed 3 main observations about
cells:
All living organisms are composed of one or
more cells
Cells are the basic units of structure and
organization of all living organisms
Cells come only from the reproduction of
existing cells
What do we use to look at cells?
 Cells were discovered using MICROSCOPES!
 Compound Light MicroscopesUses visible light to produce magnified image.
Maximum = 1,000x magnification
 Electron MicroscopesSpecimen must be dead 
Use magnets and electrons
Allows much greater magnification
Ex: Transmission Electron = up to 500,000x
Electron Microscopes
 Transmission Electron
MicroscopeElectrons are sent
through a specimen
 Scanning Electron
MicroscopeElectrons are sent over
the surface of a
speciment.
3D image
100,000x magnification
Microscope Activity!!
How do Microscopes work?
Use 2 lenses to
magnify image of
an object by
focusing light or
electrons
Light passes
through object
Light Microscopes and Cell
Stains
 1st lens = objective - just above specimen
– enlarges image of specimen
 2nd lens = ocular lens
 Can produce clear images up to 1000 times
 Must use chemical dyes (stains)
 specific - reveal only certain compounds or
structures
 Fluorescence – give of particular color of
light when viewed under specific
wavelengths of light
Objectives
List the different organelles of a
cell.
Explain the function of each
organelle.
Identify each organelle in a
diagram of a cell.
Basic Parts of any Cell
 DNA/RNA
Needs some type of genetic
information!
 Plasma membrane
Cell’s outer boundary that acts
as a barrier
Basic Parts of any cell (cont.)
 Cytoplasm
Region of cell that includes fluid, cytoskeleton and all
organelles
 Control Center
Contains a cell’s DNA
Nucleus- membrane- bound structure in eukaryotes
Nucleoid- region of DNA in prokaryotes
Prokaryotic vs. Eukaryotic
Organisms can be made up of
either prokaryotic or eukaryotic
cells.
Prokaryotic Cells…
 Do not have a distinct nucleus
 No membrane-bound organelles
 Ex: bacteria
 Many scientists think that
prokaryotes are similar to the first
EVER organisms on Earth
Eukaryotic Cells…
Contain a nucleus
Contain membrane-bound
organelles
All multicellular organisms
are Eukaryotic
Ex: US, plants, animals, etc.
(also some unicellular
organisms like algae and
yeast)
Do Now P. 2!! 
Please read the worksheet in front of
you on eukaryotes and prokaryotes.
Create a Venn diagram!
When finished, take out your organelle
packets and complete your assigned
sections.
Do Now P. 6!! 
With a partner, please read the
worksheet in front of you on prokaryotes
and eukaryotes.
Create a Venn diagram!
Do Now!! 
Please take out your organelle packets!!
Objectives
 Explain the function of each organelle through a
jigsaw activity!
 Label parts of animal and plant cells
 Introduce the plasma membrane
Quiz Study Guide (Fri 12/12)
 Organelles- what each of them do
 Diagrams- label both plant and animal cell.
 Prokaryotes vs. Eukaryotes- what’s the
difference?
Organelle Jigsaw Activity!!
Plasma Membrane
 The wall!- protects the
internal structures of the
cell.
 Determines what comes in
and out of the cell:
 Selective permeability
 Found in: Plant, Animal
and Prokaryote
Cytoplasm/Cytoskeleton
 Cytoplasm- clear fluid that
contains the organelles
 Cytoskeleton- Provides the
framework for the cell, holds
organelles in place.
 Found in: Plant, Animal and
Prokaryote
Nucleus
 Nucleus- controls the cell.
 Nucleolus- produces
ribosomes.
 Nuclear Pores- allow things in
and out of nucleus.
 Nuclear Envelope- membrane
around nucleus
Found in: Plant and
Animal
Ribosomes
 Makes polypeptide
chains of amino acids,
producing Proteins.
 Found in: Plant, Animal
and Prokaryote
Endoplasmic Reticulum
 Rough- contains
ribosomes and synthesizes
proteins.
 Smooth- No ribosomes,
synthesizes lipids (fats).
 Found in: Plant and
Animal
Golgi Apparatus
 Modifies proteins and
fats and gets them
ready for export!
 Found in: Plant and
Animal
Central Vacuole
 Large water “bubble” in
a plant cell.
 Maintains the shape of the
cell, without it, the plant
cell would shrink and the
plant would wilt.
 Found in: Plant cells
Lysosomes
 Contain enzymes,
break down
cellular waste
product and
debris.
 Found in: Animal
Centrioles
 Groups of microtubules
involved in cell division
(we will talk about this
more later when we do
mitosis!)
 Found in: Animal
Mitochondria
 Convert oxygen into
energy (we will talk about
this more when we do
cellular respiration!)
 *Powerhouse!!
 Found in: Plant and Animal
Cilia and Flagella
 Flagella- Used in cells for
movement (longer & less
numerous than cilia)
 Cilia- Used in stationary
cells for moving
substances around the
outside of the cell (hairs)
 Found in: Animal and
Prokaryote
Chloroplasts
 Capture light energy and
convert it to chemical
energy (sugar).
 Contain thylakoids (where
photosynthesis takes
place)
 Found: Plant
Cell Wall
 Rigid structure (made of
carbohydrate cellulose)
 Provides strength for the cell.
 Works with vacuole to
maintain “turgor pressure”
 Found in: Plant
coLAR Mix!!
Please download the
coLAR mix free app!
Then color code the
animal cell
Use the app to watch
some magic happen
(the dots)
The differences between animal
and plant cells…
 http://www.youtube.com/watch?v=-zafJKbMPA8
Do Now!! 
Plant vs. animal cell bucket activity!!
Do Now!! 
What is the plasma membrane?
What does it do?
What would happen if it didn’t exist?
Objectives
Discuss the role of the plasma
membrane.
Identify the components of the plasma
membrane and their functions.
Define diffusion.
So what does the plasma membrane
do?
 Maintains an internal environment that is
different from the external environment.
 Determines what molecules enter and
exit the cell (homeostasis).
 Made of a phospholipid bilayer
Selective permeability
 Controls the movement of substances in and
out of the cell
 Controls AMOUNT of substances entering and
leaving the cell
 Fish net analogy
Phospholipid Bilayer
Do Now!! 
 What are the components of a plasma
membrane?
 Which are hydrophobic/hydrophilic?
 What does selective permeability mean?
Objectives
 To define the components of a plasma
membrane
 To determine what can pass in and out of
the membrane
 To define diffusion and discuss its
importance
Structure of the plasma membrane
 Proteins: receptors, structure, transport
 Cholesterol: prevents tails from sticking
 Proteins and other components are embedded like a mosaic:
 “Fluid Mosaic Model”
 http://www.youtube.com/watch?v=Qqsf_UJcfBc
Cholesterol
 Prevents fatty acid tails from sticking together
Carbohydrates
o Attached to proteins
o Help cell identify chemical signals
o ex: help disease-fighting cells recognize harmful cells
Proteins
 Provide channels for transport
 Act as cell receptors (transmit signals)
 Provide structure
Conclusion activity
Do Now!! - Label the different
parts
 What is the name of the entire structure?
Objectives
 Define diffusion.
 Identify the conditions that effect the rate
of diffusion.
 Explain facilitated diffusion.
 Compare and contrast active and
passive transport.
What is diffusion?
 Diffusion- movement of particles from area where
there are many to area where there are fewer
 Movement of molecules from high concentration to low
concentration by random motion (no energy required)
High concentration
Low concentration
What is diffusion?
 Mixing continues until concentrations are the same
in all areas
 Dynamic Equilibrium -continues movement but no
NET overall change in concentration
Explain what’s happening…
Diffusion Video
 https://www.youtube.com/watch?v=VY0mZUDvbH4
Diffusion across the plasma membrane
*Cells also need ions and small molecules to
perform cellular functions
(ex: ions and sugars)
(ex: H2O, O2, CO2)
T.P
Large and/or ChargedTransport Protein
Small and/or nonpolar molecules
Diffusion of Water- OSMOSIS
 Water can move right through the phospholipids from high to
low concentration
Facilitated Diffusion
 Most substances cannot readily pass through the
membrane
 Facilitated diffusion: Movement of materials across the
plasma membrane using proteins
Channel Proteins
Carrier Proteins
Types of Transport Proteins
 Channel Proteins Pores that allow charged ions to pass through the
membrane
 Carrier Proteins Change shape to help molecules pass through the
membrane
Do Now!! 
 What is diffusion?
 What do you think “passive” transport is?
 What do you think the difference is between
passive and active transport?
Objectives
 To explain active and passive transport.
 To understand what happens during osmosis.
 To compare and contrast hypertonic,
hypotonic, and isotonic solutions.
Passive Transport
 Movement of particles across the cell membrane without
using energy
Diffusion of Water
Things that affect the speed of
passive transport
1. Heat- Hotter  faster
2. Size- Bigger  slower
3. State of Matter
Solid- Slow
Liquid – Fast
Gas- Fastest
What is active transport?
 Molecules move usually in opposite direction of
diffusion (Low concentration to high concentration =
going against the flow)
 Carrier proteins help movement
 Requires ENERGY (ATP)
 Ex: Sodium potassium pump
Potassium pumped in, sodium pumped out
Osmosis
Water always flows via osmosis from HIGH water
concentration to LOW water concentration
through a semi permeable membrane.
Osmosis
Which container has more water in it?
http://www.stolaf.edu/people/giannini/flashanimat/transport/osmosis.swf
Osmosis- diffusion of water across
a membrane
Remember: Water always flows via osmosis from
HIGH water concentration to LOW water
concentration
This cell would shrink!
22% Salt
5% Salt
H2O
H2O
Osmosis- diffusion of water across a
membrane
-Water always flows via osmosis from HIGH water
concentration to LOW water concentration
-This cell bursts!
22% Salt
45% Salt
H2O
H2 O
Isotonic Solution
 Water and dissolved substances diffuse
into and out of the cell at the same rate.
Plant Cell
Blood Cell
11,397x
HypOtonic Solution
 Solute concentration is higher inside the cell.
 Water diffuses into the cell, cell swells/bursts
Plant Cell
Blood Cell
13,000x
Hypertonic Solution
 Solute concentration is higher outside the cell.
 Water diffuses out of the cell, cell shrivels
Plant Cell
Blood Cell
13,000x
3 Types of Solutions
Cell in ________
Solution
Cell in ________
Solution
H2 O
H2 O
H2 O
H2 O
Cell in ________
Solution
H2 O
H2 O
For each solution, determine if the solute concentration of the
solution is high, the same, or low as compared the cell.
Real life osmosis situations
A salt water fish is put into a
freshwater aquarium.
What type of solution is the
freshwater?
What is going to happen to
the cells of the fish?
Real life osmosis examples
Your garden is infested with slugs so
you go around pouring salt on them
What type of
solution is this salt?
What is going to
happen to the cells
of the slug? (don’t
do this to the poor
slugs )
Transport of Large Molecules
Usually Transported
by Vesicles
EndocytosisInto the cell
Exocytosis-
Exiting the cell
What kind of molecules do you think are usually
found in the Vesicle?
Do Now!! 
Please take out your homework!!
Some important vocab…
Plasmolysis: State where plant cells shrink
in hypertonic environment (animal cells=
“crenation”)
Plant Cell
Blood Cell
Some important vocab…
 Cytolysis: State where cells burst in hypotonic environment
Turgid: State where plant cells swell in hypotonic
solution (animal cells=Lyse)
Plant Cell
Blood Cell
Some important vocab…
Flaccid: State where a plant cell is placed
in isotonic solution
Plant Cell