Cellular Structure and
Function
Chapter 7
Section 1:
Section 2:
Section 3:
Section 4:
Cell Discovery and Theory
The Plasma Membrane
Structures and Organelles
Cellular Transport
Section 1
Section 1: Cell Discovery and Theory
Section 1: Cell Discovery and Theory
The invention of the microscope led to the discovery of cells.
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What I Know
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What I Want to Find Out
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What I Learned
The history of Cell Theory
http://ed.ted.com/lessons/thewacky-history-of-cell-theory#watch
History of the Cell Theory
•
A cell is the basic structural and functional unit of all living organisms.
•
Cells are so small that their existence was unknown before the invention of
microscopes.
Cell Discovery and Theory
History of the Cell Theory
The cell theory
•
The cell theory is one of the fundamental ideas of modern biology, and
includes the following three principles:
• All living organisms are composed of one of more cells.
• Cells are the basic unit of structure and organization of all living
organisms.
• Cells arise only from previously existing cells, with cells passing copies
of their genetic material on to their daughter cells.
Cell Discovery and Theory
Discovery of Cells
• Cells are about 1/500th the size of a .
• In 1665 Robert Hooke used a 3-lens compound
microscope to examine thin slices of cork.
• He observed that cork is made of tiny, hollow
compartments.
• He gave them the name “cells”
• Hooke was only looking at cell walls & empty space.
Microscope Technology
Compound light microscopes
•
Use a series of glass lenses and visible light to magnify images
•
Magnify images up to ~1000× actual size
Electron microscopes
•
Create an image by illuminating a sample with a beam of electrons and
collecting the electrons that are reflected back from the sample
•
Magnify images up to 500,000× actual size
Cell Discovery and Theory
Basic Cell Types
•
All cells have at least one physical trait in common: a plasma membrane.
•
A plasma membrane is a special boundary that helps control what enters
and leaves the cell.
•
Most cells contain genetic material in some form.
•
Most cells break down molecules to generate energy.
•
There are two basic kinds of cells: eukaryotic and prokaryotic.
Cell Discovery and Theory
ALL ORGANISMS ARE MADE OF CELLS
1. ___________________________________________________________
THE CELL IS THE MOST BASIC UNIT OF LIFE.
2. ___________________________________________________________
ALL EXISTING CELLS ARE PRODUCED BY OTHER LIVING CELLS
3. ___________________________________________________________
HOOKE
_____________
CORK
The first to
IDENTIFYcells.
____________
Responsible for
NAMING them
____________
LEEUWENHOEK
_____________
ANIMALCULES
Made better
LENSES
______________
and observed cells
in greater
DETAIL
______________.
First to observe
NUCLEUS
______________
SCHLEIDEN
_____________
SCHWANN
_____________
VIRCHOW
_____________
RESPONSIBLE FOR CELL THEORY
The first to note
that
_____________
PLANTS
were made up of
CELLS
___________
Concluded that all
LIVING
THINGS
___________
___________ were
made up of
CELLS
___________
Proposed that all
cells come from
OTHER
CELLS
____________
__________
Basic Cell Types
•
Eukaryotic cells contain a nucleus and other organelles.
• Organelles are specialized structures that perform specific cell functions.
• The nucleus is the distinct central organelle that contains the cell’s
genetic material.
• Eukaryotic cells are generally much larger than prokaryotic cells.
Cell Discovery and Theory
Basic Cell Types
•
Prokaryotic cells are cells without a nucleus or other membrane-bound
organelles.
• Smaller and simpler than eukaryotes
• Probably similar to first organisms that lived on earth
Cell Discovery and Theory
Basic Cell Types
Origin of cell diversity
•
Eukaryotic cells may have evolved from prokaryotic cells.
• The endosymbiont theory proposes that a symbiotic relationship formed
between two prokaryotic cells, one of which lived inside the other.
• Eventually the symbiotic relationship led to the two cells becoming one.
•
Because eukaryotic cells are larger and more complex, they developed specific
functions.
•
These specific functions led to cell diversity, and thus organismal diversity.
Cell Discovery and Theory
Eukaryotes VS. Prokaryotes
Video
• Prokaryotes VS. Eukaryotes
Essential Questions
•
How are the advances in microscope technology related to discoveries about
cells?
•
What are the similarities and differences between compound light
microscopes and electron microscopes?
•
What are the principles of the cell theory?
•
What are the differences between a prokaryotic cell and a eukaryotic cell?
Cell Discovery and Theory
Section 2
Section 2: The Plasma Membrane
Section 2: The Plasma Membrane
The plasma membrane helps to maintain a cell’s homeostasis.
K
What I Know
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What I Want to Find Out
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What I Learned
The Cell Membrane
http://ed.ted.com/lessons/insightsinto-cell-membranes-via-dishdetergent-ethan-perlstein#watc
Function of the Plasma Membrane
•
The process of maintaining balance in an organism’s internal environment is
called homeostasis.
•
One of the structures responsible for homeostasis is the plasma membrane.
•
The plasma membrane forms a thin, flexible boundary between a cell and its
environment.
The Plasma Membrane
Function of the Plasma Membrane
•
Plasma membranes have selective permeability, meaning they allow some
substances to pass through while keeping others out.
•
Control of how, when, and how much of various substances enter and leave
a cell depends on the structure of the plasma membrane.
The Plasma Membrane
Video
• Selective Permeability
• Selective Permeability 2
Structure of the Plasma Membrane
The phospholipid bilayer
•
The plasma membrane is composed of phospholipid bilayer – two layers of
phospholipids are arranged to allow the membrane to exist in a watery
environment.
•
The phospholipid bilayer has polar heads facing outside and nonpolar tails
facing inside the cell, allowing the membrane to keep the internal and
external environments separate.
The Plasma Membrane
Phospholipids
Video
• Cell Membrane & Phospholipid Bilayer
Video
• Phospholipid Bilayer
Structure of the Plasma Membrane
Other components of the plasma membrane
•
The plasma membrane also contains cholesterol, proteins, and
carbohydrates.
•
Some proteins called receptors transmit signals to the inside of the cell.
•
Some proteins serve as support structures for the membrane.
•
Transport proteins move needed substances and wastes through the
membrane.
The Plasma Membrane
Structure of the Plasma Membrane
Other components of the plasma membrane
•
Cholesterol prevents the fatty acid tails of the phospholipid bilayer from
sticking together.
•
Cholesterol contributes to the fluidity of the membrane.
The Plasma Membrane
Structure of the Plasma Membrane
Other components of the plasma membrane
•
Carbohydrates define the cell’s characteristics
•
Help cells identify chemical signals
The Plasma Membrane
Structure of the Plasma Membrane
Other components of the plasma membrane
•
The fluid mosaic model describes the phospholipids in the bilayer as a “sea”
in which other components can float and move around.
•
The different substances in the plasma membrane create a pattern or mosaic
on the surface of the cell.
The Plasma Membrane
Fluid Mosaic Model
Video
• Fluid Mosaic Model
Essential Questions
•
How does a cell’s plasma membrane function?
•
What are the roles of proteins, carbohydrates, and cholesterol in the plasma
membrane?
The Plasma Membrane
Section 3
Section 3: Structures and Organelles
A Tour of the Cell
• https://www.youtube.com/watch?v=1Z9pqST
72is
• Crash courses (animal cell then plant)
• https://www.youtube.com/watch?v=cj8dDTH
GJBY
• https://www.youtube.com/watch?v=9UvlqAV
CoqY
Section 3: Structures and Organelles
Eukaryotic cells contain organelles that allow the specializations
and the separation of functions within the cell.
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What I Know
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What I Want to Find Out
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What I Learned
Cytoplasm and Cytoskeleton
•
The environment enclosed by the plasma membrane is a semifluid material
called cytoplasm.
• In prokaryotes, all the chemical processes of the cell take place directly
in the cytoplasm.
• In eukaryotes, these processes take place within organelles in the
cytoplasm.
Structures and Organelles
The
clear, jellylike material between the cell membrane and
_________________________________________________
the nucleus that makes up most of the cell
_______________________________________
(Most of all cell activity occurs here.)
____________________________________________
CYTOPLASM
_______________
Cytoplasm and Cytoskeleton
•
The cytoskeleton is a supporting network of long, thin protein fibers that form
a framework for the cell and proved an anchor for the organelles.
• Microtubules are long, hollow protein cylinders that form a rigid skeleton
for the cell and assist in moving substances within the cell.
• Microfilaments are thin protein threads that help give the cell shape and
enable the part or the entire cell move.
Structures and Organelles
Cell Structures
The nucleus
•
•
Contains most of the cell’s DNA, which stores information used to make
proteins that determine a cell’s growth, function, and reproduction
Is surrounded by a double membrane called a nuclear envelope
Structures and Organelles
The control center of the cell.
___________________________________________________
Parts of the Nucleus:
_________________________________________________
Nuclear Membrane:
The membrane that surrounds the nucleus.
__________________________________
Nuclear Pores: allow__________________________________
some particles to move in and out of the nucleus
Nucleolus
__________________________________
Chromosomes
__________________________________
NUCLEUS
_______________
Cell Structures
Ribosomes
•
Ribosomes are organelles that manufacture proteins.
–
–
Not membrane-bound like other organelles
Produced inside the nucleus in the nucleolus
Structures and Organelles
MAKES PROTEINS FOR THE BODY.
_____________________________________
FOUND ON ENDOPLASMICE RETICULUM AND THROUGHOUT
__________________________________________________________
CYTOPLASM
___________________________________
RIBOSOMES
_______________
Cell Structures
Endoplasmic reticulum
•
The endoplasmic reticulum (ER) is a membrane system of folded sacs and
interconnected channels that serves as the site for protein and lipid
synthesis.
–
Two types: rough and smooth
Structures and Organelles
_________________________________________________________
Moves cell materials from cell membrane to nuclear membrane and
_______________________________
visa versa.
____________________________________________
(Can usually find ribosomes on this network.)
ENDOPLASMIC
_______________
RETICULUM
_______________
Cell Structures
Golgi apparatus
•
•
The Golgi apparatus is a flattened stack of membranes that modifies, sorts,
and packages proteins.
Proteins are packaged into sacs called vesicles, which can fuse to the
plasma membrane and release the proteins to the environment.
Structures and Organelles
Packages materials for the cell.
_______________________________________
______________
GOLGI
______________
APPARATUS
Cell Structures
Vacuoles
•
•
•
A vacuole is a membrane bound sac used for temporary storage.
Vacuoles store food, enzymes, or waste.
Vacuoles are only found in plant cells.
Structures and Organelles
Stores food and water for cell
_______________________________________
ANIMAL CELL
PLANT CELL
Contains
many small vacuoles
____________________________
________________________________
Contains one large “central vacuole
________________________________
that takes up most of the space
_______________________
inside of a plant cell
VACUOLE
________
Cell Structures
Lysosomes
•
•
Lysosomes are vesicles that contain substances that digest excess or wornout organelles and food particles.
They also digest bacteria or viruses that invade the cell.
Structures and Organelles
Helps digest, (break down), waste materials of cell.
_________________________________________________
_______________________________________
LYSOSOMES
____________
Cell Structures
Centrioles
•
•
Centrioles are organelles made of microtubules that function during cell
division.
They are located in the cytoplasm.
Structures and Organelles
Parts of an ANIMAL cell that help with cell REPRODUCTION
____________________________________________
Cell Structures
Mitochondria
•
•
Mitochondria convert fuel particles into usable energy.
They have an outer membrane and a highly folded inner membrane that
provides surface area for breaking the bonds in sugar molecules.
Structures and Organelles
Responsible for supplying ENERGY to the cell.
__________________________________________________________________________
MITOCHONDRIA
____________
Cell Structures
Chloroplasts
•
•
Plant cells and some other eukaryotes contain chloroplasts, which capture
light and convert it into chemical energy in process called photosynthesis.
They are composed of multiple small disks called thylakoids, which contain
the light capturing pigment chlorophyll.
Structures and Organelles
_________________________________________________
The plant cell parts that contain the green pigment,
_________________________________________________
chlorophyll, which are responsible for producing food.
__________________________________
______________________
CHLOROPLASTS
Cell Structures
Cell wall
•
Plant cells have a cell wall – a thick, rigid, mesh of fibers that surround the
outside of the plasma membrane.
–
–
Protect the cell and give it structure
Are made from a carbohydrate called cellulose
Structures and Organelles
The_________________________________________________________
outer most side of an plant cell, (surrounds the cell membrane), that
gives the cell structure, and a specific shape.
__________________________________________________________
(More rigid than cell membrane.)
__________________________________________________________
______
CELL
______
WALL
Cell Structures
Cilia and flagella
•
•
•
Cilia are short, numerous projections that look like hair.
• Move in tandem like oars in a rowboat
Flagella are longer and less numerous than cilia.
• Move with a whip-like motion
Both are made of microtubules.
Structures and Organelles
Comparing Cells
•
Features plant cells have that animal cells generally do not:
• Chloroplasts/chlorophyll
• Vacuoles
• Cell walls
Structures and Organelles
Centrioles
Large central vacuole
Organelles at Work
•
An understanding of different organelles allows for an understanding of
cellular processes.
•
Protein synthesis:
• Begins in the nucleus with information contained in DNA
• RNA and ribosomes leave the nucleus and produce a protein on the
endoplasmic reticulum.
• Proteins produced in the ER are sent to Golgi apparatus for packaging.
• Packaged proteins are delivered to other organelles where they serve a
variety of functions.
Structures and Organelles
Plant vs animal cell rap
• https://www.youtube.com/watch?v=Yu21Shn
KhHk
Label the organelles of this animal cell.
1. NUCLEOLUS
_________________
2. NUCLEUS
_________________
3. RIBOSOMES
_________________
4. VESICLE
_________________
5. ROUGH
_________________
ER
6. GOLGI
_________________
BODIES
7. CELL
_________________
MEMBRANE
8. SMOOTH
_________________
ER
9. MITOCHONDRIA
_________________
10. VACUOLE
_________________
11. CYTOPLASM
_________________
12. LYSOSOME
_________________
13. CENTRIOLES
_________________
ANIMAL CELL
2. ____________
3. ____________
1. ____________
8. ____________
4. ____________
7. ____________
6. ____________
5. ____________
PLANT CELL
2.__________________
1.__________________
12.__________________
3.________________
4.______________
11.__________________
10.__________________
5.________________
9.__________________
8.__________________
7.__________________
6.__________________
Essential Questions
•
What are the structures of a typical eukaryotic cell, and what are their
functions?
•
What are the similarities and differences between plant and animal cells?
Structures and Organelles
Section 4
Section 4: Cellular Transport
Section 4: Cellular Transport
Cellular transport moves substances within the cell and moves
substances into and out of the cell.
Diffusion
•
Particles in solids, liquids, and gasses are in constant random motion.
•
Diffusion is the net movement of particles from an area of high
concentration to an area of lower concentration.
•
Additional energy is not required for diffusion because the particles are
already in motion.
Cellular Transport
Diffusion
•
When diffusion occurs over a long enough time, concentrations will become
uniform, and the solution will reach dynamic equilibrium.
•
Molecules continue to move, but the overall concentration remains the same.
Cellular Transport
Diffusion
Diffusion across the plasma membrane
•
•
•
Water can diffuse across the plasma membrane, but most other substances
cannot.
Facilitated diffusion uses transport proteins to move ions and small
molecules across the plasma membrane.
Diffusion and facilitated diffusion are types of passive transport – they require
no additional energy.
Cellular Transport
Osmosis: Diffusion of Water
How osmosis works
•
•
•
Osmosis is the diffusion of water across a selectively permeable membrane.
Water is the solvent in a cell and its environment
It will move across a membrane until the concentration of solute is the same
on both sides.
Cellular Transport
Video
• Diffusion
Video
• Osmosis
Video
• DIffusion VS. Osmosis
Diffusion and Osmosis
• There are three types of solutions.
•
isotonic – concentrations are equal
•
hypertonic – solution has more solutes than a cell, cell
shrivels and dies
• Hypotonic – solution has fewer solutes than a cell, cell
expands and may burst
hypertonic
hypotonic
Video
• Hypotonic, Hypertonic, & Isotonic
Active Transport
•
•
•
Sometimes substances must move from an area of lower concentration to an
area of higher concentration.
Movement of particles across the cell membrane, against the concentration
gradient, requires energy and is called active transport.
Occurs with the aid of carrier proteins, often called pumps
Cellular Transport
Active Transport
Na+/K+ ATPase pumps
•
•
Are found in the plasma membrane of animal cells
Maintain levels of sodium (Na+) and potassium (K+) inside/outside the cell
Cellular Transport
Active Transport
Na+/K+ ATPase pumps
•
•
•
Large molecules like sugar need to move against a concentration gradient
into the cell.
In a process called coupled transport, sugars can pair with Na+ ions and
enter the cell through a membrane protein called a coupled channel.
Allow sugars to enter through facilitated diffusion – saving energy
Cellular Transport
Transport of Large Particles
•
Endocytosis is the process by which a cell surrounds an object in the
outside environment in a portion of the plasma membrane.
•
Exocytosis is the excretion of materials at the plasma membrane.
Cellular Transport
Exocytosis
Video
• Endocytosis & Exocytosis
• Crash on transport
– https://www.youtube.com/watch?v=dPKvHrD1eS
4
Essential Questions
•
What are the processes of diffusion, facilitated diffusion, and active transport?
•
What is the effect of a hypotonic, hypertonic, or isotonic solution on a cell?
•
How do large particles enter and exit cells?
Cellular Transport