Transcript Cells - South Johnston High School

Chapter 7:
Cell Structure
and Function
Created by Cori Walker and April Johnson © 2014
Microscopes
History
Accomplishment/
Contribution
basic magnifying glass
Date
Scientist
1400s
??
1590
Jansen Bro
Used 1st comd
microscope (2 lenses)
1670-80s
Anton van
Leeuwenhoek
-Used a simple light
microscope (1 lens)
-1st person to observe
living microorganisms
-Father of Microbiology
Microscope T Chart
Light Microscope
Electron Microscope
Light Microscopes
• uses light
• Types:
– 1. Simple (1 lens)
– 2. Compound (2 or more lenses)
•
•
1 ocular eyepiece
1 objective eyepiece
– 3. Stereomicroscope
•
Gives a 3-D image
• Fluorescent dyes combine with video camera to
produce 3-D image of cell processes (ex: cell
movement)
Microscopes…
• Magnification:
enlarges an object’s
image (use coarse adj to focus)
• Resolution: increases
visible detail
(Use fine adj to resolve)
–Separation of 2
points
Total Magnification
How do you calculate total magnification?
• ocular lens (eye piece) x objective lens(3 on revolving nosepiece)
– Examples: (10x) x (10x) = 100x
(10x) x (40x) = 400x
• Highest magnification with a light microscope is
1500x
Electron Microscopes
• uses beams of electrons
Types
• 1. Transmission electron
microscope (TEM)
– Transmits electrons
through a specimen up
to 200,000x
– Can study structures
within a cell
• 2. Scanning electron microscope (SEM)
– Sends electrons across the surface of a
specimen to make a 3-D image up to
100,000x
• 3. Scanning tunneling microscope (STM)
– Uses a metal probe to show the arrangement of
atoms (1,000,000x)
– Investigates atoms on the surface of a molecule
Which one should I use???
• Light Microscope:
– Advantages: can look at living specimens
– Disadvantages: limited in magnification and resolution
• Electron Microscope:
– Advantages: greater magnification and resolution
– Disadvantages: cannot view living things
Cell Discovery
Robert Hooke
• Studied cork (dead
plant cells from the
bark of a tree)
• First identified cells
(basic building blocks
of all living things)
Matthias Schleiden and
Theodor Schwann (1839)
• Schleiden plants
are made up of cells
• Schwann  animals
are made up of cells
Rudolf Virchow(1859)
• He concluded
that all cells are
made by existing
cells and had to
divide to form
new cells
Cell Theory
• 3 parts to the cell theory- applies to all living
organisms
– ALL organisms are composed of 1 or more
cells
– the CELL is the basic unit of structure and
function (organization) of all living things
– ALL cells come from pre-existing cells
Intro to cells double click to show video
•
•
•
•
•
Cells
Basic units of all living things
Surrounded by a plasma membrane
Have DNA (genetic information)
Have cytoplasm (outside the nucleus)
Contain organelles
– membrane-bound structures
– small, specialized structures
– each has a specific function that helps cells survive
• 2 groups of cells (video of the 2 types)
Cell Types Venn Diagram
Prokaryotes
Eukaryotes
Prokaryotes
• Smaller in size
• Do not have membrane-bound
organelles
• Have genetic material (DNA) but
not surrounded by a membrane
– Circular DNA floats in cytoplasm
• Unicellular organisms (bacteria)
• ****No nucleus or nuclear
membrane***
• have ribosomes, cytoplasm, and
cell membrane
Eukaryotes
• Contain membrane-bound organelles
• Multicellular organisms and some
unicellular (amoeba, algae, and yeast)
• Contain a nucleus
– Control center of the cell
– Contains a cell’s genetic material
– Responsible for cell division
– Manages all cellular functions
– Identified by Rudolf Virchow
• Protists, fungi, plants, and animals
• Bigger in size than prokaryotes
Bell Ringer:
1. Cell Theory:
a. All __________ are composed of cells.
b. Cells are the basic units of _______ and ________ in
all organisms.
c. New cells are produced from ____________.
2. The cells of eukaryotes have a _________; the cells of
__________ do not.
3. Eukaryotic cells also have a variety of specialized structure
called ______________.
What is so SPECIAL
about cells and their
organelles, anyway???
Levels of Organization
• Cells in multicellular organisms are specialized (cell specialization)
– Perform specific functions (separate roles)
– Ex: nerve cells  transmit impulses
– Ex: red blood cells  carry nutrients and gas throughout body
– Ex: pancreatic cell  produce insulin
– Ex: muscle cells  contract and relax to move parts of the body
Other examples of Cell
Specialization
• Flagella of bacterium
• Cilia of a protist (Paramecium)
Other examples of Cell
Specialization
• Cilia on a protist (Paramecium)
Other examples of Cell
Specialization
Guard cells in plant leaves
organism
organ systems
organization
organs
tissues
• Cells: basic units
cells
– Ex: red blood cells, nerve cells, pancreatic cells, skin cells
• Tissues: group of cells that perform a particular function
– Ex: muscle tissue, epithelial tissue
• Organs: group of tissues that work together
– Ex: heart, liver, stomach, brain, lungs
• Organ systems: group of organs that work together to
perform a specific function
– Ex: digestive, respiratory, nervous
Organelle DNA
• Chloroplasts and mitochondria have their own DNA
• Lynn Margulis
– Proposed the Endosymbiotic
Theory
• Suggests that eukaryotic cells evolved from prokaryotic
cells
• Suggests that mitochondria and chloroplasts came from
prokaryotic cells
– Formed a relationship with early eukaryotic cells
Stem Cells:
Promises and Problems
• Multicellular organisms begin as undifferentiated masses
of cells
– Variation in DNA expression and gene activity
determines cell specialization
• Every cell in the body developed from a single fertilized
cell
– Cells that form during the first few divisions can
potentially become any type of cell in the body
Process of Cell Differentiation
• Only specific parts of DNA are activated
– Determine the function and specialized structures of a cell
• All cells initially have the potential to become any type of cell
– Once differentiation occurs it cannot be reversed
• Most will become differentiated
– Ex: Bone cells
– Ex: Skin cells
– Ex: Blood vessel cells
• Will remain that way (cannot change
into another type of cell)
• Different parts of genetic instructions
are used in different types of cells
– Influenced by environment and cell’s
history
– Chemical signals may be released by
one cell to influence the
development and activity of another
cell
Stem Cells
•
•
•
•
•
•
Are not specialized cells
Continually reproduce themselves
Can develop into any number of specialized cells
Abundant in developing embryos (embryonic stem cells)
Present in organisms (adult stem cells)
Could potentially differentiate into specialized cells with the correct
lab culture conditions
3 Kinds of Stem Cells
• Totipotent stem cells
– Potential to form a whole organism
• Pluripotent stem cells
– Do not have potential to form a whole organism
• Multipotent stem cells
– Present in adults
– Eventually specialize further to become stem cells that
give rise to specific kinds of cells
Tour of the Cell
(15 min video)
Watch at home. Very good review
Components of the
Cell
Animal Cell vs. Plant Cell
Cell Wall
Function:
• Provides additional support and protection
• Allows H2O, O2, AND CO2 to pass
Type of Cell:
• Plant cells, fungal cells, and bacterial cells
Cell Wall
DRAW DIAGRAM
ON CHART
Unique
Characteristics:
• Rigid structure
• Inflexible
• Made of cellulose (in • Nickname: “support
plants)
center”
Plasma Membrane
Function:
• Allows substances to enter and leave a
cell
• Provides protection and support
Type of Cell:
• Plant and animal cells
Plasma Membrane
Unique Characteristics:
• Flexible boundary
DRAW DIAGRAM ON CHART
• Nickname: “the
bouncer”
Cytoplasm
Function:
• Clear gelatinous fluid inside a cell
• Holds organelles in place
Type of Cell:
• Plant and animal cells
Cytoplasm
Unique
Characteristics:
• Mostly made of
water
DRAW
DIAGRAM
ON CHART
• Nickname: “Celly
jelly”
Nucleus
Function:
• Controls cell processes
• Stores DNA and info to make proteins
Type of Cell:
• Plant and animal cells
Nucleus
Unique Characteristics:
• Has chromatin
– Strands of DNA
• Has nuclear envelope
• Nickname: “Control
Center” or “The
Boss”
Nuclear Envelope
Function:
• Surrounds nucleus
Type of Cell:
• Plant and animal cells
Nuclear Envelope
Unique Characteristics:
• Has pores that allow
materials to move in
and out of the
nucleus
No nickname
Nucleolus
Function:
• Makes ribosomes
Type of Cell:
• Plant and animal cells
Nucleolus
Unique
Characteristics:
• Within the nucleus
• Small and dense
• Nickname: “Ribosome
factory”
Ribosomes
Function:
• Where proteins are made
Type of Cell:
• Plant and animal cells
Ribosomes
Unique
Characteristics:
• Not bound by a
membrane
• Can be found in
cytoplasm or ER
• Nickname “Protein
factory”
Endoplasmic Reticulum
Function:
• Site for cellular respiration
• Rough: protein synthesis
• Smooth: make and store lipids
Type of Cell:
• Plant and animal cells
Endoplasmic Reticulum
Unique
Characteristics:
• Highly folded
membranes
• Internal
membrane system
• Nickname: “Transport
system”
Golgi Apparatus or Golgi Body
Function:
• Modifies, sorts, and packages proteins
Type of Cell:
• Plant and animal cells
Golgi Apparatus or Golgi Body
Unique
Characteristics:
• Flattened system
of tubular
membranes
• Nickname: “Gift
wrap” or “UPS”
Mitochondria
Function:
• Transforms energy into usable compounds by
breaking down food
• Cellular respiration
Type of Cell:
• Plant and animal cells
Mitochondria
Unique Characteristics:
• Has double membrane
• Folded inner
membrane 
increases surface area
• Occurs in varying #’s
• Nickname:
– Example: more in muscle
cells
“Powerhouse” or
“Mighty-chondria”
Vacuole
Function:
• Temporary storage of food, enzymes, wastes,
and other materials
Type of Cell:
• Plant and animal cells
Vacuole
Unique
Characteristics:
• Sac surrounded by
a membrane
• Bigger in plants
• Used for movement • Nickname: “Storage
in protozoans (protists;
closet”
contractile vacuole)
Lysosomes
Function:
• Digests excess or worn out organelles, food,
and bacteria
Type of Cell:
• Animal cells
Lysosomes
Unique Characteristics:
• Contains digestive
enzymes
• Nickname:
“Suicide/Homicide sac”
Cytoskeleton
Function:
• Support structure within cytoplasm
• Forms framework for the cell
Type of Cell:
• Plant and animal cells
Cytoskeleton
Unique
Characteristics:
• Composed of tiny
rods and filaments
• Nickname: “Body
shaper”
Cilia
Function:
• Aids in locomotion and feeding
Type of Cell:
• Animal cells
Cilia
Unique Characteristics:
• Pairs of microtubules
• Short, numerous
hairlike projections
• Nickname: “Hair”
Flagella
Function:
• Aids in locomotion and feeding
Type of Cell:
• Animal cells
Flagella
Unique
Characteristics:
• Pairs of
microtubules
• Longer projections
• Whiplike motion
• Nickname: “Tail”
Centrioles
Function:
• Function during cell division
Type of Cell:
• Animal cells
Centrioles
Unique
Characteristics:
• None
Nickname: none
Chloroplast
Function:
• Captures light energy and makes food
• Photosynthesis
Type of Cell:
• Plant cells only
Chloroplast
Unique Characteristics:
• Double membrane
• Plastids used for
storage
• Contain chlorophyll
– Green pigment
• Nickname: “Green
sugar shack”
Animal vs. Plant Cells Venn Diagram
Animal Cells
Plant Cells
Bell Ringer:
1. Place the following terms in order from smallest to largest level of
organization:
tissues, organ systems, organs, individual cells
2. The small dense region in the nucleus where the assembly of
ribosomes begins is called the ____.
a. nucleolus
b. nuclear envelope
c. chloroplast
d. vacuole
3. Which organelles can use energy from sunlight to create energy-rich
food molecules?
a. lysosomes
b. golgi apparatus
c. vacuoles
d. chloroplasts