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The Cell
Function and structure of organelles.
Cell membrane and transportation.
Where did cells come from????
• Remember: cells are composed of the 4 families
of biochemicals. If we know how the biochemicals
were formed we can figure out how cells formed!
• Scientists Miller and Urey developed an
experiment to test the hypothesis that the
environment of early earth could produce
biochemicals.
• Biochemicals create Cells
Discovery of cells
• 1600’s Leeuwenhoek describes living cells by
using a simple light microscope.
• 1600’s Robert Hooke observes tiny hollow boxes
in cork. They reminded him of the small rooms at
the monastery called cells so he named them
CELLS.
• 1830’s Schleiden – all plants are made of cells
• 1830’s Schwann – all animals are made of cells.
• All of these discoveries combined to form the
CELL THEORY.
Cell Theory:
• All organisms are composed cells.
– Unicellular=one celled organisms.
– Multicellular=two celled organisms.
• The cell is the basic unit of organization of
organisms. (basic unit of life)
– cells—tissues—organs—systems—organism
• All cells come from preexisting cells.
Q. Where did the first cells come from?
A. Remember Miller – Urey?
Two types of cells:
Prokaryotic and Eukaryotic
Prokaryotes
• Do not have specialized membrane bound structures.
(organelles)
– NO NUCLEUS- DNA just floats around
– Cell membrane, cytoplasm, ribosomes
– Unicellular, Small, Simplistic
Ex. bacteria
Eukaryotes
• Contain specialized membrane bound structures.
(organelles)
– Keep DNA in a NUCLEUS
– Larger, More Advanced
Ex. Humans, trees
Endosymbiont Theory
• Theory that states how eukaryotes formed from prokaryotes.
• Large strong Prokaryotes engulfed smaller energy making Prokaryotes
and they started to live together and help each other and reproduce.
• These cells eventually became Eukaryotic cells.
Endosymbiont Theory
• https://www.youtube.com/watch?v=bBjD4A7R2xU
• Article at table.
Under “summary” on your notes sheet:
1. Describe the endosymbiont theory in your own words.
2. What evidence is used to support the endosymbiont
theory?
3. Define engulf. Draw a picture of bacteria engulfing
smaller prokaryotes.
Organelle Stations
• Station 1: Diagram and Chart (paste in notebook)
• Station 2: Analogy Word Sort and practice
questions (teacher initials and write in notebook)
• Station 3: Job Description for TWO organelles
(write in notebook)
Animal vs. Plant
Animal Cell
Important Similarities
Plant Cell
No Chloroplasts
Nucleus
Chloroplasts
No Cell Wall
Ribosomes
Cell Wall
Many Small Vacuoles
Cell Membrane
One Large Vacuole
Mitochondria
Microscopes
• Simple Light Microscopes-1 lens, very low magnification.
– Candles and/or mirrors were used for light.
• Compound Light Microscopes- use 2 lenses, maximum
magnification of 1,500x.
– Uses an electric light source
• Electron Microscope- uses beams of electrons to view
objects. Allows a more detailed view of smaller objects.
– Can magnify up to 500,000x !!!!!
Using the compound light microscope:
• PART II: Total Magnification
Look on one of the microscopes around the room to
fill in first two columns on the chart:
Magnification of Eyepiece and Magnification of Objective Lens
Calculate Total Magnification:
Eyepiece magnification x Objective magnification
• When focusing your microscope, always begin with
the low power lens! It has the largest field of view.
– Focus there first then increase the power and use the fine
adjustment.
PART III: Station A
– Place the ‘specimen’ on the glass slide. Put a small
drop of water on your slide and lower a cover slip down
at an angle slowly to push any air bubbles out.
– Use the materials at your station to make a wet mount
slide. Cut a lower case ‘e’ out of the newspaper to
create your wet mount slide. Continue with Part III
#2 and #3.
• View the prepared slides/pictures at all other
stations (B-E) and answer questions in your
notebook.
Plasma (Cell) Membrane
• Structure
– made of PHOSPHOLIPIDS and proteins
– A phospholipid consists of a polar phosphate head and
non-polar lipid tails
• Water is a polar molecule. Molecules like to be
near other molecules that are like themselves.
• Therefore, what part of the phospholipid would
be hydrophilic (water-loving) and what part
would be hydrophobic (water-fearing)?
All Cells Have a Membrane!!!!
• Phospholipid
• These help create a semipermeable membrane but
how do large molecules get into and out of the cell?
Don’t forget: All cells have a membrane!!!!
Fluid Mosaic Model
Add diagram to your
Cell Membrane Notes / 1.2
Functions:
• Selectively Permeable Boundary between
inside and outside of the cell (Maintains
Homeostasis).
• Communication between cells
• Identifies cells
• Keeps the cell whole and intact
Name on card:
1. Define osmosis.
2. True/False: Osmosis is a type of diffusion.
3. Does diffusion require energy from the
cell?
4. True/False: Facilitated diffusion requires a
membrane protein.
PASSIVE TRANSPORT
• Does not require ENERGY
• Particle movement occurs because of a
concentration gradient (difference in the amount
of a molecule)
• What happens if there is a concentration
gradient?
– Particles “spread out” until the concentration is equal.
– They move to maintain dynamic equilibrium (particles
still move but stay equally concentrated)
Types of Passive Transport
1. Diffusion: Particles naturally want to move
from an area of high concentration to low
concentration (WITH the gradient).
Types of Passive Transport
2. Facilitated Diffusion
– Movement of solids from high to low concentration.
JUST LIKE REGULAR DIFFUSION!
– If they are too big or not polar they need to be HELPED
by a protein.
Types of Passive Transport
3. Osmosis
– Diffusion of WATER across a cell membrane
– Still high to low/with the gradient/no energy required
Osmosis
Chart!
Types of Solutions
Salt Water
Distilled Water
Active Transport
– Requires energy to move molecules against the
concentration gradient.
– Molecules may need to be pumped in using membrane
proteins OR actually engulfed by the cell membrane.
• Examples:
– Endocytosis
– Exocytosis
– Protein Pumps
Transport Activities / 1.2
(move at your own pace)
• Activity #1: Transport Blocks
– Bags are on the front table
– Work with folks at your table
– Ask Mrs. Handest to bring the key and initial your paper.
• Activity #2: Halophytes (salt loving plants)
– Articles are on the back table.
– Make sure you get Honors or Academic.
• Activity #3: Coach Workbook
– Workbooks are on the side counter.
– Read Lesson 9 (pg.74)
– Add to your notes and answer the multiple choice questions.
Type of
Transport
Osmosis
Diffusion
Facilitated
Diffusion
*Active
Transport
Gradient?
High to low
Or
Low to high
Is energy
required?
What moves?
Solid or Water
or Both
Use a protein?