Cells!
Chapter 7
What is a cell?
A cell is the basic unit
of life.
– The smallest living
thing.
– All living things are
made of cells
How did we find cells?
1600s began to use
microscopes to observe
living things
– Robert Hooke (1665)
Came up with the phrase
‘cell’
Built a microscope that
allowed him to look at very
tiny objects
Sliced a very thin piece of
cork and looked at it
through his microscope
Anton van Leeuwenhoek
(1674)
A fabric merchant
Looked at pond scum.
First to discover
unicellular organisms.
– He named them
“animacules” or “little
animals”.
Schleiden and Schwann
Matthias Schleiden (1838)
– A German scientist who
studied cells.
– Concluded that all plants are
made of cells
Theodor Schwann (1839)
*Concluded that all animals
are made of cells
Rudolph Virchow 1855
German doctor
Discovered that cells could not develop
from anything but other cells
- This idea completed the cell theory
Cell Theory
All living things are
composed of cells
Cells are the basic
units of structure and
function in living
things
New cells come from
existing cells
Chapter 7 Vocabulary
Pages 169-193
Please add the following
15 words to your
notes!
Cell
Cell Theory
Eukaryote
Prokaryote
Organelle
Cell Specialization
Tissue
Organ
Organ System
Diffusion
Osmosis
Equilibrium
Isotonic
Hypertonic
Hypotonic
Diversity of Cellular Life
Unicellular Organisms
– Made of a single cell
– Majority of life on
Earth
Multi-cellular
Organisms
– Made of many cells
– Depend on specialized
cells
Plant v. Animal Cells
Read through the articles about plant and animal
cells.
– From the reading list 5 differences between a plant and
animal cell.
On the plant cell color:
– Nucleolus, nucleus, chloroplast, vacuole, Rough ER,
smooth ER, cell wall, cytoplasm
On the animal cell color:
– Microfilaments, lysosome, ribosome, chromatin,
centrioles, microtubules, mitochondria, nuclear pores,
nuclear envelope, cell membrane, golgi complex
Organelle Flashcards
At your desk you will find all the materials
you need to set up your flashcards.
1. Please cut out:
11 Animal cells
8 Plant cells
2. Glue the cut out cells onto one side of a
flashcard. You should have 19 total
3. We will fill out the cards together as a class
when everyone has them put together.
Organelles
Specialized structure that performs
important functions in the eukaryotic cell
Golgi Apparatus (Complex)
– Products of the endoplasmic reticulum are
modified, stored or sent to other destinations
outside of cell
– Found in plant and animal cells
Cell Membrane
– Allows passage of oxygen, nutrients, and
wastes in and out of the cell
– Provides protection and support
– Found in plant and animal cells
Cytoplasm
– Portion of the cell outside the nucleus
– Helps to maintain cellular shape
– Found in plant and animal cells
Nuclear Envelope (membrane)
–
–
–
–
Surrounds nucleus, separates from cytoplasm
Allows material to move in and out of the nucleus
Provides support and protection for the nucleus
Found in plant and animal cells
Nuclear Pore
– Holes which allow material to move into or out
of the nucleus
– Found in plant and animal cells
Cell Wall
– Protects the plant cell, maintains its shape, prevents
excessive water intake
– Found only in plant cells
Endoplasmic Reticulum
– Where lipids are assembled; proteins and
other materials released from cell
– Smooth: lacks ribosomes; synthesizes lipids,
metabolizes carbohydrates, detoxification
– Rough: ribosomes attached to surface;
responsible for protein production; modifies
proteins
Found near nucleus
– Found in plant and animal cells
Mitochondria
– Site of cellular respiration (generates energy)
Convert chemical energy in food to a form cells
can use
– Found in plant and animal cells
Nucleus
– Contains all genes (genetic information),
chromatin, chromosomes and nucleolus
– Controls protein synthesis
– Found in plant and animal cells
Chloroplast
– Site of photosynthesis, convert solar energy
to chemical energy
– Found only in plant cells
Lysosome
– Digest macromolecules (lipids, proteins,
carbohydrates)
– Found only in animal cells
Ribosome
– Where proteins are made
– Found in plant and animal cells
Vacuole
– Stores materials (water, salts, proteins,
carbohydrates)
– Large size in plants (support)
– Plant cells and some animal cells
Nucleolus
– Inside nucleus
– Synthesizes components of ribosomes
Found in plant and animal cells
Chromatin
– In nucleus
– Made of DNA + Protein which gives us
chromosomes.
– Contain instructions for traits & characteristics
– Found in plant and animal cells
Centriole
– Help cell division –only 2 in cell
– Only found in animal cells.
Cytoskeleton
– Microtubule
maintain cell shape and help form the
spindle in cell division
– Microfilament
aid in movement and support
Levels of Organization
Individual Cells
Tissues
– Cells grouped together
– A group of similar cells that perform a particular
function
Organs
– Tissues work together
Organ Systems
– Group of organs that work together to perform a
specific function
Cell specialization: cells develop in
different ways to perform different tasks
– Animal cells: red blood cells (transport
oxygen), pancreas (protein production),
muscle cells (movement)
– Plant cells: guard cells (regulate exchange in
leaves)
Cell Boundaries
Cell Membrane
– Thin flexible barrier that surrounds a cell
– Regulates what enters and leaves the cell,
provides protection and support
Cell Wall
– Strong supporting layer around the cell
membrane
Cell Membrane
Made of two layers
(lipid bilayer)
– Gives cell membranes
a flexible structure that
forms a strong barrier
Contains protein and
carbohydrate
molecules
– Helps materials cross
the membrane
Cell Wall
Found outside the cell membrane (plants)
– Main function to provide support and
protection
Allows water, oxygen, carbon dioxide to
pass through
Made from carbohydrates and protein
Diffusion
Movement of dissolved molecules from
one side of cell membrane to another
Particles move from an area where they
are more concentrated to an area where
they are less concentrated
Substances diffuse across a membrane
without the cell using any energy
Facilitated Diffusion
Cell membrane has
certain channels that
make it easy for
certain molecules to
cross the membrane
– Will only occur if there
is a higher
concentration on one
side of the membrane
Active Transport
Small molecules and ions are carried across
membranes by proteins
– Requires energy, cells use majority of their energy for
transport
Endocytosis
– Process of taking material into the cell by folding of
cell membrane
Exocytosis
– Membrane of vacuole fuses with cell membrane
forcing contents out of cell
Osmosis
Diffusion of water across a selectively
permeable membrane
– Most membranes selectively permeable
some substances can pass through and others
cannot
Water passes easily across most membranes
Osmosis
How Osmosis works…
– Water will move across the membrane until
equilibrium is reached
Moves from high to low concentration
– Osmotic pressure: pressure on the hypertonic
side of a selectively permeable membrane
Solutions
Hypertonic: side of the membrane with
more molecules; “above strength”
Hypotonic: the side of the membrane with
less molecules; “below strength”
Isotonic: concentrations the same on both
sides of the membrane; “same strength”
Osmosis Lab
Tomorrow we will be completing a lab in
class that illustrates the process of
osmosis.
Today you should…
– Read through entire lab procedure
– Complete all pre-lab questions
– Write a hypothesis
– Identify manipulated, responding and control
variables.