Transcript Cells - Davis School District

Cell Organelles
Eukaryotic Cells
Cells– (the smallest unit of life)- make up all living things, including
your own body.
Some organisms, like bacteria are unicellular – (one cell)-, but
Multicellular –(made of more than one cell)- organisms, like humans,
may consist of trillions of cells.
On the outside, plant and animals look very different, but if you
examine their cells you’ll see that they have many similarities.
Can we see cells?
In the mid 1600’s scientists Robert Hooke and
Anton Van Leeuwenhoek invented basic
microscopes and observed cells for the first
time.
Many structures in the cell are too small to see with
a light microscope.
• In the 1950s, scientists developed more powerful microscopes.
• A light microscope sends a beam of light through a specimen, or the
object you are studying.
• A more powerful microscope, called an electron microscope, passes a
beam of electrons through the specimen.
• Sending electrons through a cell allows us to see its smallest parts,
even the parts inside the cell (Figure below).
• Without electron microscopes, we would not know what the inside
of a cell looked like.
The outline of onion cells are
visible under a light microscope.
An electron microscope allows scientists to see
much more detail than a light microscope, as with
this sample of pollen.
Cell Theory
Between 1838 and 1855 Matthias Schleiden, Theodore Schwann,
and Rudolf Virchow developed the Cell Theory .
Cell theory states that:
1.All living things are composed of cells.
2.Cells are the basic unit of life.
3.All cells come from other cells.
As with other scientific theories, many hundreds, if not thousands,
of experiments support the cell theory. Since scientists developed
the theory, no evidence has ever been identified to contradict it.
Cell Parts
• Cells – the basic unit of
life
• Organelles - small
structures inside a cell
with specific functions.
Like a small city
What are the different parts of cells and what
does each do?
Cell Membrane/Plasma
Membrane
Cell
membrane
1. Function: Regulates materials entering and exiting the
cell.
2. Structure: Two layers of phospholipids, proteins
City limits
Cytoplasm
Cytoplasm
1.
Function: All cell contents that lie between the cell
membrane and the nucleus. (organelles + cytosol)
a. Cytosol = liquid portion/non-organelles.
2.
Structure: made up of fluid and organelles except for nucleus
Fruit in a Jello mold
Nucleus
Nucleus
1. Function: “Control Center.” Regulates DNA &
RNA actions.
2. Structure: membrane bound, contains DNA
Instructions to maintain stability in a crazy world
Nuclear Envelope
Nuclear
Envelope
1. Function: Regulates what enters or exits the
nucleus.
2. Structure: Double Layer of Lipids
Portals for instructions
Nucleolus
Nucleolus
1. Function: Produces RNA, which are used to
make all proteins.
2. Structure: Inside Nucleus, separate from
DNA
Brain of the cell
DNA – Deoxyribonucleic acid
DNA (chromatin)
1. Function: information on how to make
proteins.
a. Chromatin – unorganized DNA (normal state)
b. Chromosomes – organized DNA (present before
cell division
2. Structure: Made up of nucleotides, locked in
the nucleus
The Laws or City Code
Endoplasmic Reticulum
Rough ER
Smooth ER
1. Function: Transportation route for proteins.
a. Rough ER: has ribosomes
b. Smooth ER: no ribosomes
2. Structure: tubes and channels
Roads & Sidewalks
Ribosomes
Ribosomes
Free
Ribosomes
1. Function: Makes proteins.
2. Structure: small circular organelles
Protein factories
Vacuoles & Vesicles
Vesicles
1. Function: Storage for water, nutrients or
waste.
2. Structure: small membrane-bound organelle.
Packages
Lysosomes
Lysosomes
1. Function: packets of enzymes that break
down materials in a cell.
2. Structure: Small membrane-bound
organelles
The clean up crew
Mitochondria
Mitochondria
1. Function: Produce energy for the cell – site
of cellular respiration. “The Powerhouse”
2. Structure: Double membrane-bound, kidney
shaped.
Engine that runs on sugars
Golgi Apparatus
Golgi
Apparatus
1. Function: Packages, labels and ships
proteins out of the cell.
2. Structure: Pancake-shaped layered
organelle
UPS delivery
Cytoskeleton
Microfilaments
Microtubules
1. Function: Provide support and structure for
the cell.
a. Microfilaments
b. Microtubules
2. Structure: Tubules
Scaffolding for cells
Centrioles (Animals Only)
Centrioles
1. Function: microtubules that help divide the
cell during cell division.
• Structure: Tubules
Cilia & Flagella
Flagella
Flagella
Cilia
1. Function: provides movement for the cell or
objects moving by the cell.
2. Structure:
a. Flagella – 1 long fiber
b. Cilia – many short fibers
Analogy – Cars or bicycles.
Chloroplasts (Plants only)
Chloroplasts
1. Function: site of photosynthesis (converting
sun and CO2 into sugar).
2. Structure: Membrane bound organelles that
contain chlorophyll
Solar Panels for a leaf
Cell Wall (Plant cells only)
Cell Wall
1. Function: Provides support for the cell and
the plant.
2. Structure: Made of cellulose
Analogy – ground, rock wall
• Create an analogy (besides the city analogy) for the cell and its parts
• Possible ideas:
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Stadium
Cell
Parts Analogy
School
Country
Restaurant
House
Mall
Waterpark
Stadium Example:
• Cell membrane: wall of stadium, gates
• Cytoplasm: everything inside the stadium.
• Nucleus: the control room for the stadium.
• Etc…