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Chapter 1
1.2 Cells!
Cells, cells and more cells!
Living things are made up of cells!
Cells are the basic UNIT OF LIFE
Cells have different parts called
“structures” that have different jobs.
We will mostly study animal and plant cells
Cell Facts…
How many cells do we have in our body?
50 – 100 trillion (that’s 50 million million!)
That means that if you lined all
your cells up one after another
they would stretch around the Earth
47 times!!!
If you could count 1 cell each second, it would
take you 2600 years!!!
Cells
Plant and animal cells contain many of the same
structures but there are some differences.
Only PLANT cells have
- cells walls and
- chloroplasts.
Let’s look at the various cell structures….
Cell Structures
•
First let’s look at structures found in
both animal and plant cells…
1. Cell Membrane
- “the security guard”
- like skin for the cell
- it protects the cell
- regulates particles coming in and out
Cell Structures
2. The Cytoplasm
• “the jelly”
• inside of the cell
contains a jelly-like
substance
• supports all the
structures in the
cell
• also contains water
that the cell needs!
Like Jello!
Cell Structures
Smaller structures in the cell that have a
specific function are called “organelles”
3. The Nucleus
• “the brain”
• controls the cell’s activities
• the DNA for the cell is also
found inside the nucleus
Cell Structures
4. Mitochondria
(singular = Mitochondrion)
• The “energy maker”
• Makes energy so the cell
can carry out its activities
• Uses a process called
cellular respiration to make
energy
Cellular Respiration
How cellular respiration works:
We take in food (glucose) and our cells
use this glucose to make ENERGY!
Glucose + Oxygen  ENERGY + CO2 + H2O
Cell Structures
Protein plays many important roles in
living things…
What is protein?
o It’s an essential nutrient that WE need to
build muscles, hair, skin, and nails.
o CELLS need it to build various structures
and carry out specific functions
Cell Structures
Our cells have
organelles in charge
of making, moving
and storing protein…
5. Ribosomes
•little “protein factories”
•they assemble the proteins
•small round structures
•found in the cytoplasm and on the ER
Cell Structures
6. Endoplasmic Reticulum
• Looks like a fan or an
(ER)
accordian
• Network of channels
covered by a
membrane
• Proteins pass
through the ER
after they are
assembled by the
ribosomes
ER is always close to the nucleus!
Cell Structures
7. Golgi Body
• “like Fed-EX”
• Proteins go through
the ER to the Golgi
body
• Here the proteins are
sorted, packed up in
vesicles and sent
around (or out of) the
cell
Cell Structures
8. Vacuoles
• “storage sacs”
• Temporarily store
– Waste
– Water
– Nutrients
Large plant cell vacuole
Vacuoles in Plant & Animal Cells
Animals cells…
Have several small
vacuoles
Plant cells…
Have one large
vacuole (usually)
Cell Structures
9. Lysosomes
• “recycling depots”
• Recycle organelles that have worn-out
• Have digestive enzymes that break
down food, waste and worn-out cell
parts
Cell Structures…Plants Only!
10. Cell Wall
• “the city wall”
• Surrounds the cell membrane
• Tough and rigid
• Gives the cell a box-like shape
• Main jobs:
– Protects the cell
– Gives support
Cell Structures…Plants Only!
11. Chloroplasts
• “food makers”
• Look like stacked green
pancakes
• Trap the sun’s energy
• Make oxygen and food for
plant in a process called
“photosynthesis”
Photosynthesis
Energy + CO2 + H2O  Food + O2
This is a very important process…
Plants take in carbon dioxide that we
exhale and give us oxygen to
breathe!
RECAP!
Important differences
between plant and
animal cells:
1. Plant cells have CELL WALLS
2. Plant cells have CHLOROPLASTS
3. Plant cells have much larger VACUOLES