Download Cells

Cells
Cell Size
• We need a microscope to
see most cells.
Cork cells
Plant cell
Onion cell
Animal cell
Cell Theory
•All organisms are made of one or
more cells
•The cell is the basic unit of all living
things
•All cells come from existing cells
Parts of a Cell
• All cells have these 3 parts:
1.Cell Membrane: Layer that covers cell’s surface
and acts as a barrier between inside of cell and
its environment
2.Cytoplasm: The fluid inside a cell
3.DNA: The genetic material that carries
information needed to make new
cells/organisms
Copy this
chart in
your
composition
book. Work
with your
group to
complete
the chart.
Two Types of Cells
1.Prokaryotes
•Single-celled organisms
•Smaller
•Do NOT have a nucleus or organelles
•Ex: bacteria, archaea
2. Eukaryotes
•Can be single or multi-cellular
•Larger
•Have a nucleus and organelles
•Ex: animals, plants, fungi
Homeostasis
• Cells work together to maintain
homeostasis. Cells have different
functions.
• Homeostasis = stable environment in your
body; balance
• Your body maintains its homeostasis even
if outside conditions are changing.
Levels of Organization
• Tissue- group of similar cells working together
• Organ- two or more tissues that work together
• Organ system- two or more organs that work
together
• Organism- has multiple organ systems that
work together to maintain homeostasis in the
entire body
Least to Most Complex (5 Levels)
• Cell  Tissue  Organ  Organ System Organism
What surrounds a cell?
• Cell membraneprotective covering on all
cells: “gate of the cell”
• Cell wall- rigid structure
outside the cell
membrane that shapes
and protects the cell
• Only plant and fungus
cells have a cell wall.
Cytoskeleton
•Proteins in the cytoplasm
•Keeps the cell membrane
from collapsing
•Helps some cells move
Organelles
•Cells are made of different parts
(organelles).
•Each organelle has a different
function to help the cell.
•Located in the cytoplasm
Ribosomes
•Make proteins
•Small; not covered by a membrane
•In eukaryotic and prokaryotic cells
•Can float freely in cytoplasm or be
attached to something else
Nucleus
• Regulates and controls cell
activities
• Only in eukaryotic cells
• “Brain” of the cell
• “Control Center”
• Contains DNA
• Often has a dark area called
nucleolus
Nuclear Membrane
•Protects the nucleus
•Allows substances to pass in and
out of the nucleus
•“Gate of the nucleus”
Chromosomes
•where DNA is located in the nucleus
Mitochondria
• Produces energy by
breaking down sugar
• “Powerhouse of the
cell”
• A cell can have multiple
mitochondrion
Endoplasmic Reticulum (ER)
• Produce and
transport proteins
and lipids
• folded
• Smooth- no
ribosomes
• Rough- has
ribosomes
Golgi Complex/Apparatus
•Packages and distributes proteins
Vacuoles
•Store water and other materials
Lysosomes
•Digest and get
rid of waste
•Found mostly in
animal cells
Chloroplasts
•Contains chlorophyll,
which captures
energy from sunlight
and uses it to
produce food for the
cell
•Only in plant cells