cell structure & function - science in the...
TRANSCRIPT
http://koning.ecsu.ctstateu.edu/cell/cell.html
A cell is the smallest unit
that is capable of
performing life functions.
Amoeba Proteus
Plant Stem
Red Blood Cell
Nerve Cell
Bacteria
•Prokaryotic
•Eukaryotic
Simplest type of cell
No nucleus or membrane-bound organelles
One-celled organisms (unicellular); bacteria
Bacteria have a single, circular chromosome
http://library.thinkquest.org/C004535/prokaryotic_cells.html
Center contains the DNA
Surrounded by cell membrane and cell wall
Contains ribosomes (no membrane) in the cytoplasm to make proteins
http://library.thinkquest.org/C004535/prokaryotic_cells.html
Contain organelles surrounded by membranes (including
a nucleus)
Most living organisms (protists, fungi, plants, and animals)
Some are unicellular, but most are multicellular
Most complex type of cell
Plant Animal
http://library.thinkquest.org/C004535/eukaryotic_cells.html
Contains 3 basic cell structures
Nucleus
Cell membrane
Cytoplasm with membrane-bound organelles
Plant Animal
http://library.thinkquest.org/C004535/eukaryotic_cells.html
http://waynesword.palomar.edu/images/plant3.gif
Organelles
Found in bacteria,
fungus, and plant
cells only! (NOT
animal cells)
Made of cellulose
Supports & protects
cells
Found outside the
cell membrane
Composed of a double
layer of phospholipids
and proteins
Surrounds ALL cells
Outer membrane if
there is no cell wall
Controls movement in
and out of the cell
(semi-permeable) http://library.thinkquest.org/12413/structures.html
Outside of cell
Inside of cell (cytoplasm)
Cell membrane
Proteins
Protein channel Lipid bilayer
Gel-like mixture where
the organelles are
found (it is in ALL cells)
80% water
Surrounded by the cell
membrane
Protects cell
organelles
Surrounds nucleus of eukaryotic cells
Made of two layers
Openings (pores) allow material to enter and leave nucleus
Directs cell activities
in eukaryotic cells
(“control center”)
Contains genetic
material (DNA)
“Powerhouse” of the cell
Found in ALL eukaryotic cells
Produces energy (ATP) for the cell through cellular respiration by breaking down fats & carbohydrates
http://library.thinkquest.org/12413/structures.html
Makes proteins
Each cell contains
thousands. Found in
ALL cell types
Found on rough ER
& also floating
throughout the cytoplasm. http://library.thinkquest.org/12413/structures.html
Site of protein synthesis
(made by the ribosomes
on the ER surface)
Rough = ribosomes
Sends proteins and other
materials through the
interior of the rough ER
to the Golgi Body.
Has no surface ribosomes
(smooth)
Makes steroids and ions, &
destroys toxins/poisons
Sends protein, steroids,
ions, and other materials to
the Golgi Body to be USED
in the cell
Found in eukaryotic
cells
Modifies, sorts, &
packages molecules
from ER for storage
OR transport out of the
cell
Distributes materials to
other parts of the cell
via vesicles (sacs).
http://library.thinkquest.org/12413/structures.html
Merges with vacuoles to
digest unwanted materials
and transports them to the
cell membrane for removal.
Contains digestive enzymes
to break down old cell parts
Cell breaks down if
lysosome
explodes (“suicide sac”)
Sac containing
water that helps
maintain the
shape of the cell.
Stores water,
food/nutrients and
wastes
http://library.thinkquest.org/12413/structures.html
Plant cells have a LARGE central vacuole
Needed to regulate turgor pressure
Allows the plant to remain rigid (stiff)
Without enough water, the plant will wilt (droop)
http://library.thinkquest.org/12413/structures.html
Vacuole
Found ONLY in plant cells
Produces a green
pigment called chlorophyll
which absorbs light
energy
Site of photosynthesis,
which uses the energy
from the sun to produce
food (sugar) for the cell
along with oxygen
Chloroplasts inside the cells
Plant versus animal
cells
Both have a cell membrane surrounding the cell
Both have a nucleus
Both contain mitochondria
Animal Cells No cell wall
Usually round shape
Nucleus towards center
Many smaller vacuoles
No chloroplasts
Plant cells Cell wall
Usually rectangular
Nucleus near cell wall
Large central vacuole
Chloroplasts
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How can you tell?
Is this a plant cell or animal cell?
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Contains organelles; a large vacuole, a cell wall and chloroplasts!
Chloroplast
Vacuole
Cell Wall
34
How can you tell?
Is this a Prokaryotic or Eukaryotic cell?
35
Contains organelles; a central nucleus, and no cell wall or chloroplasts!