a view of a cell
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A View of a Cell. The Life Inside. The Cell Theory. Robert Hooke Studies of cork cells Nearly 200 years later… Three Main Ideas of the Cell Theory All organisms are composed of one or more cells The cell is the basic unit of organization of organisms All cells come from preexisting cells. - PowerPoint PPT PresentationTRANSCRIPT
The Cell Theory
Robert Hooke Studies of cork cells
Nearly 200 years later… Three Main Ideas of the Cell Theory
All organisms are composed of one or more cells
The cell is the basic unit of organization of organisms
All cells come from preexisting cells
Cell Types
Prokaryotes Mainly bacteria No nucleus-single strand DNA within the cell No membrane bound organelles Contain cell wall
Eukaryotes Plant and animal cells Can be unicellular organisms such as algae and
yeast Clearly defined nucleus and organelles
Cell (Plasma) Membrane
Definition Separates the cell and its contents from
the surrounding environmentFunction
“Gatekeeper”-controls what enters and leaves the cell
Cell (Plasma) Membrane
Structure Two phospholipid
layers (bilayer) Phosphate head-
hydrophilic Lipid tail-hydrophobic Protein molecules-1/2
or all of way through membrane
Carbohydrate chains
Cell Wall
Definition Cell structure found in plants Located outside of the plasma membrane
Function Rigid barrier that gives the cell support
and protectionStructure
Carbohydrate-cellulose
Nucleus
Definition “Brain” of the cell/control center
Function Contains chromosomes Nucleolus-makes ribosomes
Structure Surrounded by nuclear envelope
Cytoplasm
Definition Everything between the cell membrane
and the nucleusStructure
Cytosol-jellylike material, mostly water Organelles-“mini-organs” of the cell
Ribosomes
Function Manufactures enzymes and other
proteinsStructure
Organelle found in the nucleus, free in cytoplasm, or in the lining of the endoplasmic reticulum
Endoplasmic Reticulum (ER)
Function Transports and
processes materials through the cell
Structure Network of
membranes that connects nuclear membrane to cell membrane
“accordion folded” smooth and rough ER
Golgi Apparatus
Function Responsible for packaging and secreting
of cell products Further modifies proteins
Structure Flattened tubes
Vacuoles (animal cells)
Function Temporary storage of materials, such as
food, enzymes and other materials needed by the cell
Structure Many small vacuoles in animal cells
Lysosomes
Function Garbage collector” Digest excess or worn
out organelles, engulfed viruses and bacteria
Structure Small sacs inside
cytoplasm, can fuse with vacuoles and release enzymes
Mitochondria
Function “Powerhouse of the cell” Cellular respiration takes
place here to create energy for the cell
Structure Outer membrane and
highly folded inner membrane to allow for a large surface area in a small space
Plastids-Chloroplasts
Function Captures sunlight and coverts it into
food using CO2 and H2O (photosynthesis)
Structure Appear green because they contain
chlorophyll, a pigment that absorbs the energy in sunlight
Plastids-Vacuoles (plant)
Function Stores water,
proteins, sugar, etc Some store
pigments which give plants their color
Structure Large membrane
bound sac
Cilia and Flagella
Function Allow cell to move-important in
unicellular organismsStructure
Cilia-many short hair-like projections that move in a wave motion
Flagella-longer projections that use a whip-like motion
Cytoskeleton
Function A constantly changing structure that
provides a framework and support for the cell
Structure Composed of tiny rods and filaments,
within the cytoplasm