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Cells
Structure & Function
Recap…
• Who coined the term “cell”? __________
Cells
• Smallest living unit
• Most are microscopic
– But not all!
Principles of Cell Theory
• All living things are made of cells
- They are the structure and function
of every organism
• Smallest living unit is the cell
• All cells arise from preexisting cells
(this principle discarded the idea of
spontaneous generation)
Cell Theory-Remember?
• The cell is the basic unit of structure &
function of all living things.
• All living things (organisms) are made of
cells.
• All cells come from pre-existing cells.
– So, this disproved Spontaneous Generation
Cell Types
• Prokaryotic
– Pro=No
• Eukaryotic
– You=
Eukaryote
Prokaryotic Cells
• First cell type on earth
• No membrane bound nucleus or organelles
• Single Celled!
– Bacteria
Eukaryotic Cells
• Nucleus bound by membrane
• Include fungi, protists, plant, and
animal cells
• Possess many organelles
Protozoan
Representative Animal Cell
Representative Plant Cell
Cell Membrane
• Barrier between inside and outside of cell
• Double layer of phospholipids + proteins
• Controls what enters and leaves cell
Cell Walls
• Found in plants & fungi
• Surrounds plasma (cell) membrane
• Made of non-living material (Cellulose)
Cytoplasm
• Jelly-like fluid containing organelles
- Cushions and protects organelles
• Continually streaming (moving)
Ribosome
• Free floating or attached
• Site of Protein Synthesis
– Reads RNA to make proteins
Nucleus
• “Brain” of cell
– Controls cell
activities
• Double membrane
• Contains
– Chromosomes
(DNA)
– Nucleolus
(to make ribosomes)
DNA
• Hereditary material
– Deoxyribonucleic Acid
• Normally found as
loose Chromatin
• When Cell needs to
divide, it condenses
into Chromosomes
– Chromosomes code
for Proteins
Nucleolus
• Inside the Nucleus
• Produces
ribosomes
Lysosomes
• Contain digestive enzymes
– “LYS”!
• Functions
– Breaks down old cell parts
– Digests invaders/waste
Vacuoles
• Membrane bound storage sacs
• Plants have LARGE ones... animals
are smaller
• Stores:
– Water
– Food
– Wastes
Mitochondria
• Breaks down fuel molecules (Glucose)
(cellular respiration)
• Makes ATP
- Cell’s energy molecule
• Active Cells have
many
- Muscle cells need
more energy than
skin cells
Chloroplasts
• Solar energy is captured and changed
here
• Found in plants
and green algae
– Site of Photosynthesis
– Turns inorganic H2O
and CO2 into an organic
food molecule
– Glucose is made!
• C6H12O6