Transcript Bio 103 Cells Chp 4

http://learn.genetics.utah.edu/content/begin/cells/scale/
Cell Structure
Chapter 4
Cell Theory
Cells were discovered in 1665 by Robert
Hooke.
Early studies of cells were conducted by
- Mathias Schleiden (1838)
- Theodor Schwann (1839)
Schleiden and Schwann proposed the Cell
Theory.
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Cell Theory
Cell Theory
1. All organisms are composed of cells.
2. Cells are the smallest living things.
3. Cells arise only from pre-existing cells.
All cells today represent a continuous line of
descent from the first living cells.
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Cell Theory
Cell size is limited.
-As cell size increases, it takes longer for
material to diffuse from the cell membrane
to the interior of the cell.
Surface area-to-volume ratio: as a cell
increases in size, the volume increases
10x faster than the surface area
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Textbook pg. 60
Cell Theory
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Prokaryotic Cells
Prokaryotic cells lack a membrane-bound
nucleus.
Two types of prokaryotes:
-archaea
-bacteria
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Prokaryotic Cells
Prokaryotic cells possess
-DNA
-cytoplasm
-plasma (cell) membrane
-cell wall
-ribosomes
-no membrane-bound organelles
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Textbook pg. 63
Prokaryotic
Cells
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Prokaryotic Cells
Flagella
-present in some prokaryotic cells
-used for locomotion
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Textbook pg. 65
Prokaryotic Cells
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Eukaryotic Cells
Eukaryotic cells
-membrane-bound nucleus
-cellular functions occur within organelles
-cytoskeleton for support
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Textbook pg. 66
Eukaryotic
Cell
(animal)
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Textbook pg. 67
Eukaryotic
Cell (plant)
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Eukaryotic Cell Organelles
Nucleus
-stores the genetic material (DNA)
-surrounded by a nuclear envelope
composed of 2 phospholipid bilayers
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Textbook pg. 68
Eukaryotic Cell Nucleus
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Eukaryotic Cell Organelles
Ribosomes
-the site of protein synthesis in the cell
-composed of RNA and proteins
-free-floating or attached to E.R.
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Eukaryotic Cell Organelles
Rough endoplasmic reticulum (RER)
-attachment of ribosomes to the
membrane gives a rough appearance
-synthesis of proteins to be secreted, sent
to lysosomes or plasma membrane
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Eukaryotic Cell Organelles
Smooth endoplasmic reticulum (SER)
-synthesis of membrane lipids
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Textbook pg. 70
E.R.
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Eukaryotic Cell Organelles
Golgi apparatus
-flattened stacks of membranes
-packaging and distribution of materials to
different parts of the cell
-synthesis of cell wall components
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Textbook pg. 71
Protein transport:
Ribosome
ER
Golgi apparatus
Cell membrane
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Eukaryotic Cell Organelles
Lysosomes
-vesicles containing digestive enzymes
-digest food, destroy worn out organelles
and wastes
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Textbook pg. 72
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Eukaryotic Cell Organelles
Vacuoles
-membrane-bound structures
There are different types of vacuoles:
-central vacuole in plant cells (stores H2O)
-contractile vacuoles (rid waste)
-vacuoles for storage
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Eukaryotic Cell Organelles
Mitochondria
– Site of Cell Respiration
-contain enzymes for creating ATP (energy)
-contain their own DNA
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Textbook pg. 74
Mitochondria
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Eukaryotic Cell Organelles
Chloroplasts
-organelles present in green cells
-contain chlorophyll for photosynthesis
-double membrane
-chlorophyll contained in thylakoids/grana
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Textbook pg. 75
Chloroplasts
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Chromoplast
-organelles present in some Plant cells
-contain color Pigments (Orange - Yellow - Red)
- Fruits/Veggies – Fall Leaves
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Leucoplast
- Colorless organelles present in Plant cells
-Food storage – e.g. “Starch” in potato cells
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Cytoskeleton
Cytoskeleton
-network of protein fibers
-supports the shape of the cell
-keeps organelles in fixed locations
-helps move materials within the cell
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Textbook pg. 77
Cytoskeleton
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Extracellular Structures
Cell walls
-present surrounding the cells of plants,
fungi, Bacteria, and some protists
-plant and protist cell walls - cellulose
-fungal cell walls - chitin
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Textbook pg. 79 & 82
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