2b - LESSON Cytology (PRINT).notebook
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EukaryoteProkaryote
The Cellular Level of Organization
Cell Theory- one or more cells- basic living unit of structure and
function- all cells come from other cells
Cell (basic unit of life)
- "before a nucleus" (nucleoid & plasmid)- no membrane bound organelles- cell wall, capsule, pili- e.g. bacteria & archae
- "true nucleus"- has membrane bound organelles- e.g. animals & plants
2b - LESSON Cytology (PRINT).notebook
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Cell Size
Scale of the universe: htwins.net/scale2/
Cells must remain SMALL to keep an ideal ratio of surface area and volume (as volume increases, proportionate surface area decreases).
Adequate surface area is vital as it allows substances, such as glucose and oxygen, to diffuse in and wastes, such as carbon dioxide, to diffuse out.
Sooooo... why are some cells, like a chicken egg, so big?Because it is not actively metabolizing, just dividing without growth.
Fig 3.2 (pg.67)
2b - LESSON Cytology (PRINT).notebook
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Cell Structures
Plasma membrane- Phospholipid bilayer- Separates cell from surroundings, regulates passage in and out of cell
Mitochondria- "Power house"- Performs cellular respiration to create ATP
Vesicles- Tiny membranous sacs which store substances
Cytoplasm- Semifluid medium - Composed of water, salts, and dissolved organic molecules
Nucleus Control center of the cell, stores genetic info, synthesis of DNA & RNA
2b - LESSON Cytology (PRINT).notebook
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September 23, 2016
Cell Structures
Smooth ER- Synthesis of phospholipids- Specialized functions (testosterone in testes, detoxifying in liver)
Golgi Apparatus- Modifies lipids and proteins from the ER, sorts them and packages them into secretory vesicles- Also produces lysosomes.
Ribosomes- Protein synthesis, made of two subunits
Rough Endoplasmic Reticulum (ER)- Folding, modification & transport of proteins
Lysosome Contain hydrolytic digestive enzymes to breakdown materials within the cell
Centriole 9+0 patternMicrotubule organizing center for the cell (assembly & disassembly)
2b - LESSON Cytology (PRINT).notebook
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Cell Structures ChloroplastSite of photosynthesis: turns energy from sun into carbohydrates
Cell Wall- Contains cellulose- Provides support & protection
Vacuole - Large one in plants cells for support- Numerous smaller ones in animal cells
Cytoskeleton- Keeps cell shape- Allows movement of cell and its organelles- assembles and disassembles as needed
2b - LESSON Cytology (PRINT).notebook
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September 23, 2016
Cytoskeleton Specifics
Actin Filament- Form a dense web under cell membrane- Interact with myosin (motor molecule)
Intermediate Filaments- Fibrous and ropelike- Perform a structural role
Microtubules- Hollow cylinders- Radiate from centrosome- Maintains cell shape & act as tracks for organelles- Interact with kinesin & dynein