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18 Cards in this Set
- Front
- Back
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cell theory
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1. cells are fundamental units of life
2. all organisms composed of cells 3. all cells come from pre-existing cells |
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Why is cell size limited?
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SA:V ratio
as an object increases in volume, its surface area also increases, but not at the same rate |
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volume of a cell determines
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the amount of chemical activity it carries out per unit of time
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surface area of a cell determines
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the amount of substance that can enter/exit cell
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cell size
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less than 200 micrometers
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plasma membrane
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1. allows cells to maintain constant internal environment
2. acts as selectively permeable layer 3. important in communication and receiving signals 4. contains proteins for biding adjacent cells see book notes |
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all cells have
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DNA, PROTEIN, CARBOHYDRATES, RIBOSOMES
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prokaryotes
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exist as single cells but often found in clusters or chains; metabolically diverse, inhabit extreme environments
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prokaryotes
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contain plasma membrane, cytoplasm, nucleoid, ribosomes
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nucleoid
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region where DNA is located
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cytoplasm
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consists of cytosol (water and dissolved ions, small molecules, soluble macromolecules)
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ribosomes
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sites of protein synthesis
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special features
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pili, flagella, capsule, cells walls w/ peptidoglycan, cytoskeleton
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peripheral membrane proteins
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not embedded in bilayer; have polar/charged regions that interact with exposed parts of integral membrane proteins or with the polar heads of phospholipid molecules
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integral membrane proteins
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at least partly embedded in the phospholipid bilayer; contain both hydrophobic and hydrophilic regions
diff. polarity regions due to diff. amino acids |
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transmembrane protein
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integral protein that extends all the way through the phospholipid bilayer and protrudes on both sides
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carbohydrates
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serve as recognition sites
glycoprotein: carb att to protein glycolipid: carb att to lipid |
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tight junctions, desmosomes, gap junctions
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check book
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