BioExam4-7 - Bio Review 4-7 As cell size increases, the...

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Bio Review 4-7 As cell size increases, the volume increases faster than surface area. Prokaryotic Cells -Smallest, simplest known cells. Two Domains: 1. Eubacteria (True Bacteria) - start synthesizing each new polypeptide chain with a modified amino acid. 2. Archea - start chains with methionine. - A semi-rigid wall, around the plasma membrane helps impart shape to most species. - An array of protein filaments in the plasma membrane composes a “skeleton”. - Many prokaryotic cells have sticky polysaccharide coatings to help them stick to things. -DNA is concentrated in the nucleotide. Eukaryotic Cells -have an internal skeleton of proteins (cytoskeleton) -also have organelles, internal compartments. Advantages: 1. Organelle’s outer membrane encloses and sustains a microenvironment. 2. Membrane components selectively control the types and amounts of substances entering or leaving. -The organelles interact with each other. Components of all Cells 1. Plasma Membrane - a thin outermost membrane that maintains a cell as a distinct entity. 2. Nucleus or Nucleoid - a membrane bound sac containing DNA. 3. Cytoplasm - everything between the plasma membrane and the region of DNA. The Nucleus Two Functions 1. Isolates cell’s DNA from potentially damaging reactions in the cytoplasm. 2. Allows or restricts access to DNA’s hereditary information through controls over receptors, transport proteins and pores at its surface. - When Eukaryotic cells aren’t dividing, you can’t see individual DNA molecules. - A nuclear envelope encloses the semi fluid interior of the nucleus. Consists of two lipid bilayers studded with proteins
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BioExam4-7 - Bio Review 4-7 As cell size increases, the...

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