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bio 112 study sheet.docx

bio 112 study sheet.docx - Unit 1 The Endosymbiont Theory...

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Unit 1: The Endosymbiont Theory: all cells are thought to have evolved from a universal ancestor cell (LUCA). Eukaryotes are thought to have evolved from one cell engulfing another cell (endosymbiont). Three important factors that can limit cell size are: Surface area to volume ratio related problems - with increasing cell size, the volume of the cell increases more than does the SA (Adequate cell membrane surface area relative to cytoplasmic volume). Problem Solving: inward folding or outward protrusion of the membrane to increase surface area. Diffusion related problems - relying on diffusion to move chemicals over large distances for proper function in a cell not practical if the cell is very large. Problem solving: too large cell= slow rates of diffusion. Cytoplasmic streaming in plants. (active protein- mediated movement and mixing of cystoplasm. Dilution - Adequate concentration of substances required for cellular processes. Problem solving: compartmentalization- of cellular functions in eukaryotic cells. (as a cell doubles in size, it takes 8x more molecules to maintain concentration.) Cell Theory: All organisms are made up of cells, cells are the fundamental unit of life and cells come from pre-existing cells. NO life without cells. We define cells as the smallest entity of life capable of: self-replication, storing and transmitting information (DNA-RNA-protein), maintaining a selectively permeable, separate internal environment, has the ability to harness and transform energy. Self-Replicating cell must: have a set of instructions (ex:DNA), gather materials/energy sources (proteins), make parts, transform energy, pass instructions to new replicates, have a mechanism to read instructions and have a container to keep everything together. Three domains of life: Bacteria and archaea (prokaryotes) and eukarya (eukaryotes) Macro molecules: Directionalities: Protein: first amino acid forming an amino terminus (N-terminus), where the amino group (-NH2) is free and not attached to another amino acid. The last amino acid on the other hand has a free carboxyl group (-COOH) and is referred to as carboxy terminus (C-terminus) Nucleic Acid : The 5 → 3 directionality of an acid. 5’ phosphate to a 3’ hydroxyl group. Carbohydrates: 4’ carbon to 1’ carbon. This molecule has different ends! Asymmetry (TEAPOT) Molecules with a molecular group with a polar bond are hydrophilic. Hydrophobic molecules = non-polar. They arrange themselves in order to minimize contact with water. Phospholipids: hydrophilic head and hydrophobic tail. Making them amphipathic. Non-covalent bonds : These bonds are weak, but if there are lots of them, they hold molecules together. Molecules that have complementary shapes and chemistry (charge and bond polarity) will have lots of non-covalent interactions to keep them together longer.
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