BioTest1Essay3

BioTest1Essay3 - -structural proteins - ie hair,...

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Essay 3 Toads and professors appear in many respects to be different. Biologists assert that toads and professors are a consequence of evolution and that both types of organisms developed from fertilized eggs following instructions carried in their genes. Explain the molecular basis for the theory of evolution, including the precise reasons why genotype (or nucleotide sequences in DNA) determines phenotype. 1. DNA = chain of nucleotides in an order or sequence of 4 different bases (ATGC) coupled to sugar and phosphate. 2. DNA sequence in groups of three bases--> RNA sequence 3. When proteins are synthesized groups of three RNA bases specify which amino acid is inserted in growing protein (process occurs at ribosome). 4. Based on the amino acid sequence of a protein it assumes a three dimensional shape. 5. Proteins are or make (as enzymes) all other functional molecules in cell and direct virtually all cell processes. 6. Protein functions determined by shape: Table 5.1
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Unformatted text preview: -structural proteins - ie hair, microtubules, microfilaments - cytoskeleton-antibodies - fit with and inactivate antigens-transporters in membranes - fit glucose or amino acids and carry them across plasma membrane into cell for use.-ion channels - for example let calcium come into cell or sodium and potassium in nerve action potential.-receptors neurotransmitters, growth factors, and hormone signals between cells must be recognized and signal transduced into cell.-contractile proteins - actin and myosin in muscle cells filamentous proteins in flagella. * transcription factors proteins that control which genes are expressed, when they are expressed and to what extent they are expressed. But, toads and professors are not simply protein, how do genes--> carbohydrates, lipids--> membranes, organelles, cells, tissues? ANSWER: enzymes - responsible for controlling the synthesis of everything else . (More info on enzymes on Essay 9)...
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This note was uploaded on 04/10/2008 for the course BIOL 103 taught by Professor Neale during the Fall '08 term at Georgetown.

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