BIO 1A03 Test 2 Questions with Answers 100% Verified

one gene-one enzyme hypothesis - each gene contains the information needed to make an enzyme What did George Beadle and Edward Tatum research? - Relationship between genes and proteins using the Neurospora Crassa One gene-one enzyme hypothosis (Neuroposa Example) - Neurospora can grow well on minimal medium (simple sugar, vitamins, inorganic salts), and therefore it must have enzymes produced by a certain gene that that transform these materials into amino acids and vitamins needed for growth. Metabolic pathway of Arginine - Precursor, Ornithine, Citrulline, Arginine Adrian Srb and Norman Horowitz - Radiation treated neurospora to create mutations in DNA code. They identified three mutants Medium supplemented with arginine - POSITIVE CONTROL (Growth) Non-supplemented medium - No Growth Exceptions to one gene one enzyme hypothesis - More than one protein can be produced from a single gene - post translational modification of proteins allows for the production of diverse proteins with specific roles What allows of the synthesis of a polypeptide chain during translation? - GTP-dependent factors Where does the majority of glucose absorption take place? - Microvilli cells of the small intestine How many amino acids are translated from the insulin gene - 110 amino acids How many chains is a functional insulin protein made of? - 2 (alpha and beta) Alpha chain - 21 amino acids Beta chain - 30 amino acids Preproinsulin - Protein cleaved to become proinsulin which is cleaved to become insulin How do you get from preproinsulin to proinsulin - Cleavage of the n-terminal signal sequence Proinsulin to insulin - Undergoes folding, goes from rough ER to Golgi, where cleavage of c-chain occurs List postranslational modifications - Cleavage, phosphorylation, methylation, acetylation Phosporylation - The adding of a phospate to a molecule using kinase enzyme Receptors - Proteins that receive and interpret messages from signalling molecules dimerization - pairing of two receptor-hormone complexes glucose transporters - proteins that assist in the transport of glucose molecules across cell membranes location of translation - cytoplasm Number of anticodon loops on tRNA - 3 Direction of Anticodon - 3' to 5' What is the point of attachment for the amino acid to the tRNA - terminal adenine aminoacyl-tRNA synthetase - An enzyme that joins each amino acid to the appropriate tRNA. Once bound to the active site, these enzymes can then catalyze the covalent attachment of a tRNA molecule to its amino acid using the energy from.... - ATP hydrolysis How many codons are there? - 64 How many tRNAs are there? - 45 tRNA wobble - Accurate base pairing is required only in the first 2 nucleotide positions of an mRNA codon, so codons differing in the 3rd "wobble" position may code for the same tRNA/aa (due to degeneracy of genetic code). eukaryotic initiation of translation - 1. Initiation complex forms near the 5' cap of mRNA 2. Scans DNA until AUG codon is found Prokaryotic Initiation of Translation - Initiation complexes form at ribosome binding sites called Shine-Dalgarno sequences (few bp upstream of AUG)