MIdterm 4

MIdterm 4 - Lecture 1 Introduction to Central Dogma of...

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Lecture 1 Introduction to Central Dogma of Life: Genes are lengths of chromosomal DNA that code for the synthesis of proteins. I. DNA Replication a. Replication is Semiconservative i. Each new DNA double helix conserves half of the original b. Replication steps i. Helicase binds the origin and separates strands ii. Binding proteins keep strands apart iii. Primase makes a short stretch of RNA on the DNA template iv. DNA polymerase adds DNA nucleotides to the RNA primar v. DNA polymerase proofreading activity checks and replaces incorrect bases vi. Continuous strand synthesis continues in a 5’ to 3’ direction vii. Discontinuous synthesis produces Okazaki fragments on the 5’ to 3’ template viii. Enzymes remove RNA primers. Ligase seals sugar-phosphate backbone II. DNA Structure a. Gene i. A section of DNA molecule whose sequence of building blocks specifies the sequence of amino acids in a particular protein b. Nucleotide i. A single building block of DNA ii. Consists of 1. deoxyribose sugar 2. phosphate group 3. nitrogenous base iii. Purines 1. Adenine and Guanine 2. two-ring structure iv. pyrimidines 1. Cytosine and Thymine 2. single-ring structure c. Antiparallelism i. Opposing orientation of nucleotide chains in a DNA molecule ii. One side moves from 5’ to 3’ the other moves from 3’ to 5’ iii. Double helix d. Complementary base pairs i. A pairs with T ii. C pairs with G e. DNA binding proteins i. Double helix wrapped around 8 histones grouped together called nucleosomes
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Nucleosomes together form chromatin, chromatin wraps around scaffold protein Lecture 2 Protein Synthesis, Genetic Code I. Transcription i. The copying of a gene into an RNA molecule that is complementary to one strand of the DNA double helix and then the molecule is taken outside the nucleus b. RNA Structure and Type i. RNA 1. the bridge between gene and protein 2. single stranded 3. adenine, uracil , cytosine and guanine 4. the sugar ribose instead of deoxyribose 5. controls how DNA information is used ii. types of RNA 1. messenger RNA a. encodes amino acid sequence b. specifies a particular protein c. 3 bases in a row form a codon that specifies a certain amino acid 2. Ribosomal RNA a. Associates with proteins to form ribosomes, which structurally support and catalyze protein synthesis 3. Transfer RNA a. Transports specific amino acids to the ribosome for protein synthesis c. Steps of Transcription i. Initiation 1. TATA binding protein is attracted to a TATA box 2. transcription factors are attracted to the binding proteins 3. RNA polymerase binds on the last transcription factor just before the wanted gene expression and begins making RNA ii. Transcription Elongation 1. enzymes unwind the DNA double helix 2. RNA nucleotides bond with complimentary bases on the DNA template strand 3. RNA polymerase adds the RNA nucleotides in the sequence specified along the DNA strand 3’ to 5’ 4. terminator sequence in the DNA indicates where the RNA encoding region ends
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MIdterm 4 - Lecture 1 Introduction to Central Dogma of...

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