BMB 251 1st Edition Lecture 1Outline of Current Lecture I. HeredityII. Central Dogmaa. DNAb. RNAIII. Protein IV. Ribosome V. GeneVI. Endosymbiosis of mitochondria and chloroplastsVII. MutationsCurrent Lecture- Heredity: central definition of life; passing down genetic material from parent to offspring- most living organisms are single-celled- Central Dogma: powerful conceptual framework for molecular biologyo Replicationo Transcription o TranslationDNA (templated polymerization/transcription)RNA(translation)proteins- ALL living cells store their hereditary indo in the form of double-stranded DNA o DNA: long, unbranched paired polymer chains formed by Adenine(A), Thymine(T), Cytosine(C) and Guanine(G) monomerso Structure: each monomer in DNA (aka. Nucleotide) consists of a sugar (deoxyribose) with a phosphate group, and a base (A,T,G, or C).o Sugars are connected to one another via the phosphate group (which is why DNA is known as having a sugar-phosphate backbone)o Bonds between base pairs are weak (Hydrogen-bond) compared to sugar-phosphate linkso DNA strands can be pulled apart easily through templated polymerization: way by which DNA is copied or replicated- RNA: uses ribose as sugar with a phosphate group, and uses Uracil(U) for Thymine(T).o Single-strandedo Flexible backbone that can bend back and form weak bonds with itself)- Protein: long, unbrached polymer chains formed by monomers called amino acidso 20 types of amino acids compared to 4 monomers found in DNA/RNAThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o each amino acid has a similar core (allowing them to link easily to one another)and a side group to sidtinguish one anothero amino acid polymers bind with other molecules and act as enzymes, causing chemical reactions to occuro several codons correspond to the same amino acid; code is read by tRNA, in which one end attaches to a specific amino acid and the other bears an anticodon which can then recognize and pair to mRNA codon- Ribosome: formed of two main chains of rRNA and more than 50 proteins o site where translation occurs- Gene: segment of entire DNA that is transcribed into RNA and codes for a specific proteino cell adjusts rates of transcription and translation of a gene based on what is needed- ALL cells require phosphorylated nucleotide ATP as building block for synthesis of DNA and RNA- ALL cells are enclosed by a plasma membrane: selective barrier that takes in nutrients from environment and excretes cell wasteo Cells forming this are amphiphilic: consists of one part that is hydrophobic and another that is hydrophilic this then creates a bilayer, creating small closed vesicles Phospholipid bilayer makes a bounded surface, and proteins embedded in this sack control the transport of molecules in and out of the cello Composed of lipids and proteinso Bacteria have no internal membranes; animals have cell membranes, but no cell walls- What makes cell types different?o In any cell, most genes are turned off; a minority of genes are turned on, and only specific proteins are made for what this cell type needso Example: photoreceptor genes in eyes are NOT turned on in muscle cellso All cells have the same genotype, but the different phenotypes are due to which genes are actually turned on- Mitochondria and chloroplasts are thought to have endured endosymbiosis when becoming partof the eukaryotic cello Ancestral eukaryotic cell was thought to be a predator and took in an early bacterium. This bacterium then evolved as what we know today as mitochondria, explaining their double membrane and own circular set of DNAo These eukaryotic cells then went on later in time to consume a photosynthetic bacterium, which evolved into what we know as chloroplasts allowing some organisms to be capable of photosynthesis. This also explains why the chloroplasts have a double membrane and their own set of circular DNA as well- Evolution from earliest occurance to most recent:1. Archaea and Eubacteria Divergence2. Archaea and Eukaryotic Divergence3. Mitochondrial endosymbiosis4. Chloroplasts endosymbiosis- Mutations:o Intragenic mutation: occurs within gene; minor changeso Gene duplication: entire gene is duplicated and put somewhere else in the chromosome;larger segments are changedo DNA segment shuffling: where different genes along the chromosomes are accidentally switched in their positionso Horizontal gene transfer: bacteria can pick up genes along the way that they have come into contact with; this new info is then regenerated and replicated into their genetic info Does not occur in anything that experiences sexual reproduction because this parental offspring genetic info passing represents vertical gene
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