Molecular Basis of Genetics - Chapter 2 PDF

 How long is your DNA? Clustered Regularly Interspaced Short Palindromic Repeats SOURCE: https://www.sciencefocus.com/the-human-body/how-long-is-your-dna, https://www.nature.com/ MOLECULAR BASIS OF G...

 How long is your DNA? Clustered Regularly Interspaced Short Palindromic Repeats SOURCE: https://www.sciencefocus.com/the-human-body/how-long-is-your-dna, https://www.nature.com/ MOLECULAR BASIS OF GENETICS CHAPTER 2 Learning Objectives: Describe the structure and function of DNA. Understand the processes of DNA replication, gene expression, and regulation.  Molecular Level of Genetics SOURCE:https://giphy.com/  DNA as the Molecule of Heredity DNA (Deoxyribonucleic Acid) is the fundamental molecule of heredity. ○ carries the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms and many viruses. Gene is the functional unit of heredity. SOURCE:https://giphy.com/  The Flow of Genetic Information The Central Dogma explains how genetic information is transferred from DNA to RNA to proteins. Specifically, it outlines the processes of: Replication: DNA is copied to produce identical DNA molecules. Transcription: DNA is transcribed into messenger RNA (mRNA). Translation: mRNA is translated into a specific protein sequence. SOURCE: https://www.nature.com DNA Structure SOURCE: https://www.researchgate.net/ DNA Structure: Molecular Structure SOURCE: https://theory.labster.com/  DNA Structure: Secondary Structure Major groove of DNA is wider and more accessible, allowing many DNA-binding proteins, such as transcription factors, to recognize and bind to specific DNA sequences. Minor groove is narrower and less accessible, but it still facilitates some protein and small molecule interactions, though these are generally less sequence-specific. SOURCE: https://theory.labster.com/  DNA Structure: Tertiary and Quaternary Structure Chromatin Chromosome Chromatid Centromere Histone Nucleosome SOURCE: https://mysciencesquad.weebly.com/  DNA Structure: Tertiary and Quaternary Structure A. A long DNA strand containing many genes, organized for cell division. 1. Chromatin B B. DNA and proteins complex in the nucleus that organizes 2. Chromosome A and regulates genes. 3. Chromatid C C. One of the two identical halves of a duplicated 4. Centromere F chromosome, connected at the centromere. D. Proteins around which DNA is wrapped to form 5. Histone D nucleosomes, aiding in DNA organization and gene 6. Nucleosome E regulation. E. The basic unit of chromatin, consisting of DNA wrapped around histone proteins. F. The region where sister chromatids are joined and where spindle fibers attach during cell division. DNA Variations SOURCE: https://www.sciencelearn.org.nz/  DNA Replication SOURCE: https://www.mayoclinic.org/, LMNA gene https://www.nationalgeographic.com/ DNA Replication: Semiconservative SOURCE: https://www.youtube.com/  DNA Replication: Key Enzymes Enzyme Function DNA Helicase Unwinds and separates the double-stranded DNA by breaking hydrogen bonds between base pairs. DNA Polymerase Main enzyme for DNA synthesis, responsible for adding nucleotides during replication. Primase Synthesizes short RNA primers that provide a starting point for DNA polymerase to begin DNA synthesis. DNA Ligase Joins Okazaki fragments on the lagging strand to create a continuous DNA strand. Single-Stranded Stabilize single-stranded DNA and prevent it from re-annealing Binding Proteins or forming secondary structures. (SSBs) Topoisomerase Relieves the torsional strain caused by unwinding of the DNA by creating temporary cuts in the DNA strands. DNA Gyrase (in A type of topoisomerase that specifically alleviates supercoiling bacteria) in bacterial DNA. DNA Replication SOURCE: https://www.news-medical.net/ DNA Replication SOURCE: https://www.youtube.com/  Transcription: DNA to mRNA Initiation: Transcription begins when RNA polymerase binds to a specific region of the DNA called the promoter. This binding unwinds the DNA and initiates the synthesis of RNA. Elongation: As RNA polymerase moves along the DNA, it synthesizes a single strand of RNA by adding RNA nucleotides complementary to the DNA template. Termination: Transcription ends when RNA polymerase reaches a terminator sequence, releasing the newly synthesized mRNA.  RNA Processing Splicing: In eukaryotic cells, the primary mRNA transcript (pre- mRNA) contains introns (non-coding regions) and exons (coding regions). Splicing removes introns and joins exons together, creating a mature mRNA that can be translated into protein. Addition of 5' Cap and 3’ Poly-A Tail are added to the mRNA to protect it from degradation and help it exit the nucleus and be translated by the ribosome. Transcription: DNA to mRNA SOURCE: https://www.youtube.com/  Translation: mRNA to Protein mRNA (Messenger RNA): Carries the genetic code from DNA that specifies the sequence of amino acids in the protein. Ribosome: The molecular machine that facilitates the translation process. It has two subunits (large and small) that come together during translation. tRNA (Transfer RNA): Delivers the appropriate amino acids to the ribosome based on the codon sequence of the mRNA. Each tRNA has an anticodon region that pairs with a specific mRNA codon. Amino Acids: The building blocks of proteins. The sequence of amino acids in the polypeptide chain determines the protein's structure and function. Peptidyl Transferase: The enzyme activity within the ribosome that forms peptide bonds between amino acids. Translation: mRNA to Protein SOURCE: https://www.youtube.com/ Gene Regulation: Lac Operon SOURCE: https://microbenotes.com/ Gene Regulation: Epigenetics SOURCE: https://jackwestin.com/ Key Points DNA Structure and Function ○ DNA is the fundamental molecule of heredity, carrying genetic instructions for growth, development, functioning, and reproduction in all organisms. ○ The Central Dogma outlines the flow of genetic information from DNA to RNA to proteins, through the processes of replication, transcription, and translation. DNA Structure ○ DNA has primary, secondary, tertiary, and quaternary structures, involving chromatin, chromosomes, chromatids, centromeres, histones, and nucleosomes. DNA Replication ○ DNA replication is semiconservative, involving key enzymes such as DNA helicase, DNA polymerase, primase, DNA ligase, single- stranded binding proteins, and topoisomerase. Key Points Transcription and Translation ○ Transcription involves the conversion of DNA to mRNA, followed by RNA processing. ○ Translation is the process where mRNA is decoded into proteins, involving ribosomes, tRNA, and amino acids. Gene Regulation ○ Includes mechanisms like the Lac Operon and epigenetics, which control gene expression. Let’s Review! Molecule that carries genetic instructions ANSWER: DNA Let’s Review! Process by which DNA is copied ANSWER: REPLICATION Let’s Review! Enzyme that unwinds the DNA helix ANSWER: HELICASE Let’s Review! Process of converting DNA to mRNA ANSWER: TRANSCRIPTION Let’s Review! Region where sister chromatids are joined ANSWER: CENTROMERE Let’s Review! The protein components of nucleosomes ANSWER: HISTONES Let’s Review! Functional unit of heredity ANSWER: GENE Let’s Review! Process by which mRNA is decoded to produce a protein ANSWER: TRANSLATION Let’s Review! Enzyme that adds nucleotides during DNA synthesis ANSWER: DNA Polymerase Let’s Review! The enzyme within the ribosome that forms peptide bonds ANSWER: PEPTIDYL TRANSFERASE REFERENCES Andersson, H. C. (2021). Genomics: A revolution in health and disease discovery. Minneapolis, MN: Twenty-First Century Books™. Anomaly, J. (2020). Creating future people: The ethics of genetic enhancement. New York, NY: Routledge. Natividad, C. (2020). Principles and advances in human genetics: A primer on genetic disorders. [N.p.]: Delve Publishing. Hartl, D. L. (2020). Essential genetics and genomics. Burlington, MA: Jones & Bartlett Learning. Hartl, D. L. (2021). Essential genetics and genomics. Burlington, MA: Jones & Bartlett Learning. Hartl, D. L. (2020). Genetics: Analysis of genes and genomes (7th ed.). Burlington, MA: Jones & Bartlett Learning. 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