Central Dogma Of Molecular Biology PDF

CENTRAL DOGMA GENES - nucleotide sequences that carry of molecular biology specific instructions for the cell - The smallest hereditary unit that Central dogma of molecular...

CENTRAL DOGMA GENES - nucleotide sequences that carry of molecular biology specific instructions for the cell - The smallest hereditary unit that Central dogma of molecular biology can be passed from parent to - Process of making copies of offspring genetic information - Process of conversion into protein Note: number and structure of gene products DEPENDS per species - DNA can be replicated and converted to RNA and then into Gene expression - process of converting proteins in this information into genes into a functional protein product DNA: stored in the nucleus - Replicates after each cell division Simple organisms - more segments/genes DNA gets transcribed into RNA, - Prokaryotic RNA gets translated into protein - Es: bacteria, archaea - Tightly packed DNA with genes DNA - goes through transcription RNA- goes through Translation Note: prokaryotes or a simple organisms because there only a little can fit inside Proteins - is the final product them unlike humans - These are enzymes, antibodies Note: Eukaryotes like human have more Reverse transcription non coding material known as “introns” - Is an exception which are the gray area - Only for viruses, they process RNA to become DNA More complex organisms = more - Only exhibited by retroviruses non-coding regions Retroviruses example: Human Organism: Chromosomal segment immunodeficiency virus (HIV) Bacteria: 20kb Yeast: 20kb Drosophila: 200kb Note: All HUMAN cells , even a part of Human: 200kb human cell (like hand cells, thigh cells, etc.) are eukaryotes PROKARYOTES - the entire gene codes for a protein or molecule Musni, Pauleen Frances M. I BSN I biochem reviewer EUKARYOTES - the gene consists of Mini- satellites & Microsatellites coding and non-coding regions - Shorter repeats INNON, EXCO - Repeated in the entire genome INTRONS - non-coding region - Used to monitor mutations - Nascent mRNA - undergo RNA implicated diseases like Cancer splicing - Remains inside the nucleus Additional: - Note part of the mature RNA Genome - entirety of genetic material - removed during transcription Gene - specific segment EXONS- coding region DNA REPLICATION - The one translate in for protein synthesis REPLICATION - process by which DNA - Mature RNA/ expressed/ exits the makes copies of itself nucleus - Occurs in semi-conservative - Joined together in transcription to manner form FINAL mRNA product through - Takes place in NUCLEUS of RNA Splicing Eukaryotic cells, and CYTOPLASM of prokaryotic cells SPLICING - process of intron removal and exon joining Semi- conservative - one strand of the parent DNA becomes the template for Mature RNA only has exons the daughter strands - When two strands separate they Note: Only 3% of human DNA codes for become the template proteins Other models: Conservative model & Additional: Dispersive model Maintenance of chromosomal structure: ORIGIN OF REPLICATION - Replication starts here Disease susceptibility Where the double stranded DNA Gene expression (dsDNA) begins to open to form the SATELLITES - highly repetitive “REPLICATION BUBBLE” - A chromosome can have multiple - Is a Non coding DNA sequence origins - Provide structural stability to - Eukar: multiple origin, Prokar: one chromosomes origin Has 2 kind: mini-satellites, microsatellites Musni, Pauleen Frances M. I BSN I biochem reviewer REPLICATION FORK - where replication Additional: oligonucleotide - actively occurs polynucleotide molecules that contain small number of nucleotides REPLISOME - assembly of proteins that facilitate DNA replication at the CLAMP PROTEIN replication fork - Keeps DNA polymerase in place - All proteins, enzymes, molecules DNA POLYMERASE (DNA Pol) COMPONENTS OF REPLISOME: - Synthesizes new DNA strand GHP-CPL-SSB - Can only add to existing - DNA Gyrase/ Topoisomerase nucleotide chain and cannot - Helicase initiate replication - Primase - Clamp protein DNA LIGASE - DNA Polymerase (DNA Pol) - Joins OKAZAKI FRAGMENTS in the - DNA Ligase lagging strand - Single- stranded Binding Proteins Okazaki fragments - short DNA regions (SSB) that is replicated DNA GYRASE/ TOPOISOMERASE SINGLE-STRANDED BINDING PROTEINS - prevents DNA from supercoiling (SSB) - Prevents by introducing breaks to - Stabilizes and protects the single relieve stress stranded region of DNA during HELICASE replication - breaks the H-bonds between base pairs to unzip the dsDNA LEADING VS LAGGING STRANDS - Separate bonds Where does replication occur? PRIMASE - It occurs on both strands of the - Synthesize primers for DNA DNA on both sides of DNA polymerase replication bubble - PRIMER - initiates replication The newly synthesized DNA is called Note: without the primer made by the either leading strand or lagging strand primase DNA polymerase cannot start replication Leading strand - 3 - Synthesized using the template Note: DNA polymerase follow the primer 3’to 5 towards the replication fork - Replication is continuous Musni, Pauleen Frances M. I BSN I biochem reviewer Lagging strand - 5 - Synthesized using template 5’to 3’ What should happen for transcription to towards replication fork take place? - Replication is discontinuous - DNA must be unwind and - Forms Okazaki fragments that separated by proteins are joined together at the end Transcription bubble - opening in the Why does leading and lagging strand double helix where transcription takes happen? place - Because of the DNA polymerase - DNA polymerase can only Separated DNA strands: synthesize 5’to 3 direction - Template strand - Coding strand Lagging strand - goes against fork movement, discontinuos, 5’to 3’’ Template Strand - DNA strand that is transcribed Leading strand - goes with the fork - Also called the negative strand or movement, continuous, 3’to 5’ antisense strand Coding strand - DNA strand that is NOT DNA REPLICATION IN BRIEF transcribe 1. Opening of the DNA - Called the positive strand or sense superstructure strand 2. DNA relaxation via DNA gyrase 3. DNA unwinding via helicase RNA POLYMERASE 4. Primer synthesis bia primase - Enzyme responsible for RNA 5. DNA elongation via DNA synthesis polymerase - Reads template from 3’ to 5 6. DNA ligation via DNA ligase - Synthesizes RNA from 5’ to 3’ - RNAPol II is used for mRNA RNA TRANSCRIPTION - Cannot recognize genes on their own Transcription - process through which - Need help of transcription factors genetic information from DNA is converted into mRNA in the nucleus TRANSCRIPTION UNIT - First step of gene expression - Protein-gene - Can be divided into: Regulatory Transcript - resulting mRNA molecule regions & structural gene Musni, Pauleen Frances M. I BSN I biochem reviewer Promoter region 2. Elongation - addition of the - Located upstream, (before the appropriate complementary nucleotide to transcription site) the growing transcript - Identifies which DNA strand is the template 3. Termination - release of the complete - Initial binding site of transcription but non- functional transcript call the factors pre-mRNA upon transcription of the - call RNA polymerase for binding terminator region - Note: transcription factors - give signal to 4. Post-transcriptional modifications - where RNA polymerase binds processing of pre-mRNA into functional mature mRNA PROMOTER REGION - Consensus Sequence - Initiation signal Consensus sequence - identifies the precise nucleotide at which transcription begins - Where initial transcription factors binds - EX: TATA box Initial signal - gives RNA pol the signal when to start transcription TERMINATION REGION - Nucleotides at the end of a gene that signals RNA polymerase to end transcription - - ends transcription process RNA TRANSCRIPTION IN BRIEF 1. Initiation - binding of transcription and RNA polymerase to the promoter region Musni, Pauleen Frances M. I BSN I biochem reviewer