Biosci 0815 1st Edition Lecture 11 Outline of Last Lecture I. Development Stepsa. Cleavageb. Gastrulationc. OrganogenesisII. Egg and SpermIII. Inside the EggIV. In Vitro FertilizationV. CleavageVI. Differences between mitosis and meiosisOutline of Current Lecture I. Replication and Transcriptiona. How is replication accomplished?II. Types of RNAa. mRNAb. tRNAc. rRNAIII. Transcription.IV. Does DNA only code for proteins?V. Parts of a GeneVI. PolymeraseVII. TranslationVIII. Review of ProteinsIX. Steps of Translation:a. Initiationb. Elongationc. TerminationX. ProteinsThese 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.Current Lecture- Replication, transcription and translation- “The Central Dogma”o In Biology DNA makes RNA makes Proteins. This is done in three steps: replication, transcription, and translation. - Replication and transcription are in the nucleus- Replication:o Transcription is the process of copying a DNA nucleotide sequence into an RNA nucleotide sequence. o It is called transcription because it is copied within the same language of nucleic acids and nucleotides. o Like DNA, RNA is composed of nucleotides (sugar, phosphate group and nitrogen containing base). The nucleotides are monomers which link together to form polymers (this is nucleic acid).o Here is a review of the differences between DNA and RNA. DNA is double stranded, RNA is generally single stranded Deoxyribose is the sugar in DNA (no OH on the 2’ carbon) and plain ribose is the sugar (an OH group on the 2’) The bases differ, DNA has Thymine, and it is substituted for uracil in RNA.o How is replication accomplished? Complementary base pairing. This is what maintains the order of the nucleotides.  DNA nucleotide A matches RNA U, and vice versa. DNA nucleotide C matches RNA G, and vice versa.  Two strands of DNA: coding strand (strand opposite the template strand, should be the same as the RNA created) and template strand (RNA is matched to this strand).- Types of RNA:o mRNA: messenger RNA Three bases together make a codon. Messenger RNA is a copy of DNA that contains the “code” that is related to particular amino acids.- Some examples are AUG (methionine, MET), CCC (proline, PRO). We will not need to have these sequences memorized.o tRNA: transfer RNAo rRNA: ribosomal RNAo The last two RNAs are used in the translation step.- Transcription:o There are several steps that are needed to do transcription: Open DNA Start at the correct place Match up o Components: Nucleic acids DNA and mRNA. There are specific proteins that are used in transcription. - RNA polymerase is used. This protein in transcription is known as an assistant, or a transcription factor.- Proteins that assist the RNA polymerase to attach to the DA and begin copying at the right place.  Ribonucleotides (AUGC) o Different cells have different transcriptions factors. - Does DNA only code for proteins?o Not all of DNA codes for proteins. Some parts contain areas recognized by transcription factors, or where RNA polymerase attaches, or where other activators or repressors will attach. These are other control areas.o Polymerase: Opens up DNA so that we have access to one strand. It brings in complementary nucleotide (a – U and g – C). form temporary hydrogen bonds. o Elongation: Elongation is the middle part of transcription. In this step, DNA is opened up by RNA polymerase.  In the next step the free RNA nucleotide form temporary H bonds with their complementary bases on DNA. It continues to move down the DNA. And adds on in the direction of the 3’. A bonds to U and G bonds to C. RNA polymerase reads in a 3’ to 5’ direction along the template strand. The other strand is the coding strand.- Parts of a gene:o When making RNA there are specific parts of DNA that help the process.o Promoter or near promoter RNA polymerase and transcription factors begin to bind here.o Coding region for protein Area containing code for the proteino Termination or end of gene The RNA polymerase and transcription factors encounter hostile environment that is no good for binding, and it releases the polymerase.o One of the binding proteins is called TATA. Contains certain chemicals that are attracted to clusters of G’s and C’s. - Modification:o Once the messenger RNA is made, it goes through processing. It adds a cap to the 5’ end, and adds a string of As to the 3’ end (poly(A) tail). This assists in moving mRNA out of nucleus and protecting it from breaking down.o Splicing: Not all of the mRNA may be used. Some sections are cut out and this is called RNA splicing. (introns: intervening sequences). Some sections are kept (exon parts). This occurs in the nucleus. The protein that is used in this is spliceosome.- snRNPs (small nuclear ribonucleotides). Can make many different proteins from same section of DNA.  Transcription, modification, splicing. All of the exons are kept and joined. This is what is passed out through the nuclear core. The remaining pieces are known as the Mature Transcript.- Translation:o Translation is the process of going from the language of nucleic acids (DNA and RNA) to the language of proteins (Amino Acids). Translation occurs either in the cytoplasm or the endoplasmic reticulum. o This is done by using a codon triplet code. o Gets recognized by ribosomal subunits help to put together a protein. Ribosomesread the codons in the messenger RNA. They look for a triplet code to pick out the amino acid. There are proteins designed for secretion and use in the cytoplasm which are made by free ribosomes in the Endoplasmic Reticulum. They can be sent to the nucleus or mitochondria. They mostly make proteins used in cytoplasm.o The goal of these proteins is to match amino acids with correct codon on messenger RNA. o Ribosomes “read” the code of the RNA and match it to the correct amino acid to make the proteins. The codons are three nucleotides that specify a single amino acid that corresponds to the nucleotides to make the protein. - Review of Proteins:o Chains of amino acids. Amino acids subunits connect together.  Amino acid structure contains a central carbon, amino acid, carboxyl group, unique r group, and a hydrogen.  Linking sets from twenty possible amino acids makes polymers called polypeptides, or if longer than 100 amino acids are