Presentation on theme: "Transcription and Translation"— Presentation transcript:
1Transcription and Translation Protein SynthesisTranscription and Translation
2Protein SynthesisIs the formation of the proteins using information coded on DNA and carried out by RNASTEP 1 RNA TranscriptionSTEP RNA TranslationDNA RNA Proteins
3Protein Each protein molecule is made up of one or more polypeptides. Each polypeptide is made up of a sequence of amino acids.There are 20 different types of Amino Acids.Amino Acids Polypeptides Proteins
4Genetic CodeSystem that contains information needed for proper cell functioning.This information is built into the arrangement of nitrogen bases.
5Codon A specific group of three sequential bases on mRNA. Each codon codes for a specific amino acid. There are 64 possible codons. Coding for amino acids is universal for all animals.See Codon chart on Page 207What does the following mRNA code for?AUG UUU CCU CAA GGU GAG GCG ACA UAA
6Transcription First step in protein synthesis Occurs in the nucleus End result is RNA molecule with a complementary base sequence to DNA.Flow of Genetic InformationDNA RNA
7RNA TRANSCRIPTION STEP 1 Enzyme called RNA Polymerase binds to DNA molecule at the promoterPromoter is a sequence of nucleotides on a DNA molecule where transcription will beginOnce RNA polymerase binds to the DNA molecule it will unwind and separate the two complementary DNA strands.
8RNA TRANSCRIPTION STEP 2 RNA polymerase adds free RNA nucleotides that are complementary to the nucleotides on one of the DNA strands.They will attach by hydrogen bonds and form a strand on messenger RNA.RNA polymerase will also establish the sugar to phosphate bonds between the nucleotides in the new mRNA strand.As the RNA Polymerase passes the separated DNA strands rewind.
9RNA TRANSCRIPTION STEP 3 The enzyme will reach a pattern of bases on the DNA strand that signals termination.The enzyme will stop and release the new RNA strand.The new RNA strand now moves to the cytoplasm
10End Result of Transcription Transcription just created a RNA molecule with a complementary base sequence to DNA.Each type of RNA molecule (tRNA, mRNA, rRNA) is made this way and will start their job in protein synthesis.
11RNA TRANSCRIPTION PRACTICE PROBLEM: Transcribe a mRNA molecule from the following DNA Strands.DNA: TAC ATA TAA CGC CCG AGC TGC GGC
12Warm Up: Today: AGG TTA GGC CCG ATA AGC GCG GGC Homework: Transcribe a mRNA molecule from the following DNA Strands.AGG TTA GGC CCG ATA AGC GCG GGCToday:Homework:
13TRANSLATIONThe process of assembling protein molecules from information encoded in mRNA.Second Step in Protein SynthesisThis process uses all three types of RNAProcess occurs in the cytoplasm
14Transfer RNA (tRNA)Transfer RNA (tRNA) bears a sequence of three bases called the Anticodon.The anticodon base sequence is complimentary to the codon on the mRNAtRNA carries an amino acid to the ribosome'smRNA and tRNA will pair together during translation.
15Translation- STEP 1 INITIATION Process starts when mRNA migrates out of nucleus by nuclear pores, and migrates to the ribosome's.Amino acids floating freely in the cytoplasm are transported to the ribosome's by the tRNA
16STEP 1 INITIATION (CONT) The assembly of polypeptides start when the ribosome's attaches to the AUG(start) codon of the mRNAThe AUG codon pairs with the anticodon UAC on a specific tRNAMethionine is usually the first amino acid (not always the first in the amino acid chain because it may be removed)
17STEP 2 & 3 ELONGATION The Polypeptide chain is put together. Ribosome's moves along the chain and decodes the mRNA and attaches the amino acids together by peptide bonds.The tRNA will bring in the next amino acid, pair up with the codon on the mRNA and attach the next amino acid together
18STEP 4 TERMINATIONEventually the ribosome reaches a stop codon and the process comes to the endThe new polypeptide is complete and released.Ribosome's may be working at different parts of the mRNA simultaneously.
19STEP 5 DISASSEMBLY The components of translation separate. The last tRNA leaves.The Ribosome leaves the mRNAThe translation machinery are now ready to translate another mRNA
20Translation Practice DNA: TAC ATA TAA CGC CCG AGC TGC GGC mRNA: Amino Acid Chain: