RNA Structure and Protein Synthesis GT Biology Feb. 23, 2011 RNA Structure and Protein Synthesis
Warm-up How does DNA replicate? What is the central dogma? Quiz on Thursday March 3rd
Objective SWBAT explain the structure of RNA, its role in protein synthesis and how proteins are synthesized
Homework Read pgs 190-192 Complete questions 1-6
Today RNA Structure Types of RNA
RNA Structure
What is RNA? RiboNucleic Acid It is involved in the relaying of genetic information from DNA to the cytoplasm of the cell to produce proteins The production of proteins is known as protein synthesis RNA is found in the nucleus and the cytoplasm
RNA Structure Like DNA, RNA is made of nucleotides which contain: A sugar called ribose A phosphate group One of 4 nitrogenous bases Cytosine Guanine Adenine Uracil (this is in the place of thymine)
RNA Structure Cont. Single helix There are 3 types of RNA: Messenger RNA (mRNA) Transfer RNA (tRNA) Ribosomal RNA (rRNA)
Messenger RNA (mRNA) Carries the genetic information from the DNA in the nucleus to ribosomes in the cytoplasm
Transfer RNA (tRNA) Match the proper amino acid with the mRNA code to produce a protein Each tRNA contains an anticodon which contains 3 bases the correspond the codons on the mRNA Amino Acid
Ribosomal RNA (rRNA) Make up the ribosome (this is where proteins are made) These also allow mRNA to attach to the ribosome
Contain the genetic information DNA vs RNA Type of Nucleic Acid DNA RNA Sugar Nitrogenous Bases Structure Location Function Deoxyribose Ribose A,T,G,C A,U,G,C Double Helix Single Helix Nucleus and Cytoplasm Nucleus Contain the genetic information Protein formation
Protein synthesis
http://www.youtube.com/watch?v=8dsTvBaUMvw
Protein Synthesis Begins in the nucleus with the DNA mRNA is created by a process called transcription
Transcription The first step in transcription is to “unzip” the DNA Just like in replication this means the weak hydrogen bonds must be broken Next RNA polymerase matches complimentary RNA to the DNA C with G A with U instead of T Once the mRNA has been created the DNA strand closes back up
Transcribe the DNA DNA: ATGGCACTGCAT mRNA: UACCGUGACGUA
Translation After transcription the mRNA leaves the nucleus and enters the cytoplasm Once in the cytoplasm the mRNA attaches to a ribosome to begin making proteins The ribosome moves down the mRNA and “reads” the information The information on mRNA is read in codons (a groups of 3 bases)
Codons 3 bases make up 1 codon Each codon corresponds to a specific amino acid Amino acids are the building blocks of proteins Amino acids can be found free floating in the cytoplasm To determine what amino acid each codon codes for there is a codon table
ACU CGA GGC UAA Thr Arg Gly STOP
Translation The end of the protein is signaled by the reading of 1 of the 3 stop codons The series of amino acids produced by the ribosome create a protein Each protein produced plays a specific role in the appearance and behavior of the organism
http://www.youtube.com/watch?v=983lhh20rGY
Putting It All Together Beginning in the nucleus, DNA is unzipped so mRNA strands can be created from the template The mRNA strand exits the nucleus and enters the cytoplasm The mRNA attaches to the ribosome which is composed of rRNA The ribosome reads the mRNA with each codon producing a different amino acid, the amino acids are brought in by tRNAs The amino acids string together to create proteins
The Central Dogma DNA RNA Protein
What Protein Is Produced? DNA: GTTATCCTTCGCAATCACATTGCG mRNA: Protein: GUUAUGGAAGCGUUAGUGUAACGC --- Met Glu Ala Leu Val STOP ---
Practice http://learn.genetics.utah.edu/units/basics/transcribe/