Video http://
www.youtube.com/watch?v=41_Ne5mS2ls
RNA STRUCTUREDNA responsible for information
to make proteinsRNA is responsible for making
proteins using DNA’s genetic information
Nucleotide chain made of◦Phosphate group◦Sugar – ribose◦Nitrogenous bases
RNA vs. DNADNA
Double strandedDeoxyribose sugar Bases: C,G A,T
RNASingle strandedRibose sugarBases: C,G,A,U
Both contain a sugar, phosphate, and base.
TYPES OF RNAmRNA – Messenger RNA
◦Synthesized from DNA and carries the instructions to make proteins
tRNA – Transfer RNA ◦ Responsible for reading mRNA and
placing correct amino acids together to form a protein
rRNA – Ribosomal RNA ◦RNA found in ribosomes
tRNA
Transfer RNABound to one
amino acid on one end
anticodon on the other end complements mRNA codon
If mRNA sequence = UCG
tRNA sequence = AGC
REVIEWList one way in RNA and DNA are
similarList one way in RNA and DNA are
differentList the 3 types of RNA
TranscriptionHappens in nucleus of the cellThe information in DNA is copied into
MrnaRNA Polymerase binds to a site on DNA
at the promoter (start location)RNA polymerase unwinds and
separates DNA and then adds the complimentary RNA bases, producing a strand of mRNA
Behind RNA polymerase the DNA strands close up and reform the helix
TRANSLATIONAfter mRNA is made it is
transported into the cytoplasm of the cell in order to be translated
Needs to be changed from language of RNA to the language of proteins(amino acids)
Each three-nucleotide sequence on RNA is called a codon and each codon corresponds to an amino acid
STEPS OF TRANSLATIONmRNA joins with a ribosome and tRNA
◦ tRNA contains anticodons which are complimentary to mRNA’s codons, and also carries the corresponding amino acid
◦ mRNA has start signal (AUG) and an end signal◦ As tRNA binds it leaves the correct amino acid
behind ◦ The next tRNA and amino acid move in and
places the second amino acid◦ Amino acids keep bonding together to form a
long chain until a stop signal is encountered.◦ When finished the newly formed polypeptide
falls off of the ribosome.
tRNA
Transfer RNABound to one
amino acid on one end
Anticodon on the other end complements mRNA codon
If mRNA sequence = UCG
tRNA sequence = AGC
Practice transcription/translation
Mleonessciencepage.wikispaces.com◦DNA Section
Click on Transcribe & Translate a Gene Zero Bio – Protein Synthesis Print screen shot when finished and turn
in with your name
Purpose of Protein Synthesis
Create ProteinsProteins differ from one another in the number
and sequence of amino acidsProteins can be 50-3,000 amino acids in lengthProteins are part of almost all cell functions
◦AB’s◦Muscles◦Enzymes◦Hormones (insulin)◦Structural ( collagen, keratin)◦Storage◦Transport ( hemoglobin)