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DNA replication DNA makes a copy of itself BEFORE the cell divides Transcription RNA is made by base pairing with a DNA template Translation mRNA templates.

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Presentation on theme: "DNA replication DNA makes a copy of itself BEFORE the cell divides Transcription RNA is made by base pairing with a DNA template Translation mRNA templates."— Presentation transcript:

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2 DNA replication DNA makes a copy of itself BEFORE the cell divides Transcription RNA is made by base pairing with a DNA template Translation mRNA templates are decoded into proteins

3  Process › DNA Helicase unwinds and unzips the double helix › DNA polymerase brings in free DNA nucleotides to the two sides of the DNA molecule  DNA can only replicate in the 3’ to 5’ direction so small replication bubbles form instead of one long continuous process › DNA Ligase proofreads and bonds the new strands › Hydrogen bonds form › Process is semiconservative – each DNA molecule has an old and a new side

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5  Occurs in the NUCLEUS › DNA can’t leave the nucleus because there is a risk of damage or lost sections  Decodes 1 gene  Process › RNA polymerase brings in free RNA nucleotides to the DNA template (1side of DNA) › DNA base pairs match with RNA base pairs › RNA nucleotides bond together and leave the nucleus through a nuclear membrane pore

6  DNA Side 1 = ___ ___ ___ ___ ___ ___  DNA Side 2 = ___ ___ ___ ___ ___ ___ (template)  RNA = ___ ___ ___ ___ ___ ___  Three types of RNA can be made › Messenger (mRNA) = the code of DNA; the type we will focus on for protein synthesis › Ribosomal (rRNA) = RNA used to make a ribosome › Transfer (tRNA) = moves amino acids around in the 2 nd part of protein synthesis

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9  Three nitrogen bases make up a codon which makes a protein oh yes it does.  When mRNA lands on a ribosome the process has begun.  Each codon pairs up with an anticodon found on the transfer RNA  Each tRNA brings an amino acid to ribosome to stay  When two of them are side by side a peptide bond forms right away  This keeps on going until a stop code is read and a polypeptide has been made.  This is the process of translation. There is not much more to say.  But proteins are made all the time every second of the day.

10  The process of converting an mRNA codon into a polypeptide (protein) chain  Occurs in the cytoplasm or rough ER  Important Terms › mRNA Codon – 3 nitrogen bases that code for an amino acid; 64 possible combinations › tRNA Anticodon – 3 nitrogen bases that complimentary base pair with a mRNA codon › Peptide bond – bond formed between two amino acids

11  Process › mRNA lands on a ribosome (space for 2 mRNA codons at a time) › Start codon of a gene AUG attracts a tRNA anticodon › tRNA codon bring in an amino acid (met) › The next mRNA codon attracts another tRNA anticodon which brings in another amino acid › A peptide bond forms when two amino acids are side by side › Ribosome moves down and another mRNA codon is read followed by another amino acid coming in; 1 st tRNA moves out › New amino acid bonds to the existing bonded amino acids › Process continues until a STOP codon (UAA, UAG, UGA) is read › Polypeptide is molded into it’s shape to make a protein

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14  DNA Side 1___ ___ ___ ___ ___ ___  DNA Template___ ___ ___ ___ ___ ___  mRNA codon___ ___ ___ ___ ___ ___  rRNA anticodon___ ___ ___ ___ ___ ___  Amino Acid ___________ ____________


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