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From DNA to Proteins

From DNA to Proteins. Review (from BJ): What are proteins?. Proteins are made of Amino Acids. Provide structure (nails, skin, hair…). Function (enzymes-speeds up reactions). Introduction.

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From DNA to Proteins

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  1. From DNA to Proteins

  2. Review (from BJ): What are proteins?

  3. Proteins are made of Amino Acids. Provide structure (nails, skin, hair…) Function (enzymes-speeds up reactions)

  4. Introduction • DNAcontains information that controls how cells function, grow and reproduce. It controls how you look like (traits) and how you function. • Your DNA has pieces of DNA called genes that codes for proteins. • These proteins determine your traits.

  5. You are different from the people around you because you all have different proteins Traitsare characteristics. Example: Eye color If genes change, then the protein changes and horrible things can happen to the organism.

  6. But how can one little protein affect you? • Melaninis a protein that gives your hair color. If the gene that makes melanin was destroyed, would you have black or brown hair? What color would your hair be? • So, remember genes are pieces of DNA and they code for proteins that are necessary for structure and for our bodies to function in a particular way!

  7. Like we’ve got to break this code , Scoob. Codes are a set of rules and symbols used to carry info. DNA and RNA has many, many codes for proteins hidden within.

  8. How do we go from DNA to protein? DNA RNA  Protein(Central Dogma) When cells need to make proteins, they transcribe (copy) the information found in DNA into an RNA molecule and then the code in RNA is used to build proteins. Going from DNA to RNA to Protein is called the Central Dogma.

  9. 99 From DNA to proteins: Step 1: DNA is converted into RNA in a process called TRANSCRIPTION. This occurs in the nucleus. Step 2: The RNA is released into the cytoplasm where RNA is read forming a chain of amino acids (Protein) . Going from RNA to protein is called TRANSLATION and this occurs in the cytoplasm. Nucleus DNA RNA Protein Cytoplasm DNA  RNA  Protein

  10. Remember, these proteins that are made determine your traits: hair color, eye color, and so on. They provide structure and function (enzymes).

  11. 99 There are 3 types of RNA!

  12. 101 How do we go from DNA to mRNA? • Transcription!! You are rewriting DNA’s message! Steps: 1 ) DNA unwinds (unzips), then RNA polymerase adds RNA nucleotides using a DNA strand. 2) RNA polymerase adds bases that include: A, C, G and U (Uracil)---NO thymine exists in RNA, only in DNA! 3) Then you end up with a single mRNA strand. * Paste your picture.

  13. 101 RNA: G = C A = U DNA: G = C A = T Base Pair Rules Transcribe the following DNA strand. (DNA to mRNA) A T G G C A T (DNA) U A C C G U A (mRNA)

  14. DNA Replication (making more DNA): A T C T G A A (old DNA strand) T A G A C T T (new/complementary DNA strand) Transcription: DNA mRNA A T C T G A A (old DNA Strand) U A G A C UU (new/complementary RNA strand)

  15. (pg103) Replicate the following Strand: C A T A G (old DNA strand) __ __ __ __ __ Transcribe the following DNA strand: G A T A G (old DNA strand) __ __ __ __ __ (single stranded mRNA)

  16. RNA RNA is a nucleic acid like DNA, but is different in 3 important ways:

  17. Let’s go from RNA to Protein! Finally!! • After mRNA leaves the nucleus, it encounters rRNA and tRNAs in the cytoplasm! • As the strand of mRNA slides through a ribosomes (rRNA), it binds with tRNA bases, three nucleotides at a time. • A group of 3 nucleotides is called a codon. Each codon codes for 1 Amino Acid • 3 nucleotides = 1 codon= 1 Amino Acid! • As each tRNA binds to each codon on the mRNA, it attaches an amino acid to a chain. • The chain of amino acids that form is your protein.

  18. This is how we translate codons into amino acids. • Look at the left side, find the 1st letter in the codon. • Then look at the top and find the 2nd letter of that codon • Then look to the right and find the 3rd letter in the codon. • Example: CGU is a codon that codes for Arginine (Arg) • Try: (Find A. Acid) -UUA __________ -AAG __________

  19. From mRNA to Protein To translate an mRNA strand to protein: 1) start at the far left 2) Find your start codon (AUG) 3) divide the mRNA message into codons 4) look the codons up in the genetic code chart. Example: CCGCAUGCGAAAUAGA (mRNA) AUG | CGA | AAU | AGA Look at genetic code to find Amino Acids: Methionine- Arginine-Asparagine-Arginine (Protein!)

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