Docstoc

RNA _ Protein Synthesis - Essential Question

Document Sample
RNA _ Protein Synthesis - Essential Question Powered By Docstoc
					   RNA & Protein Synthesis

         Essential Question:
How do our cells determine who we are?
Why are proteins important to living things?

•   Control rate of chemical reactions as _e__________
                                            nzymes
•   Building materials for skin, bone, and _m_________
                                              uscles
•                               ntibodies
    Help fight infections as _a__________________
•   Help control what goes in and out of cell through cell
    _m____________________
       embranes
1. What is a gene?

• Small section of DNA that holds code for making a
  particular protein, or for particular trait.
2. What is RNA? What are three differences between
DNA and RNA?

• Ribonucleic acid.
• RNA has only one strand, DNA has two
• DNA has G, C, A, and T as bases; RNA has G, C, A,
  and U. Uracil instead of thymine.
• RNA uses ribose as sugar, DNA uses deoxyribose.
3. What happens to DNA in the process of transcription?
 • DNA in nucleus is “unzipped.” A copy of one
   strand is made in the form of messenger RNA
   (mRNA)

            Adenine (DNA and RNA)
            Cystosine (DNA and RNA)
            Guanine(DNA and RNA)
            Thymine (DNA only)
            Uracil (RNA only)


 mRNA


 DNA
4. Proteins are made by joining ___________________
                                    amino acids
into long chains called polypeptides.
5. Each polypeptide
contains a combination
of how many different
amino acids?
     20
__________
6. “Words” in the genetic code of DNA and RNA are
                                   3
made up of how many bases? __________
7. How are codons translated into different amino acids?
• Codon made up of
  3 nucleotide bases,
  e.g. AAG, CUA, etc.
• Each set of 3 bases
  translates into
  different amino acid,
  e.g. AAG = lysine,
• CUA = _________
           leucine
8. What do “start” and “stop” codons do?

• Start = beginning of
  polypeptide
• Stop = end of polypeptide.
• If protein = paragraph,
  polypeptide = sentence,
  amino acids = words.
Quick Lab: How does a cell interpret DNA?

1. A certain gene has the following sequence of
nucleotides:
            GACAAGTCCACAATC
    Write this sequence on your sheet of paper.

2. From left to right, write the sequence of the
mRNA molecule transcribed from this gene:

           C UGUUC AGGUGUU AG
     Quick Lab: How does a cell interpret DNA?
    3. Look at Figure 12-17.
    Reading the mRNA
    codons from left to right,
    write the amino acid
    sequence of the
    polypeptide translated
    from the mRNA.
    CUGUUCAGGUGUUAG
•            Leucine
     CUG = ______________
•           Phenyl-alanine
     UUC = ______________
•             Arginine
     AGG = ______________
•    UGU = ______________
              Cysteine
•             Stop
     UAG = ______________
    Quick Lab: How does a cell interpret DNA?

4. Repeat step 3, reading
the codons from right to
left.

CUGUUCAGGUGUUAG
•           Aspartic acid
    GAU = ______________
•           Cysteine
    UGU = ______________
•   GGA = ______________
            Glycine
•           Leucine
    CUU = ______________
•   GUC = ______________
            Valine
  Analyze and Conclude

1. Why did steps 3 and 4
produce different
polypeptides?

 Reading bases from left
 to right produces
 different codons from
 reading right to left.
 Analyze and Conclude
2. Do cells usually
decode nucleotides in
one direction only or in
either direction?

Usually one direction only
9. What happens to messenger RNA (mRNA) in the process
of translation?
  • mRNA is translated into chains of amino acids that
    form proteins.
9. What happens to messenger RNA (mRNA) in the process
of translation?
  • mRNA is translated into chains of amino acids that
    form proteins.
10. Explain the role of the following in protein synthesis:
     a. gene

      Contains code for making a protein
10. Explain the role of the following in protein synthesis:
     b. mRNA

  Copy of gene that can be taken out of nucleus into
  cytoplasm.

             Adenine (DNA and RNA)
             Cystosine (DNA and RNA)
             Guanine(DNA and RNA)
             Thymine (DNA only)
             Uracil (RNA only)


 mRNA


  DNA
10. Explain the role of the following in protein synthesis:
     c. tRNA
 Transfers amino acids over to mRNA, where they can be
 joined together to form protein.
10. Explain the role of the following in protein synthesis:
     d. codon
 3-letters/bases on mRNA that holds code for 1 amino
 acid
10. Explain the role of the following in protein synthesis:
     e. anticodon

3 letters/bases on tRNA that match with codon on mRNA




anticodon




 codon
10. Explain the role of the following in protein synthesis:
     f. ribosome

Helps join amino acids together to form protein/polypeptide




ribosome
10. Explain the role of the following in protein synthesis:
     g. amino acid
    Molecules that join together to form protein
 11. Create a diagram of how proteins are synthesized from DNA
 using the terms in question 10.
       DNA

           A G C T T A G C
                             Codon

Gene
11. Create a diagram of how proteins are synthesized from DNA
using the terms in question 10.
      DNA                            mRNA


                            G C U A A G C U
          A G C T T A G C
11. Create a diagram of how proteins are synthesized from DNA
using the terms in question 10.
      DNA                                       mRNA

          A G C T T A G C
                                    G C U A A G C U
                            Amino Acid




                                                       C G A
                                                               Anti-Codon
                              Arg



                                         tRNA
11. Create a diagram of how proteins are synthesized from DNA
using the terms in question 10.
      DNA                           mRNA

          A G C T T A G C
                            G C U A A G C U
                            C G A U U C




                             Arg        Phe
  12. This is the part of the sequence of the Tay-Sach’s gene that
  causes the disease. Transcribe the sequences into mRNA and then
  translate them into amino acids.
DNA:
Normal sequence: AGGCGAGUGTTAGCC Mutated sequence: AGGCGAGUGTAGCC

mRNA:
Normal sequence: ________________ Mutated sequence: ________________

Amino acids:
Normal sequence: ________________ Mutated sequence: ________________
  12. This is the part of the sequence of the Tay-Sach’s gene that
  causes the disease. Transcribe the sequences into mRNA and then
  translate them into amino acids.
DNA:
Normal sequence: AGGCGAGUGTTAGCC Mutated sequence: AGGCGAGUGTAGCC

mRNA:
Normal seq: UCC GCU CAC AAU CGG   Mutated seq: UCC GCU CAC AAU CGG

Amino acids:
Normal seq: ________________      Mutated seq: ________________
   12. This is the part of the sequence of the Tay-Sach’s gene that
   causes the disease. Transcribe the sequences into mRNA and then
   translate them into amino acids.
DNA:
Normal sequence: AGGCGAGUGTTAGCC Mutated sequence: AGGCGAGUGTAGCC

mRNA:
Normal seq: UCC GCU CAC AAU CGG              Mutated seq: UCC GCU CAC AUC GG

Amino acids:
Normal seq: Ser Ala His Asp Arg            Mutated seq: Ser Ala His Iso --

a. What is the difference between the normal DNA sequence and the mutated sequence?

    The mutated sequence is missing one base (an A)
b. What does this change do to the amino acid sequence?

   Changes it from Asp Arg to Iso --
    Video: Protein Synthesis

http://www.youtube.com/watch?v=41_Ne5mS2ls
What happens to DNA in the process of transcription?
 • DNA in nucleus is “unzipped.” A copy of one
   strand is made in the form of messenger RNA
   (mRNA)

            Adenine (DNA and RNA)
            Cystosine (DNA and RNA)
            Guanine(DNA and RNA)
            Thymine (DNA only)
            Uracil (RNA only)


 mRNA


 DNA
What happens to messenger RNA (mRNA) in the process of
translation?
  • mRNA is translated into chains of amino acids that
    form proteins.
What happens to messenger RNA (mRNA) in the process of
translation?
  • mRNA is translated into chains of amino acids that
    form proteins.
What happens to messenger RNA (mRNA) in the process of
translation?
  • mRNA is translated into chains of amino acids that
    form proteins.

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:1
posted:3/20/2014
language:English
pages:37