Chapter 9

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Chapter 9
2010-02-25 12:04:40
BIO 302

Gene Expression: From Genes to Proteins
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  1. DNA is translated into proteins, the intermediary between ____ and _____

  2. Phenotypes of what, all result from protein function
    cells, tissues, and organisms
  3. The sequence of nucleotides in our DNA encodes....
    1. the proteins we produce

    2. how much of each is expressed in a given cell
  4. The amount of information stored in a cell is related to....
    the number of nucleotides within that cell
  5. genes are made up of....
    4 nucleotides
  6. Proteins are made-up of....
    20 amino acids
  7. Direct relationship of nucleotides to amino acids is...
    genetic code
  8. The information to encode a single amino acid is carried in a sequence of how many nucleotides
  9. 3 nucleotides give 4*3 different combinations to encode the....
    20 amino acids
  10. Each triplet is called a what
    a codon
  11. How is the linear sequence of nucleotides in a gene converted into the linear sequence of amino acids in a protein
    1. DNA is in the nucleus

    2. proteins are synthesized in the cytoplasm

    3. information transfer must be indirect... via RNA
  12. 1. In transcription, genetic information is copied into mRNA in the what?

    2. The information within the mRNA is then translated from ____ to ____ in the cytoplasm during translation

    *End result is a phenotype
    1. nucleus

    2. nucleotide, amino acid
  13. The process of transcription
    1. RNA polymerase binds DNA at the gene's promoter (the DNA helix unwinds)

    2. initiation of transcription (RNA synthesis begins)

    3. elongation: pairing up (a-u)

    4. Termination when RNApol reaches terminator region

    *In eukaryotic cells there is on more step= RNA processing
  14. Heterogeneous Nuclear RNA
    Newly synthesized RNA; must be modified before it is fully functional
  15. Introns
    Nucleotides that are transcribed, but not translated (noncoding sequences)
  16. Exons
    coding sequence
  17. RNA Processing
    1. Caps are added for initiation of translation and stability

    2. a poly adenine tall is also added
  18. Splicing
    introns are removed
  19. Transcriptional Regulation of Genes
    *mature mRNA transcripts are released into the cytoplasm through pores in the nuclear envelope

    • *highly regulated process:
    • 1. initiation of transcription
    • 2. splicing
    • 3. nuclear export
  20. Translation into Amino Acids
    • *The nucleic acid code in the mRNA is translated into amino acids to synthesize polypeptides
  21. All 20 amino acids have 3 characteristic groups
    1. an amino group (NH2)

    2. a carboxyl group (COOH)

    3. a unique side chain ( R)
  22. During protein synthesis, amino acids are linked by the formation of....
    peptide bonds
  23. A dipeptide contains how many amino acids
    2 (10+ form a polypeptide)
  24. Polypeptides are read from....
    Their N-terminus to the C-terminus
  25. How can four nucleotides code for 20 amino acids
    They have to have 3 nucleotides at a time
  26. The number/sequence of bases in a gene determines....
    the information that it carries
  27. In eukaryotes, mature mRNA is exported out of the nucleus into the cytoplasm where it is translated by...
  28. There are 4 stages in protein synthesis
    1. initiation- requires amino acids, tRNA's and energy

    2. Elongation

    3. Translocation

    4. Termination- Elongation ceases once a STOP codon is reached; the complex falls off
  29. After a polypeptide is formed, it folds into a 3D shape determined by...
    its amino acid sequence
  30. Polypeptide folding is guided by proteins called
  31. The process in which polypeptides can be chemically modified after they are created is called...
    post-translational modification
  32. Once a polypeptide is folded, modified, and sometimes complexed with other polypeptides, a functional____ is formed
  33. Four levels of Protein structure
    1. Primary: linear amino acid sequence in polypeptide chain

    2. Secondary: 3D configurations that result from interactions between amino acids' NH and CO groups

    3. Tertiary: folding of secondary structure back on itself

    4. Quaternary: interactions between two or more polypeptide chains
  34. Protein refolding diseases are called...
    prion diseases
  35. Prions are...
    protein folded into an infectious conformation that is the cause of several disorders
  36. Enzymes....
    1. catalyze biochemical reactions and accelerate reaction rates

    2. They sequester substrates in their active site, providing the proper environment for the reaction to occur rapidly and with relatively little energy

    3. without enzymes, most chemical reactions in our body would take longer than our lifespan to complete