Biochemistry Test 1

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Biochemistry Test 1
2013-10-05 20:45:02
bichemistry test

Topics covered for test 1 in biochemistry
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  1. What is the central dogma of molecular biology?
    DNA replicates to make more DNA. DNA is also transcriped to make RNA. RNA is then translated into proteins.
  2. The chemical structure of adenine
    • This a ribose sugar. Remember that deoxyribose sugar doesn't have a hydroxyl group on the 2' carbon.
  3. The chemical structure of thymine

    This a ribose sugar. Remember that deoxyribose sugar doesn't have a hydroxyl group on the 2' carbon.
  4. The chemical structure of cytosine
    • This one's missing a phosphate group.
  5. The chemical structure of guanine
    • This one's missing a phosphate group.
  6. Explain transcription.
    The protein RNA polymerase tracks DNA, using it as a template, and synthesizes a single-stranded RNA.
  7. Briefly describe translation.
    Translation is when ribosomes converge on the single-stranded RNA and begin to synthesize proteins. 
  8. How many genes and proteins are in the human body?
    • There are 46 chromosomes (23 pairs) in the human body, so there are approximately 21,000 genes in the human body. There are many more proteins in the human body than genes, approximately 100,000
    • Point is more proteins than genes. 
  9. Regarding DNA/RNA, Which is the 5' end, which is the 3' end?
  10. What are nucleases?
    Nucleases are a class of enzymes that can cleave DNA or RNA. Some nucleases can cleave in the middle (endonucleases), and some can cleave at the ends (exonucleaes). Endonucleaes can be sequence specific or not.
  11. What and where are the major and minor grooves of DNA?
  12. What type of chemical bonds are responsible for the stability and structure of DNA?
    Hydrogen Bonds
  13. What are bends in DNA? 

    Is it functional?
    Bends in DNA are caused naturally when ther are long stretches adenines, which only has two hydrogen bonds with thymine, and this allows DNA to be more pliable. Bends can also be be caused by drug, such as the anit-cancer drug cisplatin. Cisplatin binds to guanine in the same or different strands, which cannot be unbounded or bypassed,causing apoptosis. Also BENDS ARE EXTREMELY WIDESPREAD!

    Yes, bends are functional in bacteria. Bacteria have bends that poke out and contain promoters, making them easier to transcribe.
  14. What are the levels of organization of eukaryotic DNA?
    • Naked DNA is DNA not wrapped around histones. Histone is composed of 8 defferent protein molecules. A string of DNA wrapped around histones are called 10 nm nucleofilament. Multiple strings of DNA wrapped around histones in a solinoid structure are called a 30 nm fiber. 30 nm fibers wrapped and twisted are called a chromosome. 
    • NAKED DNA -> (around histones) 10 NM NUCLEOFILAMENT -> (into a solinoid structure) 30 NM FIBERS -> CHROMOSOME
  15. What are G-Quartets?
    Due to the structure of guanine, it can form two hydrogen bonds with three other guanines, which is stabilized by a metal ion. G-quartets are functional are found in the telomeres of eukaryotic DNA.
  16. What are supercoiling and topoisomerases?
    In bacterial, circular DNA, as the DNA is being replicated or transcribed, the DNA is moved to compensate for the immobility of the enzymes DNA polymerase and RNA polymerase. When is moves through the polymerase, it twists. Supercoiling can be a problem because DNA can become so supercoiled that the enzyme cannot move along DNA. There are enzymes called topoisomerases, which can grab DNA, either one or both strands, cut DNA, untwist it, put it back together.
  17. What is a primary structure of protein? 

    What type of chemical bonds are involved?
    The primary structure of proteins refers to the sequence of individual amino acids. 

    Peptide bonds
  18. What the two types of secondary structure of DNA? 

    What type of chemical bonds are involved?
    Secondary structure of proteins is referred to local 3D configuration of a polypeptide. The two types are alpha-helix and beta-sheet. 

    Hydrogen bonds
  19. What is the tertiary structure of proteins? 

    What type of chemical bonds are involved?
    Tertiary structure of proteins is the 3D organization of a single polypeptide. 

    Hydrogen bonds, electrostatic interactions, hydrophobic interactions, and S-S bridges