TPR MCAT Biological Sciences - Eukariotic Cell

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TPR MCAT Biological Sciences - Eukariotic Cell
2011-07-28 17:32:58
TPR MCAT Biological Sciences biology BS

These notecards contain select must-knows from in transcription, translation, and structure of DNA. Some of the first cards have some Molecular biology, as I confused the cards, so make sure to check out both ;)
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  1. In DNA, which basepairs take less energy to pull apart? AT or CG?
    • AT.
    • AT are held together by only 2 h-bonds, whereas CG are held together by 3 h-bonds, thus AT bonds are easier to break.
    • Mnemonic: Automatic Transmissions (AT) are easier to break!
  2. What is each letter in the genetic code (U, C, A, G, T) called?
  3. What is the common name of a group of three nucleotides joined together?
  4. how many nucleotides are required to code for a single nucleic acid?

    • Each codon codes for one nucleic acid
    • a codon is made up of three nucleotides (three letters)
  5. What is a basepair?
    • a pair of a nucleotide with its respective nucleotide in the other strand of DNA or RNA
    • basepairs:
    • AT
    • CG
    • AU (U instead of T in RNA)
  6. type of mutations that cause an aminoacid to be replaced by another aminoacid?

    What type of mutation is this?
    missense mutations

    these are a type of point mutations
  7. what type of mutations cuase a stop codon?
    what type are they?
    nonsense mutations

    these are a type of point mutations
  8. what type of mutations don't cause make no difference because they code for the same aminoacid?
    silent mutations

    these are a type of point mutations
  9. What are the three different types of point mutations?
    • missense
    • nonsense
    • silent
    • .... mutations
  10. What are the most deleterious type of mutations? and why?
    • insertion
    • deletion

    because they are "frameshift mutations". they cause a shift in reading frame
  11. what does an insertion mutation do? what significance does this have?
    insertion mutation causes inserts a new nucleotide to the DNA sequence

    bigger impact? - this causes a shift in the reading frame.
  12. what type of mutation results in the removal of nucleotides from the DNA seqence? What is their impact?
    deletion mutations.

    Superbad because they cause a shift in reading frame
  13. Grab a piece of paper and draw the cell cycle.
    Clearly draw Interphase and mitotsis regions.
    What are the subphases of Interphase?
    • Note that
  14. What is the G0 subphase of interphase?
    What cells are in G0?
    • G0 is a subphase of interphase used by cells that are stuck in interphase and never come out of it.
    • The more specialized a celld become, the less likely they are to divide: neurons, RBC, outter skin cells
    • Since they dont form by mitosis, their precursors: stem cells
  15. In what phase of the cell cycle is G1 located?
    What happens in it? Describe it
    • G1 is a subphase of Interphase
    • high rates of protein synthesis (new organelles made)
    • enzymes made (specially those needed for DNA replication)
  16. In what phase of the cell cycle is S subphase located?
    What happens in it? Describe it
    • S stands for Synthesis of new DNA so DNA Replication occurs
    • by the end of S subphase, cell contains two identical copies of the genome
  17. What are the subphases of mitosis?
    • Prophase
    • Metaphase
    • Anaphase
    • Telophase
    • mnemonic: "P-MAT"
  18. What is the first sign of prophase?
    • the genome becomes visible after condensing into tightly packed chromosomes, instead of diffuse chromatin.
    • Chromosomes appear joined with their sisters (Ms. Chromatids) by their centromeres.
  19. what are chromatids?
    • Ms. Chromatids, are the sisters of Mr. Chromosomes.
    • chromatids, are the names of the sisters of the crhomosomes., thus in prophase is where they first appear, and they appear holing hands, ( joined by their centromeres)
    • (just coming up with some type of story so I remember this, as I keep forgeting it. not any more thanks to this analogy)
  20. what is the name when Mr. Crhomosome is seen holding hands (joined at centromere) with his sister, Ms. Chromatid, what is this group called?
    homologous pair
  21. What happens in prophase?
    • DNA becomes visible as homologous pairs of sister chromatids
    • nucleolus dissapers
    • Spindle & kinetochore fibers appear
    • asters form: centriole pairs move to oppocite ends of cell
  22. What happens in Metaphase and Anaphase?
    • Metaphase: homologous pairs line up in center of cell
    • Anaphase (A-shape): spindle fibers shorten pulling sister chromatids apart and this looks like two A's
  23. What happens in Telophase
    • nuclear membrane reforms in each half of the cell
    • nucleolus reappears
    • genome decondenses
    • cytokinesis (cells split)
  24. What is kinetochore?
    protein structure where spindle fibers attach to each sisster chromatid during metaphase and anaphase