Biology Lecture 2

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  1. A series of DNA nucleotides that generally code for the production of a single polypeptide or mRNA, rRNA, or tRNA
  2. _____________ have multiply copies of some genes, while __________ have only one copy of each gene.
    • Eukaryotes
    • Prokaryotes
  3. The entire DNA sequence of an organism is known as __________. There are between 26000 and 38000 genes in human's
  4. The Central Dogma of gene expression is that DNA is transcribed to ___________, which is then translated to amino acids forming a _____.
    • RNA
    • Protein
  5. Name the four nitrogenous bases  that exist in DNA
    adenine, cytosine, thymine, guanine
  6. adenine and guanine are two ring structures called _______
  7. Cytosine and thymine are single ring structures called ______.
  8. Each nucleotide is bound to the next by this type of bond between the third carbon of one deoxyribose and the phosphate backbone of a single strand of DNA with a 5' to 3' directionality.
    phosphodiester bond
  9. Adenine is bonded to thymine with ___ hydrogen bonds
  10. cytosine is bonded to guanine with _____ hydrogen bonds
  11. DNA replication is this meaning that when a new double strand is created, it contains one strand from the original DNA and one newly synthesized strand
  12. Replication proceeds in both directions from an origin. Each direction produces a leading and a lagging strand. This process is _______
  13. What is the enzyme that builds the new DNA strand?
    It cannot initiate a strand from two nucleotides but can only add nucleotides to an existing strand. Requires RNA primer to get started.
    DNA polymerase

    remember: "ase" = enzyme
  14. Reading DNA is like padding upstream from _________. Once the DNA is read, synthesizing DNA is downstream, from __________
    • 3' to 5'
    • 5' to 3'
  15. name the five steps in DNA replication:
    • 1. Helicase unzips the double helix
    • 2. RNA Polymerase builds a primer
    • 3. DNA Polymerase assembles the leading and lagging strands
    • 4. the primers are removed
    • 5. Okazaki fragments are joined
  16. The lagging strand is made from a series of disconnected strands called
    Okazaki fragments
  17. This moves along the lagging strand and ties the Okazaki fragments together to complete the polymer
    DNA lagase
  18. The process of replication in which the formation of one strand is continuous and the other fragmented is called
  19. List the differences between DNA and RNA
    DNA is made from deoxyribose; RNA is made from ribose. DNA is double stranded; RNA is single stranded. DNA has thymine; RNA has uracil. DNA is produced by replication; RNA is produced with transcription. In animals, DNA is only in nucleus and mitochondrial matrix; RNA is also in the cytosol. There is only one major DNA; but three major RNA
  20. This RNA delivers the DNA code for amino acid to the cytosol where the proteins are manufactured.
    mRNA (messenger RNA)
  21. This RNA combines with proteins to form ribosomes
    rRNA (ribosomal RNA)
  22. This is the cellular complexes that direct the synthesis of proteins
  23. This RNA collects amino acids in the cytosol and transfers them to the ribosomes for incorporation into a protein
    tRNA (transfer RNA)
  24. All RNA is manufactured from a DNA template in a process called ____________.
    It requires a promoter
  25. This is a spot on the DNA that tells RNA polymerase where to begin transcription.
    a promoter
  26. This is a short piece of RNA that jump starts DNA replication
    a primer
  27. The beginning of transcription is called
  28. During this second step of transcription, RNA polymerase transcribes only one strand of the DNA nucleotide sequence into a complementary RNA nucleotide sequence
  29. This final step in transcription requires a special termination sequence and special proteins to dissociate RNA polymerase from DNA
  30. For all cells, most regulation of gene expression occurs at the level of transcription via proteins called _______ and _________. They bind to DNA close to the promoter, and either activate or repress the activity of RNA polymerase.
    activators and repressors
  31. The genetic unit usually consisting of the operator, promoter, and genes that contribute to a single prokaryotic mRNA is called ______
    the operon
  32. The initial mRNA nucleotide sequence arrived at through transcription is called the ________
    primary transcript
  33. This serves as an attachment site in protein synthesis and as a protection against degradation by exonucleases
    the 5' cap
  34. the 3' end is polyadenylated with a _____, also to protect it form exonucleases
    a poly A tail
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Biology Lecture 2
2014-03-05 01:30:40
MCAT biology

biology lecture 2 for MCAT
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