Biology 40s Exam - Molecular Genetics, DNA, and Protein Synthesis

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Biology 40s Exam - Molecular Genetics, DNA, and Protein Synthesis
2015-01-26 13:10:32

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  1. what is dna
    • deoxyribonucleic acid
    • carries hereditary information
    • dna and proteins make up the chromosomes of cells
    • viruses have RNa
    • the variability inherent in dna forms the basis of natural selection and life's diversity
  2. what are the characteristics of dna
    • double stranded, double helix
    • composed of 4 types of nucleotides
    • has deoxyribose sugar
    • stored in nucleus
  3. what are the characteristics of rna
    • single stranded
    • has uracil instead of thymine
    • has ribose sugar
    • can leave the nucleus
    • 3 types (mRNA, tRNA, rRNA)
  4. describe the structure of dna
    • double helix
    • two spiraling chains of necleotides
    • held together by complementary base pairs
  5. what is dna made out of
    • two strands that run antiparallel so proper hydrogen bonds between bases can form
    • deoxyribose sugar
    • phosphate group
    • nitrogenous base
  6. what did phoebus levine discover in 1929
    • deoxyribose is present in nucleic acids
    • dna is made out of:
    • -deoxyribose sugar
    • phosphate grou
    • one of four nitrogenous bases
    • dna and rna are distinct nucleic acids but composed of nucleotides
  7. what did erwin chargoff discover in 1950
    • broke down purified dna into its four nitrogenous bases
    • -adenine=thymine
    • -guanine=cytosine
  8. what did alfred hersey and martha chase discover in 1952
    showed that viral dna directs the replication of new viruses
  9. what did rosalind watkins and maurice wilkins do
    • took x-ray images of dna¬†
    • dna has a helical shape
  10. what did james watson and francis crick discover in 1953
    • described the 3 dimensional structure of dna as a double helix
    • two spiraling strands held together by complimentary base pairs
  11. which nitrogenous bases pair together
    • A-T
    • G-C
  12. which nitrogenous bases are purine (2 carbon ring)
    • adenine
    • guanine
  13. which nitrogenous bases are pyrimidine (1 carbon ring)
    • cytosine
    • thymine
  14. what is nucleic acid
    long, single or double stranded molecules composed of nucleotides (dna/rna)
  15. what is semi-conservative dna replication
    • there is an original strand that acts as a template for each new strand
    • half of the dna is kept and half is new
  16. what is the functions of nucleic acids
    • carry genes that determine an organism's characteristics
    • transmit species traits between generations
    • control the production of cell's proteins, enzymes and hormones
    • indirectly controls all cell functions, determines cell structure and activities
  17. nitrogen bases are held together by what
    hydrogen bonds
  18. what are the dna replication steps
    • 1. enzymes unwind dna to expose the two original strands
    • 2. dna polymerase uses the two strands as templates to make complementary strands
    • 3. new nucleotides will pair with exposed dna
    • 4. the two resulting double-helix molecules coil up to form two chromatids in the chromosome
  19. what is a nucleotide made of
    • sugar
    • phosphate
    • base
  20. why is dna replication essential
    • cells duplicating
    • organisms growing
    • baby > adult
  21. describe protein synthesis
    proteins are macromolecules made from amino acids and joined by covalent peptide bonds
  22. what are the functions of proteins
    • build new cells and repair damaged ones
    • cell membrane - structure
    • skeleton - collagen, cartilage, ligaments, tendons
    • muscle - cardiac, skeletal, smooth
    • hormones - transmit signals
    • antibodies - protection
    • pigments - skin, blood, hair
    • enzymes - control chemical reactions
  23. what are the 2 steps of protein synthesis
    • transcription
    • translation
  24. what are the steps in transcription
    • 1. RNA polymerase attaches to DNa and opens it at a certain spot
    • 2. free-floating RNA necleotide bases will pair with exposed DNA nitrogenous vases
    • 3. new mRNa strand leaves the nucleus and begins traveling to the cytoplasm for protein synthesis
  25. what are the steps in translation
    • 1. ribosomes binds to the mRNA
    • 2. mRNA has a start codon (methionine) that attaches to an anticodon on tRNA
    • 3. the amino acid attacheswhen the first codon is read, the mRNA moves over so that the next codon can be read
    • 4. a second tRNA anticodon will come and attach to mRNa codon
    • 5. process continues until a stop codon is reached
  26. what are the 3 main types of rna
    • messenger RNA (mRNA)
    • transfer RNA (tRNA)
    • ribosomal RNA (rRNA)
  27. describe messenger rna
    • formed in the nucleus but functions in cytoplasm
    • forms from translated dna
    • nucleus > ribosomes
  28. describe transfer rna
    • formed in nucleus but functions in cytoplasm
    • translates codons into amino acids which for a protein sequence
  29. describe ribosomal rna
    • in the ribosome
    • translates mRNA codons that specify what amino acid is required and what order it is
  30. define codon
    sequences of 3 nitrogenous bases
  31. define anticodon
    anticodon on tRNA will base pair with a codon on mRNA base on what amino acid it codes for