microbio chapter 7

• Gregor Mendel (1822-1884)


  Austrian monk that wasn't acknowledged till 30 years later. Worked with pea plants and is known as the father of genetics
• Transcription


  is the process in which RNA is made in a complimentary sequence that is antiparallel to the DNA strand

  
• In RNA uracil replaces what?

  Thymine
• What is a sigma factor and what does it do?


  Sigma factor is a protein that aids the initiation of transcription. It allows RNA polymerase to bind to the promoter on the DNA. Not present in archaea and eukarya
• How does DNA get to be protien?


  Starts as DNA transcription occurs in nucleus, turning it into mRNA, then gets translated at the ribosomes, which then becomes a polypeptide
• What does the genetic code start with generally?

  AUG (methionine)
• What is a Codon?

  it is a group of 3 mRNA bases which are read together
• What do ribosomes do during translation?


  The ribosomes read the transcription. It does so by directing specific tRNA towards the polypeptide chain growing it.
• What is tRNA and its function?

  it is the transfer RNA that binds to specific amino acids to move them.
• Eukaryote ribosome


  60S + 40S = 80S
• Prokaryote ribosome


  50S+30S=70S
• What is an anticodon?


  a sequence of three nucleotides forming a unit of genetic code in a transfer RNA molecule, corresponding to a complementary codon in messenger RNA.

  
• Where do amino acids attach on an anticodon?

  3 prime end
• aminoacyl-tRNA synthetase


  An enzyme that joins each amino acid to the appropriate tRNA.
• How many reading frames are there?

  there are only three reading frames, which depend on the start of the coding region
• What delivers amino acids to ribosomes?


  tRNA, each one has a specific anticodon sequence that binds with the correct codon. After delivering the tRNA can be recycled.
• What is the genetic code?

  it is 3 nucleotides which makes a codon
• initiation of transcription


  Small ribosomal subunit attaches to the mRNA, then initiator tRNA pairs with the mRNA start codon
• elongation of transcription


  RNA polymerase goes down the template strand of DNA adding a complimentary nucleotide
• termination of transcription


  RNA polymerase reaches a terminator sequence (Stop codon) and detaches from the template
• Transcription in Prokaryotes


  occurs in cytoplasm, No CAP, polyA tail, or splicing. Translation occurs simultaneously-coupled
• mRNA processing in eukaryotes


  primary mRNA transcript is synthesized by RNA polymerase II
• What is RNA polymerase II, And its Function?


  It transcribes all protien coding genes and noncoding RNA, lacks the ability to start transcription.
• Where do genes reside?

  in chromosomes
• Mendels Theory of inheritance


  1. Parents do not transmit traits directly to their offspring

  2.Each parent contains two copies of the factor governing the traits

  3.Alternative forms of a factor lead to alternative traits

  4.the two alleles that an individual possesses do not affect each other

  5. Th presence of an allele does not ensure that a trait will be expressed in the individual who carries it
• Thomas Hunt Morgan


  used Drosophila melangaster (fruit flies) to confirm the existence of sex-linked traits
• One gene; one enzyme


  that genes are the direct production of enzymes
• Who discovered the double helix


  James Watson and Francis Crick
• Who is Rosalind Franklin


  She is best known for her work on DNA and X-ray diffraction photographs, critical contributions to the glorified work of Watson and Crick.
• Who is Francois Jacob and Jacques Monod?


  they are considered the fathers of modern genetics. They determined E.coli regulates gene expression as well developed operon model for gene expression. Also discovered Lac operon functions
• What is DNA composed of?


  Adenine, Guanine, Thymine, Cytosine
• What are purines?


  Adenine (A) and Guanine (G)
• What are the pyrmidines?


  thymine and cytosine
• Nucleotide composition


  Base, Phosphate, 5 carbon sugar(deoxyribose)

  Base attaches to #1 carbon, phosphate attaches to #5 carbon
• What has two hydrogen bonds


  adenine and thymine
• What has three hydrogen bonds

  Cytosine and Guanine
• DNA


  An antiparallel structure composed of 4 nucleotides that have a 3prime and 5 prime ends. At the end of 3 prime groups hydroxal groups allow new nucleotides to add on
• Hydroxal group


  OH, which is a hydrogen and oxygen atom available to add on new nucleotides
• Gene expression


  The process by which information encoded in DNA directs the synthesis of proteins or, in some cases, RNAs that are not translated into proteins and instead function as RNAs.
• Gene expression in bacteria


  Rna polymerase synthesizes single stranded RNA in a 5' to 3' direction, binds to promoter(transcription starts) then stops at terminator.