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65 Cards in this Set
- Front
- Back
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Haploid or Diploid: Bacteria?
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Haploid
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Haploid or Diploid: Archaea?
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Haploid
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Haploid or Diploid: Eukaryotes?
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Diploid
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What molecule in a cell carries hereditary genetic information?
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DNA
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Why was DNA questioned as the genetic material, what was thought as the more likely candidate, and how did they figure out it was DNA?
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It was thought to be too simple, Protein, Griffith figured out that non-virulent bacteria could transform into virulent ones and then MacLeod and McCarty figured out it was DNA
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What are the monomers of nucleic acids, DNA and RNA?
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Nucleotides
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What is the sugar in DNA?
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Deoxyribose
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What is the backbone to DNA?
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Sugar phosphate
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3’ End is sugar or phosphate?
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Sugar
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5’ End is sugar or phosphate?
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Phosphate
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Name the 4 bases in nucleotides?
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ATGC
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Tell me about DNA
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Double helix, antiparallel, AT 2X h-bond, GC 3x H-bonds, Major and minor groves form when the 2 strands twist around eachother
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Tell me about RNA
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Polymer of nucleotides, contains U instead of T, sugar is ribose, and most RNA molecules are single stranded but some are double stranded
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What are the 4 main types of RNA?
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mRNA, rRNA, tRNA, sRNA
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How are amino acids linked together?
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Peptide bonds
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What is the C terminal of a protein?
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The carboxylic acid side of the amino acid
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What is the N terminal of a protein?
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The amino group in an amino acid
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Where does the peptide bond form in Amino acids?
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Between C-terminal and N-terminal
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What determines the charge/polarity of amino acids?
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R group
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Shape of most bacterial DNA?
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Circular
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Where does replication end?
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Terminus
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What is the replication fork?
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Where DNA is unwound and synthesis of new DNA strand occurs
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What does a DNA polymerase require?
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Template, primer and a dNTP
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What DNA polymerase is important?
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3
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What is the direction of DNA polymerase synthesis?
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5’-3’
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How are lagging strands synthesized?
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Okazaki fragments
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What do okazaki fragments need at the end of each fragment for synthesis?
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Primer
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How are mistakes in DNA detected and corrected?
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DNA Polymerase 3 removes the mismatched base from the 3’ end of a growing strand.
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How do the two circular daughter chromosomes separate?
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Topoisomerases temporarily break the DNA molecule to separate it.
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What is the problem with linear chromosomes?
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Crap wants to degrade the ends, the shortening of chromosomes after each round of replication
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How do eukaryotes ‘solve’ the end replication problem in linear chromosomes?
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Telomerase enzymes
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How do bacteria ‘solve’ the end of replication problem in linear chromosomes?
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The bacteria disguise the ends of the linear chromosomes
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What is a gene
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The basic unit of genetic information, also the nucleic acid sequence that codes for a polypeptide, tRNA or rRNA
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Where are codons found?
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mRNA and code for single amino acids
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What strand of DNA directs RNA synthesis?
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Template strand
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What does the promoter do and why is it a problem if it gets a mutation?
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It is the binding site for RNA polymerase. If it gets mutated, then the polymerase might not get bound.
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What is N-formylmethionine and where is it found?
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A modded amino acid found in bacteria.
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What immediately follows a stop codon?
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An untranslated region (UTR) which has a termination sequence to stop transcription
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Which strand of DNA produces RNA that is complementary to it?
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Template
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What does mRNA do?
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Carries the message for protein synthesis
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What does tRNA do?
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Carries amino acids during protein synthesis
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What does rRNA do?
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Components of ribosomes
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What does sRNA do?
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Small regulatory RNA that aren’t typically made into proteins
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Define monocistronic mRNA
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one gene/protein is produced from one mRNA
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Define polycistronic mRNA
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More than one polypeptide contained within one mRNA molecule (it can make multiple proteins)
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What carries out transcription?
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RNA polymerase
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What is a sigma factor?
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Part of RNA polymerase which has no catalytic activity but helps the core enzyme recognize the DNA at the promoter
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How many parts does the promoter contain and name them?
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2 parts: -10 and -30 position
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List the steps to translation in bacteria
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sigma factor interacts with the RNA polymerase core enzyme and directs it to a promoter. RNA poly unwinds a short stretch of DNA forming an operon complex. RNA poly begins to synth RNA after about 12 nucleotides have been linked together, the sigma factor dissociates from the core RNA polymerase and transcription enters the elongation phase. Elongation continues until a terminator is encountered, RNA poly stops transcription and the RNA is released
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How does RNA polymerase work?
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RNA polymerase slides along DNA creating an open complex as it moves. The template strand is used to make a complementary copy of RNA as an RNA-DNA hybrid. RNA is synthesized in a 5’3’ direction using ribonucleoside triphosphates as precursors. Pyrophosphate is released. The complementary rule is the same as the AT/CG rule but the U is substituted for T in RNA
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Where does the polymerase pause?
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PolyA tail
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What does the polymerase pausing cause?
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A stem loop to form, which will unstabilize the UA bonds, and it will cause the RNA to fall off the DNA and termination to occur.
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Describe Rho-Dependent termination
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There is a site on the mRNA called rut site. Rho will bind there and move along the mRNA in the direction of the RNA polymerase, and when the RNA pauses at the terminator Rho will run right into it and knock the damn thing off.
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What is the difference translation and transcription?
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Tranlation is translating the RNA into Protein. Transcription is DNA to RNA
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How is the mRNA code translated into proteins?
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Every 3 nucleotides is called a codon. This is a code (61 codons) which specify an amino acid which will link together to form a protein
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What are the exceptions to the codon code?
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There are the stop codon exceptions: Some protists use UGA only as a stop codon. UAA and UAG are actually an amino acid called Glutamine. Some microbes and eukaryotes incorporate rare amino acids into polypeptides like selenocysteine and pyrrolysine. Then there are the start codon exceptions: There are alternative start codons in bacteria such as GUG and UUG. However, they are still translated as methionine
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What is the direction of translation synthesis?
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Nterminal to C terminal
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What is a ribosome?
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The site of translation (also transcription in bacteria/Archaea)
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How many tRNA molecules are there?
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70-95
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What is the structure of a tRNA and why?
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It’s a tertiary structure due to the base pairing within the tRNA molecule. It base pairs with itself.
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What is an anticodon and where is it found?
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An anticodon is a part of the tRNA that is complementary to the codon and will bind to the codon.
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Which end of the tRNA will bind the amino acid?
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The 3’ end. They all have a terminal CCA sequence which binds it
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Describe how Aminoacyl-tRNA synthetases work?
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It’s an enzyme which binds an amino acid, an ATP molecule, and a tRNA to it. Then it binds the tRNA to the amino acid.
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How do bacteria initiate translation?
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N-formalmethionine
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How do archaea initate translation?
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Methionine
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