DNA and RNA Structure

• Purines


  2 ringed nitrogenous bases
• Pyrimidines


  1 ringed nitrogenous base
• Purines


  Adenine and Guanine type
• Pyrimidines


  Cytosine, Thymine, Uracil type
• Nucleotide


  DNA and RNA monomer
• Nitrogenous bases are considered bases because they can pick up a lot of H+, which would reduce the acidity of a solution
• Ribose


  5 carbon sugar that has a hydroxyl group attached to the 2nd carbon
• Deoxyribose


  5 carbon sugar with just a hydrogen attached to the 2nd carbon
• Phosphate groups attach to the 5 prime carbon of the sugar in nucleic acids. A nucleotide that isn't part of a chain has three of them, and loses 2 when it joins a chain, so every nucleotide in a chain has only one phosphate backbone
• Directionality


  Characteristic of nucleic acid polynucleotide chains meaning their ends are different
• 5 prime end


  Phosphate group at the beginning of the chain sticks out
• 3 prime end

  Hydroxyl of the last nucleotide added sticks out
• Sugar phosphate backbone


  Forms the sides of the ladder, holds nucleotides in a DNA double helix
• Antiparallel


  Direction in which DNA strands run against each other in double helix
• Complemetary


  When two strands of DNA match with each other (have paired bases)
• Properties of RNA

  • single stranded
  • Uracil instead of thymine
  • Ribose instead of deoxyribose
• Messenger RNA


  RNA that gets signaled by sections of DNA to transcribe it into a ribosome so the protein can be produced. Each set of 3 nucleotides on it is read as a codon by the ribosome, which then codes for the right amino acids
• Codon


  Set of 3 mRNA nucleotides that gets read by the ribosomes during transcription
• Ribozymes


  RNAs that act as enzymes
• Ribosomal RNA


  Helps mRNA bind to the right spots on the ribosome so that its sequence information can be read out
• Transfer RNAs


  Bring the right amino acids to the ribosome so it can create the protein its coding for. Single stranded but folds over into a complex 3d structure that's important for it to do its job
• Regulatory RNAs (miRNA and siRNA)


  Non coding RNA about 22 nucleotides long that attaches to other RNAs to reduce their stability or interfere with their translation to fine tune or decrease their levels
• Prokaryotes


  Single celled organisms belonging to the domains Bacteria and Archaea
• Prokaryotes do not have a membrane bound nucleus or other organelles
• Capsule


  Sticky outer layer made of polysaccharides that most prokaryotes have. Helps them stick together
• Cell wall


  All prokaryotes have them to help maintain their shape and rigidity. Located underneath the capsule, if it has one
• Peptidoglycan


  Polymer of linked sugars and polypeptides, containing weird amino acids. Make up the cell wall
• Some archaea have their plasma membrane phospholipid tails actually connect, creating a phospholipid monolayer. Helps them maintain their structure at high temperatures
• Fimbriae


  Thin filaments that are prokaryote appendages, helping them stick to surfaces
• Sex pili


  Longer appendages on prokaryotes that help hold two bacterial cells together to allow for transfer of DNA between them (conjugation)
• Pili


  Longer appendages on prokaryotes that have many purposes, from holding cells together while they exchange DNA to letting them move around in their environments
• Flagella


  Tail like appendage that whips around, most common prokaryotic ovement appendage
• Nucleoid


  Where the singular circular chromosome of a prokaryote is held in the cytoplasm
• R genes


  Genes carried in plasmids that help bacteria have resistance to antibiotics
• Plasmids


  Small rings of double stranded extra-chromosomal DNA that carry a small amount of genes and are copied apart from the chromosome inside of the cell. Can be transferred, which might be beneficial to the population (like R genes)
• Photosynthetic bacteria usually have a lot of membrane folds so they can get more light in