bio unit 3 review

• Transcription: The process of copying the DNA sequence of a gene into a sequence of nucleotides
• translation: the process of converting the information in DNA into a sequence of amino acids
• differences between DNA and RNA: DNA is double stranded and RNA is single stranded. DNA is deoxyribose and RNA is ribose. DNA has thymine and RNA has uracil.
• three classes of RNA: mRNA, tRNA, rRNA
• start codon: AUG, stop codons: UAA and UAG and UGA
• promoter: region rich in A and T bases that binds to RNA polymerase, upstream to gene thats transcribed.
• template/coding strand: the strand that is copied during DNA replication, it is the template for the new strand
• anticodon: the sequence of bases on the tRNA that complement the codon on the mRNA (UAC)
•  acceptor & peptide site: where new aminoacyl-tRNAs enter and position their amino acids for addition to the polypeptide chain. 
• lac Operon

  • Promoter/Operator: A region of DNA where the lac repressor binds (operator) and RNA polymerase binds (promoter) to control transcription initiation.
• lac Operon

  • Repressor Protein: Encoded by the lacI gene, it binds to the operator in the absence of an inducer, blocking transcription of the structural genes (lacZ, lacY, lacA).
• lac Operon

  • Signal Molecule/Inducer: Binding of the inducer to the repressor causes a conformational change, preventing it from binding the operator and allowing transcription.
• Silent Mutation: A nucleotide substitution that does not change the amino acid sequence.
• Missense Mutation: A nucleotide substitution that changes the amino acid sequence.
• Nonsense Mutation: A nucleotide substitution that introduces a premature stop codon, shortening the protein.
• Frameshift Mutation: An insertion or deletion that shifts the reading frame of the genetic code.
• Point Mutation: A single nucleotide substitution.
• Transposable Elements: DNA sequences that can move from one location to another within the genome.
• Spontaneous/Induced Mutations: Spontaneous mutations occur randomly, induced mutations are caused by agents like radiation & chemicals.
• Coupled Transcription- In prokaryotes, translation (protein synthesis) begins while the mRNA is still being transcribed, allowing for fast gene expression.
• Chromatin: Complex of DNA and proteins that forms the chromosomes in eukaryotes.
• Histones: Proteins that DNA wraps around to form nucleosomes. the basic unit of chromatin.
• Nucleosome: A unit of chromatin consisting of DNA wrapped around a histone core.
• VNTRs (Variable Number Tandem Repeats): Short DNA sequences repeated in synced arrays, which can vary in number.
• Telomeres: Repetitive DNA sequences at the ends of linear chromosomes that protect them from degradation.
• Pseudogenes: Nonfunctional relatives of known genes that have lost their protein-coding ability due to mutations
• causes for genetic mutations: uv rays, x rays, cosmic rays, chemicals
• housekeeping genes: genes that need to be on all the time for cell function
• operon: cluster of genes controlled by promoter, operator, and structural genes
• oncogenes: damaged copies of genes that control cell devision
• aminoactyl-tRNA: tRNA with its specific amino acid
• LINES and SINES: long/short interspersed nuclear elements. defective copies.
• everything involved in replication: helicase, DNA pol III, girase, DNA ligase, primase, RNA primer, DNA pol I, SSBs.