DNA, RNA, and Protein Synthesis

DNA, RNA, and Protein Synthesis

• Replication: The cell duplicates its DNA before division (S phase). Product: DNA. One original strand and one new strand are in the resulting DNA.
• Nucleotide Composition (DNA): A sugar molecule, a nitrogenous base, and a phosphate group.
• Pyrimidines: Cytosine (C) and Thymine (T). Uracil (U) replaces Thymine in RNA.
• Purines: Adenine (A) and Guanine (G).
• DNA vs. RNA Differences:
  • Sugar: Ribose (RNA) vs. Deoxyribose (DNA).
  • Strandedness: Generally single-stranded (RNA) vs. double-stranded (DNA).
  • Bases: Uracil (RNA) vs. Thymine (DNA)
• Codon: A three-nucleotide sequence that codes for an amino acid. One codon codes for one amino acid.
• Amino Acids and Codons: 12 amino acids require 36 nucleotides (12 codons)
• Types of RNA: messenger RNA (mRNA), transfer RNA (tRNA), ribosomal RNA (rRNA).
• Replication Enzymes: DNA polymerase and DNA helicase.
• Transcription Enzyme: RNA polymerase.
• Anticodon: Three-base sequence on tRNA that is complementary to an mRNA codon. If the anticodon is UAA, the complementary codon is AUU.
• Translation Termination: A stop codon on mRNA signals the end of translation.
• DNA to RNA Transition: DNA unzips to expose one strand, then this strand is copied into mRNA.
• DNA Discoverers: Francis Crick, James Watson, Maurice Wilkins, and Rosalind Franklin.
• Types of Mutations:
  • Deletion: Removal of a nucleotide.
  • Insertion: Addition of a nucleotide.
  • Substitution: One nucleotide replaces another.
• Start Codon: AUG (methionine).
• DNA Strands: Complementary or collinear strands.
• Least Harmful Mutation: Substitution (sometimes no effect on the amino acid). Insertions/deletions cause significant issues.
• Transformation: Bacteria acquiring new genetic material. The transforming factor is DNA.
• Bacteriophage: Virus that infects bacteria.
• DNA's Role: Storing, copying, and expressing information, crucial for protein production.
• Central Dogma: DNA → RNA → Protein.
• Chargaff's Rule: A=T and C=G.
• DNA Structure Study Method: X-ray diffraction. Proved DNA's helical structure.
• DNA Strands Arrangement: Antiparallel (3' to 5' and 5' to 3').
• DNA Strand Bonding: Held together by hydrogen bonds.
• Base Pairing: Explains Chargaff's rule: A with T, and G with C.
• DNA Polymerase Function: Synthesizes new DNA by adding nucleotides.
• Telomeres: DNA at chromosome ends.
• Telomerase: Lengthens telomeres in germ cells (important for DNA replication).
• Telomerase in Adult Cells: Usually inactive, except for cancer cells. This contributes to rapid proliferation.
• Histones: Proteins around which DNA coils in chromatin.
• Chromatin: DNA-protein complex within the nucleus.
• Prokaryotic Replication: Starts at a single point and proceeds bidirectionally.
• Eukaryotic Replication: Initiates at multiple points and proceeds bidirectionally.
• Separation of DNA Copies: Occurs in anaphase of cell division.
• DNA Location (prokaryotes vs. eukaryotes): Cytoplasm vs. Nucleus.
• Genetic Instructions Initial Step: DNA's base sequence is copied to RNA.
• mRNA Role: Carries genetic instructions from DNA to ribosomes.
• tRNA Role: Carries amino acids to ribosomes.
• rRNA Role: Forms ribosomes, the site of protein synthesis.
• Promoters: DNA sequences where RNA polymerase binds.
• Introns: Noncoding DNA sequences within genes. Removed from mature mRNA.
• Exons: Coding sequences within genes. Spliced together to form mRNA.
• Genetic Code: Set of codons that specify amino acids. Each amino acid isn't always correlated to only one codon.
• Codons in Protein Synthesis: Ribosomes use codons in mRNA to assemble amino acids into polypeptide chains.
• tRNA Process in Translation: tRNA molecules bring the correct amino acid to the ribosome based on the mRNA codon.
• Prokaryotic Gene Regulation: DNA-binding proteins control transcription.
• Operon: Group of genes regulated together.
• Operator: DNA sequence that controls RNA polymerase access.
• Transcription Factors: Proteins that bind to DNA to affect transcription.
• Differentiation: Cells become specialized.
• Homeotic Genes: Control body form development (where body parts go).
• Homeobox Genes: Code for transcription factors that influence cell development and differentiation.
• Master Control Genes: Like gene switches that regulate patterns of development.
• Epigenetics: Study of changes in gene expression without altering the DNA sequence.
• Mutation Effects on DNA: Changes in nucleotide sequence or chromosome structure.
• Silent Mutation: Doesn't change the amino acid produced.
• Missense Mutation: Changes one amino acid to another.
• Nonsense Mutation: Changes codon to a stop codon.
• Frameshift Mutation: Insertion or deletion of nucleotides altering the reading frame.
• Chromosomal Mutations: Alterations in chromosome structure (deletion, duplication, inversion, translocation).
• Mutagens: Agents that cause mutations (chemical or physical). Examples: chemicals, radiation.
• Mutation Types: Spontaneous or induced.
• Beneficial Mutations: Can produce proteins with new/altered functions.
• Polyploidy: Having extra sets of chromosomes (can be advantageous in some crops).

Test your knowledge on the processes of DNA replication, RNA transcription, and protein synthesis. This quiz covers the differences between DNA and RNA, nucleotide composition, and the roles of various types of RNA and enzymes involved. Challenge yourself with questions on codons, amino acids, and more!