DNA, RNA, and Protein Synthesis Quiz

DNA, RNA, and Protein Synthesis

• Replication: A cell duplicates its DNA during the S phase of the cell cycle. The result is two identical DNA molecules, each containing one original and one new strand. Key enzymes involved are DNA polymerase and DNA helicase.
• Transcription: A process of copying a base sequence from DNA to RNA. The product is RNA. The key enzyme is RNA polymerase.
• Translation: Decoding of an mRNA message into a polypeptide chain (protein). The product is a protein. Ribosomes, mRNA, and tRNA are crucial in this process.
• Nucleotide Structure (DNA): A nucleotide is comprised of a sugar molecule, a nitrogen-containing base, and a phosphate group.
• Pyrimidines: Cytosine (C) and Thymine (T). In RNA, Uracil (U) substitutes for Thymine.
• Purines: Adenine (A) and Guanine (G).
• DNA vs. RNA Differences: RNA uses ribose sugar instead of deoxyribose, RNA is typically single-stranded, and Uracil replaces Thymine in RNA.
• Codons: A three-nucleotide sequence that codes for an amino acid.
• Codons per amino acid: One codon specifies a single amino acid.
• Number of codons for many amino acids: The number of codons needed to code for a specific number of amino acids would be that quantity multiplied by 3.
• Types of RNA: Messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).
• Anticodon: A three-base sequence on tRNA that is complementary to an mRNA codon.
• Codon-Anticodon Example: If an anticodon is UAA, the complementary codon is AUU.
• Translation Termination: Translation stops when a stop codon on the mRNA is reached.
• DNA to RNA Process: DNA must unzip to allow one strand to act as a template for transcription into mRNA.
• DNA Scientists: Francis Crick, James Watson, Maurice Wilkins, and Rosalind Franklin elucidated the structure of DNA, though Franklin's contributions were often overlooked.
• Types of Mutations: Deletions, insertions, and substitutions.
• Deletion Mutation: Loss of one nucleotide.
• Insertion Mutation: Addition of one nucleotide.
• Substitution Mutation: Replacement of one nucleotide with another.
• Start Codon: AUG, specifying methionine.
• DNA Strands: Two DNA strands are called complementary or collinear strands.
• Least problematic mutation type: Substitutions could be less problematic than insertions or deletions because they preserve the frame.
• Transformation: A change in bacteria that is caused by genes from another strain/a source.
• Transforming Factor: DNA.
• Bacteriophage: Viruses that infect bacteria.
• DNA Role: Storing, copying, and expressing information (instructions to produce proteins).
• Central Dogma: DNA → RNA → Protein.
• Chargaff's Rule: A=T and C=G (Base pairing).
• Franklin's Technique: X-ray diffraction, which determined that DNA has a helical structure.
• Antiparallel Strands: The two strands of DNA run in opposite directions (3' to 5' and 5' to 3').
• DNA Strand Bonding: Hydrogen bonds hold the two DNA strands together.
• Base Pairing Principle: Adenine bonds with Thymine, and Guanine bonds with Cytosine.
• DNA Polymerase Role: Synthesizes new DNA strands by adding nucleotides to the 3' end of a primer.
• Telomeres: DNA at the tips of eukaryotic chromosomes.
• Telomerase: Lengthens telomeres in germ cells, preventing loss of genes.
• Telomerase in Adult Cells: Often inactive, except in cancer cells, allowing for rapid cell division.
• Histones: Proteins around which DNA is tightly coiled in chromatin.
• Chromatin: DNA, RNA, and associated proteins in the nucleus.
• Prokaryotic Replication: Begins at one spot, proceeds in two directions.
• Eukaryotic Replication: Begins at multiple spots, proceeds in two directions.
• DNA Separation (Cell Division): Separates during anaphase of cell division.
• DNA Location (Eukaryotes vs. Prokaryotes): Eukaryotic DNA is in the nucleus, prokaryotic DNA is in the cytoplasm.
• Decoding Genetic Instructions: Copying part of the DNA base sequence to RNA.
• mRNA Role: Carries genetic information from DNA to ribosomes.
• tRNA Role: Carries amino acids to ribosomes.
• rRNA Role: Forms ribosomes for protein synthesis.
• Promoters: DNA segments where RNA polymerase binds for transcription.
• Introns: Non-coding segments of DNA that are removed from the final mRNA.
• Exons: Coding segments of eukaryotic DNA, rejoined to form the final mRNA.
• Genetic Code: Collection of mRNA codons that specify amino acids.
• Codons per amino acid (variability): Each amino acid may correspond to several codons.
• Special Codons: Start and stop codons.
• Protein Synthesis Role of Ribosomes: Ribosomes use the mRNA sequence to assemble amino acids into polypeptide chains.
• tRNA and Amino Acid Delivery: tRNA molecules bring the correct amino acids to the ribosome during translation.
• Anticodon Location: tRNA
• Prokaryotic Gene Regulation: DNA-binding proteins control gene transcription.
• Operon: A group of genes regulated together.
• Operator: DNA segment that controls gene access to RNA polymerase.
• Transcription Factors: Regulatory proteins that bind to DNA, affecting gene transcription and expression.
• Differentiation: The process of cells becoming specialized.
• Homeotic Genes: Genes responsible for determining the body plan's general features
• Homeobox Genes: Code for transcription factors, regulating development via gene expression.
• Master Control Genes: Genes that act like switches, triggering developmental patterns.
• Epigenetics: Changes in gene expression without changing the DNA sequence.
• Mutation Effects on DNA: Changes in nucleotide sequences or chromosome structure.
• Mutation Definitions: A permanent change in the DNA sequence.
• Silent Mutation: No change in the amino acid sequence.
• Missense Mutation: Change in amino acid.
• Nonsense Mutation: Changes a codon to a stop codon.
• Frameshift Mutation: Insertion or deletion of nucleotides, altering the reading frame.
• Chromosomal Mutations: Changes in chromosome structure (deletion, duplication, inversion, translocation).
• Mutagens: Chemical or physical agents causing mutations (radiation, chemicals).
• Mutation Types: Spontaneous or induced (environmentally caused).
• Helpful Mutation Effects: Proteins with new functions, adaptable in changes in environments.
• Polyploidy: Extra chromosome sets in an organism; can be beneficial in some crops.

Test your knowledge on the essential processes of DNA replication, transcription, and translation. Explore the structural differences between DNA and RNA, as well as the roles of various nucleotides and enzymes involved in protein synthesis.