Molecular Biology Vocabulary

Nucleic Acids and DNA Replication

Nucleic Acids

• Rosalind Franklin: Key contributor to the discovery of the structure of DNA.
• Double Helix: The structure of DNA is that of a double helix.
• Nucleic Acids: DNA and RNA are nucleic acids.
• Deoxyribose: The sugar found in DNA.
• Semi-Conservative Method: DNA replication follows a semi-conservative method, where each new DNA molecule contains one original and one newly synthesized strand.

DNA Replication

• Replication Forks: Points where the DNA double helix separates during replication.
• RNA Primers: Short RNA sequences that initiate DNA synthesis.
• DNA Polymerase: Enzyme responsible for adding nucleotides to the growing DNA strand.
• Leading Strand: Synthesized continuously in the 5' to 3' direction towards the replication fork.
• Lagging Strand: Synthesized discontinuously in fragments.
• Okazaki Fragments: Short DNA fragments synthesized on the lagging strand.
• DNA Ligase: Enzyme that joins Okazaki fragments to create a continuous strand.
• Telomere: Protective caps at the end of chromosomes.
• Telomerase: Enzyme that maintains the length of telomeres.

Mutations

• Mutation: A change in the nucleotide sequence of DNA.
• Point Mutation: A mutation affecting a single nucleotide.
• Heritable Mutations: Mutations that can be passed on to offspring.
• Non-Heritable Mutations: Mutations that occur in somatic cells and are not passed on.

Central Dogma of Molecular Biology

• Central Dogma: The flow of genetic information from DNA to RNA to protein.
• Transcription: The process of synthesizing RNA from a DNA template.
• Translation: The process of synthesizing a protein from an RNA template.
• mRNA: Messenger RNA, carries genetic information from DNA to the ribosomes.
• rRNA: Ribosomal RNA, a structural component of ribosomes.
• tRNA: Transfer RNA, brings amino acids to the ribosomes during translation.

Transcription Details

• Transcription Bubble: The region of unwound DNA where transcription occurs.
• RNA Polymerase: Enzyme that synthesizes RNA using a DNA template.
• Alternative Splicing: A process by which different combinations of exons are joined together to produce multiple mRNA transcripts from a single gene.

Translation Details

• Genetic Code: The set of rules by which information encoded in genetic material (DNA or RNA sequences) is translated into proteins (amino acid sequences) by living cells.
• Codon: A sequence of three nucleotides that codes for a specific amino acid or a stop signal during translation.
• Anticodon: A sequence of three nucleotides in tRNA that is complementary to a codon in mRNA.
• Elongation: The process by which the polypeptide chain grows during translation.
• Termination: The process by which translation ends, triggered by a stop codon.

Gene Expression

• Gene Expression: The process by which information from a gene is used in the synthesis of a functional gene product. These products are often proteins, but also can be functional RNA.