Molecular Biology of the Gene

These flashcards cover key concepts from molecular biology, focusing on genetic material, DNA replication, and gene expression processes.

Genetic Material

Substance that carries genetic information, primarily DNA.

Transformation

Process where a non-virulent strain of bacteria acquires virulence by taking up DNA from dead virulent cells.

Avery Experiment

Demonstrated that DNA is the transforming substance in Griffith's experiment.

Hershey and Chase Experiment

Confirmed that DNA, not protein, is the genetic material in viruses.

Chargaff's Rules

States that in DNA, the amount of adenine equals thymine, and the amount of guanine equals cytosine.

Double Helix

Structure of DNA, resembling a twisted ladder with sugar-phosphate backbones and paired bases.

Nucleotide

The basic building block of DNA and RNA, composed of a sugar, phosphate group, and nitrogenous base.

Semiconservative Replication

Method of DNA replication where each new DNA molecule contains one old strand and one new strand.

DNA Polymerase

Enzyme responsible for synthesizing new DNA strands during replication.

Okazaki Fragments

Short segments of DNA synthesized on the lagging strand during DNA replication.

RNA

Single-stranded nucleic acid that plays various roles in coding, decoding, regulation, and expression of genes.

Messenger RNA (mRNA)

Type of RNA that carries the genetic message from DNA to the ribosome for protein synthesis.

Transfer RNA (tRNA)

Type of RNA that transports amino acids to the ribosome during protein synthesis.

Ribosomal RNA (rRNA)

Type of RNA that makes up the major part of ribosomes.

Codon

A sequence of three RNA nucleotides that correspond to a specific amino acid.

Stop Codon

Codon that signals the termination of translation.

Start Codon

Codon that signals the start of translation, usually AUG (Methionine).

Exons

Segments of RNA that code for proteins and are expressed after splicing.

Introns

Non-coding segments of RNA that are removed during mRNA processing.

Promoter

Region of DNA that initiates transcription of a gene.

Termination Sequence

Sequence in DNA that signals the end of transcription.

Transcription

Process of copying a specific segment of DNA into RNA.

Translation

Process where ribosomes synthesize proteins from mRNA.

Ribosome

Cell organelle where protein synthesis occurs, composed of rRNA and protein.

Peptide Bond

Covalent bond formed between two amino acids during protein synthesis.

Gene Expression

Process by which information from a gene is used to synthesize functional gene products, typically proteins.

Telomeres

Repeated sequences at the ends of chromosomes that protect them from degradation.

DNA Ligase

Enzyme that joins Okazaki fragments on the lagging strand during DNA replication.

Helicase

Enzyme that unwinds and separates the double-stranded DNA during replication.

Spliceosome

Complex that splices introns out of pre-mRNA.

Wobble Hypothesis

The ability of a tRNA to recognize multiple codons due to flexibility in base pairing at the third nucleotide position.

Anticodon

Sequence of three nucleotides in tRNA that is complementary to a codon in mRNA.