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Flashcards covering key concepts from Chapter 12: Molecular Genetics, including DNA structure, replication, transcription, translation, gene regulation, and mutations.
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What is the central dogma of molecular biology?
DNA codes for RNA, which guides the synthesis of proteins.
What are the three major types of RNA?
Messenger RNA (mRNA), Ribosomal RNA (rRNA), and Transfer RNA (tRNA).
What is transcription?
The synthesis of mRNA from DNA.
What is translation?
The process through which mRNA attaches to a ribosome and a protein is assembled.
What are introns?
Non-coding sequences of DNA that are removed from pre-mRNA.
What are exons?
The coding sequences that remain in the final mRNA.
What is a codon?
A three-base code in DNA or mRNA that codes for a specific amino acid.
What is gene regulation?
The ability of an organism to control which genes are transcribed in response to the environment.
What is an operon?
A section of DNA that contains the genes for the proteins needed for a specific metabolic pathway.
What is a mutation?
A permanent change in a cell's DNA.
What is a mutagen?
Substances that cause mutations.
What is semiconservative replication?
When parental strands of DNA separate, serve as templates, and produce DNA molecules that have one strand of parental DNA and one strand of new DNA.
What is the function of DNA helicase?
Unwinds and unzips the double helix during DNA replication.
What is the function of DNA polymerase?
Catalyzes the addition of appropriate nucleotides to the new DNA strand.
What are Okazaki fragments?
Small segments synthesized discontinuously on the lagging strand during DNA replication.
Briefly explain Griffith's experiment
Griffith discovered that a strain of bacteria could be transformed into another strain.
Briefly explain Avery's experiment
Avery discovered that DNA was the transforming factor in Griffith's experiment.
Briefly explain the Hershey-Chase experiment
Hershey and Chase provided definitive evidence that DNA, not protein, was the transforming factor by using bacteriophages.
What is Chargaff's rule?
That the amount of guanine nearly equals the amount of cytosine, and the amount of adenine nearly equals the amount of thymine.
What is a double helix?
DNA is a double helix, or twisted ladder shape, formed by two strands of nucleotides twisted around each other.
What is a nucleosome?
A structural unit of a eukaryotic chromosome, consisting of a length of DNA coiled around a core of histones.