63 terms

AP Biology Test Prep Chapter 11: Molecular Genetics

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Adenine and Guanine
Nitrogenous bases that are classified as Purines.
Purine
A nitrogenous base that contains a double ring structure.
Cytosine and Thymine
Nitrogenous bases that are classified as Pyrimidines
Pyrimidine
A nitrogenous base that contains a single ring structure.
DNA Replication
The process by which DNA is copied. This process occurs during the S phase of the cell cycle to ensure that every cell produced during mitosis and meiosis recieves the proper amount of DNA.
Conservative DNA Replication
Theory that the original helix of DNA does not change at all; it is as if the DNA is placed on a copy machine and an exact duplicate is made. DNA from the original parent appears only in one of the two daughter cells.
Semi-conservative DNA Replication
Theory that before the parent strand is copied, the DNA unzips, with each single strand serving as a template for the creation of a new double strand. One strand of DNA from the parent goes to one daughter cell and the second parent strand goes to the second daughter cell.
Dispersive DNA Replication
Theory that suggests that every daughter strand contains some parental DNA, but it is spread out among pieces of DNA not of parental origin.
Helicase
Enzyme that unzips DNA, breaking the hydrogen bond between the nucleotides and producing the replication fork for replication.
Replication Fork
Opened in DNA strand so that DNA replication can occur.
Primer Sites
DNA segments that signal where replication should originate.
DNA Polymerase
The main enzyme in DNA replication that attaches to primer proteins and adds nucleotides to the growing DNA chain in a
5'-to-3' direction.
Okazaki Fragments
The lagging DNA strand consists of these tiny pieces that are later connected by DNA ligase to produse the completed double-stranded DNA molecule.
Mismatch Repair
Process during DNA replication by which DNA polymerase replaces an incorrectly placed nucleotide with the proper one.
Excision Repair
Process during DNA replication by which a section of DNA containing an error is cut out and the gap is filled by DNA polymerase.
Frameshift Mutation
Deletion or addition of DNA nucleotides that does not add or remove a multiple of three nucleotides. Usually produces a nonfunctional protein unless it occurs late in protein production.
Missense Mutation
Substitution of the wrong nucleotides into the DNA sequence. Still leads to the addition of amino acids, but can lead to addition of incorrect amino acids.
Nonsense Mutation
Substitution of the wrong nucleotides into the DNA sequence. Leads to the premature stoppage of protein synthesis by the early placement of a stop codon.
Stop Codon
Codon:UGA
Thymine Dimers
Mutation when thymine nucleotides located adjacent to one another on the DNA strand bind together when excess exposure to UV light occurs. Negatively affects DNA replication and assists in the creation of further mutations.
RNA Polymerase
Enzyme that runs transcription and adds the appropriate nucleotides to the 3' end of the growing strand.
Promoter Region
A recognition site that shows the polymerase where transcription should begin.
TATA Box
Group of nucleotides found in the promoter region that assists in the binding of RNA polymerase to the DNA strand for transcription.
Transcription Factors
Helper proteins that assist RNA polymerase in finding and attaching to the promoter region.
Termination Site
Region of DNA that tells the polymerase when transcription should conclude.
Introns
Noncoding regions produced during transcription that are cut out of the mRNA.
Exons
Coding regions produced during transcription that are glued back together to produce the mRNA that is translated into a protein.
RNA Splicing
Process that removes introns from newly produced mRNA and then glues exons back together to produce the final product.
Start Codon
Codon:AUG
A Site
Region in protein synthesis machinery that holds the tRNA carrying the next amino acid.
P Site
Region in protein synthesis machinery that holds the tRNA carrying the growing protein.
Aminoacyl tRNA Synthetase
Enzyme that makes sure that each tRNA molecule picks up the appropriate amino acid for its anticodon.
Wobble
Theory that states that nucleotides in the third position of an anticodon are able to pair with many nucleotides instead of just their normal partner.
Stop Codon
Codon:UAA
Stop Codon
Codon:UAG
Operator
A short sequence near the promoter that assists in transcription by interacting with regulatory proteins/ transcription factors.
Operon
A promoter/operator pair that services multiple genes.
Lac Operon
Operon that aids in the control of transcription of lactose metabolizing genes.
Repressor
Protein that prevents the binding of RNA polymerase to the promoter site.
Enhancer
DNA region that is located thousands of bases away from the promoter that influences transcription by interacting with specific transcription factors, also known as a regulator.
Inducer
A molecule that binds to and inactivates a repressor.
DNA Methylation
Addition of CH3 groups to the bases of DNA.
Virus
Parasitic infectious agent that is unable to survive outside a host organism.
Capsid
Protein shell that surrounds genetic material of viruses.
Viral Envelope
Protective barrier that surrounds some viruses but also helps them attach to cells that a virus is able to infect.
Host Range
The range of cells that a virus is able to infect.
Retrovirus
An RNA virus that carries an enzyme called reverse transcriptase.
Reverse Transcriptase
Enzyme carried by retroviruses that function to convert RNA to DNA.
Lytic Cycle
When the cell actually produces many viral offspring.
Lysogenic Cycle
When the virus falls dormant and incorporates its DNA into the host DNA as an entity called a provirus.
Provirus
A virus genome that is integrated into the DNA of a host cell that can be transmitted from one generation to the next without causing lysis.
Viroids
Plant viruses that are only a few hundred nucleotides in length.
Prion
Incorrectly folded form of a brain cell protein that works by converting other normal host proteins into misshapen.
Transformation
The modification of a cell or bacterium by the uptake and incorporation of external DNA.
Transduction
The movement of genes from one cell to another by phages.
Phage
A virus that infects bacteria.
Sex Pili
Bacterial appendage vital to the process of conjugation.
Conjugation
The transfer of DNA between two bacterial cells connected by appendages called sex pili.
F Plasmid
Plasmid that contains the genes necessary for the production of a sex pillus.
Restriction Enzyme
Enzymes that cut DNA at specific nucleotide sequences.
Sticky-Ends
Single-stranded DNA fragments formed when DNA is treated with restriction enzymes that find and reconnect with other fragments with the same ends.
Vector
Agent that moves DNA from one source to another.
Southern Blotting
Procedure used to determine if a particular sequence of nucleotides is present in a sample of DNA.
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