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42 Cards in this Set
- Front
- Back
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What is transcription?
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It is the process by which RNA polymerase uses a DNA template to produce mRNA.
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What is an operon?
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An operon is 2 or more genes in a bacterial chromosome that are transcribe into 1 mRNA molecule. Eukaryotic cells do not have operons.
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What is translation?
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Is the process of rRNA translating the mRNA codons into proteins by polymerizing the correct amino acid in the correct order.
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Give the function of RNA polymerase
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Used to produce the RNA copy of each gene.
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Give the function of mRNA
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A template for the coded genetic information in DNA to be translated into protein.
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What is the function of ribosomes?
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Enzymes that carry out the process of translation.
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What is the function of a codon?
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A nucleotide triplet that codes for a specific amino acid.
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What is the copled transcription and translation?
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Coupled transcription and translation is the simultaneous sythesis of RNA and protein that occurs in the cytoplasm of prokaryotes.
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What does a triplet of bases encode?
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Each triplet codon in mRNA codes for 1 amino acid.
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How did Griffith demonstrated a gene transfer?
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Griffith showed that capsular production could be restored to a capsular mutant from dead, wild-type bacteria.
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Hos did Avery show that genes are made of DNA?
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Avery and his co-workers showed that the bacterils ubstance that caused strong evidenc that tranferal of DNA rather thean protein or RNA was necessary for capsule production
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What did Hershey and Chase's experiment confirm?
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Confirmed that DNA rather than protein, is the genetic material
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Define: Gene
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The DNA coding material for a single proteing
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Define: Chromosome
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A large circular molecule of several million base pairs of DNA that contains cellular genes
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Define: Genome
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The collection of all the genes in a cell
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Define: Complementary DNA
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DNA that will base pair with another DNA molecule because it has A in place of every T, C in place of every G of the other molecule.
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How many genes might there be in an average bacterium? In a human cell
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5,000 GENES IN BACTERIUM
50,000 GENES IN A HUMAN CELL |
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What cells have diploid or haploid genomes?
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Prokaryotic cells have haploid genomes; Eukaryotic cells have diploid genomes.
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What must happen to the genetic material when division of a cell occurs?
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When division of a cell occurs, the genome must be duplicated.
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Where does DNA sythesis begin?
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DNA sythesis begins at the origin of replication.
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What is produced by DNA replication?
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DNA replication produces 2 double stranded DNA molecules identical to the starting DNA.
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How does DNA proofread?
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DNA proofreads through DNA polymerase, which cheeks to see if the newly added nucleotides are complementary to the template. If they are not complementary, DNA polymerase removes and replaces them with a new nucleotide.
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Are human viruses harmful or beneficial?
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Human viruses can be both harmfual and beneficial. When a virus causes damage to the host, it is harmful. When a virus is used by gene therapy to repair human genetic defect, it is beneficial.
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What is a viral vector
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A viral vector is a virus sued in gene therapy to deliver a gene with jproper activity to host cells that need the gene.
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When do bacteria normally regulate gene expression?
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Bacteri ususally regulate gene expression during transcriptions
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How is lac operon induced?
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Lactose combines with the lac repressor to inactivate it. RNA polymerase can then bind to the promoter and trancribe the lac operon.
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How is the tryptophan operon repressed?
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Tryptophan binds to the trp operon aporepressor to form an active comples, which binds to the trp operator and jprevents RNA polymerase binding and transcriptions
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Describe feedback inhibition
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Feedback inhibition is associated with repressible opersons where end product of the operon pathwaymakes a complex with the aporepressor to inhibit transcriptions
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Give 2 ways that inducible and repressible expression control differs
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Inducible systems turn on expression while repressible systems turn them off. Repressible systems have fine control over how much expression occurs.
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What is a function proteses?
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Proteases rid the cell of unwanted proteins.
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List 3 things that can cause mutation
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3 things that cause mutation are as follows: a mistake in the DNA-dependent DNA polymerase; chemicals found in the enviroment; and ultrviolet rays from the sun and tanning lights.
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What process causes spontaneous genetic change?
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Mutation causes spontaneous gentics changes
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What is a heritable change in the base sequence of DNA called?
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Aheritable change in the base sequence of DNA is called mutation.
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Define: Nonsense mutation
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Gives rise to s stop codom in the middle of a gene so that translation stops before it is complete
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Define: Fram-shift deletion
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Indicates that nucleotides, perhaps 1 or 2 (not 3), have been deleted from a gene so that downstream codons are no longer in register.
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Give an example of phenotypic and genotypic changes in the lac operon.
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A mutation in an undefined are of the lac operon, and of the 3 structural genes of the control promoter or operator regions could result in the cell becoming phontypicall lactose-. If we knew that the mutations spcifically rendered the lacZ gene nonfunctional, we would call ina lacZ genotype.
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How might regulatory mutations in the lac operon or promoter affect cell function?
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A mutant lac operator would not bind the repressor, so that lactose operon would be expressed contituitvely. A mutant lac promoter would be unable to bind RNA polymerase so no transcription or expression would be possible.
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What does the Ames test show?
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The Ames test shows whether test chemicals increase the frequency of mutations. If the frequency increases, the chemical is called a mutagen or even a carcinogen.
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In which type of transfer does a sex pilus form a bridge between 2 bacteria?
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A sex pilus forms a bridge between 2 bacteria in conjugation
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What is the difference in location of the F-factor in a F+ cell and and Hfr cell?
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The F-factor of and F+ cell resides in the extra-chromosomeal plasmid: the F-factor of and Hfr cell integrates into and becomes a part of the bacterial chromosome.
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What type of gene transfer transports naked DNA through the cell membrane?
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Transformation transports naked DNA through a cell memebrane
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What type of gene transfer is mediated by bacteriphage?
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Transduction is medicated by bacteriophages.
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