Questions and Answers
What is genetics?
The study of what genes are, how they carry information, how information is expressed, and how genes are replicated.
Define a gene.
A segment of DNA that encodes a functional product, usually a protein.
What is a genome?
All the genetic material in a cell.
Define genomics.
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What is a genotype?
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What is a phenotype?
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What is genetic information expression?
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Define genetic information recombination.
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What is genetic information replication?
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What is semi-conservative DNA synthesis?
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Define transcription.
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What does transcription require?
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What are repressible enzymes?
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What are inducible enzymes?
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Define translation.
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MRNA is translated in ____.
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What is degeneracy in genetics?
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Translation of mRNA begins at the __:.
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Translation of mRNA ends as ____:__.
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What is the genetic code?
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Define tRNA.
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What is the site of translation?
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____ direct the building of tRNA and mRNA codon.
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What starts the protein synthesis?
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When can prokaryotic cells start translation?
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Where is mRNA transcribed in eukaryotes?
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When are start codons exposed?
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For what are enzymes needed?
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What are constitutive enzymes?
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Define catabolite repression.
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What is an operon?
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In the operon model for an inducible system, what does a regulatory gene code for?
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What happens when the inducer is absent in an operon?
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What happens when the inducer is present in an operon?
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Define mutation.
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What is a mutagen?
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What is a spontaneous mutation?
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Define missense mutation.
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What is a nonsense mutation?
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Define frameshift mutation.
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Give examples of mutations.
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What is a mutation rate?
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What is the spontaneous mutation rate?
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Mutagens increase the mutation rate to what values per replicated gene?
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How do mutations occur?
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What is a low rate of spontaneous mutation beneficial for?
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What are chemical mutagens?
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What are the effects of ionizing radiation on mutation?
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What are the effects of ultraviolet (UV) radiation on mutation?
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Define nucleotide excision repair.
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What is light repair?
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How can mutations be detected?
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What is positive selection?
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Define replica plating.
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What is positive (direct) selection?
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What is negative (indirect) selection?
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What is the Ames test?
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Define vertical gene transfer.
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What is horizontal gene transfer?
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Define genetic recombination.
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What is a recombinant?
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What is transformation vs recombination?
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What is conjugation?
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What type of cells are F+ and F-?
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What happens when a plasmid becomes incorporated into the chromosome?
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What can an Hfr cell do during conjugation?
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Define transduction.
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What are plasmids?
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What are the types of plasmids?
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Define transposons.
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What are insertion sequences (IS)?
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What are complex transposons?
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Why can transposons spread between cells?
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Study Notes
Genetics Overview
- Genetics is the study of genes, their information storage, expression, and replication.
- A gene is a DNA segment encoding functional products, primarily proteins.
- The genome includes all genetic material within a cell.
- Genomics focuses on the molecular analysis of genomes.
Genetic Concepts
- Genotype refers to the genetic makeup of an organism, while phenotype is the observable expression of these genes.
- Genetic information is expressed through protein production needed for cell function.
- Recombination allows genetic information transfer between cells during the same generation.
- Replication ensures genetic information is passed between generations.
Transcription and Translation
- Transcription is the process of synthesizing RNA from DNA, involving RNA polymerase and starting at the promoter.
- mRNA is translated in codons, with a total of 64 combinations encoding 20 amino acids.
- Translation initiates at the start codon (AUG) and terminates at nonsense codons (UAA, UAG, UGA).
- tRNA carries anticodons complementary to mRNA codons and plays a vital role in translation.
- Ribosomes act as the site for translation, assembling proteins by decoding mRNA.
Regulatory Enzymes and Operons
- Repressible enzymes stop protein synthesis when excessive material is present, while inducible enzymes initiate transcription upon activation.
- A catabolite repression inhibits the use of alternative carbon sources when glucose is available.
- The operon model describes groups of structurally related genes regulated together, including promoter and operator cites.
- The presence of an inducer causes the repressor to detach from the operator, leading to mRNA synthesis.
Mutation and Its Effects
- Mutation refers to changes in genetic material, which can be neutral, beneficial, or harmful.
- Mutagens are agents that directly cause mutations, while spontaneous mutations occur without mutagen involvement.
- Various types of mutations include missense (amino acid substitution), nonsense (premature stop codon), and frameshift (insertion or deletion of nucleotides).
- The mutation rate is the probability a gene will mutate during cell division, represented as a negative exponent.
Mutation Detection and Selection
- Positive selection identifies mutant cells that grow or differ visibly, while negative selection detects mutants that fail to grow.
- The Ames test is a method for screening potential chemical carcinogens based on the reversion of mutant cells.
Gene Transfer Mechanisms
- Vertical gene transfer occurs during reproduction, passing genes to offspring.
- Horizontal gene transfer involves gene exchange between cells of the same generation, enhancing genetic diversity.
- Transformation involves DNA uptake without cell contact, while conjugation requires direct contact between living cells.
- Transduction is the gene transfer mediated by bacteriophages, incorporating DNA into recipient bacteria.
Plasmids and Transposons
- Plasmids are self-replicating circular DNA molecules with genes that are typically non-essential for survival.
- Types of plasmids include conjugative, dissimilation, bacteriocin, and resistance factors.
- Transposons, or jumping genes, can move across DNA regions, facilitating gene transfer between chromosomes and organisms.
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Description
Dive into the essential terms of Microbiology with this Chapter 8 flashcard quiz. Each card explores pivotal concepts in genetics, from the definition of genes to the complete genetic makeup of an organism. Perfect for students looking to reinforce their understanding of genetic principles.