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21 Cards in this Set
- Front
- Back
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Codon |
A sequence of three nucleotides in DNA or RNA that codes for an amino acid or a start or stop signal for protein synthesis. |
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Gene |
A section of DNA (or RNA, for some viruses) that encodes information for building one or more related polypeptides or functional RNA molecules along with the regulatory sequences required for its transcription. |
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Gene expression |
The set of processes, including transcription and translation, that convert information in DNA into a product of a gene, most commonly a protein. |
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Genotype |
All the alleles of every gene present in a given individual. Often specified only for the alleles of a particular set of the genes under study. |
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Mutation |
Any change in the hereditary material of an organism (DNA in most organisms, RNA in some viruses). The only source of new alleles in populations. |
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Phenotype |
The detectable traits of an individual. |
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Reverse transcriptase |
An enzyme that can synthesize double-stranded DNA from a single-stranded RNA template. |
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RNA polymerase |
An enzyme that catalyzes the synthesis of RNA from ribonucleotides using a DNA template. |
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Explain the central dogma of molecular biology including the names and end products of the two main processes. |
The central dogma of molecular biology summarizes the flow of information in cells. It simply states that DNA codes for RNA, which codes for proteins. DNA —> RNA —> proteins
DNA to mRNA is Transcription.
mRNA to Proteins is Translation. |
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List and describe the five properties of the genetic code. |
The code is redundant: All amino acids except methionine and tryptophan are coded by more than one codon.
The code is unambiguous: A single codon never codes for more than one amino acid.
The code is non-overlapping: Once the ribosome locks onto the first codon, it then reads each separate codon one after another.
The code is nearly universal: With a few minor exceptions, all codons specify the same amino acids in all organisms.
The code is conservative. When several codons specify the same amino acid, the first two bases in those codons are almost always identical. |
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When talking about the five properties of the genetic code, what does it mean to say:
The code is redundant |
All amino acids except methionine and tryptophan are coded by more than one codon. |
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When talking about the five properties of the genetic code, what does it mean to say:
The code is unambiguous |
A single codon never codes for more than one amino acid. |
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When talking about the five properties of the genetic code, what does it mean to say:
The code is non-overlapping |
Once the ribosome locks onto the first codon, it then reads each separate codon one after another. |
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When talking about the five properties of the genetic code, what does it mean to say:
The code is nearly universal |
With a few minor exceptions, all codons specify the same amino acids in all organisms. |
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When talking about the five properties of the genetic code, what does it mean to say:
The code is conservative |
When several codons specify the same amino acid, the first two bases in those codons are almost always identical. |
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What are the types of point mutates: |
Frameshift Missense Nonsense Silent |
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Frameshift mutation: |
The addition or deletion to a nucleotide in a coding sequence that shifts the frame of the mRNA. |
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Missense mutation: |
A point mutation (change in a single base pair) that changes one amino acid for another within the sequence of a protein. |
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Nonsense mutation: |
A point mutation (change in a single base pair) that converts an amino-acid-specifying codon into a stop codon. |
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Silent mutation: |
A point mutation that changes the sequence of a codon without changing the amino acid that is specified. |
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Describe two exceptions to the central dogma of molecular biology. |
1. Mana genes code for RNA molecules that do not function as mRNAs — they are not translated into proteins.
2. In some cases, information flows from RNA back to DNA. |
