Explain DNA Sequence Encoding - Biology
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What is transcription in gene expression?
What is transcription in gene expression?
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Synthesis of RNA from a DNA template. DNA serves as the template for making RNA copies.
Synthesis of RNA from a DNA template. DNA serves as the template for making RNA copies.
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What is a codon in the context of the genetic code?
What is a codon in the context of the genetic code?
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A three-nucleotide sequence in mRNA that specifies an amino acid or stop. Each triplet codes for one amino acid or termination signal.
A three-nucleotide sequence in mRNA that specifies an amino acid or stop. Each triplet codes for one amino acid or termination signal.
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Which codon is the most common start codon for translation?
Which codon is the most common start codon for translation?
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AUG. This codon initiates protein synthesis in most genes.
AUG. This codon initiates protein synthesis in most genes.
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What is meant by the term "reading frame" in translation?
What is meant by the term "reading frame" in translation?
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The grouping of mRNA nucleotides into consecutive, nonoverlapping codons. The reading frame determines which amino acids are produced.
The grouping of mRNA nucleotides into consecutive, nonoverlapping codons. The reading frame determines which amino acids are produced.
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What does it mean that the genetic code is "degenerate"?
What does it mean that the genetic code is "degenerate"?
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Most amino acids are specified by more than one codon. Multiple codons code for the same amino acid.
Most amino acids are specified by more than one codon. Multiple codons code for the same amino acid.
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What does it mean that the genetic code is "unambiguous"?
What does it mean that the genetic code is "unambiguous"?
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Each codon specifies only one amino acid or a stop signal. No codon codes for multiple different amino acids.
Each codon specifies only one amino acid or a stop signal. No codon codes for multiple different amino acids.
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What does it mean that the genetic code is "nearly universal"?
What does it mean that the genetic code is "nearly universal"?
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Most organisms use the same codon-to-amino-acid assignments. The genetic code is shared across nearly all life forms.
Most organisms use the same codon-to-amino-acid assignments. The genetic code is shared across nearly all life forms.
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Which base is present in RNA in place of thymine found in DNA?
Which base is present in RNA in place of thymine found in DNA?
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Uracil. RNA uses uracil instead of thymine found in DNA.
Uracil. RNA uses uracil instead of thymine found in DNA.
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Identify the mRNA complement transcribed from the DNA template sequence 3'-TAC-5'.
Identify the mRNA complement transcribed from the DNA template sequence 3'-TAC-5'.
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5'-AUG-3'. A pairs with U, T pairs with A during transcription.
5'-AUG-3'. A pairs with U, T pairs with A during transcription.
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Identify the mRNA complement transcribed from the DNA template sequence 3'-GGC-5'.
Identify the mRNA complement transcribed from the DNA template sequence 3'-GGC-5'.
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5'-CCG-3'. C pairs with G, G pairs with C during transcription.
5'-CCG-3'. C pairs with G, G pairs with C during transcription.
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Identify the DNA coding strand sequence that matches the mRNA codon 5'-AUG-3'.
Identify the DNA coding strand sequence that matches the mRNA codon 5'-AUG-3'.
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5'-ATG-3'. The coding strand has the same sequence as mRNA (except T/U).
5'-ATG-3'. The coding strand has the same sequence as mRNA (except T/U).
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Which direction is the DNA template strand read during transcription?
Which direction is the DNA template strand read during transcription?
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It is read in the 3'
rightarrow
5' direction. RNA polymerase moves along the template in this direction.
It is read in the 3' rightarrow 5' direction. RNA polymerase moves along the template in this direction.
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What is the difference between a DNA coding strand and a DNA template strand?
What is the difference between a DNA coding strand and a DNA template strand?
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Coding matches mRNA (T for U); template is complementary to mRNA. Only the template strand serves as the transcription template.
Coding matches mRNA (T for U); template is complementary to mRNA. Only the template strand serves as the transcription template.
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What is a point mutation in a DNA base sequence?
What is a point mutation in a DNA base sequence?
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A change in a single nucleotide base pair. The smallest possible DNA sequence change.
A change in a single nucleotide base pair. The smallest possible DNA sequence change.
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What is an operator in the operon model of prokaryotic gene regulation?
What is an operator in the operon model of prokaryotic gene regulation?
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A DNA site where a repressor binds to block transcription. Operators control gene expression in bacterial operons.
A DNA site where a repressor binds to block transcription. Operators control gene expression in bacterial operons.
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What is an enhancer in eukaryotic gene regulation?
What is an enhancer in eukaryotic gene regulation?
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A DNA sequence that increases transcription when bound by activators. Enhancers boost gene expression when regulatory proteins bind.
A DNA sequence that increases transcription when bound by activators. Enhancers boost gene expression when regulatory proteins bind.
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What is a promoter in a gene, and what is its main function?
What is a promoter in a gene, and what is its main function?
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A DNA region where RNA polymerase binds to start transcription. Promoters control where and when genes are transcribed.
A DNA region where RNA polymerase binds to start transcription. Promoters control where and when genes are transcribed.
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What is phenotype in relation to DNA-encoded information?
What is phenotype in relation to DNA-encoded information?
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Observable traits produced by gene expression and environment. Phenotype results from genotype expression plus environmental factors.
Observable traits produced by gene expression and environment. Phenotype results from genotype expression plus environmental factors.
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What is genotype in terms of genetic information encoded by DNA?
What is genotype in terms of genetic information encoded by DNA?
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An organisms set of alleles (its DNA sequence variants). Genotype represents the genetic blueprint in DNA sequences.
An organisms set of alleles (its DNA sequence variants). Genotype represents the genetic blueprint in DNA sequences.
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What is an allele in terms of DNA sequence?
What is an allele in terms of DNA sequence?
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An alternative DNA sequence version of the same gene. Different alleles produce different versions of the same protein.
An alternative DNA sequence version of the same gene. Different alleles produce different versions of the same protein.
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Identify the mutation type: insertion of one nucleotide early in a coding region.
Identify the mutation type: insertion of one nucleotide early in a coding region.
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Frameshift mutation. Single nucleotide insertion shifts the reading frame.
Frameshift mutation. Single nucleotide insertion shifts the reading frame.
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Identify the mutation type: a base substitution changes a codon into UAA, UAG, or UGA.
Identify the mutation type: a base substitution changes a codon into UAA, UAG, or UGA.
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Nonsense mutation. The mutation creates a premature stop codon.
Nonsense mutation. The mutation creates a premature stop codon.
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Identify the mutation type: a single-base substitution changes one amino acid to another.
Identify the mutation type: a single-base substitution changes one amino acid to another.
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Missense mutation. One amino acid changes to another due to base substitution.
Missense mutation. One amino acid changes to another due to base substitution.
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What is a frameshift mutation, and what causes it?
What is a frameshift mutation, and what causes it?
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A reading-frame shift caused by nucleotide insertion or deletion. Changes all downstream amino acids, severely affecting the protein.
A reading-frame shift caused by nucleotide insertion or deletion. Changes all downstream amino acids, severely affecting the protein.
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What is a nonsense mutation in a protein-coding DNA sequence?
What is a nonsense mutation in a protein-coding DNA sequence?
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A base change that creates a premature stop codon. Creates early termination, usually destroying protein function.
A base change that creates a premature stop codon. Creates early termination, usually destroying protein function.
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What is a missense mutation in a protein-coding DNA sequence?
What is a missense mutation in a protein-coding DNA sequence?
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A base change that substitutes one amino acid for another. Changes one amino acid, potentially affecting protein function.
A base change that substitutes one amino acid for another. Changes one amino acid, potentially affecting protein function.
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What is a silent mutation in a protein-coding DNA sequence?
What is a silent mutation in a protein-coding DNA sequence?
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A base change that does not alter the amino acid sequence. Code degeneracy protects against some mutations.
A base change that does not alter the amino acid sequence. Code degeneracy protects against some mutations.
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Identify the complementary DNA strand for the sequence 5'-ATCG-3'.
Identify the complementary DNA strand for the sequence 5'-ATCG-3'.
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3'-TAGC-5'. A pairs with T, C pairs with G in antiparallel strands.
3'-TAGC-5'. A pairs with T, C pairs with G in antiparallel strands.
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What is the role of aminoacyl-tRNA synthetase in decoding genetic information?
What is the role of aminoacyl-tRNA synthetase in decoding genetic information?
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It attaches the correct amino acid to its corresponding tRNA. This enzyme ensures accurate amino acid-codon matching.
It attaches the correct amino acid to its corresponding tRNA. This enzyme ensures accurate amino acid-codon matching.
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Which molecule directly links a specific mRNA codon to a specific amino acid?
Which molecule directly links a specific mRNA codon to a specific amino acid?
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tRNA (charged by aminoacyl-tRNA synthetase). tRNA carries amino acids and recognizes specific codons.
tRNA (charged by aminoacyl-tRNA synthetase). tRNA carries amino acids and recognizes specific codons.
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