The genetic code is a set of rules by which information encoded in genetic material is translated into proteins. The codon UUG is one of the six codons that code for the amino acid leucine. It is a standard component of the universal genetic code used by almost all living organisms.
42
What is the term for a molecule formed by the linkage of two amino acids?
A dipeptide is a chemical compound consisting of two amino acids joined by a single peptide bond. This condensation reaction involves the carboxyl group of one amino acid reacting with the amino group of another, releasing a water molecule in the process. It serves as the fundamental building block for longer polypeptide chains.
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What is the term for a sequence of three nucleotides that specifies a particular amino acid?
A codon is a specific sequence of three consecutive nucleotides in DNA or mRNA that functions as a unit of genetic information. Each codon corresponds to a specific amino acid or a stop signal during the process of protein synthesis, ensuring the correct assembly of polypeptides at the ribosome.
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What is the functional role of the UAA codon in protein synthesis?
UAA is one of the three stop codons (along with UAG and UGA) in the genetic code. It signals the termination of protein synthesis by causing the ribosome to release the newly synthesized polypeptide chain from the mRNA template.
45
DNA contains the genetic instructions for synthesizing proteins, which serve as the primary components of what aspect of life?
Proteins are essential macromolecules that fulfill both structural roles (e.g., collagen, keratin, cytoskeleton) and functional roles (e.g., enzymes, hormones, antibodies) within living organisms. Since DNA encodes the information for protein synthesis, it effectively dictates the structural and functional characteristics of the cell, making proteins the fundamental building blocks and operational machinery of life.
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What is the functional role of the codon AUG in protein synthesis?
The codon AUG serves as the universal start codon in protein synthesis, signaling the initiation of translation. It also codes for the amino acid methionine. In eukaryotes, it is the first codon recognized by the ribosome to begin building the polypeptide chain from the mRNA template.
47
Which biological concept describes the phenomenon where multiple codons can encode the same amino acid?
Degeneracy is a fundamental property of the genetic code, meaning that most amino acids are specified by more than one codon. This redundancy helps minimize the impact of point mutations, as a change in the third base of a codon often results in the same amino acid being incorporated into the protein.
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Which amino acid is encoded by the mRNA codons GUU, GUC, GUA, and GUG?
In the genetic code, the codons GUU, GUC, GUA, and GUG are degenerate codons that all specify the amino acid valine. This redundancy is a fundamental feature of the genetic code, allowing for wobble base pairing at the third position of the codon, which helps protect against the effects of point mutations.
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Which specific type of RNA is responsible for transporting amino acids from the cytoplasm to the ribosomes during protein synthesis?
Transfer RNA (tRNA) acts as an adapter molecule in protein synthesis. Each tRNA molecule carries a specific amino acid at one end and possesses an anticodon at the other. It recognizes the corresponding codon on the mRNA strand at the ribosome, ensuring that amino acids are added to the growing polypeptide chain in the correct sequence as dictated by the genetic code.
50
What is the process of synthesizing proteins from an mRNA template at the ribosome called?
Translation is the biological process where the genetic code carried by mRNA is decoded by ribosomes to produce a specific sequence of amino acids, forming a polypeptide chain. This process involves transfer RNA (tRNA) molecules, which bring the appropriate amino acids to the ribosome based on the codon sequence on the mRNA. It is the final step in the central dogma of molecular biology, converting genetic information into functional proteins.
