8.1 genes and genetic coad Flashcards
Q: What is a gene?
A: A section of DNA that codes for the amino acid sequence of a polypeptide or functional RNA (e.g., rRNA or tRNA).
Q: Where are genes located?
A: On chromosomes within the nucleus of a cell.
Q: What is the locus of a gene?
A: The specific position of a gene on a chromosome.
Q: What is the relationship between genes, proteins, and traits?
A: Genes code for polypeptides, which fold into proteins that determine traits.
Q: What are codons?
A: Triplets of nucleotide bases in mRNA that code for a specific amino acid.
Q: What is the genetic code?
A: The sequence of nucleotide bases in DNA or RNA that determines the sequence of amino acids in a polypeptide.
Q: Why is the genetic code described as “universal”?
A: Because in almost all organisms, the same codons code for the same amino acids.
Q: How is DNA involved in the genetic code?
A: DNA stores the genetic information in its sequence of nucleotide bases.
Q: Why is the genetic code described as “degenerate”?
A: Most amino acids are coded for by more than one codon, reducing the effect of mutations.
Q: Why is the genetic code described as “non-overlapping”?
A: Each base is read only once in the triplet code, and codons are read in sequence without overlapping.
Q: What are stop codons?
A: Codons that do not code for an amino acid but signal the end of translation (e.g., UAA, UAG, UGA).
Q: What are exons?
A: The coding regions of a gene that are expressed as polypeptides.
Q: What are introns?
A: Non-coding regions of a gene that are removed during RNA splicing.
Q: Do prokaryotic genes contain introns?
A: No, prokaryotic genes are continuous, with no introns.
Q: How is mRNA involved in the genetic code?
A: mRNA is a complementary copy of the DNA sequence and carries the code from the nucleus to the ribosome for protein synthesis.
