Genetics, Biodiversity and Classification

• What do some genes code for instead of polypeptides?

  Functional RNA
• What are introns in eukaryotic DNA?

  Sections that don't code for amino acids
• What are the coding sections of a gene called?

  Exons
• What happens to introns during protein synthesis?

  They are removed
• What type of DNA does prokaryotic DNA lack?

  Introns
• What are non-coding repeats in eukaryotic DNA?

  DNA sequences that repeat multiple times
• How many pairs of chromosomes do humans have?

  23 pairs
• What are homologous pairs of chromosomes?

  Pairs of matching chromosomes
• Where are alleles found in a homologous pair?

  At the same fixed position (locus)
• What is a gene?

  A sequence of DNA bases
• What does the order of bases in a gene determine?

  The order of amino acids in a polypeptide
• What is a triplet in DNA?

  A sequence of three bases
• What is the first stage of protein synthesis?

  Transcription
• What is the role of mRNA?

  To carry genetic code to ribosomes
• What is the structure of tRNA?

  Single polynucleotide strand folded into clover shape
• What is the role of RNA polymerase in transcription?

  To attach to DNA and synthesize mRNA
• What happens to the DNA strands during transcription?

  They are separated by RNA polymerase
• What is pre-mRNA?

  mRNA containing both introns and exons
• What is splicing in eukaryotic cells?

  Removal of introns from pre-mRNA
• What occurs during translation?

  Amino acids are joined to form a polypeptide
• What provides energy for the bond between amino acids and tRNA?

  ATP
• What is the role of the anticodon on tRNA?

  To pair with the codon on mRNA
• What happens when a stop signal is reached during translation?

  The polypeptide chain is released
• What is the genetic code described as?

  Non-overlapping, degenerate, and universal
• What does it mean that the genetic code is degenerate?

  More triplet combinations than amino acids
• What are start and stop codons?

  Signals for starting and stopping protein production
• How is mRNA related to the DNA template strand?

  It is a complementary copy of the DNA
• What is the relationship between mRNA codons and tRNA anticodons?

  tRNA anticodons are complementary to mRNA codons
• What are the stages of protein synthesis?

  1. Transcription: DNA is copied into mRNA.
  2. Splicing (in eukaryotes): Introns are removed from pre-mRNA.
  3. Translation: mRNA is translated into a polypeptide chain.
• What are the differences between eukaryotic and prokaryotic transcription?

  • Eukaryotes: Transcription occurs in the nucleus; introns are spliced out.
  • Prokaryotes: Transcription occurs in the cytoplasm; no splicing occurs.
• What is the difference between a genome and a proteome?

  • Genome: Complete set of genes in a cell.
  • Proteome: Full range of proteins a cell can produce.
• What are the roles of different types of RNA in protein synthesis?

  • mRNA: Carries genetic code from DNA to ribosomes.
  • tRNA: Brings amino acids to ribosomes for protein assembly.
  • rRNA: Forms part of ribosomes.
• What is the significance of the genetic code being universal?

  • The same codons code for the same amino acids in all organisms.
  • This supports the idea of common ancestry among living organisms.
• What is the importance of complementary base pairing in protein synthesis?

  • Ensures accurate transcription of DNA to mRNA.
  • Guarantees correct translation of mRNA to amino acids.
• What codes for tyrosine in all organisms?

  UAU
• Why is the genetic code described as universal?

  Same base triplets code for same amino acids
• How can you interpret data about nucleic acids?

  By analyzing tables of mRNA codons
• What does the mRNA codon UOU code for?

  Serine
• What is the relationship between mRNA and DNA?

  mRNA is a complementary copy of DNA
• How do you determine tRNA anticodons from mRNA codons?

  By finding complementary sequences