Molecular biologyLesson 1 of 1 in the course Genes and Proteins

Genetic Code, Translation, and Comparing DNA Yield in Fruit

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

This lesson explains how genetic information moves from DNA to RNA and then to protein. Understanding this flow helps show how a gene can direct the production of a protein while the cell protects its DNA.

The central dogma describes the usual flow of genetic information in cells: DNA is used to make RNA, and RNA is used to make protein. A gene specifies the sequence of an mRNA molecule, which in turn specifies the order of amino acids in a protein.

All flashcards

What is the central dogma?
It describes the usual flow of genetic information: DNA specifies RNA, and RNA specifies the amino acid sequence of a protein.
What is transcription?
Transcription is the process of using a DNA gene as a template to produce an RNA copy, commonly mRNA.
What is translation?
Translation is the process in which ribosomes read mRNA codons and assemble the corresponding amino acids into a polypeptide.
What does colinear translation mean?
It means the order of codons along the mRNA corresponds to the order of amino acids in the protein.
How can amino acid sequence affect a protein?
Amino acids have different chemical properties and structural constraints. Their sequence influences how a protein folds and therefore helps determine its structure and function.

Quiz questions

  1. Why do genetic instructions use three-nucleotide codons rather than two-nucleotide codons to specify amino acids and translation signals?Answer: Three-nucleotide codons provide 64 combinations, while two-nucleotide codons provide only 16.
  2. What role does AUG usually have in translation?Answer: It acts as a start signal and specifies methionine.
  3. What do the three stop codons do during translation?Answer: They signal translation to end rather than specifying an amino acid.
  4. What does it mean that the genetic code is nearly universal?Answer: Most organisms use the same codon meanings, with a few exceptions.
  5. Why do chromosome counts alone not establish which of two fruit samples will yield more DNA?Answer: DNA yield also depends on factors such as DNA per chromosome, cell number, and sample amount.

Based on Biology 2e by Mary Ann Clark, Matthew Douglas, Jung Choi (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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