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11.1 The Functions of Genetic Material

3 min readLast Updated on June 18, 2024

Genetic material in microbes is the blueprint for life, storing instructions and enabling reproduction. DNA replication, transcription, and translation form the core processes, allowing information to flow from genes to proteins, shaping microbial function and survival.

Genotype, phenotype, and environment interact in complex ways, influencing microbial characteristics and behavior. Gene expression, mutations, and phenotypic plasticity enable microbes to adapt to changing conditions, highlighting the dynamic nature of microbial genetics.

Functions and Flow of Genetic Material

Functions of microbial genetic material

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  • Stores genetic instructions for development, functioning, and reproduction of microorganisms encoded in the sequence of nucleotide bases (A, T, C, G)
  • Replicates to produce identical copies of DNA during cell division ensuring genetic continuity from one generation to the next (heredity)
  • Undergoes transcription where genetic information in DNA is used to produce complementary RNA molecules (mRNA, tRNA, rRNA) by RNA polymerase using one strand of the DNA double helix as a template
  • Participates in translation where genetic information in mRNA is used to synthesize proteins by ribosomes reading the genetic code and translating it into a sequence of amino acids

Information flow in molecular biology

  • DNA replication occurs when the DNA double helix unwinds, separates into two strands, and each strand serves as a template for DNA polymerase to synthesize new complementary strands
  • Transcription (DNA to RNA) begins with RNA polymerase binding to a promoter region, unwinding the DNA double helix, separating the strands, and using one strand (template strand) to synthesize a complementary RNA strand
  • Translation (RNA to protein) involves:
    1. Ribosomes (composed of rRNA and proteins) binding to the mRNA
    2. tRNA molecules carrying specific amino acids base-pairing with codons on the mRNA
    3. Ribosomes catalyzing the formation of peptide bonds between adjacent amino acids
    4. The polypeptide chain growing until a stop codon is reached, signaling the end of translation
  • The central dogma describes the flow of genetic information from DNA to RNA to proteins

Genotype, Phenotype, and Environmental Factors

Interactions in microbial genetics

  • Genotype refers to the genetic makeup of a microorganism determined by the sequence of nucleotides in its DNA with different alleles (versions) of genes resulting in different phenotypes
  • Phenotype encompasses the observable characteristics of a microorganism resulting from the expression of its genotype (morphology, biochemical properties, behavior)
  • Environmental factors are external conditions (temperature, pH, nutrient availability, toxins) that influence gene expression and the resulting phenotype
  • Gene expression is the process of using information from a gene to synthesize functional gene products (proteins) which can be affected by environmental factors influencing transcription and translation
  • Phenotypic plasticity allows microorganisms to change their phenotype in response to environmental conditions without altering their genotype enabling adaptation to changing environments
  • Mutations are changes in the DNA sequence caused by environmental factors (UV radiation, chemical mutagens) that can alter the genotype, potentially the phenotype, and may enhance survival and reproduction in specific environments if beneficial

Genetic organization and regulation

  • The genome is the complete set of genetic material in an organism, including all genes and non-coding sequences
  • Epigenetics involves heritable changes in gene expression that do not involve changes to the underlying DNA sequence
  • The genetic code is the set of rules by which information encoded in genetic material is translated into proteins
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© 2025 Fiveable Inc. All rights reserved.
AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.

© 2025 Fiveable Inc. All rights reserved.
AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.
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