Model Organisms

• What is a model organism?

  A model organism is a non-human species extensively studied to understand basic biological phenomena.
• Why are discoveries made in model organisms expected to be applicable to humans?

  Because genetic mechanisms are similar in most organisms.
• What are the two main reasons for using model organisms in research?

  1. Genetic mechanisms are the same in most organisms.
  2. They have characteristics that make them suitable for genetic research.
• What are typical characteristics of model organisms?

  • Small adult size
  • Rapid development with short life cycles
  • Can be bred in large numbers
  • Readily available and inexpensive maintenance
  • Similar genes or similar-sized genomes to humans
  • Tractability to experimental methodology
• Which organisms were the first generations used as genetic models?

  The mouse and fruit fly.
• What was the Human Genome Project aimed at achieving?

  To comprehensively study all of the DNA of a selected set of organisms.
• Which five model organisms' genomes were sequenced during the Human Genome Project?

  1. Bacteria (Escherichia coli)
  2. Yeast (Saccharomyces cerevisiae)
  3. Fruit fly (Drosophila melanogaster)
  4. Ground worm (Caenorhabditis elegans)
  5. Mouse (Mus musculus)
• What are some other model organisms mentioned?

  1. Zebra fish (Danio rerio)
  2. Chick Embryo (Gallus gallus domesticus)
  3. Mustard plant (Arabidopsis thaliana)
• Why are bacteria considered foundational in molecular biology?

  Because studies of bacteria laid the groundwork for molecular biology.
• Who studied infant gut microbes and discovered Escherichia coli?

  Theodor Escherich in 1884.
• What are some applications of Escherichia coli in research?

  Used for recombinant DNA technologies and drug development.
• What is a limitation of using bacteria as a model organism for studying human diseases?

  Bacteria cannot be used directly to study manifestations of human diseases.
• Why is Escherichia coli considered an excellent model organism for geneticists?

  It is small, easy to grow, has a short generation time, and is genetically manipulable.
• What is the generation time of Escherichia coli under ideal conditions?

  15 to 20 minutes.
• What is the significance of Baker's Yeast (Saccharomyces cerevisiae) in research?

  It helps understand connections between genes and proteins and their functions in cells.
• What type of organism is Baker's Yeast?

  Eukaryotic.
• How has yeast contributed to cancer research?

  It has been used to study genes involved in hereditary non-polyposis colorectal cancer.
• What are the key genes shared between humans and yeast that are involved in cancer?

  1. MutS Homolog 2 (MSH2)
  2. MutL homolog 1 (MLH1)
• What is Arabidopsis thaliana commonly known as?

  Rock cress.
• Why is Arabidopsis thaliana considered a model organism for plant biology?

  It has a small genome and is easily grown under laboratory conditions.
• What insights can be gained from studying Arabidopsis thaliana?

  Insights into plant biology, agriculture, energy, environment, and human health.
• What is Caenorhabditis elegans commonly known as?

  Nematode ground worm.
• What is unique about the structure of Caenorhabditis elegans?

  Each worm is made up of about 1,000 somatic cells, including nerve cells.
• How does the life cycle of Caenorhabditis elegans contribute to research?

  It has a short life cycle of about 2 weeks and produces over 1,000 eggs daily.
• What makes Caenorhabditis elegans a valuable model for studying human diseases?

  It provides models for neurological disorders, congenital heart disease, and kidney diseases.
• What are some areas of research where Caenorhabditis elegans is utilized?

  Developmental and cell biology, neurobiology, aging, and human disease studies.
• What is Drosophila melanogaster commonly known as?

  Fruit fly.
• Why is Drosophila melanogaster considered a versatile model organism?

  It has an easy-to-manipulate genetic system and can be used to study various biological processes.
• How does the biological complexity of Drosophila compare to mammals?

  Drosophila has biological complexity comparable to that of a mammal.
• What types of diseases have been studied using Drosophila?

  Forms of cancer, neurodegenerative diseases, and various human diseases.
• What is the life cycle duration of Drosophila melanogaster?

  8 to 14 days.
• What is the significance of Danio rerio in research?

  It is used to study vertebrate development and human health-related mutations.
• What is a notable feature of Danio rerio's embryonic development?

  It can be observed through its transparent egg.
• How does the genome size of Danio rerio compare to that of mice and humans?

  Its genome is half the size of the mouse and human genomes.
• Why is the chick embryo a valuable model organism for research?

  Most of its development takes place within an egg that is incubated outside of the mother.
• What is a key advantage of studying chick embryos?

  Early developmental stages can be accessed and manipulated easily.
• What is Mus musculus commonly known as?

  Mouse.
• Why is Mus musculus considered the closest mammalian model organism to humans?

  It shares a high degree of similarity in genes that code for vital biological processes.
• How often can mice reproduce?

  As often as every three weeks.
• What is a knockout mouse?

  A knockout mouse is one where one or more genes have been turned off.