Model Systems

What are model systems?

Simpler organisms, cells or experimental set ups that are used by scientists to study biological processes that would be difficult to study directly in humans

Provide examples of model systems

• E coli - study genes, DNA and protein production

• yeast - cell division and metabolism

• Fruit flies (Drosophila) - study genetics and development

• Mice - study diseases and how organs work

Why are model systems used?

To not expose humans to anything harmful and because they are easier, cheaper and faster to study

Define phenotype

An observable characteristic or trait of an organism resulting from its genes and their interaction with the environment

Why are the fruit files, Drosophila melongaster, used as model systems?

They are

• inexpensive easy to maintain

• reproduce quickly so many generations can be studied

• scientists can deliberately knock out or alter genes

• shares many evolutionarily conserved genes and cellular pathways with humans, including genes involved in human disease such as alzhimers, cancer and diabetes

What is an embyro?

The early development stage of a multicellular organism that begind just after fertilisation and lasts until major organ systems form

What is a signaling pathway?

How cells communicate with eachother

What is the ‘Wingless Intergration Site’ (Wnt) signaling pathway responsible for?

• Embryonic development

• Cell proliferation

• Cell differentiation

• Stem - cell regulation

• Tissue maintenance

What is the Notch signaling pathway responsible for?

• development

• cell differentation

• stem - cell biology

• tissue maintenance

What is the Hedgehog signaling pathway responsible for?

• embyronic development

• tissue patterning

• cell differentiation

• stem - cell regulation

How do scientists name Drosophila genes?

Based on the phenotype observed when the gene was mutated