Model Systems Flashcards
Certain Assumptions made for Model Systems (2):
1) you can extrapolate what you learn from a few model species to other organisms
2) Models are a representative sample of extant diversity
Criteria for a model biological system (EASY)
- The organism used should be easy to _____
- Its _____ should be convenient
- Should be ____ to _____
- The model organism should have a _____
- The organism used can be _____
- It has potential to deliver ____
- The organism used should be easy to maintain
- Its operation size should be convenient
- Should be inexpensive to maintain
- The model organism should have a short life cycle
- The organism used can be genetically manipulated
- It has potential to deliver economically important results
Criteria for a model biological system (6)(HARD)
- The organism used should be easy to maintain
- Its operation size should be convenient
- Should be inexpensive to maintain
- The model organism should have a short life cycle
- The organism used can be genetically manipulated
- It has potential to deliver economically important results
Model organisms tackled
A. Worm
B. Fly
C. Frog
D. Fish
E. Plant
F. Mice
G. Chick
A. Worm - Caenorhabditis elegans
B. Fly - Drosophila melanogaster
C. Frog - Xenopus laevis
D. Fish - Zebrafish (Danio rerio)
E. Plant - Arabidopsis thaliana
F. Mice - Mus musculus
G. Chick - Gallus Gallus
A. Worm
Scientific name ______
It is a bacteriovorous nematode first described by _____ in 1900
However, _____ from Cambridge, UK made it a global phenomenon. They won three Nobel Prizes.
It is less than 1 mm long but it has fewer than 1000 cells, making it possible to screen regulators and define neural connections for development and behavior.
Caenorhabditis elegans
Emile Maupas
Sydney Brenner
A. Worm - Caenorhabditis elegans
Advantages:
It’s easy to grow. It thrives in a ____ and has a simple life cycle.
It’s easy to visualize under the microscope. See-through at all stages.
It has muscles, nervous system, a digestive system and skin.
Petri-dish culture
A. Worm - Caenorhabditis elegans
Advantages part 1:
- Does not need complex rearing conditions as it feeds on _____ and can be maintained on agar plates at room temp.
-It is small (_____) and can be housed in a small space
-It is easy to observe as it is ____
- It has a short life, taking only ___ days to go from fertilized egg to adult
- Propagation is simple, as the standard sexual morph is the _____, inbreeding issues are absent
Escherichicia coli
1mm in size
Transparent
3 days
Self-fertilising hermaphrodite
A. Worm - Caenorhabditis elegans
Advantages part 2:
- _____ is still possible between males for outcross offspring
- It can be cryopreserved at ____ C allowing strains to be preserved and not continuously evolve
- The community has sponsored ___ and ____ that are searchable online. Some strains can be delivered to you.
- Genetic resources of V. Elegans is unrivaled. The ____, resources of ____ and of ____ targeting all genes make the process of identifying and detailing genetic underpinnings streamlined.
Genetic crossing
-80 C
strain and genetic resource collections
The genome sequence, resources of transgenic strains and RNA interference reagents
A. Worm - Caenorhabditis elegans
Toolkit:
C. elegans is usually used in areas of ____ and ____
It is also used in high-thoroughput experiments like genome-wide screending for ____ of toxicity and ____ for new chemicals
biomedical and environmental toxicology
molecular targets of toxicity
rapid toxicity assessment of new chemicals
A. Worm - Caenorhabditis elegans
C. elegans provides several characteristics that complement ___ or ____ applications.
This includes research into the genetic basis of ____ and ____
in vitro or cellular models applications
Longevity and aging
A. Worm - Caenorhabditis elegans
Technologies involved:
_____ nuclei are killed by the action of a laser directed through the objective of a microscope
_____ light responsive ion channels and enzymes can be induced for cell-level investigation
C. elegans can be genetically transformed by _____ of foreign DNA, hence allowing transgenic analysis. For example, the use of _____
Genes can be knocked down by feeding e coli with ____
laser ablation
optogenic manipulation
microinjection
Green fluorescent protein
RNAi
A. Worm - Caenorhabditis elegans
Disadvantages:
Small at 1mm, making it difficult to obtain biochemical amounts of aged nematodes. Aside from lack of movement, they are also considered dead when there is a loss of _____
C. elegans is also evolutionary far from humans, separated by hundreds of millions of years. Many genes have no ____ in mammals.
They also have no ____ system. THus, they must use ____ developments.
Turgor Pressure
homologs
immune system
dauer
