Model Systems

Question 1

Certain Assumptions made for Model Systems (2):

Answer 1

1) you can extrapolate what you learn from a few model species to other organisms

2) Models are a representative sample of extant diversity

Question 2

Criteria for a model biological system (EASY)

1. The organism used should be easy to _____
2. Its _____ should be convenient
3. Should be ____ to _____
4. The model organism should have a _____
5. The organism used can be _____
6. It has potential to deliver ____

Answer 2

1. The organism used should be easy to maintain
2. Its operation size should be convenient
3. Should be inexpensive to maintain
4. The model organism should have a short life cycle
5. The organism used can be genetically manipulated
6. It has potential to deliver economically important results

Question 3

Criteria for a model biological system (6)(HARD)

Answer 3

1. The organism used should be easy to maintain
2. Its operation size should be convenient
3. Should be inexpensive to maintain
4. The model organism should have a short life cycle
5. The organism used can be genetically manipulated
6. It has potential to deliver economically important results

Question 4

Model organisms tackled

A. Worm
B. Fly
C. Frog
D. Fish
E. Plant
F. Mice
G. Chick

Answer 4

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

Question 5

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.

Answer 5

Caenorhabditis elegans

Emile Maupas

Sydney Brenner

Question 6

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.

Answer 6

Petri-dish culture

Question 7

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

Answer 7

Escherichicia coli

1mm in size

Transparent

3 days

Self-fertilising hermaphrodite

Question 8

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.

Answer 8

Genetic crossing

-80 C

strain and genetic resource collections

The genome sequence, resources of transgenic strains and RNA interference reagents

Question 9

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

Answer 9

biomedical and environmental toxicology

molecular targets of toxicity
rapid toxicity assessment of new chemicals

Question 10

A. Worm - Caenorhabditis elegans

C. elegans provides several characteristics that complement ___ or ____ applications.

This includes research into the genetic basis of ____ and ____

Answer 10

in vitro or cellular models applications

Longevity and aging

Question 11

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 ____

Answer 11

laser ablation

optogenic manipulation

microinjection
Green fluorescent protein

RNAi

Question 12

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.

Answer 12

Turgor Pressure

homologs

immune system
dauer