Transcript Yeast are… - mvhs

Yeast Signal
Transduction Lab
Saccharomyces
cerevisiae
Yeast are…
•
•
•
•
•
Eukaryotes
Single celled organisms
Kingdom Fungi
Commonly used in biological experiments
Also used in commercial applications such
as bread and wine preparation
Fungi vs. Bacteria
FUNGI
Eukaryote
Unicellular or
Multicellular
Cell Wall
Never photosynthetic
BACTERIA
Prokaryote
Always Unicellular
Cell Wall
Can be photosynthetic
Haploid Strains of Yeast
• MAT a
– Release “a factor” pheromones
– Have receptors for a factor
• MAT a
– Release a factor pheromones
– Have receptors for “a factor”
Yeast Mating
• When the appropriate factors are released, a
MATa and MAT a cell can mate
• The binding of the pheromone to the
receptor causes a signal transduction
pathway to be activated.
• Cells start to grow towards one another–
they shmoo!
Diploid vs. Haploid
• What are the advantages of being diploid?
– 2 copies of every gene
– Allows you to compensate for a “bad” gene
Growth of Yeast
• YED media
– Complete media
– Any yeast should be able to grow on it.
• MV media
– Minimal media
– Lacks some nutrients that yeast might need
– If a yeast cell can’t make these nutrients
themselves, they can’t grow on MV media
Yeast mutants
• Some yeast contain mutations that do not
allow them to produce specific compounds
= auxotrophic
• When a yeast mutant is auxotrophic for a
specific compound, it will be unable to
grow on MV media.
Yeast mutants (continued)
• In order for an auxotrophic yeast to grow
– The compound has to be added to the media
OR
– The yeast must mate with another yeast strain
that can complement it (so it can make the
compound) = complementation
Lab Experiment
• Week 1: Mate haploid yeast and observe
growth on MV media (to show
complementation), observe shmooing
• Week 2: Determine the defect in haploid
yeast strains through mating and
complementation on MV media
Your homework:
• Study for the Pre Lab Quiz
• Set up lab notebook:
–
–
–
–
Write a SPECIFIC title
Write an Intro (2-5 sentences)
Paste in procedure
Make a flowchart for EACH page of the
procedure