Download CO 3 2

Interested in Being a Preceptor?
• Reinforce your understanding of Bio182 topics
• Help peers navigate 182L
• Help make the course better
• Learn teaching techniques while earning 3 credits
Interested in Being a Preceptor?
• Work with TAs to teach and develop labs
• Travel to exotic locations (okay, not that)
• Contact Kevin Baker ([email protected])
for more info (link on Bio182L homepage)
Lab 9: In a Family Way
Goals for Today:
• Understand properties of light and
molecules
• Dark side of recombination
• Develop skill at deducing genotype by
observation of phenotype and
inheritance patterns
What is “color”?
And how do we ‘see’ it?
Wavelengths (nm)
Gamma X-rays Ultrarays
violet
Shorter
wavelength
Infrare
d
Visible light
Microwaves
Radio
waves
Longer
wavelength
nm
Higher
energy
Lower
energy
Looking in at looking out
http://www.bio.miami.edu/dana/pix/retina.jpg
Looking Deeper
Where are we?
The difference between
2 and 3 receptors…
Or, the beautiful colors of fall
Can ~10 million American males be wrong?
http://www.rgblind.com/
http://www.rgblind.com/
http://www.rgblind.com/
What IS ‘color’?
Wavelengths (nm)
Gamma X-rays Ultrarays
violet
Shorter
wavelength
Infrare
d
Visible light
Microwaves
Radio
waves
Longer
wavelength
nm
Higher
energy
Lower
energy
The brain’s
interpretation of
the eye’s report
of (three)
samplings of a
narrow bit of the
electromagnetic
spectrum
Wavelengths (nm)
Gamma
rays
Shorter
wavelength
X-rays Ultraviolet
Infrared
Visible light
Microwaves
Radio
waves
Longer
wavelength
nm
Higher
energy
Lower
energy
If the light is
red (680 nm),
which
receptor do
you expect to
‘hear’ it more
loudly?
‘green’ receptor
How do you get a ‘new’
receptor?
What’s in an Opsin
• Week 9 calendar: click on ‘Go_Opsin’
link
• Retinal eats the photon -> changes
shape
– Change is directly transmitted to change in
opsin (which is holding retinal)
• Work through the handout
Launch ‘Opsinize’
• Starting with “red-tuned” opsin (559
nm)
• Your objective: make a ‘green-tuned’
(as close to 531) nm
• Your tool: mutating codon sequences
• From each menu you can mutate the
codon (which reflects changes in DNA)
3-Letter Code
• Leu: Leucine
• Ala: Alanine
• Arg: Arginine
• Lys: Lysine
• Asn: Asparagine
• Met: Methionine
• Asp: Aspartic Acid
• Phe: Phenylalanine
• Cys: Cysteine
• Pro: Proline
• Gln: Glutamine
• Ser: Serine
• Glu: Glutamic Acid
• Thr: Threonine
• Gly: Glycine
• Trp: Tryptophan
• His: Histidine
• Tyr: Tyrosine
• Ile: Isoleucine
• Val: Valine
Thinking it through…
• Shown: the only amino acid
differences between red and
green opsins
• DNA sequences would be…
how similar?
• What happens in meiosis when
the maternal and paternal
chromosomes pair?
• Think anything might ever go
wrong?
How do you get a ‘new’
receptor?
• What’s the ‘easiest’ way to get a
slightly different protein?
– Make a new segment of DNA that
happens to be similar
– Start with a random stretch of
existing DNA and randomly mutate
until…
– Copy the original gene and ‘tweek’
Remember Recombination?
Things don’t always go smoothly
Where to Recombine?
Oooooops
2
How do the restriction
enzymes ‘know’ where
to cut and recombine?
G
G
G
G
But….
G
G
So…..
• Is it easier to make a gene, or tinker
with an existing one?
This one
So what if
this gamete
‘fertilized’ with...
G
G
G
How many colors?
G
G
R
G
But what if you altered
the protein to make it
sensitive to a
different wavelength
NOW what do you have?
Red and green 98% similar.
Why?
“New” Genes – Sound
Familiar?
“New” Genes – Sound
Familiar?
• Green -> “Red” Opsin
• Myoglobin -> Hemoglobin
• Adult vs. Fetal Hemoglobin
What’s seX got to do with it?
• The “X” is big
• The “Y” not so
much
• What does this
mean?
What’s seX got to do with it?
• Autosomal: chromosome NOT X or Y
• Sex chromosome: X or Y (b/c of where each
is joined together during meiosis)
• Symbolism: normally, we don’t care what
chromosome given allele is on; in sex, it
matters
– On the X, we designate : XA, Xa
– On the Y, generally designate: Y How come no A or
a?
• Hemizygous
What’s seX got to do with it?
• Consider A and a
• How many genotypes for females? Males?
• How many possible crosses?
– How to distribute
What’s seX got to do with it?
• Consider A and a
• How many genotypes for females? Males?
• How many possible crosses?
– How to distribute
• Do the cross
– How can you tell it’s sex-linked?
– Compare sex-linked crosses to corresponding
autosomal
• What is the equivalent of Y?
It sucks to be XY
• R/G Colorblind
• Hemophilia
• Different anemias
How is this useful?
Pedigrees!
PTC and parentage
•
•
•
•
WASH HANDS
Who can taste this?
Separate into haves, have-nots
Each: if trait is dominant, what can
you deduce about your parents?
• If trait is recessive?
Boys
vs
Girls
Makin’ Babies
Pair up, decide who’s the adult consenting
male & who the similarly conscientious
female
You’re both heterozygotes (recall:
‘different-pairing’)
Make the babies--hold an allele in each
hand, partner picks
How to determine the sex of the baby?
Pediducer
Deductions from Pedigrees
Two Phases
• Phase I: Assign genotypes and justify
• Phase II: Rule model “plausible” or
“out”
Pediducer
Rules and Conventions
• What assumption about randomly
selected, ‘healthy’ individual?
• Justification is “Outsider”
• REASON must be sufficient &
necessary
Pediducer
Rules and Conventions
• What does affected indiv. look like?
• You are TESTING models
– How many right for model to be right?
– How many wrong...
• Justification
• “Check me”
Explore
• Menu progression: left to right
• If not logged in, first menu tells you
what the ‘answer’ is
• Third menu specifies the model you
are currently considering
• You are seeking to prove (how much
data?) or disprove model (how many
internal contradictions?)
NO POINTS!!!!!
If you don’t rule models in/out
Preparing for next week
Let me intreduce myself
• RHC=O + H2O => RCOOH +
2H+ + 2e• 2CU2+ + 2e- => 2Cu+
• 2Cu+ + 2OH- => Cu2O (red ppt.)
+ H 2O
Who is oxidized (loses electron ownership--often to oxygen)?
Who is reduced?
Reagents for glucose
(do all three)
• 1% glucose
• 0.2% glucose
• water
Capturing CO2
H2O + CO2 -> H2CO3
H2CO3 -> HCO3– -> CO32–
CO32– + Ba2+ ->BaCO3 (white ppt.)
Do it!
• Appendix C--the supplies are on
your benches
• Do the Benedict’s test on C-1
(substituting 0.1% glucose for the
1% starch indicated)
• Candidate solution = glucose
• Do the CO2 test on C-2
53
– Place dry ice in flasks with
appropriate tubes/stopper
– Why dry ice?
Homework
If you don’t rule models in/out
Pedid
Three
pedig
solve
plaus
out fo
three
hypot