Relationships and Biodiversity Relationships and Biodiversity

Transcription

6/19/11
Relationships and Biodiversity
State Lab (Pg 131-147)
Plants
No seeds
State Lab (Pg 131-146; you turn in 141-146)
seeds
Gymnosperms
(naked seed; pine,
spruce, fir, etc…)
Angiosperms
(vessel seed (protective
chamber); flowering plants)
dicots monocots
Angiosperms diverged into
monocots and dicots
State Lab
State Lab
Angiosperms: Monocots vs. Dicots
PLANT VASCULAR TISSUE - tissues that conduct food and water
(phloem and xylem)
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State Lab
State Lab
Curol
Curol
Curol is a mitotic inhibitor used in cancer chemotherapy. It was discovered in a National
Cancer Institute program at the Research Triangle Institute in 1967 when Monroe E.
Curoli and Mansukh C. Cancurcere isolated it from the leaves of the tree Botanus
curus.
State Lab
Curol prevents polymerization of microtubules,
which would kill cancer cell because…
State Lab
Curol
Problem: Botanus curus is an endangered
species and we cannot synthesize curol in
a lab yet.
Microtubles (in yellow) are critical in cell division.
State Lab
What do we do?
Botanus curus
State Lab
Are there other species related to Botanus curus that
also produce Curol?
Scientists have found three candidates:
Are there other species related to Botanus curus that
also produce Curol?
Scientists have found three candidates:
Species X – Botanus dienerhlus
Species Y – Botanus lolevinus
Species Z – Botanus liuginus
Your goal is to gather evidence to try and determine
which species might also produce Curol.
What evidence might you gather?
Species X – Botanus Dienerhlus
Species Y – Botanus Lolevinus
Species Z – Botanus Liuginus
Your goal:
1. Gather structural and molecular evidence to determine which
plant species is most closely related to Botanus curus and therefore
may also produce Curol.
2
6/19/11
State Lab
State Lab
1. You will be separated into 7 groups of 2 or 3.
2. Each group will begin at one of the 7 stations.
3. There will be a rotation every 7 minutes.
Stations 1 and 2 - Structural Evidence
Station 1 - Structural Characteristics of plant
Compare the structural characteristics of the plant
samples. Record your observations in Table 1.
Station 2 - Structural Characteristics of Seeds
Compare the structural characteristics of the seed
samples. Record your observations in Table 1.
State Lab
State Lab
Station 3 - Microscope Internal Structure of Stems
1. There are four microscopes.
2. Each microscope has a cross section of one of the
species (Botanus curus, species X, Y, and Z).
3. Use the low magnification. Compare the arrangement
of the bundles (circular or scattered) and record you
observations using words or diagrams in Table 1.
State Lab
Remember Paper chromatography?
What famous individual used this technique and for what did
Chargaff, the A,T,C,G ratios of DNA from
this person use it to observe? Erwin
different organisms
- Analytical technique for separating and identifying mixtures
that are or can be colored, especially pigments.
State Lab
Station 4 - Paper Chromatography to Separate Plant Pigments
- The leaves of Botanus curus, species X, species Y and species Z
have been crushed up for you and an ethanol extraction was performed
to pull out the partially hydrophobic pigments.
How does Paper chromatography work?
The solvent (water in this case) will wick (travel) up the paper. The solvent will eventually make
its way to the sample absorbed on the paper. The molecules in the sample will have a different
affinity for both the paper and the solvent. If the affinity is high for the solvent, the molecule will
move quickly up the paper with the solvent. If the molecule has a high affinity for the paper, it
will resist movement and only move slowly up the paper.
What should you do with the pigment extract?
You should run them each on paper chromatography to separate
the pigments and compare the different species. The species most
similar to B. curus would be expected to have similar pigment
molecules since pigments are made by enzymatic reactions and
therefore the species would have similar enzymes…
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State Lab
State Lab
1. Take four strips of chromatography paper and try to straighten them the
best you can by curling them in the opposite direction and putting a slight
crease down the center (see example setup on the bench).
3. Add about 1cm of water to each beaker.
2. Draw a line 2 cm from the bottom of each of the four chromatography
papers. Use a pencil to label the top edge of the chromatography paper either
Bc (Botanus curus), X, Y, or Z (look at Figure 2 in the lab manual).
5. Place the paper into the water and allow the water to move up the
paper. Repeat steps 4 and 5 for the other samples.
State Lab
4. Place two drops of plant extract from Botanus curus just above the
pencil line as shown in Figure 2.
Pigment Sample MUST BE above the water level
or the pigment will just diffuse into the water!!!!!!
State Lab
Station 5 - Indicator Tests for Enzyme M
DO NOT contaminate the samples!!
Enzyme M is an enzyme
in Botanus curus that is
part of the Curol
biosynthetic pathway.
Label with your name and staple the four pieces of chromatography paper
to the lab when you turn it in.
GOGGLES
State Lab
State Lab
- It is not possible to test a plant directly for Curol (concentration
is too low).
- However, if enzyme M, an enzyme known to be a part of the
Curol synthesis pathway, is present, the plant may produce
Curol.
- Test the plant extract of each species for enzyme M by adding 5
drops of each extract to the substrate for enzyme M.
The product of enzyme M is a non-hazardous gas and
therefore bubbling indicates that enzyme M is present.
- Record the results in Table 1.
DO NOT contaminate the samples!!
GOGGLES
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State Lab
State Lab
Station 6 – Restriction fragment
analysis using Gel Electrophoresis
Station 6 – Restriction fragment
analysis using Gel Electrophoresis
Use restriction fragment length analysis to
determine relatedness between the
different species.
The species that is more closely related to B. curus should have more
similar restriction sites in its DNA and therefore will produce similar length
fragments when run on a gel.
Chapter 12 - DNA Technology and the Human Genome
How can we use bacteria to manipulate DNA and protein?
Recall how a bacterium defends itself when a bacteriophage
injects its DNA into a bacterium…
The bacterium has enzymes called restriction enzymes that
attempt to cut up the bacteriophage DNA before it can take
over the cell. Different species have different restriction
enzymes…
A. Use the colored DNA sequence strips,
which represent the DNA of each species
B. Do a restriction fragment analysis using
a restriction enzyme (scissors) that cut at
CCGG.
1. Cut all CCGG sites
2. Run a simulated gel electrophoresis using Table 2.
Draw a line indicating the size of the band on Table 2.
3. Attach fragments to the lab when you turn it in.
Restriction enzymes
1. molecular DNA scissors (enzymes that cut DNA)
2. Different restriction enzymes cut different sequences.
3. Scientists have isolated hundreds of different restriction enzymes from
many different bacteria – EcoRI, BamHI, NcoI, etc…
Aside: Why do these enzymes not cut the bacterial chromosome?
The bacterial chromosome is methylated (modified by adding –CH3
groups so the enzymes can’t bind to it)
Restriction enzymes
Restriction enzymes
Ex. EcoRI
Ex. EcoRI
EcoRI
Notice anything interesting about this sequence?
- It is palindromic, read the same way forward and backward.
- Majority of restriction sites are palindromic…
Fig. 12.4
Notice that is doesn’t cut straight through like paper scissors. The enzyme cuts each
strand after the G nucleotide generating single-strand regions called sticky ends.
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AIM: What are some other tools of DNA technology?
Restriction enzymes
Gel Electrophoresis
restriction enzymes
This technique allows one to not only indirectly view the DNA, but also
to separate and view the DNA fragments.
Fig. 12.10
Gel Electrophoresis
Gel Electrophoresis
Gel (like jell-o)
The gel is made of either agarose or polyacrylamide. It has tiny,
microscopic pores that DNA can fit through.
Gel (like jell-o)
The DNA sample is loaded in the wells at the top of the gel. One
sample per well.
Fig. 12.10
Fig. 12.10
Gel Electrophoresis
Gel Electrophoresis
Electricity (electrons flow
from top of gel by the samples
to the bottom of the gel)
Electricity is then run through the gel. Why do you think the negative
end is on the sample side and the positive end is on the other end of
the gel?
DNA is negative because the phosphates are negative. The negative
Fig. 12.10 electrons move down and push (repel) the DNA down with them.
Which will move faster through the micro-porous gel, the longer DNA
fragments or the shorter DNA fragments?
The small fragments (fewer nucleotides) will move more easily through the gel and hence go
faster than the large ones.
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6/19/11
Gel Electrophoresis
State Lab
Station 7 – Transcribe and Translate the DNA of each
organism to determine if an enzyme in species X, Y and Z
has a similar amino acid sequence indicating a close
relationship.
What can you say about the amino acid
sequence of the same protein in two
different species if they have a recent
common ancestor?
The gel is soaked with a a compound called ethidium bromide, which
sticks to DNA and lights up when you hit the gel with UV light…
Fig. 12.10
Chapter 13 – How Populations Evolve
AIM: What evidence do we have for evolution?
State Lab
Station 7 – Transcribe and Translate the DNA of each
organism to determine if an enzyme in species X, Y and Z
has a similar amino acid sequence indicating a close
relationship.
8
Number of different amino acids in
hemoglobin.
125
The sequence shown in the lab that
you need to transcribe is the noncoding/anti-sense/template strand.
The more recent the common ancestor, the more similar the amino acid
sequence should be since the DNA should be more similar.
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Relationships and Biodiversity Relationships and Biodiversity

Transcription

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