Transcript LB145-lecture1

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Front ->
NAME (in
BIG LETTERS)
Back ->
Career; What do
you want to learn
in this class?
Thinking of what you want to get out of your
college education and this course, which of
the following is most important to you?
a) Acquiring information (facts,
principles, concepts)
b) Learning how to use information and
knowledge in new situations
c) Developing lifelong learning skills
Of these three goals, which one do you think
you can make headway on outside of class
by your own reading and studying?
a) Acquiring information (facts,
principles, concepts)
b) Learning how to use information and
knowledge in new situations
c) Developing lifelong learning skills
These goals are not achieved by reading or
listening to a lecturer—you must actively do
things in order to learn (Bio or Kung Fu) like
These goals are not achieved by reading or
listening to a lecturer—you must actively do
things in order to learn (Bio or Kung Fu) like
• When you discuss what you are reading
• When you practice what you are learning
• When you apply practices and ideas to
new areas
See different
You are an intern
PCR photocopies DNA
Biological Information
inter-species
molecular communication
organismal communication in a population
Photographs of Pneumococcus Strains
Photographs of Pneumococcus Strains
R strain
S strain
Photographs of Pneumococcus Strains
R strain
S strain
Photographs of Pneumococcus Strains
R strain

S strain
Photographs of Pneumococcus Strains
R strain
harmless

S strain
lethal
Griffith’s Experiments
Griffith’s Experiments
Griffith’s Experiments
Griffith’s Experiments
Griffith’s Experiments
Griffith’s Experiments
Griffith’s Experiments
Griffith’s Experiments
Griffith’s Experiments
Griffith’s Experiments
Integrating Questions (set #1)
1. To help you think about what makes the S strain lethal and the R strain
harmless, describe the differences you observe in Figure 1.2. What part of the
cell do you think would be altered in order to change the overall appearance
of the colony?
2. It is helpful to keep in mind the origin of a bacterial colony. What is the
difference between a colony and a single cell?
3. Summarize the outcome of all four experiments in Figure 1.3. What
conclusions can you draw from the final experiment involving both R and S
cells? Can you use Griffith’s data to demonstrate that either DNA or protein is
the heritable material?
Bio-Math Exploration Integrating Questions
1.1a: Make a two-column table listing the number of possible DNA and
protein sequences of length 5, 10, 20, 50 and 100. Put your answers in
scientific notation so you can easily see how many digits are in each
answer.
1.1b: Looking at the numbers in your table, can you see why Griffith and
his contemporaries predicted that protein would be the heritable material?
Integrating Questions (set #2)
4. Since the “S factor” was associated with the bacterial capsule, why
couldn’t Griffith demonstrate that proteins are the heritable material? What
type of experimental design would you like to see before being fully
convinced of which kind of molecules contained the information that is
passed from one generation to the next and defines each species?
5. To understand why washed capsules could no longer transform R cells
into S cells, think about molecules that dissolve in water. Do fats dissolve in
water? Bacterial chromosomes are made of DNA, they are loosely attached
to the cell membrane, and they dissolve in cytoplasm. Speculate why
washed capsules lost their transforming capacity.
Genetic Material Determines Phenotype
Genetic Material Determines Phenotype
Genetic Material Determines Phenotype
R strain
S strain
Genetic Material Determines Phenotype
Integrating Questions (set #3)
6. Hypothesize what the white stringy material is in Figure 1.4a. (You may
have performed a similar procedure during a lab at some point in your
education.) If the cellular extract was clear before adding the ethanol, how
did the white threads suddenly appear from nowhere?
7. At this stage, can you determine if the white substance is pure, or could it
be a mixture of two or more types of molecules such as proteins and DNA?
Avery’s Transforming Factor
Avery’s Transforming Factor
Avery’s Transforming Factor
Avery’s Transforming Factor
DNA and 4 samples
had similar N
composition
Avery’s Transforming Factor
DNA and 4 samples
had similar P
composition
Avery’s Transforming Factor
nitrogen/phosphorous
ratios similar for 4
preparations and DNA
Avery’s Transforming Factor
Five Amino Acids
Five Amino Acids
peptide bonds
Five Amino Acids
amino acid backbones
Five Amino Acids
amino acid side chains
Four Nucleotides
Four Nucleotides
4 phosphates
Four Nucleotides
4 deoxyribose
sugars
Four Nucleotides
guanine = G
cytosine = C
4 bases
adenine = A
thymine = T
Four Nucleotides
Integrating Questions (set #4)
8. Table 1.1 highlights the nitrogen to phosphorous ratio (N/P) of the
transforming material. Determine the N/P ratios for the five amino acids and
four nucleotides shown in Figure 1.5. Why was the N/P ratio so important to
Avery’s interpretation of their data?
9. Adding a protease to the S factor is a pretty good way to show proteins
are not involved, but is this proof? Describe how a protein might not get
inactivated when treated with these two proteases? Would the same
consideration be true for RNA treated with RNase?
10. Perform a PubMed search using the phrase “Belanger Avery's” to find a
2004 paper that sheds new light on the pneumococcus strain R36A. PubMed
is the “Google” of biomedical research papers. Read the abstract. What new
information does this team from the drug company Eli Lilly uncover about
the R colony morphology, or shape, seen in R36A?