22. Identify two scientists who influenced Charles Darwin’s thinking. What did each person hypothesize? Were their hypotheses correct? Why or why not

Scenario: The butterflies Heliconius melpomene and H. erato each show extraordinary geographical variation in coloration, and their colors vary in parallel.

Both species gain a fitness advantage by resembling the other because birds are more likely to associate their coloration with distastefulness and so avoid attacking them.

In field experiments, butterflies were marked and released with two color patterns: the local pattern and a pattern from one of the neighboring races.

Butterflies with the local pattern survive more than twice as well as those with the “wrong” color pattern.

What does this experiment suggest about the type of selection is occurring in these butterflies?

SUMMARY OF DNA-RELATED CHANGES DURING MITOSIS & MEIOSIS

(fill in the blanks with the correct number)

-------------------------------------------------Meiosis I ---------Meiosis II -------------------------- ----- Mitosis

chromatids/chromosome:      ____    -->    _____       --> _____ ........................ _____     --> _____

# chromosome sets:               ____n     --> _____n    -->   ____n................... .... _____n   -->  ____n

(1n = haploid)

change in cell #                        _____ --> _____    --> _____ ............................... _____     --> _____

In pea plants, purple flower color is dominant over white. If one sees a purple pea plant and has no prior knowledge of its ancestry, what can be said its genotype?

A. It is pp

B. It is Pp

C. It is PP

D. It is either PP or Pp

In impactor method, why not conduct outdoor air sampling on rainy or snowy weather

List three different types of retrovirus-encoded oncogenes that are represented by proto-oncogenes in normal cells. Briefly describe the general function of the viral oncogene or its corresponding proto-oncogene.

1. Draw and describe the meiotic events during oogenesis, which may lead to trisomy 18.

How did comparisons of different rRNA sequences lead to the discovery of Archaea? Why did Woese use rRNA genes to construct molecular phylogenies? Which groups are most similar (bacteria, archaea, and eukaryotes) with respect to the following structures or processes: cellular membrane biochemistry, DNA replication, RNA transcription, mechanism of protein translation, initiation of protein translation. Explain the argument that the most fundamental divide in the Tree of Life is between Bacteria and Archaea. Why is membrane composition cited as the basis of the ‘eukaryote paradox’? Know the arguments for discontinuing use of the term “prokaryote” and be able to explain why you think (or don’t think) that prokaryote is a useful and/or accurate term. How do Lateral Gene Transfers (LGT), aka horizontal gene transfer, confound reconstruction of phylogenetic trees? Name three processes of bacteria and archaea that result in LGT. How can we overcome this difficulty in understanding the (vertical) evolutionary history of microbes? What kinds of genes seem resistant to LGT? Explain the statement “we are embedded in a microbial world” – be sure to include the production of oxygen on Earth in your answer. Remember that thermodynamics tells us that energy flows out of all systems, but matter cycles. Much of the nutrient (matter) cycling that we all depend on requires microbial activity. Name the nutrient cycles that we described in lecture that require microbial activity. When did the plant- nitrogen-fixing-bacterial symbiosis emerge in earth’s history? Chlorophylls are an innovation of which group of organisms? Why is nitrogen limiting in most ecosystems?

let's imagine a diploid plant cell.

a) draw the five stages of mitosis and meiosis assuming N=3

b) briefly explain each step of mitosis and meiosis.

Chapter 1(microbiology)

5. What was the contribution of each of the following scientists: Jenner, Lister, Leeuwenhoek, Redi, Ehrlich, and Fleming.

6. What is spontaneous generation?

7. What was Pasteur’s approach to disproving spontaneous generation? What other discoveries did he make?

8. What are Koch’s postulates? What are the key features of these postulates? Be able to apply these ideas to a real life scenario. Explain when someone would need to follow the steps of Koch’s postulates?

9. Identify type of study performed by etiology, epidemiology, virology, mycology, parasitology, bacteriology.

CHEM 4722/5722 Homework Set #3 (due beginning of class Thu Apr 2)

Homework is to be turned in prior to class and should be done on plain white printer paper. If not, it will be returned for resubmission with a penalty assessed. Word processing should be used for any narrative answers. Calculations and mechanisms can be done freehand but must be very neat, organized, legible and on plain white paper. No lined paper will be accepted.

1. An example of a unsaturated fatty acid is cis-11-heptadecenoic acid. If this compound is oxidized down to CO2 and water via β-oxidation and subsequent pathways, how many ATP equivalents can be obtained? Show all work and list where all of the ATPs come from.

2. Draw out both steps of the malic enzyme mechanism for the conversion of malate to pyruvate. Include nicotinamide moieties, acid/base catalysis, and electron movement.

3. Write a balanced stoichiometric equation for the synthesis of squalene from acetyl-CoA. Indicate the reactions you used to determine your answer and show all work.

4. Refer to your lecture notes or your book for the synthesis of sphingomyelin. Write out the mechanisms (reactant, product structures and electron movement) for each synthetic step to the final product.

5. Mice were divided into four groups, two of which were fed a normal diet and two of which were fed a cholesterol-rich diet. HMG-CoA reductase mRNA and protein levels from liver were measured.

   1. a) What is the effect of cholesterol feeding on HMG-CoA reductase mRNA?

   2. b) What is the effect of cholesterol feeding on HMG-CoA reductase protein?

   3. c) Why is the result in panel B surprising in light of the result in panel A?

   4. d) Suggest possible explanations for the result in panel B.

IgM, unlike other heavy chain isotypes, appears in the serum as a pentamer of the basic four-chain Ig monomer; thus making it decavalent rather than bivalent in terms of combining sites. One intriguing result of this is an increase in the likelihood - all other things being equal - that the IgM will be bound (versus free). Another way of saying this is that even though the affinity constant (Ka) of each individual combining site is the same regardless of the overall molecule's valency, this decavalent version will have more whole Ig molecules bound (to antigen) at equilibrium than would a bivalent version (given equimolar levels of combining sites). This phenomenon is sometimes called increased "avidity" (to avoid using the rigorously defined chemical term "affinity" incorrectly). I'd like you to discuss a few issues raised by this:

• First, bearing in mind that IgM is the first isotype made during primary responses,why does this higher "avidity" make intuitive sense?
• Second, can you foresee ways that this added "stickiness" might also engender problems?
• Finally, does this mean that IgM molecules are more or less "specific" than their IgG counterparts? (watch it, that last one is tricky)

   Slide 11 problem:

   5’ UGG 3’ -  mRNA

                      -Template DNA stand

  -Nontemplate DNA strand

Slide 33 problem:

The following sequence of nucleotides in a DNA strand was used as a template to synthesize a mRNA that was then translated into protein:

                        5’-TTAACGGCTTTTTTCCAT-3’

Predict the C-term aa and the N-term aa of the resulting polypeptide.

Slide 34 problem:

True or False? Explain your answer!

1.An individual ribosome can make only one type of protein.

2.The large and small subunits of an individual ribosome

always stay together and never exchange partners.

3.An mRNA may contain the sequence ATTGACCCCGGTCAA

Slide 35 problem:

A mutation in DNA generates a UGA stop codon in the middle of the mRNA coding for protein X. You are studying protein X and isolating it from mutated cells. Which one best describes your findings:

1. No changes whatsoever are found between protein X isolated from wild type and mutant cells
2. Protein X from wild type cells is shorter than the one from mutant cells
3. Protein X from wild type cells is longer than the one from mutant cells
4. Protein X from mutant cells has a new function