Download doc CHEE_370_HW_1_

McGill University
CHEE 370 Elements of Biotechnology
Fall 2009
Homework Assignment #1
Due Date: September 17th
1. (10 points)
Select a microorganism of relevance to humans (e.g., in biotechnology, agriculture,
energy, environment, or food production). This does not have to be an organism
discussed in class. Write a 200 word (maximum) description of the organism which
includes the following information:
- common habitat (soil, water, etc.)
- Gram + or Gram – ?
- metabolism (aerobic, anaerobic, chemolithotroph, etc…)
- how is this organism of human importance?
- pathogen or benign?
- motile or non-motile?
- fimbriated or non-fimbriated?
- any other special characteristics
If you can find one, include a photo of the organism in your homework submission.
2. (10 points)
Explain briefly what major concepts we owe to Sergei Winogradsky?
3. (10 points)
How do chemoorganotrophs differ from chemolithotrophs from the standpoint of energy
metabolism? What carbon sources do members of each group use? Are they therefore
heterotrophs or autotrophs?
4. (10 points)
Cells of the genus Halobacterium, an archeon that lives in very salty environments,
contain over 5 M potassium (K+). Because of this high K+ content, many cytoplasmic
proteins of Halobacterium cells are enriched in two specific amino acids that are present
in much higher proportions in Halobacterium proteins than in functionally similar
proteins from Escherichia coli (which has very low levels of K+ in its cytoplasm). Which
amino acids do you think are enriched in Halobacterium proteins and why? (Hint: which
amino acids could best neutralize the positive charges due to K+?)
5. (10 points)
RNA and DNA are similar types of macromolecules but show distinct differences as
well. (i) List three ways in which RNA differs chemically or physically from DNA. (ii)
What is the cellular function of DNA and RNA?
6. (10 points)
Calculate the amount of time it would take a cell of Escherichia coli (1 x 3 μm)
swimming at maximum speed to travel up a 3-cm long capillary tube containing a
chemical attractant.
7. (10 points)
Cells of Escherichia coli take up lactose via the Lac permease system, glucose via the
phosphotransferase system, and maltose via an ABC-type transporter. For each of these
sugars describe: (i) the components of their transport system, and (ii) the source of energy
that drives the transport event.
8. (10 points)
Define the terms primary, secondary, tertiary, and quaternary as they apply to proteins.
Which of these is (are) affected by the denaturation process?
9. (10 points)
Draw the structure of a simple lipid (triglyceride) and a complex lipid (phospholipid).
Where are each of these macromolecules commonly found in the prokaryotic cell?
10. (10 points)
How do plasmids differ from chromosomes?
11. (10 points)
Select a protein of relevance to humans. This does not have to be a protein discussed in
class. Write a 50 word (maximum) description of the protein and include an image of the
protein structure.