MGY377H1 Midterm: Study notes for midterm

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redtermite204

24 Dec 2011

School

UTSG

Department

Molecular Genetics and Microbiology

Course

MGY377H1

Professor

William Navarre

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Document Summary

Normal growth conditions based on human frame of reference. Any ecological niche outside this range considered extreme. Salt concentration of 0. 9: such life organisms called extremophiles. Four key factors: temperature, ph, water availability, oxygen. Cardinal temperatures for each organism: minimal temp, optimal temp, maximum temp. Below minimum temp, membrane gelling, transport processes so slow that growth cannot occur. Above maximum temp, protein denaturation, collapse of cytoplasmic membrane, thermal lysis. Classes: psychrophile optimal growth is fifteen degrees or less. survive in small pockets of water in ice, glaciers, glacial lakes, snowfields. grow in hot places, like soils with full sunlight, fermenting compost piles. Most organisms show range of two to three units. Classes: acidophiles grow at low ph. Internal ph is near neutral: neutrophiles grow best at ph 7, alkaliphiles grow best at high ph. use sodium gradient to drive transport, atp synthesis, motility. Water availability depends on water concent of environment and concentration of solutes.

Related Questions

a large population of an animal live on a beach with high levels of sunlight, and only a small shaded area. During the day, the temperatures reach almost 40 degrees Celsius, which is the optimal temperatures for protein denaturation in these species. provide a feature in the animal that would make it successful in this environment.

How does optimal temperature results for fungal amylase activity relate to environmental conditions for the organisms natural habitat?

I need help on this microbiology question:

Contrary to our favorite science fiction books and movies, the chances of us finding another planet with a civilization comparable to, or even more advanced than our own, seems highly unlikely. But, through your work as a microbiologist at NASA, you have been able to help change our views as to what forms of life we should be looking for on planets in our solar system and around neighboring stars. Instead of radio signals or errant transmissions, we have begun looking for planets that have environments similar to those capable of sustaining life as we know it here on Earth. To determine what we could find out there, you have begun studying different unique and atypical environments found here on Earth. Although the harsh conditions of hot springs or undersea sulfur vents seem incompatible with most forms of life, organisms known collectively as "extremophiles" have still managed to survive and adapt to these extreme conditions. You believe extremophiles may help you gain insight into the potential metabolic requirements, processes, and challenges of extraterrestrial life. Thus far in your search, you have identified some prokaryotic cells that have evolved to survive in the extreme conditions of sulfur vents on the sea floor. These vents are found at great depths, where the crushing pressure and lack of light and oxygen are prohibitive to many forms of life. Bacteria that are not considered extremophiles reside in most ecological niches on this planet. There are some common criteria for the environment that would sustain these bacteria. Availability of water, pH that lies between 5 and 9, temperatures that will remain steady and below boiling; these are some of the characteristics that bacteria will require in their environment if they are to succeed. But in the environment of the ocean floor vents, not only is the pH of the water very low, but also the water temperature is unusually high due to the geologic activity that fuels the vents. Organisms that are adapted to such harsh conditions have necessarily evolved enzymes able to function beyond average optima, as well as a chemosynthetic metabolism capable of using vent organic and inorganic compounds as energy sources.

Part A - Comparable Earth Environments to Be Found on Another Planet

You identify the prokaryotic cells you've found as a species of bacteria. These bacteria appear to be living off of nutrients and sulfur compounds released from the vents on the sea floor. Over time, the bacteria must have evolved extreme metabolic and enzymatic capabilities to allow them to tolerate and even benefit from the extreme depths, the lack of oxygen, the low pH of the surrounding waters, high temperatures due to volcanic releases, and the unique nutrient source of the vents.

Choose the characteristics and their impact on enzyme activity that are not correct from the following statements. (more than one may be chosen)

Archaea are able to tolerate highly acidic pH environments and have proteins that will not denature in the low-pH environments that the bacteria are found in.

Archaea are able to colonize water that is at or above the boiling temperature due to high levels of disulfide bridges that maintain the three-dimensional structure of the enzyme.

Archaea are only able to survive exceedingly well at high temperatures due to the amount of activation energy required by their enzymes.

Archaea are able to grow in extremely shady or low-light conditions that allow for optimal enzyme activity.

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MGY377H1 Midterm: Study notes for midterm

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