BIOLOGY 2F03 Lecture Notes - Lecture 7: Photosynthetically Active Radiation, Crassulacean Acid Metabolism, Vascular Bundle

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26 Nov 2016

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3 sources of energy: solar radiation, organic molecules, inorganic molecules. Tropic (feeding) biology: grouping organisms based on functional similarities among species (like how they get energy). Heterotrophs (other feeders): use organic molecules as a source of carbon and energy. Include bacteria, fungi, protists, animals and parasitic plants. Prokaryotes: have cells with no membrane-bound nucleus/organelles, include bacteria and archaea: archaea: prokaryotes that differentiate themselves from bacteria by structural, physiological features. Widely spread in biosphere (especially in ocean): prokaryotes include photo/chemo synthetic and heterotrophic species. Rhodopsin are light absorbing pigments found in animal eyes and in bacteria/archaea. In bacteria/archaea function as proton pump, atp synthesis: bacterial rhodopsin is mainly in oceans. Light sensitivity is adapted to local variations in light quality. In deep clear waters rhodopsin absorbs light strongly in blue range, while in shallow waters absorb green range. When light interacts with matter it acts as a particle. Longer wavelengths (infrared light) have less energy than visible/ultraviolet light.

Related Questions

1) A chemoautotroph would use _____ as an energy source.

A	carbon dioxide

B	chemical bonds within high energy molecules

sunlight

D	heat energy

2) A photoheterotroph would use _____ as a source of carbon atoms.

A	high energy organic molecules (e.g., sugars)

sunlight

C	carbon dioxide

D	inorganic molecules

3) Biologists sometimes divide living organisms into two groups: autotrophs and heterotrophs. These two groups differ in _____.

A	their electron acceptors

B	their mode of nutrition

C	the way that they generate ATP

D	their sources of energy

1. Which statement is FALSE regarding bacterial and archaeal cells?

Select one:

A. Archaeal and bacterial plasma membranes consist of a thin bilayer of lipid molecules penetrated by proteins.

B. Bacteria and archaea have group specific specializations in their cell envelope.

C. Archaea can have a single- or double-layered membrane.

D. Bacteria can have a single- or double-layered membrane.

E. Both bacteria and archaea have a layer of peptidoglycan in their cell envelope.

2.Which reason is MOST probable for why carbon is used in living organisms but not silicon?

Select one:

A. Carbon can make four bonds, whereas silicon can only make three.

B. Silicon is heavier, and therefore its bonds are stronger.

C. Carbon can form more preferred geometries when bonding.

D. Carbon is lighter, and therefore its bonds are stronger.

E. Carbon can make double bonds, but silicon cannot.

Which statement is TRUE regarding energy sources used by organisms?

Select one:

A. All phototrophs are autotrophs that can use carbon dioxide as a carbon source.

B. Phototrophs can use carbon dioxide as an energy source.

C. Phototrophs can use carbon dioxide as a carbon source.

D. All phototrophs are autotrophs.

E. All chemotrophs are heterotrophs.

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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BIOLOGY 2F03 Lecture Notes - Lecture 7: Photosynthetically Active Radiation, Crassulacean Acid Metabolism, Vascular Bundle

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