Bio29 Group H21 Homework2

Bio29 Group H21 Homework2 - Acidic Environment C H (excess...

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H I J C D E Acidic Environment Acidic Environment (excess protons) (excess protons) Basic Environment Basic Environment (deficient in protons) (deficient in protons) B C D F G H 1. Which organelles are believed to have arisen by endosymbiosis? What is the evidence for the endosymbiotic origin of those eukaryotic organelles? Which eukaryote organelle was created first, and why? The mitochondria and chloroplasts are thought to have arisen by endosymbiosis. The evidence supporting this assertion is that DNA is present in the two organelles and is of alternate geometric structure. It is circular as in prokaryotic cells. The ribosomes found therein are of the type 70S as opposed to the 80S type found in eukaryotes. «find to which he is referring» 2. What class of organisms contains species that produce potent toxins that can cause extensive fish kills, contaminate shellfish, and poison humans? Algae 3. Why do red algae appear red, why do green algae appear green, and brown algae appear brown when they all have chlorophyll A photosystems? Red algae appear red because of the pigment present in them that has the purpose of filtering light that cannot reach to the depths at which they live. . Green have chloroplasts and less of the red-pigment. . Blue algae have an alternate balance of the pigment to filter different spectra of light. Brown algae exist in brackish tidal zones and are therefore less reliant on photosynthesis for generation of energy. 4. On land all plants appear green, where as aquatic plants vary in color. Why do land plants have one photosynthetic strategy where aquatic plants use different light harvesting strategies? Water filters various wavelengths of light at different depths forcing evolutionary response to harvest the energy available. 5. Define the terms producer, primary consumer, secondary consumer, tertiary consumer? Give an example of each term. What is a trophic level? How many trophic levels exist? Why is there a limit? In what trophic level do plants belong? A producer is the first step in the environmental chain of biochemical synthesis. An organism that uses external energy sources such as the sun or inorganic molecules. Plants, through photosynthesis, and some eukaryotes, through oxidation of inorganic molecules are producers. A primary consumer is an herbivore; an animal that eats producers. A manatee is an example of a primary consumer. A secondary consumer is an organism that consumes primary consumers. An example of a secondary consumer is a lion. A tertiary consumer is a carnivore that eats other carnivores, such as a vulture or mongoose.
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Biology 29 Homework II Homework II Group H21 Ilana Blum Homeira Chalim Chana Landa Eli Lazar  Charles Forgy Matthew Sherian 2 6a. Melvin Calvin, James Bassham, and Andrew Benson pieced together the light- independent (or dark reactions ) that fix CO2 into organic molecules. When they exposed photosynthesizing green algae with radioactive CO2, and then extracted the organic
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This note was uploaded on 04/14/2010 for the course BIOL 29.1 taught by Professor Ovalle during the Fall '09 term at CUNY Brooklyn.

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Bio29 Group H21 Homework2 - Acidic Environment C H (excess...

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