The Chemical Basis of Life Chapter 2 The Chemical Basis of Life

Concept Check In order to understand the chemical basis of inheritance, one must understand the molecular structure of DNA. This is an example of the application of __________ to the study of biology? emergent properties the cell theory reductionism philosophy

Answer In order to understand the chemical basis of inheritance, one must understand the molecular structure of DNA. This is an example of the application of __________ to the study of biology? reductionism

Concept Check The reactive properties or chemical behavior of an atom mostly depend on the number of the electrons in each electron shell of the atom. the neutrons found in the nucleus. the filled electron shells. the electrons in the outer electron shell of the atom.

Answer The reactive properties or chemical behavior of an atom mostly depend on the number of the electrons in the outer electron shell of the atom.

Concept Check Water molecules form hydrogen bonds because Water molecules form hydrogen bonds because the water molecule is polar. the oxygen molecule is positively charged. the water molecule forms a tetrahedron. the hydrogen atoms are negatively charged.

Answer Water molecules form hydrogen bonds because Water molecules form hydrogen bonds because the water molecule is polar.

Interpreting Data This is the general equation for photosynthesis—the process of capturing sunlight energy and converting it to chemical energy. Which of the following are the reactants of this reaction? C6H12O6 and O2. CO2 and H2O.

Answer This is the general equation for photosynthesis—the process of capturing sunlight energy and converting it to chemical energy. Which of the following are the reactants of this reaction? CO2 and H2O.

Interpreting Data Earth’s oceans are immense. Small floating plants called phytoplankton contribute to ocean productivity. As ocean productivity (the rate of photosynthesis) goes up what would you predict would happen to global carbon dioxide levels? CO2 levels should also go up. CO2 levels should go down CO2 levels should remain constant.

Answer Earth’s oceans are immense. Small floating plants called phytoplankton contribute to ocean productivity. As ocean productivity (the rate of photosynthesis) goes up what would you predict would happen to global carbon dioxide levels? CO2 levels should go down

Interpreting Data Ironically, the world’s oceans throughout the tropics are not very productive. (these oceans do not capture much sunlight through the process of photosynthesis.) On the other hand some of the most productive ocean are the Arctic and Antarctic. What might be limiting production in the tropical oceans? Low temperature. Low sunlight. Low nutrients. High nutrients.

Answer Ironically, the world’s oceans throughout the tropics are not very productive. (these oceans do not capture much sunlight through the process of photosynthesis.) On the other hand some of the most productive ocean are the Arctic and Antarctic. What might be limiting production in the tropical oceans? Low nutrients.

Interpreting Data Iron is the fourth most common element (by weight) in the Earth’s crust. Iron is an essential trace element for all living organisms. Ocean waters, particularly the Southern Ocean have very minute amounts of iron. The Iron hypothesis states that Iron availability limits ocean productivity.

Interpreting Data These are the results of a laboratory experiment to test the effect of trace nutrients on the productivity of Pacific Ocean water. After 6 days which nutrient had the greatest effect on productivity? Iron. Manganese. Copper. Zinc. Adapted from Coale, Kenneth H. 1991. Effects of Iron, Manganese, Copper and Zinc Enrichments on Productivity and Biomass in the Subarctic Pacific. Limnology and Oceanography. 36: 1851-1864

Answer These are the results of a laboratory experiment to test the effect of trace nutrients on the productivity of Pacific Ocean water. After 6 days which nutrient had the greatest effect on productivity? Iron. Adapted from Coale, Kenneth H. 1991. Effects of Iron, Manganese, Copper and Zinc Enrichments on Productivity and Biomass in the Subarctic Pacific. Limnology and Oceanography. 36: 1851-1864

Interpreting Data The stability of atoms. The unity of life on earth. Some have suggested that fertilizing the oceans with iron might be a possible solution to the increasing carbon dioxide levels in the atmosphere. Iron’s function as a trace nutrient in phytoplankton possibly affecting the atmosphere and possibly global climate is a good example of? The stability of atoms. The unity of life on earth. Emergent properties.

Answer Emergent properties. Some have suggested that fertilizing the oceans with iron might be a possible solution to the increasing carbon dioxide levels in the atmosphere. Iron’s function as a trace nutrient in phytoplankton possibly affecting the atmosphere and possibly global climate is a good example of? Emergent properties.

Biology and Society A. B. C. D. E. Carbon dioxide contributes to global warming as a greenhouse gas. Large scale experiments have been done and the results do indicate that there is at least a short term increase in productivity and a decrease of carbon dioxide immediately in the area of iron fertilization. Do you think we should pursue this line of research with more large scale experiments to introduce iron to ocean systems? Strongly Agree Strongly Disagree A. B. C. D. E.

Biology and Society A. B. C. D. E. Too little iodine in the diet can lead to goiter—the condition afflicting this person. Goiter is not common in developing countries because iodine is added to salt and other foods. Do you think that adding trace elements to food items is good public policy? Strongly Disagree Strongly Agree A. B. C. D. E.

Biology and Society A. B. C. D. E. One of the authors of your text once overheard the following: “It’s paranoid and ignorant to worry about industry or agriculture contaminating the environment with their chemical wastes. After all, this stuff is just made of the same atoms that were already present in our environment anyway.” What do you think of this statement? Strongly Disagree Strongly Agree A. B. C. D. E.