Monday, November 17, 2008

Chapter 8.4 Vocab., Summary, Concept Check

8.4 Vocab.-

carbon cycle- the process by which carbon moves from inorganic to organic compounds and back.

greenhouse effect- a property that keeps the average temp. on Earth some 10 degrees Celsius warmer than it would be otherwise.

8.4 Summary-

The carbon cycle is a process that occurs on Earth that the depend on the metabolism of tiny chloroplasts and mitochondria. A key element of the carbon cycle is carbon dioxide. Plants use carbon dioxide to make sugars, and organisms, consuming plants, give off carbon dioxide as waste. Carbon dioxide in the atmosphere traps heat from the sun that would have escaped from Earth into space. Some heat radiating from Earth's surface towards space is trapped by carbon dioxide (along with other types of gases) in the atmosphere. This property is called the greenhouse effect, which keeps the Earth warm enough for living things.

Concept Check

1. An example of carbon moving from an inorganic compound to an organic compound in the carbon cycle is a Cape buffalo eating the organic compunds by eating the plants. An example of carbon moving from an organic to an inorganic compound is the release of carbon dioxide from a Cape buffalo into the air and a plant uses the carbon dioxide in photosynthesis.

2. Because the carbon dioxide in the atmosphere traps heat from escaping into space.

Wednesday, November 12, 2008

Summary, Vocab., Concept Check of 8.3

Vocabulary of Chp. 8.3

Summary of 8.3

The Calvin cycle is like sugar factoy within a chloroplast. The Calvin cycle is a cycle because the starting material that gets regenerated is a compund that's a sugar with five carbons. In every turn of the Cycle there are chemical inputs and outputs. The inputs are carbon dioxide and the ATP and NADPH produced by the light reactions. The cycle uses carbon from carbon dioxide, energy from ATP, and high-energy elections and hydrogen ions from NADPH. The cycle's output is a sugar molecule rich in energy. The sugar molecule isn't glucose, but a much smaller molecule called G3P. G3P is used in a plant cell as raw material to make the organic molecules the plant cell needs.
The equation for photosynthesis is:
6CO2 + 6H2O >>> C6H12O6 + 6O2
Light reactions use the reactant water in the equation above to release the product oxygen. The cycle takes place in the stroma of a chloroplast, using ATP and NADPH to convert carbon dioxide into sugar. By converting light energy into chemical energy, some of the energy is passed on to consumers.

Concept Check 8.3

1. The inputs of the Calvin cycle are carbon dioxide, energy from ATP, and electrons and hydrogen ions from an NADPH. The output is an energy-rich sugar molecule called G3P.

2.The Calvin cycle uses every reactant from the overall photosynthesis equation. Also the Calvin cycle generates each product from the overall photosynthesis equation.

3. The Calvin cycle is called a cycle because the starting material is regenerated each time the process occurs.

4. The G3P molecule is a direct product of the photosynthesis. The G3P molecule is used to produce organic molecules that a plant cell needs.