Chapter 8 Section 4 Vocab, Summary, and Concept Check

Vocabulary

carbon cycle: process by which carbon moves from inorganic to organic compounds and back
greenhouse effect: process by which atmospheric gases trap heat close to Earth's surface and prevent it from escaping into space


Summary

-Some of the processes that occur on a global scale on Earth depend on the metabolism of tiny chloroplasts and mitochondria
-Consumers such as a Cape buffalo obtain the organic compounds by eating the producers
-Cellular respiration by both producers and consumers returns carbon dioxide to the atmosphere
-Key element of the carbon cycle is carbon dioxide
-Plants use carbon dioxide to make sugars in photosynthesis, and most organisms give off carbon dioxide as waste from cellular respiration
-Carbon dioxide in the atmosphere also traps heat from the sun that would otherwise escape from Earth back into space


Concept Check 8.4

1. Give an example of carbon moving from an inorganic compound to an organic compound in the carbon cycle. Give an example of carbon moving from an organic to an inorganic compound.
Throughout the photosynthesis, the producer, such as plants converts inorganic compound to an organic compound. Then, when rabbit comes along and eats the grass, then the carbon would move from an organic to an inorganic compound.

2. How is carbon dioxide important to Earth's climate?
Carbon dioxide is a key element of the carbon cycle. Plus, carbon dioxide in the atmosphere traps heat from the sun and keep the Earth warm. If it wasn’t carbon dioxide, Earth would be really cold.

Chapter 8 Section 3 Vocab, Summary, and Concept Check

Summary

-Calvin cycle uses carbon from the carbon dioxide, energy from the ATP, and high-energy electrons and hydrogen ions from the NADPH
-each turn of the Calvin cycle, there are chemical inputs and outputs

-Calvin cycle is called a cycle because, like the Krebs cycle in cellular respiration, the starting material is regenerated each time the process occurs
-sugar is not yet glucose, but a smaller sugar named G3P
-6 CO2 + 6 H2O -> C6H12O6 + 6 O2
-converting light energy to chemical energy, photosynthesis is the first step in the flow of energy through an ecosystem
-Photosynthesis is the ultimate source of all the food you eat and all the oxygen you breathe


Concept Check 8.3

1. What are the inputs and outputs of the Calvin cycle?
Inputs of the Calvin cycle are carbon dioxide from the air and the ATP and NADPH produced by the light reactions. Outputs of the Calvin cycle are an energy-rich sugar molecule.

2. Which stage of photosynthesis uses each reactant from the overall photosynthesis equation? Which stage generates each product from the overall photosynthesis equation?
The light reactions of photosynthesis uses each reactant from the overall photosynthesis equation. In the other hand, Calvin cycle generates each product from the overall photosynthesis equation.

3. Why is the Calvin cycle called a cycle?
Calvin cycle called a cycle because like the Krebs cycle in cellular respiration, the starting material is regenerated each time the process occurs.

4. What molecule is the direct product of photosynthesis? How is that molecule then used by plant cells?
The direct product of photosynthesis are carbohydrates. That molecule then used by plants cell by changing the glucose into the ATP by doing cellular respiration.

Chapter 8 Section 2 Vocab, Summary, and Concept Check

Vocabulary

wavelength: distance between adjacent waves

electromagnetic spectrum: range of types of electromagnetic energy from gamma waves to radio waves

pigment: chemical compound that determines a substance's color

paper chromatography: laboratory technique used to observe the different pigments in a material

photosystem: cluster of chlorophyll and other molecules in a thylakoid

Summary

-Sunlight is a form of electromagnetic energy

-Electromagnetic energy travels in waves that can be compared to ocean waves rolling onto a beach

-Visible light—those wavelengths that your eyes see as different colors—makes up only a small fraction of the electromagnetic spectrum

-Shorter wavelengths have more energy than longer wavelengths

-When light shines on a material that contains pigments, three things can happen to the different wavelengths: they can be absorbed, transmitted, or reflected

-The chloroplasts convert some of this absorbed light energy into chemical energy. But the chloroplast pigments do not absorb green light well

-As the solvents move up the paper strip, the pigments dissolve in the solvents and are carried up the strip

-Each photosystem contains a few hundred pigment molecules, including chlorophyll a, chlorophyll b, and carotenoids

-Each time a pigment molecule absorbs light energy, one of the pigment's electrons gains energy—the electron is raised from a low-energy "ground state" to a high-energy "excited state."

-The electron transport chain connecting the two photosystems releases energy, which the chloroplast uses to make ATP

-The second photosystem can be thought of as the "NADPH-producing photosystem."

-This photosystem produces NADPH by transferring excited electrons and hydrogen ions to NADP+.

Concept Check 8.2

1. Explain why a leaf appears green.

A leaf appears green because the green light is not absorbed. When light shines on a material that contains pigments, three things can happen to the different wavelengths: they can be absorbed, transmitted, or reflected. The chloroplasts convert some of this absorbed light energy into chemical energy. But the chloroplast pigments do not absorb green light well.

2. Describe what happens when a molecule of chlorophyll a absorbs light.

When a molecule of chlorophyll a absorbs light, the molecule excited due to the light energy and transfers the light to another molecule.

3. Besides oxygen, what two molecules are produced by the light reactions?
Besides oxygen, hydrogen ions and NADPH is released.

4. Where in the chloroplast do the light reactions take place?

Light reactions take place in the thylakiod membrane in the chloroplast.

Chapter 8 Section 1 Vocab, Summary, and Concept Check

Vocabulary

Chloroplast: organelle found in some plant cells and certain unicellular organisms where photosynthesis takes place
Chlorophyll: pigment that gives a chloroplast its green color; uses light energy to split water molecules during photosynthesis

Stroma: thick fluid contained in the inner membrane of a chloroplast

Thylakoid: disk-shaped sac in the stroma of a chloroplast; site of the light reactions of photosynthesis

Light reactions: chemical reactions that convert the sun's energy to chemical energy; take place in the membranes of thylakoids in the chloroplast

Calvin cycle: cycle in plants that makes sugar from carbon dioxide, H+ ions, and high-energy electrons carried by NADPH

Summary

-when you observe a plant, all the green parts you can see contain cells with chloroplasts and can carry out photosynthesis

-leaves contain the most chloroplasts and are the major sites of photosynthesis

-tiny pores called stomata

-thylakoids are arranged in stacks called grana

-the "fall" of electrons from glucose to oxygen releases energy, which is then used to make ATP

-the opposite occurs in photosynthesis

-electrons from water are boosted "uphill" by the energy from sunlight

-photosynthesis occurs in two main stages, each with many steps: the light reactions and the Calvin cycle

-The chloroplasts also use the captured light energy to generate ATP

-Calvin cycle is sometimes referred to as the "light-independent reactions" because, unlike the light reactions, it does not directly require light to begin

-The Calvin cycle requires two inputs supplied by the light reactions, ATP and NADPH

Concept Check 8.1

1. Draw and label a simple diagram of a chloroplast that includes the following structures: outer and inner membranes, stroma, thylakoids.

2. What are the reactants for photosynthesis? What are the products?

The reactants for photosynthesis are carbon dioxide and water. The products are glucose and oxygen.

3. Name the two main stages of photosynthesis. How are the two stages related?

The two main stages of photosynthesis are the light reactions and the Calvin cycle. These two stages are realated because after the light reactions process, the Clavin cycle isgoing to do the work of photosynthesis. Plus, these two stages collaborate together to produce glucose and oxygen.