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Biology Exploring Life: Chapter 7 Concept Checks


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Chap 7 concept checks

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Concept Check 7.1
1. Define Autotroph and Heterotroph, and give an example of each.
2. Explain the role of food (glucose) in both photosynthesis and cellular respiration.
3. Explain how life on Earth depends on the sun.
Answers:
1.        An autotroph, example is a tree because it produces its own food. A heterotroph, example is bear or shark, gets food by eating another organism.
2.       Glucose comes from photosynthesis and an ingredient in cellular respiration.
3.       Most producers use the sun’s energy to do photosynthesis. Both producers and consumers depend on the products of photosynthesis to live.

Concept Check 7.2
1. Identify the types of energy you have at the top of a staircase and as you go down the stairs.
2. Explain how your body uses chemical energy during exercise.
3. If a food has 10 kcal of energy, how much could it increase the temperature of 100 g of water?
Answers:
1.       Potential energy is stored energy due to an object’s position or arrangement at the top of a hill or slid. Potential Energy is converted to kinetic energy, is the energy of motion as you go down.
2.       Exercise causes your cells to increase their rate of cellular respiration, increasing the conversion of chemical energy to ATP and heat.
3.       100 ˚ C

Concept Check 7.3
1. In what way is ATP like a compressed spring?
2. List three main types of cellular work.
3. What is the source of energy for regenerating ATP from ADP?
Answers:
1.       Compressed springs and ATP molecules store potential energy. Potential energy is released when one of the ATP molecules’ chemical bonds is broken, particularly between the phosphate groups in the ATP tail. The phosphate groups repel each other because they have like charges.
2.       Mechanical work,  Chemical work,  Transport work
3.       Chemical energy from organic molecules in food.

Concept Check 7.4
1. Compare and contrast breathing and cellular respiration.
2. List the reactants and products in cellular respiration.
3. What is meant by the "falling" of electrons to oxygen? How does this process release energy?
4. How does an electron transport chain result in the gradual release of energy stored in glucose?
Answers:
1.       Both involve the exchange of O 2 and CO 2 . In cellular respiration, cells take O 2 from their surroundings and release CO 2 . In breathing, the exchange takes place in the lungs and results in exchange of gases between blood and outside air.
2.       Reactants: glucose, oxygen
Products:, water,  ATP, and carbon dioxide
3.       The positively charged oxygen nucleus exerts an electrical pull on negatively charged electrons from other atoms. As electrons “fall” toward the oxygen nucleus, potential energy is released.
4.       As high-energy electrons from glucose are transferred from one electron carrier to another, a small amount of energy is released at each step.

Concept Check 7.5
1. How is the mitochondrion's structure suited to its function?
2. Identify the three stages of cellular respiration, where in the cell each takes place, and how many ATP molecules it produces.
3. Summarize the use and production of ATP in one cycle of cellular respiration.
Answers:
1.       The complex folding patterns of the mitochondria creates many sites where cellular respiration reactions may occur.
2.       Glycolysis , in the cytoplasm, 2 ATP molecules Krebs cycle , in the matrix within the mitochondria, 2 ATP molecules Electron Transport + ATP Synthase , inner membranes of the mitochondria, 34 ATP molecules
3.       Glycolysis : Uses 2 ATP; Produces 4 ATP Krebs Cycle : Uses 0 ATP; Produces 2 ATP Electron Transport + ATP Synthase : Uses 0 ATP; Produces 34 ATP

Concept Check 7.6
1. How is fermentation different from cellular respiration? 
2. Describe one example of how fermentation in microorganisms produces human foods.
3. What is the waste product of fermentation in your muscle cells?

Answers:
1.       Fermentation does not require oxygen to make ATP. It produces only 2 ATP molecules per molecule of glucose, while cellular respiration can produce 38.
2.       Microbes transform milk into cheese or yogurt; soybeans into soy sauce; cabbage into sauerkraut.
3.       Lactic acid