Tanya-Alexis-CR+essays

**26:**  Tom notices that he is a lot more short of breath after he finishes a 200 meter sprint than when he jogs for 3 miles. He is confused because he feels as if he should feel more tired when he runs for a much longer distance. Explain to him why it makes sense that he is indeed more short of breath after running a sprint than jogging. Make sure to explain it using your scientific knowledge of cellular respiration.

**A:** While Tom is sprinting, his muscle cells do not receive enough oxygen from the blood cells, so they have to go through anaerobic respiration (lactic acid fermentation). When he is sprinting, he uses up the oxygen in his body faster then he is recieving the oxygen.Therefore his cells are in oxygen debt, so he must breathe faster to gain the oxygen back. Since sprinting is more strenuous, there would be less oxygen present in Tom’s cells because he is using it so quickly causing him to feel out of breath.

**A:** When the scientist put the mitochondria into the acid, the acid entered the mitochondria. Acid that is placed into a solution makes hydrogen ions. The hydrogen ions can help form glucose, since the mitochondria is not producing glucose by itself. The mitochondria uses the glucose to make ATP through aerobic respiration.
 * 27 : **A scientist isolates mitochondria form human cells and places them in an acid solution. The acid penetrates the intermembranous space of the mitochondria. The scientist then notices that the mitochondria start making ATP despite the fact that he is not providing any glucose for them. How is it possible that the mitochondria are still making ATP? (Think back to what an acid is, what it releases when placed in a solution and why this would make the mitochondria synthesize ATP).

**28:** Genetic testing reveals that baby Helen has a defective gene that results in the defective production of one of the proteins in the electron transport chain. Because of faulty instructions in her DNA, one of the proteins in her ETC is mis-shapen, and therefore it cannot perform its function as efficiently. Baby Helen is “failing to thrive” as she is having a hard time gaining weight and reaching developmental milestones. Using your knowledge of the ETC and its role in making ATP, explain why you think baby Helen is having the problems described above.

**A:** When a protein in the electron transport chain is defective, the hydrogen ions are not able to move through the protein. If the hydrogen ions can not move through the protein, ATP synthase can not occur, so the baby’s cells are not able to make ATP. She is not able to develop properly if she can not make ATP.

**29:** <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 12pt; font-style: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> Compare the basic transformation of energy during photosynthesis and cellular respiration.

<span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 12pt; font-style: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">**A:** <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 12pt; font-style: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">In photosynthesis, energy starts off in the photons in the sun. From the sun, the energy enters the chlorophyll in the chloroplast of a plant cell. Each electron from the chlorophyll is passed through the electron acceptor and onto proteins in the electron transport chain. After electrons pass through the ETC, they replace electrons in Photosystem I. From Photosystem I, electrons make NADPH and NADP+. While the electrons are in the ETC, hydrogen ions are actively passing though the proteins in the chain into the thylakoid sac. Then they pass through the ATP synthase and turn into ADP and phosphate (ATP). During cellular respiration, glucose made during photosynthesis and oxygen are converted to ATP, water, and carbon dioxide. This can be done either aerobically or anaerobically. In aerobic respiration it goes through Krebs cycle, where carbon dioxide is released and and the ETC, where ATP is made. In anaerobic respiration, the cell goes through lactic acid fermentation, where the NAD+ that is made is then used back in glycolysis.

<span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 12pt; font-style: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">**30:** <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 12pt; font-style: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Describe the role of ATP in biochemical reactions. What is ATP used for in your cells? How do your cells get energy out of a molecule of ATP? How is ATP recharged?

<span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 12pt; font-style: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">**A:** <span style="background-color: transparent; color: #000000; font-family: Arial; font-size: 12pt; font-style: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">ATP is the energy in the cell and it is used during all reactions that occur in the cell. Since energy is stored in the bonds of a molecules, the ATP breaks off a phosphate group, creating energy. ATP is then recharged when a new phosphate group reattached to the ADP molecule.