Lab Quiz 3

CONCLUSIONS: How much slower would hydrogen peroxide likely be decomposed if catalase was not available in cells? A. 1,000,000 times B. 10 times C. 1,000 times D. 100 times

A - 1,000,000 times

EXPERIMENT 2: At which substrate concentration(s) did catalase produce the greatest volume of gas during the experimental period? A. It was equal for all the substrate concentrations. B. the two highest substrate concentrations C. the lowest substrate concentration D. the two middle substrate concentrations

B

EXPERIMENT 3: What was the appearance of the Elodea cells in hypotonic solution? A. The cell membrane was shriveled and pulled away from the cell wall. B. The chloroplasts were located in the anterior of the cell. C. The cell membrane was pressed against the cell wall, and the cell was almost bursting. D. The cytoplasm and chloroplasts will be evenly distributed throughout the cell.

C

EXPERIMENT 1: Based on your results with iodine and starch, what material(s) diffused across the membrane? A. starch and iodine B. neither starch nor iodine C. starch D. iodine

D

EXPERIMENT 2: At which substrate concentration(s) did catalase produce the smallest volume of gas during the experimental period? A. the two middle substrate concentrations B. the two highest substrate concentrations C. It was equal for all the substrate concentrations. D. the lowest substrate concentration

D

EXPERIMENT 3: What was the appearance of the Elodea cells in aquarium water? A. The cell membrane shriveled and pulled away from the cell wall. B. The chloroplasts were located mostly at the periphery of the cell. C. The chloroplasts were located mostly in the center of the cell. D. The cell membrane was pressed against the cell wall.

D

EXPERIMENT 3: How did the Elodea cells change when aquarium water was replaced with hypertonic solution? What caused those changes?

Hypertonic - cell shrunk and cell membrane moved inward, because water left the cell due to higher concentration of solute in the hypertonic solution compared to inside the cell

EXPERIMENT 1: At which temperatures did catalase function somewhat, but not optimally?

21.5 and 60 degrees C

EXPERIMENT 1: What caused the bubbles to form when you added the catalase to the hydrogen peroxide and water mixture at 40 °C? A. Oxygen gas formed during the decomposition of hydrogen peroxide. B. The constant temperature bath heated the solution to its boiling point. C. Catalase activity heated the solution to its boiling point. D. Hydrogen gas formed during the formation of hydrogen peroxide.

A

EXPERIMENT 1: What was the color of the starch solution in the beaker after dialysis? A. The starch solution turned bluish black after dialysis. B. The starch solution did not change color after dialysis. C. The starch solution turned reddish brown after dialysis. D. The starch solution turned white after dialysis.

A

EXPERIMENT 1: Why was iodine able to diffuse across the membrane whereas starch was not? A. The pores of the bag are larger than the iodine molecules but smaller than the starch molecules. B. Molecules can only diffuse out of the bag, but they cannot diffuse into it because the pores are unidirectional. C. Iodine is a charged ion so it is attracted to the diffusion bag and pulled through, whereas starch has no charge. D. The bag is not semipermeable because it only allows small molecules such as iodine to pass.

A

EXPERIMENT 2: Explain the results of the experiment in which the diffusion bag contained 5% fructooligosaccharides. A. The sugar concentration was higher in the beaker than in the bag, so water moved from the bag to the beaker. B. The sugar concentration was the same in the beaker and the bag, so there was no net movement of water. C. The sugar concentration was lower in the beaker than in the bag, so water moved from the beaker to the bag. D. The sugar concentration was higher in the beaker than in the bag, so water moved from the beaker to the bag.

A

EXPERIMENT 3: What caused the changes you observed between the slides of Elodea in aquarium water and Elodea in hypertonic solution? A. The hypertonic solution caused water to leave the cell. This shrunk the cytoplasm and pulled the cell membrane away from the cell walls, a condition called plasmolysis. B. There was no difference between the two slides. C. The cells contained a higher concentration of fructooligosaccharides than the hypertonic solution did, and water needed to move from the solution to the cells to equalize the concentrations. D. The salt diffused into the cell, causing the chloroplasts to be repelled to the center of the cell.

A

EXPERIMENT 3: What was the appearance of the Elodea cells in hypertonic solution? A. The cell membrane shriveled and pulled away from the cell wall. B. The cell membrane was pressed against the cell wall and the cell was almost bursting. C. The chloroplasts were located in the anterior of the cell. D. The chloroplasts were located mostly at the periphery of the cell.

A

EXPERIMENT 1: At which temperature did the catalase enzyme function at its best? A. 40 °C B. 10 °C C. 21.5 °C D. 80 °C

A - 40 C

CONCLUSIONS: Do the optimal conditions for catalase functioning that you found correspond with the conditions in the mammalian liver where it came from? A. No, catalase functioned best at a much higher pH than in mammalian tissue and at a much lower temperature. B. Yes, catalase worked best at a neutral pH and temperature of 40 °C, both of which are close to mammalian tissue conditions. C. No, catalase functioned best at several very different pHs and temperatures, whereas the pH and temperature of mammalian tissue do not fluctuate. D. Yes, catalase functioned best at the same low pH and temperature as occur in mammalian tissue.

B

CONCLUSIONS: Is diffusion the only way materials can enter a cell? A. Yes, diffusion is the only way materials can enter a cell. B. No, a cell is capable of actively transporting materials across its membrane. C. Multicellular organisms have organs that can transport materials across cell membranes, whereas unicellular organisms do not. D. No, charged ions enter a cell because of their electrical attraction, not the concentration gradient.

B

EXPERIMENT 1: What was the color of the iodine solution in the diffusion bag before and after dialysis? A. The iodine solution was reddish brown before dialysis and bluish black after dialysis. B. The iodine solution was reddish brown before dialysis and did not change color during dialysis. C. The iodine solution was bluish black before dialysis and did not change color during dialysis. D. The iodine solution was bluish black before dialysis and reddish brown after dialysis.

B

EXPERIMENT 2: Explain the results of the experiment in which the diffusion bag contained 10% fructooligosaccharides. A. The sugar concentration was higher in the beaker than in the bag, so water moved from the bag to the beaker. B. The sugar concentration was the same in the beaker and the bag, so there was no net movement of water. C. The sugar concentration was lower in the beaker than in the bag, so water moved from the beaker to the bag. D. The sugar concentration was higher in the beaker than in the bag, so water moved from the beaker to the bag.

B

EXPERIMENT 2: Explain the results of the experiment in which the diffusion bag contained 20% fructooligosaccharides. A. The sugar concentration was lower in the beaker than in the bag, so water moved from the bag to the beaker. B. The sugar concentration was lower in the beaker than in the bag, so water moved from the beaker to the bag. C. The sugar concentration was higher in the beaker than in the bag, so water moved from the bag to the beaker. D. The sugar concentration was the same in the beaker and the bag, so there was no net movement of water.

B

EXPERIMENT 2: Water was able to move across the dialysis membrane but the fructooligosaccharide molecules were not. Explain why this is the case. A. Water is attracted to pores in the membrane because of its polarity. B. The fructooligosaccharide molecules are larger than water molecules, and will not fit through the pores in the dialysis membrane. C. The fructooligosaccharide molecules were immobilized because they adhered to the membrane. D. Fructooligosaccharide molecules are smaller than water molecules and will fit through the pores in the dialysis membrane.

B

EXPERIMENT 1: Why did catalase fail to function at 80 °C?

Because the high temperature caused denaturation, which caused damage beyond repair

EXPERIMENT 2: Before the catalase concentration was saturated with hydrogen peroxide, why did the enzyme function vary with substrate concentration?

Because there was still available substrate to be used

CONCLUSIONS: Based on your results from this lab, would you expect the hydrogen peroxide you buy from the store to bubble like soda when you open it? A. Yes, catalase had little effect on hydrogen peroxide decomposition. It would bubble quickly no matter what. B. Yes, hydrogen peroxide is only stable in the presence of catalase. Without it, store-bought hydrogen peroxide decomposes quickly. C. No, catalase sped up the rate of the reaction. Store-bought hydrogen peroxide will decompose into water and oxygen gas too slowly for visible bubbles to form. D. No, hydrogen peroxide can only decompose into water and oxygen gas in the presence of catalase.

C

CONCLUSIONS: Based on your results in Experiment 3, why do the vegetables in dressed salads wilt over time? A. The experiment did not demonstrate any difference between aquarium water and the hypertonic solution. Therefore, it does not relate to wilted salad. B. The salt, sugar, or other spices dissolved in the dressing diffuse into the cells, repelling the chloroplasts to the center of the cell. The uneven distribution of the organelles causes the vegetable as a whole to wilt. C. The dressing is a hypertonic solution because it has salt, sugar, or other spices dissolved in an aqueous base. Plasmolysis in the cells of the vegetables causes the vegetable as a whole to wilt. D. There are more solutes in the vegetable cells than in the dressing, therefore the solutes diffuse out of the cells and into the dressing. The loss of the solvents causes the vegetables to wilt.

C

EXPERIMENT 2: Explain the results of the experiment in which the diffusion bag contained 15% fructooligosaccharides. A. The sugar concentration was lower in the beaker than in the bag, so water moved from the bag to the beaker. B. The sugar concentration was higher in the beaker than in the bag, so water moved from the bag to the beaker. C. The sugar concentration was the same in the beaker and the bag, so there was no net movement of water. D. The sugar concentration was lower in the beaker than in the bag, so water moved from the beaker to the bag.

D

EXPERIMENT 2: When the diffusion bag contained 20% or 15% fructooligosaccharides, the net movement of water was from the beaker to the bag. However, the change in mass was greater when the dialysis bag contained 20% fructooligosaccharides than when it contained 15% fructooligosaccharides. Why? A. The concentration of fructooligosaccharides in the 20% solution was higher than the concentration in the beaker while the concentration of fructooligosaccharides in the 15% solution was lower, resulting in the observed difference in mass. B. Water moves across the membrane more quickly when the concentration is higher, but if you wait long enough, the change in mass would be the same. C. The bag containing the 20% fructooligosaccharides solution was heavier, so the change in mass was more noticeable. D. The concentration of fructooligosaccharides in the 20% solution was higher than in the 15% solution, so more water needed to move from the beaker to the bag to equalize the concentration.

D

EXPERIMENT 2: Why did the catalase function level off when different hydrogen peroxide concentrations were tested? A. High concentrations of hydrogen peroxide raised the pH levels above the point of optimal catalase activity. B. Catalase activity continually increased, so the experiment must have been done incorrectly to produce results that appeared to level off. C. High concentrations of hydrogen peroxide caused oxidative damage to the catalase enzymes and they were not able to perform at their optimal level. D. At some point, all the catalase in solution was catalyzing reactions, so even if the hydrogen peroxide concentration was increased, the rate of the reaction could not increase any more.

D

EXPERIMENT 3: At which pH level(s) did catalase fail to function? A. 2 and 10 B. 6 C. 6 and 10 D. 2

D - 2

EXPERIMENT 1: At which temperature did catalase function at the slowest rate, but still produce gas? A. 40 °C B. 21.5 °C C. 10 °C D. 60 °C

D - 60 C

CONCLUSIONS: What are the enzyme, substrate, and product in these experiments?

Enzyme - catalase Substrate - hydrogen peroxide Product - oxygen

CONCLUSIONS: What role does catalase play in the mammalian liver, or any other cell it is found in?

Hydrogen peroxide is a byproduct of some reactions that occur in the body. Catalase helps to break it down into oxygen.

EXPERIMENT 3: Why did catalase only function in a limited range of pH values?

If there is too many hydrogen or hydroxide ions, distortion of the active site occurs to the point that it can no longer function as a catalyst

EXPERIMENT 1: Which material did NOT diffuse across the membrane? Why not?

Starch - too large of a molecule to pass

EXPERIMENT 1: Initially, Lugol's iodine was placed inside the diffusion bag, and starch was placed outside the bag. Which of these materials was able to pass through the diffusion membrane? How do you know?

The Lugol's iodine was able to pass through the diffusion membrane as evidenced by the liquid in the beaker turning bluish/black, whereas there was no change to the color of the liquid in the diffusion bag.

CONCLUSIONS: In Experiment 2, for both trials 1 and 2, net movement of water was from the beaker to the bag. However, the change in mass for the diffusion bag in trial 1 was greater than that for trial 2. Why?

The change in mass for diffusion bag in trial 1 was greater than for trial 2 because the bag in trial 1 had a greater concentration of FOS than the bag for trial 2.

EXPERIMENT 2: For each trial you performed, explain how and why the water moved.

Trials 1 and 2 - since both were hypertonic solutions, water exited the beaker to balance the concentrations inside and outside of the cells Trial 3 - isotonic solution meaning the concentration was equal in the bag and the beaker, so no water movement Trial 4 - hypotonic solution so the concentration was lower in the bag than the beaker, so water left the bag to help balance the concentrations

EXPERIMENT 3: What was the pH value at which catalase functioned the best?

pH 6