A slice of apple left on a table slowly goes brown due to an enzymatic reaction. Dipping the apple slice in lemon juice prevents it from browning Which of the following best explains this result?

A. Lemon juice has enzymes which reverse the browning reaction

B. Lemon juice has a pH which inactivates the enzymes

C. Lemon juice functions to bleach the brown material

D. Lemon juice functions to dilute the brown material

Answer Explanation:

Browning of the apple surface is due to the action of the enzyme polyphenol oxidase. Lemon juice is acidic and lowers the pH of the apple's surface. This inactivates the enzyme polyphenol oxidase, which works best at a neutral pH. This in turn reduces the browning action on the apple.

Therefore, the Correct Answer is B.

Q #1: Which of the following demonstrates a chemical reaction of water?

A. Water boils to produce steam at 100° C (252)

B. Water Dissolves sugar

C. Water produces gas with sodium metal

D. Water and all separate when combined

Answer Explanation

a. Water boils to produce steam at 100°C - This is a phase change (from liquid to gas) and not a chemical reaction of water.

b. Water dissolves sugar - This is a physical change, not a chemical reaction of water.

c. Water produces gas with sodium metal - This reaction involves the chemical reaction of water with sodium metal to produce hydrogen gas.

d. Water and oil separate when combined - This is a physical separation, not a chemical reaction of water.
Q #2: Which of the following describes one difference between skeletal muscles and cardiac muscles?

A. Skeletal muscles are found in the viscera whereas cardiac muscles are found in the cranium

B. Cardiac muscles contain intercalated discs, whereas skeletal muscles do not

C. Cardiac muscles are voluntary, whereas skeletal muscles are involuntary

D. Skeletal muscles are autorhythmic, whereas cardiac muscles are not

Answer Explanation

Cardiac muscles have intercalated discs that enable them to contract in a coordinated manner. Skeletal muscles do not have intercalated discs, as their contraction is under voluntary control and does not require the same level of synchronization seen in the involuntary contraction of cardiac muscle.
Q #3: A study found two processes. Process A and Process B, are to be correlated. Which of the following is true for these processes?

A. The study indicates that Process A causes Process B

B. The study cannot indicate whether Process A and B have a negative relationship

C. The study does not indicate a causal relationship between the processes.

D. The study cannot indicate whether Process A and B have a positive relationship

Answer Explanation

Correlation does not imply causation. Even if two processes are found to be correlated, it does not necessarily mean that one causes the other. It could be that they are both influenced by a third factor, or the correlation could be coincidental. Therefore, the study does not indicate a causal relationship between the processes.

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A slice of apple left on a table slowly goes brown due to an enzymatic reaction. Dipping the apple slice in lemon juice prevents it from browning Which of the following best explains this result?

More Questions on TEAS 7 Science

Q #1: Which of the following demonstrates a chemical reaction of water?

Answer Explanation

Q #2: Which of the following describes one difference between skeletal muscles and cardiac muscles?

Answer Explanation

Q #3: A study found two processes. Process A and Process B, are to be correlated. Which of the following is true for these processes?

Answer Explanation

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