A chemical that reacts with an enzyme in place of the substrate, is not turned into product and blocks the active site temporarily or permanently is known as what?
Correct answer A. Inhibitor
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Everyday Science MCQs
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What is a substance that binds to an enzyme’s active site but does not lead to product formation called?
Correct answer D. Competitive inhibitor
Which statement about the cell membrane is NOT true?
Correct answer D. It contains charged pores, so ions, being charged particles, cross the cell membrane much more easily than neutral particles
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Inhibitors that block an enzyme by forming weak bonds are called what?
Correct answer B. Both a and b
Compared with the human eye, about how many times does an electron microscope magnify?
Correct answer B. 250,000X
Malonic acid is an example of which type of inhibitor?
Correct answer A. Competitive inhibitor
Which type of inhibitor alters the structure of an enzyme?
Correct answer A. Irreversible inhibitor
In cell fractionation, what determines the layers in which cell components and organelles separate?
Correct answer D. Both their size and weight and the density of the medium
If enzyme concentration is low while substrate, pH and temperature are all at their optimum, what will increase the rate of reaction?
Correct answer D. Increase in concentration of enzyme
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What does an excessive rise in temperature do to an enzyme molecule?
Correct answer C. Denatured
How fine a detail can a compound microscope resolve?
Correct answer D. 2.0 µm
What does an extreme change in pH cause?
Correct answer B. Denaturation of the enzyme
Adding more substrate to an ongoing enzyme reaction has no effect on its rate. What is this condition called?
Correct answer D. Saturation
Where in the cell are ribosomes made?
Correct answer A. Nucleolus
Which statement about the active site of an enzyme is correct?
Correct answer B. Determined by structure and the specificity of the enzyme
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With enzyme concentration constant, increasing substrate eventually stops raising the reaction rate. Why?
Correct answer C. All the active sites on enzyme molecule are occupied
Which statement about the lock and key model is incorrect?
Correct answer B. It explains the mechanism of every chemical reaction
The rate of reaction is directly proportional to enzyme concentration. Which statement about this relationship is incorrect?
Correct answer B. This relation is for unlimited time period with unlimited enzyme concentration
What is a group of ribosomes attached to a single mRNA called?
Correct answer D. Polysomes
Adding more substrate to an ongoing enzyme reaction increases enzyme activity. Why?
Correct answer D. There is probably more enzyme available than there is substrate.