Pennsylvania Keystone Exam - Biology Practice Questions - Pennsylvania Keystone Exam - Biology (PDE STEELS Aligned) Exam - Pennsylvania Keystone Exam - Biology Practice Questions - Pennsylvania Keystone Exam

Question 1

Water molecules form hydrogen bonds between adjacent molecules because of their polar covalent structure. Which property of water directly results from hydrogen bonding and allows water striders to walk across the surface of a pond?

High specific heat capacity Surface tension Universal solvent capability Expansion upon freezing

Correct Answer:

Surface tension

Question 2

Enzymes are biological catalysts that speed up chemical reactions in living organisms. How do enzymes increase the rate of a biochemical reaction?

By increasing the temperature of the cellular environment By lowering the activation energy required for the reaction By adding energy to the substrates to transform them into products By permanently changing their shape to match the substrate

Correct Answer:

By lowering the activation energy required for the reaction

Question 3

Adenosine triphosphate (ATP) serves as the primary energy currency of the cell. Which process directly yields the energy needed to power cellular work such as muscle contraction?

Synthesis of ATP from ADP and inorganic phosphate Hydrolysis of the terminal phosphate bond in ATP Binding of glucose to the active site of ATP synthase Reduction of NADP+ to NADPH during photosynthesis

Correct Answer:

Hydrolysis of the terminal phosphate bond in ATP

Question 4

Which general chemical equation correctly summarizes the overall process of aerobic cellular respiration?

6CO2 + 6H2O + Light Energy -> C6H12O6 + 6O2 C6H12O6 + 6O2 -> 6CO2 + 6H2O + ATP Energy C6H12O6 + 6CO2 -> 6H2O + 6O2 + ATP Energy 6CO2 + C6H12O6 -> 6O2 + 6H2O + Light Energy

Correct Answer:

C6H12O6 + 6O2 -> 6CO2 + 6H2O + ATP Energy

Question 5

A student measures the rate of an enzyme-catalyzed reaction across a temperature range from 10°C to 60°C. The reaction rate rises steadily until 37°C, after which it drops sharply to zero by 55°C. What best explains the rapid decline in activity above 37°C?

The substrate molecules are destroyed by excessive thermal energy The enzyme loses its tertiary structure due to denaturation of hydrogen bonds The enzyme converts into a different functional enzyme isoform The activation energy of the reaction increases beyond normal biological limits

Correct Answer:

The enzyme loses its tertiary structure due to denaturation of hydrogen bonds

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About this Exam

Prepare with the Pennsylvania Keystone Exam - Biology Practice Questions - Pennsylvania Keystone Exam - Biology (PDE STEELS Aligned) Exam practice quiz. This question bank includes 100 questions covering cell, cells, water, membrane, and cellular. Use it to review important concepts, identify knowledge gaps, and build confidence for the related exam, course, or assessment.

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Pennsylvania Keystone Exam - Biology Practice Questions - Pennsylvania Keystone Exam - Biology (PDE STEELS Aligned) Exam

This practice set contains 100 questions from the matching question bank and focuses on cell, cells, water, membrane, and cellular. Work through each question carefully, review the provided solutions, and revisit topics that need more study before your next attempt.

This is an independent study resource intended for practice and review; it is not an official examination or an endorsement by any organization named in the title.

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Pennsylvania Keystone Exam - Biology Practice Questions - Pennsylvania Keystone Exam - Biology (PDE STEELS Aligned) Exam

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