1. Which two substances are required as the primary inputs, or reactants, for cellular respiration to occur?
- A. Water and carbon dioxide
- B. Sunlight and carbon dioxide
- C. Glucose and oxygen
- D. Nitrogen and water
2. If a plant cell were kept in complete darkness and deprived of oxygen, what would be the immediate consequence for cellular respiration?
- A. The rate of respiration would speed up to produce its own oxygen.
- B. The cell would start using carbon dioxide for energy instead.
- C. The process would stop because a key reactant is missing.
- D. The cell would produce extra water to try and restart the process.
3. What is the primary purpose of cellular respiration in a living organism?
- A. To create oxygen for the cells to breathe
- B. To break down glucose to release usable energy
- C. To produce water to keep the cell hydrated
- D. To combine carbon dioxide and water into food
4. During cellular respiration, a glucose molecule is broken down. What are the resulting waste products of this reaction?
- A. Oxygen and energy
- B. Glucose and water
- C. Carbon dioxide and water
- D. Oxygen and glucose
5. An athlete is running a marathon. What process is occurring at a high rate in their muscle cells to provide the necessary energy for this prolonged activity?
- A. The cells are primarily focused on removing water to become lighter.
- B. Photosynthesis is happening to generate quick energy from sunlight.
- C. The cells are absorbing carbon dioxide to directly fuel the muscles.
- D. Cellular respiration is breaking down glucose with oxygen to release large amounts of energy for muscle contraction.
6. Which statement best describes the role of atoms and bonds in a chemical reaction?
- A. Atoms are permanently separated from each other and exist individually.
- B. The bonds within molecules break, allowing atoms to be reorganized into new combinations.
- C. The bonds between molecules strengthen, but the atoms inside do not change their positions.
- D. New atoms are introduced from an outside source to bond with the original molecules.
7. Imagine the reaction where hydrogen gas (H₂) and chlorine gas (Cl₂) combine to form hydrogen chloride (HCl). What happens to the individual hydrogen and chlorine atoms?
- A. They are destroyed and replaced by new "hydrogen chloride atoms."
- B. They are shuffled and form new bonds to become part of the HCl molecules.
- C. They remain in their original H₂ and Cl₂ molecules but are now mixed together.
- D. The chlorine atoms are destroyed, while the hydrogen atoms attach to each other.
8. Why do the new substances formed in a chemical reaction have different properties from the original substances?
- A. The atoms have been rearranged into new molecules.
- B. The reaction always adds new types of atoms to the mixture.
- C. The total mass of the substances has changed significantly.
- D. Energy is lost, which permanently changes the original atoms.
9. What is the fundamental process that occurs to atoms during a chemical reaction?
- A. Atoms are converted into energy.
- B. Atoms are completely destroyed.
- C. The original atoms are rearranged into new molecular structures.
- D. New atoms are created to form the new substances.
10. When a chemical reaction is complete, what has happened to the original molecules that you started with?
- A. They have changed their physical state, like melting or freezing.
- B. They have been broken apart and no longer exist in their original form.
- C. They have simply mixed with the new molecules without changing.
- D. They are still present but are now invisible.