which of the following quantities do catalysts alter to control the rate of a chemical reaction

ATI TEAS 7

ATI TEAS 7 Science Practice Test

1. Which of the following quantities do catalysts alter to control the rate of a chemical reaction?

A. Substrate energy
B. Activation energy
C. Inhibitor energy
D. Promoter energy

Correct answer: B

Rationale: The correct answer is B: Activation energy. Catalysts function by reducing the activation energy needed for a chemical reaction to proceed. By lowering the activation energy, catalysts facilitate the reaction without being consumed themselves. Substrate energy, inhibitors, and promoters are not directly altered by catalysts in the same way activation energy is. Substrate energy refers to the energy of the reactants, which is not altered by catalysts. Inhibitors increase the activation energy required for a reaction, while promoters enhance the effectiveness of a catalyst but do not represent a quantity altered by catalysts.

2. What is the difference between mass and weight?

A. Mass is the amount of matter in an object, whereas weight is the force of gravity acting on an object.
B. Mass is a measure of inertia, whereas weight is a measure of the force of gravity acting on an object.
C. Mass is measured in pounds, whereas weight is measured in kilograms.
D. Mass is a vector quantity, whereas weight is a scalar quantity.

Correct answer: A

Rationale: Mass is the amount of matter in an object and is a scalar quantity, whereas weight is the force of gravity acting on an object and is a vector quantity. Mass remains constant regardless of the location, while weight can vary depending on the strength of gravity at different locations. Answer choice A correctly defines the difference between mass and weight, making it the correct answer. Choice B is incorrect because mass is not a measure of inertia. Choice C is incorrect as mass is typically measured in kilograms, not pounds. Choice D is incorrect as mass is a scalar quantity, and weight is a vector quantity.

3. Which organelle is responsible for controlling the activities of the cell?

A. Golgi apparatus
B. Mitochondria
C. Nucleus
D. Ribosomes

Correct answer: C

Rationale: The nucleus is the organelle responsible for controlling the activities of the cell. It contains the cell's genetic material (DNA) and serves as the command center of the cell, regulating gene expression and directing cellular activities. The nucleus plays a crucial role in cell growth, metabolism, and reproduction. While the Golgi apparatus is involved in processing and packaging proteins, the mitochondria are responsible for producing energy in the form of ATP, and ribosomes are involved in protein synthesis, none of these organelles have the primary function of controlling the activities of the cell like the nucleus does. Therefore, the correct answer is the nucleus.

4. Which dome-shaped muscular structure separates the chest cavity from the abdominal cavity?

A. Diaphragm
B. Sternum
C. Pericardium
D. Trachea

Correct answer: A

Rationale: The diaphragm is the correct answer. It is a dome-shaped muscular structure that separates the chest cavity from the abdominal cavity. The diaphragm plays a crucial role in breathing by contracting and relaxing to change thoracic volume during inhalation and exhalation. The sternum is a flat bone in the center of the chest and is not the structure that separates the chest and abdominal cavities. The pericardium is a membrane that surrounds the heart, not involved in separating cavities. The trachea is the windpipe that connects the larynx to the bronchi and is not the structure that separates the chest and abdominal cavities.

5. What macromolecules are formed from amino acids, and what are their roles?

A. Lipids; store energy
B. Carbohydrates; provide energy
C. Proteins; perform various functions like catalysis, transport, and structural support
D. Nucleic acids; store genetic information

Correct answer: C

Rationale: The correct answer is C. Proteins are macromolecules formed from amino acids and have diverse roles, such as serving as enzymes, transport molecules, and providing structural support. They are essential for catalysis, cellular communication, immune response, and many other functions in living organisms. Choices A, B, and D are incorrect. Lipids are not formed from amino acids but from fatty acids and glycerol, mainly serving as energy storage molecules. Carbohydrates are composed of sugars and provide energy to the body. Nucleic acids, like DNA and RNA, are made up of nucleotides and store genetic information in cells.