what is the lock and key model

ATI TEAS 7

TEAS 7 science practice questions

1. What is the 'lock-and-key' model?

A. Protein folding
B. Enzyme-substrate interaction
C. Muscle contraction
D. Blood clotting

Correct answer: B

Rationale: The 'lock-and-key' model describes the specificity of the interaction between enzymes and their substrates. In this model, the enzyme's active site acts like a lock that can only be opened by the specific substrate molecule, which serves as the key. This specific binding ensures that enzymes catalyze particular reactions and do not interact with other molecules indiscriminately. Protein folding (option A) is the process by which a protein attains its functional three-dimensional structure but is not directly related to the lock-and-key model. Muscle contraction (option C) and blood clotting (option D) are complex biological processes but are not directly associated with the lock-and-key model of enzyme-substrate interaction.

2. Which of the following is a strong acid?

A. Acetic acid (CH₃COOH)
B. Hydrochloric acid (HCl)
C. Citric acid
D. Carbonic acid (H₂CO₃)

Correct answer: B

Rationale: Hydrochloric acid (HCl) is a strong acid because it completely ionizes in water to produce hydrogen ions, leading to a high concentration of H⁺ ions in solution. This characteristic makes it a strong acid. Acetic acid (CH₃COOH), citric acid, and carbonic acid (H₂CO₃) are weak acids as they only partially ionize in water, resulting in a lower concentration of H⁺ ions compared to strong acids. Therefore, hydrochloric acid is the correct choice as a strong acid.

3. During January, Dr. Lewis worked 20 shifts. During February, she worked three times as many shifts as she did during January. During March, she worked half the number of shifts she worked during February. Which equation below describes the number of shifts Dr. Lewis worked in March?

A. shifts = 20 + 3 + 1/2
B. shifts = (20)(3)(1/2)
C. shifts = (20)(3) + 1/2
D. shifts = 20 + (3)(1/2)

Correct answer: B

Rationale: During January, Dr. Lewis worked 20 shifts. Shifts for January = 20. During February, she worked three times as many shifts as she did during January. Shifts for February = (20)(3) = 60. During March, she worked half the number of shifts she worked in February. Shifts for March = (60)(1/2) = 30. Therefore, the correct equation to describe the number of shifts Dr. Lewis worked in March is 'shifts = (20)(3)(1/2)', representing the calculation based on the given scenario. Choices A, C, and D do not accurately represent the correct mathematical relationship between the shifts worked in the different months, making them incorrect.

4. Which of these descriptions provides the most detailed and objective support for the claim that drinking and driving is unsafe?

A. A dramatized television commercial reenacting a fatal accident.
B. The Department of Transportation's press release noting the deployment of additional patrol units.
C. Congressional written testimony on drinking incidents.
D. A highway bulletin warning of penalties for drinking and driving.

Correct answer: C

Rationale: Congressional written testimony on drinking incidents provides the most detailed and factual data on the subject, making it the most objective support for the claim that drinking and driving is unsafe. Choice A, the dramatized television commercial, may be emotionally impactful but lacks detailed data. Choice B, the Department of Transportation's press release, focuses on enforcement actions rather than detailed information on the dangers. Choice D, the highway bulletin warning of penalties, emphasizes consequences rather than providing detailed support for the claim.

5. A pediatrician notes that an infant's cartilage is disappearing and being replaced by bone. What process has the doctor observed?

A. Mineralization
B. Ossification
C. Osteoporosis
D. Calcification

Correct answer: B

Rationale: The doctor has observed the process of ossification. Ossification is the natural process where cartilage in the body is replaced by bone. This process takes place during fetal development, growth, and bone fracture healing. Ossification involves the formation of bone tissue by depositing minerals like calcium and phosphorus within the cartilage matrix, leading to the development of a bone structure. Choice A, mineralization, refers to the process of forming mineral deposits in tissues, but it does not involve the replacement of cartilage by bone. Choice C, osteoporosis, is a condition characterized by bone density loss and increased fragility, not the natural process of cartilage replacement by bone. Choice D, calcification, is the process of deposition of calcium salts in various tissues, but it does not specifically involve the replacement of cartilage by bone as in ossification.