ATI TEAS 7
Mometrix TEAS 7 science practice test
1. What are the tiny contractile units within muscle cells called?
- A. Myocytes
- B. Myofibrils
- C. Sarcomeres
- D. Tendons
Correct answer: C
Rationale: Sarcomeres are the smallest contractile units within muscle cells. They consist of overlapping filaments of actin and myosin proteins, which interact to produce muscle contractions. Myocytes are the entire muscle cells, myofibrils are bundles of protein filaments found within muscle cells, and tendons are tough connective tissues that connect muscles to bones. Therefore, sarcomeres specifically represent the contractile units responsible for muscle contraction, making them the correct answer in this context.
2. Antibodies, crucial for immune defense, are produced by:
- A. Neutrophils
- B. Lymphocytes
- C. Monocytes
- D. Basophils
Correct answer: B
Rationale: Antibodies are produced by a specific type of lymphocyte known as B cells. B cells are a critical component of the adaptive immune system and are responsible for producing antibodies in response to pathogens. Neutrophils, monocytes, and basophils are types of white blood cells that are part of the innate immune response and do not have the function of producing antibodies. Neutrophils are primarily involved in phagocytosis, monocytes differentiate into macrophages and dendritic cells for antigen presentation, while basophils are involved in allergic reactions and parasitic infections.
3. Which digestive enzyme is primarily responsible for breaking down proteins?
- A. Pepsin
- B. Lipase
- C. Amylase
- D. Maltase
Correct answer: A
Rationale: The correct answer is A, Pepsin. Pepsin is primarily responsible for breaking down proteins in the stomach. It is produced in an inactive form called pepsinogen, which becomes activated by the acidic environment in the stomach. Pepsin functions by breaking down proteins into smaller peptides, which are further digested by other enzymes in the small intestine. Lipase is responsible for breaking down fats, amylase for carbohydrates, and maltase for converting maltose into glucose. Therefore, choices B, C, and D are incorrect as they are associated with breaking down fats, carbohydrates, and converting maltose, respectively, not proteins.
4. Two identical balls, one made of clay and the other made of steel, are dropped from the same height. Which ball reaches the ground first, neglecting air resistance?
- A. The clay ball due to its lower density
- B. The steel ball due to its higher density
- C. Both balls reach the ground simultaneously
- D. It depends on the initial velocities of the balls
Correct answer: C
Rationale: In the absence of air resistance, both balls will experience the same acceleration due to gravity (9.8 m/s^2) regardless of their densities or materials. This means that both balls will reach the ground at the same time, assuming they are dropped from the same height simultaneously. The differences in density or material composition do not affect the rate at which objects fall in a vacuum. Therefore, both the clay and steel balls, being identical in shape and starting position, will have the same free-fall acceleration and will hit the ground simultaneously. Choices A and B are incorrect because the density of the materials does not impact the time it takes for objects to fall under gravity alone. Choice D is incorrect as the initial velocities do not play a role in the time taken to fall in a vacuum, where only the acceleration due to gravity affects the motion.
5. What is the difference between DNA and RNA?
- A. Both are double-stranded.
- B. DNA contains deoxyribose sugar, while RNA contains ribose sugar.
- C. RNA contains the nitrogenous base uracil, while DNA contains thymine.
- D. Both are identical molecules.
Correct answer: B
Rationale: A) Incorrect. DNA is double-stranded, but RNA is typically single-stranded. B) Correct. DNA contains deoxyribose sugar, which lacks an oxygen atom on the 2' carbon of the sugar ring, while RNA contains ribose sugar, which has an additional hydroxyl group on the 2' carbon. C) Incorrect. RNA contains the nitrogenous base uracil, while DNA contains thymine. D) Incorrect. DNA and RNA have distinct structures and functions, so they are not identical molecules.
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