ATI TEAS 7
TEAS 7 science practice
1. What is the shape of the DNA molecule?
- A. Linear
- B. Circular
- C. Double helix
- D. Straight chain
Correct answer: C
Rationale: The correct answer is C: Double helix. The shape of the DNA molecule is a double helix, a structure first described by James Watson and Francis Crick in 1953. This shape consists of two strands twisted around each other in a spiral. The double helix structure allows DNA to be compactly stored within the cell nucleus and provides stability to the molecule. Options (A) Linear, (B) Circular, and (D) Straight chain are incorrect as they do not accurately represent the shape of the DNA molecule. DNA is not linear but rather forms a twisted double helix; it is not circular like a ring but has a spiral structure, and it is not a straight chain but a twisted ladder-like structure.
2. What is the process by which cells respond to external stimuli, such as chemicals, temperature, or touch, called?
- A. Signal transduction
- B. Homeostasis
- C. Adaptation
- D. Metabolism
Correct answer: A
Rationale: Signal transduction is the correct answer. It is the process by which cells respond to external stimuli like chemicals, temperature, or touch. When a cell receives a signal from its environment, it triggers a series of molecular events leading to a specific cellular response. This process involves transmitting signals from the cell surface to the interior, triggering various cellular activities. Homeostasis, on the other hand, refers to an organism's ability to maintain internal stability in response to external changes. Adaptation involves an organism adjusting to its environment over time through genetic changes or behavioral modifications, which is distinct from the process of cells responding to immediate external stimuli. Metabolism, although essential for cellular functions, is not specifically about cells responding to external stimuli but rather the biochemical processes involved in energy production, storage, and utilization within cells.
3. If Silicon (Si) has an atomic mass of 28.1 AMU (atomic mass units), which of the following is the most likely number of neutrons an atom of Silicon would have?
- A. 28.1
- B. 14
- C. 28
- D. 14.2
Correct answer: B
Rationale: Silicon has an atomic number of 14, indicating it has 14 protons. The atomic mass of 28.1 AMU accounts for both protons and neutrons in the nucleus. By subtracting the atomic number from the atomic mass, we can estimate the number of neutrons in the atom. Thus, 28.1 - 14 = 14 neutrons. Choice A is incorrect as it represents the total atomic mass, not the number of neutrons. Choice C is incorrect; it is the atomic number (protons) rather than the number of neutrons. Choice D is incorrect as it is a value that does not reflect the number of neutrons in the silicon atom.
4. Which of the following is NOT a recommended method for preventing healthcare-associated infections (HAIs)?
- A. Handwashing with soap and water
- B. Proper use of personal protective equipment (PPE)
- C. Disinfecting and reusing sterile medical devices
- D. Using single-use sterile medical devices
Correct answer: C
Rationale: Disinfecting and reusing sterile medical devices is not a recommended method for preventing healthcare-associated infections (HAIs). Reusing sterile medical devices can increase the risk of infections due to inadequate sterilization or potential damage to the devices during the reprocessing process. Proper sterilization and disposal of single-use medical devices are essential in preventing the transmission of infections in healthcare settings. A) Handwashing with soap and water is a crucial method for preventing HAIs as it helps to remove and reduce the number of pathogens on the hands of healthcare workers, preventing the spread of infections. B) Proper use of personal protective equipment (PPE) such as gloves, gowns, masks, and eye protection is important in preventing the transmission of infections between patients and healthcare workers. C) Disinfecting and reusing sterile medical devices is not a recommended practice as it can lead to the transmission of infections if the devices are not adequately sterilized. Using single-use sterile medical devices helps to ensure that each patient receives a sterile device, reducing the risk of infections.
5. What type of nuclear force is responsible for holding protons and neutrons together in the nucleus of an atom?
- A. Electromagnetism
- B. Gravity
- C. Strong nuclear force
- D. Weak nuclear force
Correct answer: C
Rationale: The correct answer is the strong nuclear force. It is an incredibly powerful force that overcomes the repulsive electrostatic force between protons, binding them together and stabilizing the nucleus. The strong nuclear force is essential for maintaining the integrity and stability of an atom's nucleus. Electromagnetism (Choice A) is responsible for interactions between charged particles but is not the primary force holding the nucleus together. Gravity (Choice B) is a very weak force at the nuclear level and is not responsible for binding protons and neutrons in the nucleus. The weak nuclear force (Choice D) is involved in certain types of radioactive decay processes, but it is not the force responsible for holding the nucleus together.
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