action potentials the all or nothing electrical signals traveling along neurons are generated by the movement of

ATI TEAS 7

Mometrix TEAS 7 science practice test

1. What generates action potentials, the all-or-nothing electrical signals traveling along neurons?

A. Glucose
B. Sodium and potassium ions
C. Neurotransmitters
D. Myelin

Correct answer: B

Rationale: Action potentials, the all-or-nothing electrical signals traveling along neurons, are generated by the movement of sodium and potassium ions across the neuronal membrane. This movement creates changes in the membrane potential, leading to the propagation of the electrical signal along the neuron. Glucose is a source of energy for neurons but is not directly involved in generating action potentials. Neurotransmitters are involved in communication between neurons but do not directly generate action potentials. Myelin is a fatty substance that insulates and speeds up the conduction of action potentials but does not generate them.

2. Which of the following is NOT a symptom of asthma, a chronic respiratory condition?

A. Wheezing
B. Difficulty breathing
C. Chest tightness
D. Fever

Correct answer: D

Rationale: The correct answer is 'Fever.' Fever is not a symptom commonly associated with asthma. Asthma symptoms typically include wheezing, difficulty breathing, and chest tightness due to inflammation and narrowing of the airways. Fever is more commonly seen in conditions such as infections or inflammatory diseases rather than asthma. Choices A, B, and C are common symptoms of asthma and are related to the constriction and inflammation of the airways, leading to breathing difficulties and chest discomfort.

3. When is a solution formed?

A. One substance dissolves in another
B. Two or more substances react chemically
C. A solid changes to a liquid
D. None of the above

Correct answer: A

Rationale: A solution is formed when one substance dissolves in another. This process creates a homogeneous mixture where the solute is dispersed in the solvent, resulting in a uniform composition throughout the mixture. Choice B is incorrect because chemical reactions involve the transformation of substances into new compounds, not the formation of solutions. Choice C is incorrect as it describes a physical change from a solid to a liquid, not the formation of a solution. Choice D is incorrect as one substance dissolving in another is the defining characteristic of a solution.

4. What happens to the frequency of a wave if its wavelength decreases while the speed remains constant?

A. Frequency decreases
B. Frequency increases
C. Frequency remains constant
D. Frequency becomes zero

Correct answer: B

Rationale: The correct answer is B: Frequency increases. Frequency and wavelength are inversely proportional in a wave with a constant speed. When the wavelength decreases while the speed remains constant, the frequency must increase to maintain the constant speed of the wave. This relationship is governed by the equation: speed = frequency x wavelength. Choice A is incorrect as frequency increases when wavelength decreases. Choice C is incorrect as the frequency changes in this scenario. Choice D is incorrect as the frequency does not become zero but increases when the wavelength decreases.

5. Which of the following is a component of the immune system?

A. Red blood cells
B. White blood cells
C. Platelets
D. Plasma

Correct answer: B

Rationale: White blood cells are a crucial component of the immune system as they play a key role in fighting infections and foreign invaders. Red blood cells are primarily involved in oxygen transport, platelets are important for blood clotting, and plasma is the liquid component of blood that carries various substances but is not directly involved in the immune response.