the defining characteristic of an element is determined by the number of

ATI TEAS 7

TEAS 7 science practice

1. What determines the defining characteristic of an element?

A. Neutrons in its nucleus
B. Electrons surrounding the nucleus
C. Protons in its nucleus
D. All of the above

Correct answer: C

Rationale: The defining characteristic of an element is determined by the number of protons in its nucleus, which is referred to as the atomic number. The number of protons uniquely identifies an element. The correct answer is choice C because the number of protons in the nucleus of an atom defines its elemental identity, as different elements have a unique number of protons. Neutrons and electrons do play essential roles in the atom, but they do not determine the defining characteristic of an element. Neutrons contribute to the stability of the nucleus and isotopes of an element, while electrons are involved in chemical bonding and the reactivity of an atom.

2. Which part of the brain generates the rhythmic electrical activity responsible for brain waves?

A. Cerebrum
B. Thalamus
C. Hypothalamus
D. Reticular formation

Correct answer: D

Rationale: The reticular formation is a network of neurons located in the brainstem that plays a crucial role in regulating arousal and consciousness. It generates the rhythmic electrical activity responsible for brain waves, which are measured using electroencephalography (EEG). The cerebrum, thalamus, and hypothalamus do not primarily generate brain waves; they have other specialized functions within the brain. The cerebrum is responsible for higher brain functions such as thinking and voluntary movements. The thalamus acts as a relay station for sensory information. The hypothalamus is involved in various functions such as regulating body temperature, hunger, and hormonal activities.

3. Which neurotransmitter is associated with pleasure, reward, and motivation, and is often implicated in conditions such as addiction?

A. Acetylcholine
B. Dopamine
C. Serotonin
D. GABA (Gamma-aminobutyric acid)

Correct answer: B

Rationale: Dopamine is the neurotransmitter associated with pleasure, reward, and motivation. It plays a crucial role in the brain's reward system and is often implicated in conditions such as addiction. Acetylcholine is involved in muscle movement and memory, serotonin is linked to mood regulation, and GABA is an inhibitory neurotransmitter that helps reduce neuronal excitability. Therefore, the correct answer is dopamine as it aligns with the neurotransmitter functions related to pleasure, reward, and motivation, distinct from the roles of acetylcholine, serotonin, and GABA.

4. What is the rigid structure that provides shape and support to plant cells?

A. Cell wall
B. Plasma membrane
C. Nucleus
D. Cytoplasm

Correct answer: A

Rationale: The correct answer is the cell wall, as it is the rigid structure that provides shape and support to plant cells. The cell wall is located outside the plasma membrane and is primarily composed of cellulose, giving it its rigid nature. The plasma membrane (option B) is a semi-permeable membrane surrounding the cell that regulates the movement of substances in and out of the cell. The nucleus (option C) houses the cell's genetic material and controls cellular activities. Cytoplasm (option D) is the gel-like substance within the cell that surrounds organelles and where various cellular processes take place, but it does not provide the rigid structure and support that the cell wall does.

5. What is the difference between a sensory neuron and a motor neuron?

A. Sensory neurons carry signals from sensory receptors towards the central nervous system, while motor neurons carry signals away from the central nervous system to muscles and glands.
B. Sensory neurons control voluntary muscles, while motor neurons control involuntary muscles.
C. Sensory neurons are located in the peripheral nervous system, while motor neurons are located in the central nervous system.
D. Sensory neurons detect light, while motor neurons detect sound.

Correct answer: A

Rationale: Sensory neurons are responsible for carrying signals from sensory receptors towards the central nervous system (brain and spinal cord), allowing the brain to receive information about the external environment. On the other hand, motor neurons carry signals away from the central nervous system to muscles and glands, enabling the brain to control voluntary and involuntary movements. Choice B is incorrect because sensory neurons do not control muscles, and motor neurons control both voluntary and involuntary muscles. Choice C is incorrect as sensory neurons are located in the peripheral nervous system, while motor neurons are located in the central nervous system. Choice D is incorrect because sensory neurons detect various stimuli such as touch, taste, smell, and sound, while motor neurons are not involved in detecting sensory stimuli.