TEAS 7 science practice

Correct Answer: B

Rationale: The primary function of the cell membrane, also known as the plasma membrane, is to regulate the movement of substances in and out of the cell. It acts as a selectively permeable barrier, allowing specific molecules to pass through while blocking others. This role is crucial for maintaining the internal environment of the cell by enabling essential nutrients to enter and waste products to exit. While the cell membrane provides some structural support for the cell, its main function is substance transport. Protein and lipid synthesis predominantly occur in organelles like the endoplasmic reticulum and Golgi apparatus, and storing genetic material is the nucleus's responsibility. Therefore, choices C (To synthesize proteins and lipids) and D (To store genetic material) are incorrect as these functions are carried out by other cell organelles, not the cell membrane.

Correct Answer: C

Rationale: During a physical change in matter, the original substance undergoes a change in its physical state or appearance without any change in its chemical composition. This means that the original substance can be recovered by physical means, such as melting, freezing, boiling, or condensing. No new substance is formed (option A), the chemical composition remains the same (option B), and energy changes can occur but are not a defining characteristic of a physical change (option D). The ability to recover the original substance by physical means distinguishes physical changes from chemical changes.

Correct Answer: D

Rationale: Volume is the measure of the total amount of space occupied by an object. Mass refers to the amount of matter in an object, density is the mass per unit volume, and weight is the force of gravity acting on an object. When determining the space occupied by an object, volume is the appropriate measurement to consider. Therefore, the correct answer is D. Choices A, B, and C are incorrect as they do not directly indicate the total amount of space occupied by an object. Mass, density, and weight are relevant in different contexts and measurements compared to volume.

Correct Answer: B

Rationale: Acetylcholine is the neurotransmitter responsible for stimulating muscle contraction at the neuromuscular junction. When an action potential reaches the end of a motor neuron, acetylcholine is released into the synaptic cleft and binds to receptors on the muscle cell membrane, leading to muscle contraction. Dopamine, serotonin, and norepinephrine are neurotransmitters that have different functions in the nervous system and are not directly involved in stimulating muscle contraction. Dopamine is involved in reward and pleasure pathways, serotonin regulates mood and behavior, and norepinephrine is involved in the 'fight or flight' response.

Correct Answer: B

Rationale: Smooth muscle is responsible for causing the hair follicles to stand on end when you get a goosebump. This type of muscle tissue is found in the skin attached to hair follicles and contracts in response to stimuli such as cold or fear, causing the hair to stand up. Skeletal muscle is responsible for voluntary movements, and cardiac muscle is found in the heart and is not directly involved in causing goosebumps. Therefore, choices A, C, and D are incorrect as they do not represent the specific type of muscle tissue responsible for this physiological response.