TEAS Science Practice Test #5 3 — Questions and Answers
Question 1: Which of the following correctly describes negative feedback in the endocrine system?
- A hormone stimulates the release of more of the same hormone
- The output of a system inhibits further production, maintaining balance (Correct answer)
- A positive signal causes an amplified response
- Hormones are released in response to nerve impulses only
Correct answer: The output of a system inhibits further production, maintaining balance
Negative feedback loops maintain homeostasis by having the output of a system suppress the initial stimulus. For example, rising blood glucose levels trigger insulin release, which lowers glucose levels, reducing the stimulus for further insulin secretion.
Question 2: What is the structural and functional unit of skeletal muscle?
- Sarcomere (Correct answer)
- Myosin
- Neuromuscular junction
- Motor unit
Correct answer: Sarcomere
The sarcomere is the basic contractile unit of skeletal muscle, bounded by Z-lines. It contains overlapping thick (myosin) and thin (actin) filaments that slide past each other during muscle contraction according to the sliding filament theory.
Question 3: Which of the following statements about viruses is correct?
- Viruses are living cells that reproduce by binary fission
- Viruses can reproduce independently without a host cell
- Viruses consist of genetic material enclosed in a protein coat and require a host cell to replicate (Correct answer)
- Viruses are always larger than bacteria
Correct answer: Viruses consist of genetic material enclosed in a protein coat and require a host cell to replicate
Viruses are acellular particles consisting of nucleic acid (DNA or RNA) enclosed in a protein coat (capsid). They are not independently alive — they must invade a host cell and hijack its cellular machinery to replicate.
Question 4: Which of the following correctly describes the law of conservation of mass?
- Mass can be created during exothermic chemical reactions
- The total mass of reactants equals the total mass of products in a chemical reaction (Correct answer)
- Energy and mass can be interconverted, so mass is not always conserved
- Mass is destroyed when substances are burned completely
Correct answer: The total mass of reactants equals the total mass of products in a chemical reaction
The law of conservation of mass states that in a chemical reaction, matter is neither created nor destroyed. The total mass of all reactants equals the total mass of all products, which is why chemical equations must be balanced.
Question 5: What is the function of the meninges?
- To produce cerebrospinal fluid (CSF)
- To transmit nerve signals between the brain and spinal cord
- To protect the brain and spinal cord with three layers of connective tissue (Correct answer)
- To regulate blood flow to the brain
Correct answer: To protect the brain and spinal cord with three layers of connective tissue
The meninges are three protective membranes (dura mater, arachnoid mater, and pia mater) that surround and protect the brain and spinal cord. They also help contain the cerebrospinal fluid (CSF) that cushions the central nervous system.
Question 6: Which of the following correctly pairs an organ with its primary function in the endocrine system?
- Thyroid gland — regulates immune response
- Pancreas — produces insulin to regulate blood glucose (Correct answer)
- Adrenal gland — produces estrogen for reproduction
- Pineal gland — regulates blood pressure
Correct answer: Pancreas — produces insulin to regulate blood glucose
The pancreas produces insulin (from beta cells) and glucagon (from alpha cells) to regulate blood glucose levels. The thyroid regulates metabolism; the adrenal glands produce stress hormones (cortisol, epinephrine); the pineal gland produces melatonin.
TEAS Science Practice Test #5 3
Which of the following correctly describes negative feedback in the endocrine system?