calcitonin a hormone that helps regulate calcium levels is produced by the

ATI TEAS 7

TEAS 7 science practice questions

1. Calcitonin, a hormone that helps regulate calcium levels, is produced by the:

A. Thyroid gland
B. Parathyroid gland
C. Thymus gland
D. Adrenal gland

Correct answer: A

Rationale: Calcitonin is a hormone produced by the thyroid gland. It helps regulate calcium levels in the body by inhibiting the breakdown of bone and promoting calcium excretion by the kidneys. The parathyroid gland produces parathyroid hormone (PTH), which works in opposition to calcitonin to regulate calcium levels. The thymus gland is involved in the development of the immune system, and the adrenal gland produces hormones such as cortisol and adrenaline. Therefore, the correct answer is the thyroid gland as it specifically secretes calcitonin for calcium regulation.

2. Differentiate between genotype and phenotype in the context of gene expression.

A. Genotype refers to the physical manifestation of a trait, while phenotype represents its underlying genetic makeup.
B. Genotype encompasses the spectrum of possible traits encoded by an organism's genes, while phenotype signifies the specific trait observed.
C. Genotype denotes the presence of dominant alleles, while phenotype reflects the influence of recessive alleles.
D. There is no distinction; both terms are interchangeable.

Correct answer: B

Rationale: - Genotype refers to the genetic makeup of an organism, including all the genes and alleles it possesses. - Phenotype, on the other hand, refers to the observable physical characteristics or traits of an organism, which result from the interaction between its genotype and the environment. - While genotype represents the genetic potential or range of traits that an organism can express, phenotype reflects the actual expression of specific traits. - Therefore, option B correctly captures the distinction between genotype and phenotype in the context of gene expression.

3. What is the waste product of protein digestion?

A. Glucose
B. Amino acids
C. Fatty acids
D. Ammonia

Correct answer: D

Rationale: The waste product of protein digestion is ammonia. Protein digestion breaks down proteins into amino acids, and during this process, ammonia is produced. Ammonia is toxic and needs to be converted into urea in the liver for excretion via urine. Glucose is a product of carbohydrate digestion, amino acids are building blocks of proteins, and fatty acids are the end products of fat digestion. Therefore, the correct answer is ammonia.

4. Which structure in the lungs is the site of gas exchange?

A. Trachea
B. Alveoli
C. Bronchioles
D. Diaphragm

Correct answer: B

Rationale: The correct answer is B: Alveoli. Alveoli are tiny air sacs in the lungs where gas exchange occurs. Oxygen from inhaled air diffuses into the bloodstream, while carbon dioxide from the blood is released into the alveoli to be exhaled. The trachea (Choice A) is the windpipe that carries air to and from the lungs, but it is not involved in gas exchange. Bronchioles (Choice C) are small air passages within the lungs that branch off from the bronchi, leading air to the alveoli but not directly involved in gas exchange. The diaphragm (Choice D) is a muscle below the lungs that helps in breathing by expanding and contracting the chest cavity, but it is not the site of gas exchange.

5. A rock has a mass of 3 grams (g) and a volume of 4 cm³. What is its density?

A. 8.90 g/cm³
B. 0.38 g/cm³
C. 77.22 g/cm³
D. 2.65 g/cm³

Correct answer: D

Rationale: Density is determined by the formula Density = Mass / Volume. For this rock, the mass is 3g, and the volume is 4 cm³. Applying the formula: Density = 3g / 4cm³ = 0.75 g/cm³. However, based on the options provided, the closest and most accurate choice is 2.65 g/cm³, corresponding to option D. Choice A, 8.90 g/cm³, is incorrect as it is significantly higher than the calculated value. Choice B, 0.38 g/cm³, and Choice C, 77.22 g/cm³, are also incorrect and do not match the correct calculation.