GRE Subject Test: Biology : GRE Subject Test: Biology

Study concepts, example questions & explanations for GRE Subject Test: Biology

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Example Questions

Example Question #2 : Understanding Hormone Functions

What is the name of the hormone responsible for raising blood calcium levels?

Possible Answers:

Calcitonin

Parathyroid hormone

Thyroxine

Glucagon

Correct answer:

Parathyroid hormone

Explanation:

Blood calcium levels are controlled primarily by two hormones: parathyroid hormone and calcitonin. Calcitonin is synthesized by the thyroid gland and decreases blood calcium levels. Parathyroid hormone acts as an antagonist to calcitonin and raises blood calcium levels.

Thyroxine, or T4, is a thyroid hormone involved in increasing basal metabolic rate. Glucagon stimulates the liver to release glucose into the blood, and raise blood glucose levels.

Example Question #1 : Endocrine System

What is the purpose of antidiuretic hormone in the body?

Possible Answers:

Concentrates the urine

Raises the basal metabolic rate

Increases blood calcium levels

Lowers the blood pressure

Correct answer:

Concentrates the urine

Explanation:

Antidiuretic hormone is released by the posterior pituitary gland, and acts on the kidneys in order to concentrate the urine. Alcohol can inhibit ADH, which can result in excessive urine production and potential dehydration.

Example Question #1 : Endocrine System

Which of the following hormones will increase cortisol secretion in a normal individual?

Possible Answers:

Adrenocorticotropic hormone

Luteinizing hormone

Aldosterone

Thyroid stimulating hormone

Correct answer:

Adrenocorticotropic hormone

Explanation:

Cortisol is secreted by the adrenal gland. We need to identify the hormone responsible for stimulating the adrenal gland and prompting it to release cortisol. This job is accomplished by adrenocorticotropic hormone (or ACTH). While aldosterone is secreted by the adrenal gland, it does not impact the release of cortisol to any significant degree.

Example Question #2 : Endocrine System

Which of the following features would you expect to see in an individual with a deficient posterior pituitary gland?

Possible Answers:

Low blood calcium levels

Reduced basal metabolic rate

Dehydration

Low testosterone levels

Correct answer:

Dehydration

Explanation:

The two main hormones of interest that are secreted by the posterior pituitary gland are antidiuretic hormone (ADH) and oxytocin. Antidiuretic hormone plays a key role in retaining water at the level of the kidney. In patients with no ADH, fluid retention is severely diminished. Symptoms of this include frequent urination, hyperosmolality, and dehydration.

Example Question #3 : Endocrine System

Which gland releases hormones that help regulate blood glucose levels?

Possible Answers:

Parathyroid gland

Adrenal cortex

Pancreas

Anterior pituitary gland

Correct answer:

Pancreas

Explanation:

The two major hormones that control blood sugar levels are glucagon and insulin. Glucagon helps raise blood glucose levels, while insulin decreases blood sugar levels. Both of these hormones are created and secreted by the pancreas.

The parathyroid gland secretes parathyroid hormone, which stimulates the synthesis of bone matrix to lower blood calcium levels. The adrenal cortex releases glucocorticoids, such as aldosterone, cortisone, and cortisol. The anterior pituitary gland secretes a number of hormones, including adrenocorticotropic hormone, thyroid-stimulating hormone, and growth hormone.

Example Question #261 : Gre Subject Test: Biology

Which gland releases oxytocin and antidiuretic hormone?

Possible Answers:

Posterior pituitary gland

Adrenal cortex

Thyroid gland

Anterior pituitary gland

Correct answer:

Posterior pituitary gland

Explanation:

The pituitary gland has two separate sections: the anterior and posterior lobes. The anterior pituitary gland releases, among other hormones, growth hormone, prolactin, and thyroid-stimulating hormone. The posterior pituitary gland only releases two hormones: oxytocin and antidiuretic hormone. These hormones are synthesized in the hypothalamus and transferred to the posterior pituitary for release.

The thyroid gland releases the thyroid hormones T3 and T4, as well as calcitonin. The adrenal cortex secretes glucocorticoids, such as aldosterone, cortisone, and cortisol.

Example Question #3 : Endocrine System

Adrenocorticotropic hormone will enter the blood stream, and act on which structure in the body?

Possible Answers:

Liver

Adrenal gland

Kidney

Pituitary gland

Correct answer:

Adrenal gland

Explanation:

Adrenocorticotropic hormone (ACTH) is secreted by the anterior pituitary gland. It then travels and stimulates the adrenal gland cortex to release its hormones.

Example Question #2 : Understanding Glands And Target Organs

Which endocrine gland releases aldosterone?

Possible Answers:

Thyroid gland

Pancreas

Adrenal gland

Posterior pituitary gland

Correct answer:

Adrenal gland

Explanation:

Aldosterone is secreted by the adrenal gland, specifically the adrenal cortex.

Example Question #5 : Endocrine System

A person with low blood calcium will have increased activity in which gland?

Possible Answers:

Thyroid gland

Pancreas

Pituitary gland

Parathyroid glands

Correct answer:

Parathyroid glands

Explanation:

Blood calcium levels are controlled primarily by the thyroid and parathyroid glands. The parathyroid glands secrete parathyroid hormone (or PTH), which raises blood calcium levels, while the thyroid gland decreases blood calcium levels via the hormone calcitonin. Since the person currently has low blood calcium, the goal is to raise the blood calcium to normal levels. As a result, we can expect to see increased activity in the parathyroid glands.

Example Question #1 : Reproductive System

What is the purpose of the prostate gland in males?

Possible Answers:

Produce sperm

Store sperm

Release hormones to create sperm

Add to the fluidity of semen

Correct answer:

Add to the fluidity of semen

Explanation:

The prostate gland is used to release fluid that adds to the fluidity of semen, and makes the semen alkaline in nature. This alkalinity helps counteract the acidity of the vaginal tract, and prolong the lifespan of the sperm.

Sperm are produced in the testes and are stored in the epididymis prior to release. The hormones involved in spermatogenesis are testosterone, produced by Leydig cells in the testes, and follicle-stimulating hormone, produced by the anterior pituitary.

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