MCAT Biology : Types of Hormones

Study concepts, example questions & explanations for MCAT Biology

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Example Questions

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Example Question #1 : Types Of Hormones

ACTH is this type of hormone __________.

I.  eicosanoid

II.  steroid

III.  polypeptide

IV.  paracrine

V.  None of these is a correct description

Possible Answers:

III

IV

V

II

I

Correct answer:

III

Explanation:

There are many types of hormones, including all of the categories listed.

Gaseous?  The dissolved gas, NO, is now known to be an important second messenger.  Paracrine hormones are those that act on cells in close proximity to the secreting cell. ACTH is a polypeptide hormone secreted by the pituitary and conveyed by the bloodstream to the adrenal gland a meter away, so it is clearly not paracrine. ACTH causes the secretion of steroid hormones, but it is not a steroid.

Example Question #2 : Types Of Hormones

Which of the following is NOT a characteristic of steroid hormones?

Possible Answers:

They are synthesized by smooth endoplasmic reticulum.

They are derived from amino acids

They require carrier proteins to travel through the bloodstream

They are hydrophobic

Correct answer:

They are derived from amino acids

Explanation:

Steroid hormones are hydrophobic molecules, synthesized by smooth endoplasmic reticulum. As they are hydrophobic, they require a hydrophilic carrier protein to transport them through the bloodstream. Steroid hormones are generally derived from cholesterol, not amino acids. 

Example Question #1 : Types Of Hormones

Which of the following is a direct hormone?

Possible Answers:

Growth hormone (GH)

Thyroid-stimulating hormone (TSH)

Adrenocorticotropic hormone (ACTH)

Follicle-stimulating hormone (FSH)

Correct answer:

Growth hormone (GH)

Explanation:

The pneumonic to remember the hormone of the anterior pituitary is "FLAT PEG." Hormones in the word "FLAT" are tropic hormones, meaning that they act upon other endocrine glands as their target organs. Hormones in the word "PEG" are direct hormones, meaning they act directly on non-endocrine organs.

F - Follicle-stimulating hormone

L - Luteinizing hormone

A - Adrenocorticotropic hormone

T - Thyroid-stimulating hormone

P - Prolactin

E - Endorphins

G - Growth hormone

Example Question #2 : Types Of Hormones

Which of the following statements is a key difference between a peptide hormone and a steroid hormone?

Possible Answers:

They attach to receptors in different parts of the target cell

Only one travels through the bloodstream in order to reach target cells

One travels a shorter distance than the other

They affect the body for different lengths of time

Correct answer:

They attach to receptors in different parts of the target cell

Explanation:

All hormones travel through the bloodstream in order to reach their target cells, but nonpolar hormones typically require a carrier protein. A key difference between peptide hormones and steroid hormones is their solubility. Peptide hormones are polar, which makes it difficult for them to pass through cell membranes. As a result, they attach to a receptor on the outside of the membrane. Steroid hormones, on the other hand, are nonpolar and can pass through cell membranes. They enter the nucleus and directly affect the cell at the transcription level.

Example Question #5 : Types Of Hormones

Which of the following hormones would not require a carrier protein in the bloodstream?

Possible Answers:

Aldosterone

Oxytocin

Testosterone

Triiodothyronine

Correct answer:

Oxytocin

Explanation:

There are three main types of hormones: peptide hormones, steroid hormones, and tyrosine derivatives. Only peptide hormones are soluble in water, and do not require carrier proteins in the bloodstream. Oxytocin is a peptide hormone, so it will not require a carrier protein.

Aldosterone and testosterone are all steroid hormones, and require a carrier protein. Triiodothyronine (T3) is a tyrosine derivative, and also requires a carrier.

Example Question #6 : Types Of Hormones

Which of the following hormones is a steroid hormone?

Possible Answers:

Epinephrine

Follicle-stimulating hormone

Luteinizing hormone

Testosterone

Correct answer:

Testosterone

Explanation:

It is important to know the three types of hormones: steroid, peptide, and tyrosine-derived hormones. Thyroid-stimulating hormone and the catecholamines (including epinephrine) are tyrosine-derived hormones. Luteinizing hormone, follicle-stimulating hormone, and growth hormone are all peptide hormones. Steroid hormones include testosterone and estrogen. 

Example Question #7 : Types Of Hormones

Which of the following is a peptide hormone?

Possible Answers:

Luteinizing hormone

Thyroid-stimulating hormone

Epinephrine

Estrogen

Correct answer:

Luteinizing hormone

Explanation:

It is important to know the three types of hormones: steroid, peptide, and tyrosine-derived hormones. Thyroid-stimulating hormone and the catecholamines (including epinephrine) are tyrosine-derived hormones. Luteinizing hormone, follicle-stimulating hormone, and growth hormone are all peptide hormones. Steroid hormones include testosterone and estrogen.

Example Question #8 : Types Of Hormones

Hypersensitivity reactions occur when body tissues are affected by an abnormal immune reaction. The result is damage to normal tissues and clinical illness. A peanut allergy is an example of a hypersensitivity reaction, but there are three additional broad classes.

One class involves the abnormal production or deposition of antibodies. Antibodies are B-cell derived molecules that normally adhere to pathogens, rendering them unable to continue an infection. When antibodies are produced against normal tissues, however, disease can result. Figure 1 depicts a schematic structure of an antibody.

Antibodies can be divided into two peptide chains: heavy and light. Heavy chains form the backbone of the antibody, and are attached to light chains via covalent bonding. Each heavy and light chain is then further divided into constant and variable regions. Variable regions exhibit molecular variety, generating a unique chemical identity for each antibody. These unique patterns help guarantee that the body can produce antibodies to recognize many possible molecular patterns on invading pathogens.

 

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In some hypersensitivity reactions, antibodies circulating in the blood can bind to and activate hormone receptors. For example, in Graves disease, antibodies can activate cell surface receptors for thyroid stimulating hormone (TSH) on thyroid tissue and cause excessive secretion of thyroid hormones. Based on this information, TSH most likely:

I. Is a peptide hormone

II. Modifies nuclear gene transcription

III. Is derived from cholesterol

Possible Answers:

III only

II only

I and II

I, II, and III

I only

Correct answer:

I only

Explanation:

The question specifies that thyroid-stimulating hormone (TSH) binds to cell surface receptors. This is in contrast to steroid hormones, which are derived from cholesterol and bind to intracellular receptors before moving to the nucleus to directly modify gene expression. Remember, steroids are fat soluble and thus have no need for a receptor on the cell surface; they are small and nonpolar, allowing them to cross the membrane freely. In contrast, peptide hormones are not able to traverse the lipid membrane, and thus require a surface receptor.

Example Question #9 : Types Of Hormones

Researchers are studying a newly-discovered hormone that concentrates in the nuclei of exposed cells. Based on this finding, from which of the following molecules could this hormone possibly be synthesized?

Possible Answers:

Thyroid-stimulating hormone

Glucose

Cholesterol

Tyrosine

Correct answer:

Cholesterol

Explanation:

One commonality between all steroid hormones is that they are active in the nucleus. Due to their nonpolar design, these hormones can pass through phospholipid membranes. All steroid hormones can be derived from cholesterol. This class of hormones includes testosterone, estrogen, progesterone, and aldosterone.

The other two classes of hormones are peptide hormones and tyrosine derivatives. Peptide hormones are proteins, synthesized from amino acids residues, and are unable to cross the lipid membrane due to their size and polarity. Thyroid-stimulating hormone is a peptide hormone. Tyrosine derivatives are modified from molecules of the amino acid tyrosine, making them polar. Thyroid hormones and epinephrine are derived from tyrosine.

Glucose is not used to synthesize hormones.

Example Question #10 : Types Of Hormones

Which of the following hormones is not a peptide hormone?

Possible Answers:

Follicle-stimulating hormone

Luteinizing hormone

Growth hormone

T4 (thyroid hormone)

Correct answer:

T4 (thyroid hormone)

Explanation:

It is important to know the three types of hormones: steroid, peptide, and tyrosine-derived hormones. T4, known as tetraiodothyronine, and the catecholamines are tyrosine-derived hormones. Luteinizing hormone, follicle-stimulating hormone, and growth hormone are all peptide hormones. Steroid hormones include testosterone and estrogen.

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