Biology Multiple Choice Questions on “Chemical Control and Coordination – Mechanism of Hormone Action”.
1. Hormone receptors are ______
a) glycolipids
b) lipids
c) polysaccharides
d) proteins
Answer: d
Clarification: Hormone receptors are proteinaceous in nature. These receptors are located on or inside the cells. It is where a hormone binds on a cell. The binding of the hormone signals the cells to perform their tasks.
2. Which of these is false regarding receptors?
a) Intracellular receptors are present within the cell
b) Receptors form complexes with hormones
c) Receptors disintegrate after contact with hormones
d) Receptors are specific
Answer: c
Clarification: Receptors are the structures of the cell to which hormones bind and form hormone-receptor complex. They do not disintegrate. Receptors are specific for each hormone. Intracellular receptors are present in the cytoplasm.
3. What type of hormone is glucagon?
a) Iodothyronines
b) Steroids
c) Peptide
d) Amino acid derivatives
Answer: c
Clarification: Glucagon is a peptide hormone. It is synthesized and secreted by the alpha cells of the pancreas. The function of glucagon is to break glycogen into glucose. This raises the blood sugar level.
4. Hypothalamic hormones are ______
a) peptides
b) steroids
c) iodothyronines
d) amino acid derivates
Answer: a
Clarification: Hypothalamic hormones are peptides. They are secreted by the hypothalamus. Peptides, steroids, iodothyronines and amino acid derivatives are the different categories of hormones.
5. Adrenaline is derived from ______
a) lipopolysaccharides
b) amino acids
c) lipids
d) sugars
Answer: b
Clarification: Adrenaline or epinephrine is derived from amino acids. It is secreted by the outer cortex of the pair of adrenal glands. It is the emergency hormone secreted during a fight or flight response.
6. Which of these is a secondary messenger?
a) Ca2+
b) Mg2+
c) Na+
d) K+
Answer: c
Clarification: Ca2+ is an important secondary messenger. It carries signals or messages from membrane receptors to the designated areas inside the cells. It is also important for muscle contractions.
7. IP3 is a(n) _____
a) secondary messenger
b) membrane receptor
c) intracellular receptor
d) nuclear receptor
Answer: a
Clarification: IP3 is an important secondary messenger. When a hormone binds to a receptor, it forms a hormone receptor complex. This hormone receptor complex transmits a secondary signal inside the cell via secondary messengers.
8. Which of these functions is not regulated by intracellular hormone-receptor complexes?
a) Regulation of gene expression
b) Regulation of chromosome function
c) Interaction with the genome
d) Regulation of K+ entry into the cell
Answer: d
Clarification: Intracellular hormone-receptor complexes transmit signals mainly to the nucleus for the regulation of gene expression, regulation of chromosome function through indirect interaction with the genome.
9. Identify the structure ‘x’.
a) Nuclear receptor
b) Intracellular receptor
c) Hormone-receptor complex
d) Gap junction
Answer: c
Clarification: When a hormone binds to a receptor it forms a hormone-receptor complex. The given hormone-receptor complex lies on the cell membrane. Hence, the hormone is bound to a membrane receptor.
10. The receptor for estrogen is intracellular. True or false?
a) True
b) False
Answer: a
Clarification: Estrogen is a steroid hormone secreted by the ovaries. Since it is a steroid hormone, estrogen can easily pass through the lipid bilayer of the cell membrane without a receptor. Thus its receptor lies in the cytoplasm, or the receptor is intracellular.