Question

Which one of the following pairs of chemical substances is correctly categorized?

• A. Secretin and rhodopsin – Polypeptide hormones
• B. Pepsin and prolactin – Two digestive enzymes secreted in stomach
• C. Troponin and myosin – Complex proteins in striated muscles
• D. Calcitonin and thymosin – Thyroid hormones

Answer 1

The correct option is C

Troponin and myosin – Complex proteins in striated muscles

The correct option is C

Explanation for the correct option:

1. Actin filaments contain protein troponin
2. Myosin filaments contain protein myosin.
3. Bands of actin and myosin filaments are alternatively contained by the striated muscles
4. Troponin and myosin are complex proteins contained by striated muscles

Explanation for the incorrect options:

Option A:

1. As 100-500 amino acids together formed the polypeptide hormone ,for example Insulin and endorphins.
2. It plays key role in metabolic pathways.
3. Rhodopsin belongs to the family of G-protein coupled receptors, whereas secretin regulates water homeostasis and these are not an example of Polypeptide hormones.

Option B:

1. The Digestive enzymes secreted for the digestion process such as amylase and protease.
2. To digest the protein the Pepsin is secreted inside the stomach.
3. The Pituitary gland secretes Prolactin hormone which helps women produce milk.

Option D:

1. Thymosin stimulates released from the thymus helps in the growth of certain immune cells.
2. Calcium is a hormone produced by the thyroid gland's parafollicular cells.

Final answer: The chemical pair Troponin and myosin – Complex proteins in striated muscles are correctly categorized.