Which of the following statements about hormones is correct?
A. ADH is synthesized in the hypothalamus and released from the posterior pituitary.
B. Growth hormone is secreted by the posterior pituitary.
C. Oxytocin is produced by the anterior pituitary.
D. Prolactin stimulates uterine contractions.
Answer: Option A
Solution (By JKExamLibrary)
ADH and oxytocin are synthesized in the hypothalamus and stored/released from the posterior pituitary. Growth hormone and prolactin are anterior pituitary hormones.
Explanation:
Hemoglobin is a red, iron-containing protein in red blood cells (erythrocytes) that reversibly binds oxygen to form oxyhemoglobin. Each molecule has four heme groups, each binding one O₂ molecule. Hemocyanin (copper-based) is found in some invertebrates. Myoglobin stores oxygen in muscles. Cytochromes are electron carriers in respiration. Hemoglobin also transports CO₂ as carbaminohemoglobin.
Explanation:
Alveoli are thin-walled air sacs where O₂ and CO₂ exchange occurs. The voice box is the larynx; diaphragm is skeletal muscle; pulmonary veins carry oxygenated blood.
Consider statements about plant biology: 1. Xylem transports water upwards. 2. Phloem transports food bidirectionally. 3. Cambium is responsible for secondary growth. Which are correct?
Explanation:
Xylem is the vascular tissue responsible for the unidirectional upward transport of water and dissolved minerals from the roots to the aerial parts of the plant. Phloem is the vascular tissue responsible for the translocation of organic nutrients (primarily sucrose) from sources to sinks, which can be bidirectional (up or down depending on the plant's needs). Cambium (vascular and cork) is a lateral meristem responsible for secondary growth, which is the increase in the girth or thickness of stems and roots. All statements are correct.
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