Which of these is not an important component of
initiation of parturition in humans?
Explanation:
The onset of parturition in humans involves increased estrogen–progesterone ratio, synthesis of prostaglandins, and release of oxytocin to stimulate uterine contractions. Prolactin mainly stimulates milk production after birth, not the initiation of labor. Therefore, option 4 (Release of Prolactin) is not an important component of initiating parturition according to NCERT.
🧠 Did You Know?
Prostaglandins help ripen the cervix and enhance uterine contractions, while oxytocin directly stimulates strong labor contractions.
💡 NCERT Memory Line:
Labor is initiated by increased estrogen–prostaglandin–oxytocin activity, not by prolactin.
Which of the following secretes the hormone,
relaxin, during the later phase of pregnancy?
Explanation:
Relaxin is secreted by the corpus luteum during the later phase of pregnancy. It helps in the remodeling of connective tissue and relaxation of the pelvic ligaments to aid childbirth, and also supports the uterus during pregnancy as progesterone does. Thus option 2 is correct.
🧠 Did You Know?
Relaxin reaches peak levels in the later stages of pregnancy and works with other hormones to prepare the birth canal for delivery.
💡 NCERT Memory Line:
Corpus luteum of ovary secretes progesterone and relaxin during pregnancy, aiding uterus in sustaining pregnancy and preparing for parturition.
Statement I: The condon 'AUG' codes for methionine and phenylalanine. Statement II: 'AAA' and 'AAG' both codons code for the amino acid lysine.
In the light of the above statements, choose the
correct answer from the options given below.
Assertion (A): A person goes to high altitude and experiences 'altitude sickness' with symptoms like breathing difficulty and heart palpitations. Reason (R): Due to low atmospheric pressure at high altitude, the body does not get sufficient oxygen.
In the light of the above statements, choose the
correct answer from the options given below.
