Which one of the following hormones is responsible for the development of female sexual characters ?
- A.Prolactin
- B.Estrogen
- C.Oxytocin
- D.Progesterone
Correct answer
Explanation
The correct answer is B, Estrogen. Estrogen, made mainly by the ovaries, brings about the female secondary sexual characters at puberty.
At puberty the pituitary releases FSH and LH, which stimulate the ovaries to secrete estrogen. Estrogen causes the growth of breasts, widening of the hips, deposition of fat in a female pattern, growth of the uterus and the start of the menstrual cycle. It also rebuilds the lining of the uterus after each menstruation. In males the matching role is played by testosterone from the testes, which produces the beard, deeper voice and muscle growth.
A is wrong because prolactin from the anterior pituitary stimulates milk production after childbirth. C is wrong because oxytocin from the posterior pituitary causes contraction of the uterus during birth and the ejection of milk. D is wrong because progesterone from the corpus luteum prepares and maintains the uterine lining for pregnancy rather than producing the sexual characters.
Exam tip: Estrogen for female characters, testosterone for male; progesterone is the pregnancy hormone.
Practice Questions
View allThe fact that the planets move around the Sun, not in circles but in ellipses, was first demonstrated by
- A.Galileo
- B.Martin Luther
- C.Johannes Kepler
- D.Copernicus
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In 1609 Kepler showed that the planets move around the Sun in elliptical orbits, with the Sun at one focus of the ellipse.
Read the full explanation →Which one of the following statements is correct?
- A.Urea is produced in liver.
- B.Urea is produced in blood.
- C.Urea is produced from digestion of starch.
- D.Urea is produced in lung and kidney.
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Liver cells turn the toxic ammonia released from the breakdown of amino acids into urea through the ornithine cycle, also called the urea cycle.
Read the full explanation →Which one of the following is the correct sequence of passage of light in a compound microscope?
- A.Condenser-Objective lens-Eyepiece-Body tube
- B.Objective lens-Condenser-Body tube-Eyepiece
- C.Condenser-Objective lens-Body tube-Eyepiece
- D.Eyepiece-Objective lens-Body tube-Mirror
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Light passes through the condenser to the specimen, is picked up by the objective lens, travels up the body tube and reaches the eye through the eyepiece.
Read the full explanation →Which one of the following statements regarding haemoglobin is correct?
- A.Haemoglobin present in RBC can carry only oxygen but not carbon dioxide.
- B.Haemoglobin of RBC can carry both oxygen and carbon dioxide.
- C.Haemoglobin of RBC can carry only carbon dioxide.
- D.Haemoglobin is only used for blood clotting and not for carrying gases.
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It binds oxygen at its iron-containing haem groups and carries some carbon dioxide on its protein chains. Each haemoglobin molecule has four polypeptide chains and four haem groups, and each haem iron can hold one oxygen molecule, forming oxyhaemoglobin in the lungs.
Read the full explanation →Which one of the following statements regarding histone proteins is correct?
- A.Histones are proteins that are present in mitochondrial membrane.
- B.Histones are proteins that are present in nucleus in association with DNA.
- C.Histones are proteins associated with lipids in the cytosol.
- D.Histones are proteins associated with carbohydrates in the cytosol.
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They are the proteins around which DNA winds to form chromatin in the nucleus of eukaryotic cells. Histones are small basic proteins, rich in the positively charged amino acids lysine and arginine, which attract the negatively charged phosphate groups of DNA.
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