Fertilization and Development — Practice Questions

Free NEET Biology multiple-choice questions on Fertilization and Development. Attempt each question and reveal the answer with a full explanation.

Which of the following is a 'non-steroidal' oral contraceptive pill? Saheli Mala-D Mala-N Quinacrine Which hormone is primarily responsible for stimulating the growth of mammary glands and the actual synthesis/formation of milk within them? Prolactin Oxytocin Estrogen Progesterone Which hormone is primarily responsible for the 'Let-down' reflex (milk ejection) from the mammary glands? Oxytocin Prolactin Estrogen Progesterone In humans, the first polar body is formed during which stage of oogenesis? Completion of Meiosis I Completion of Meiosis II Mitotic division of Oogonia During fertilization What is the function of the enzyme 'Hyaluronidase' found in the sperm acrosome? To dissolve the ground substance of the follicle cells To trigger the cortical reaction To provide energy for sperm motility To facilitate the fusion of nuclear membranes At which stage of embryonic development does implantation into the uterine wall typically occur? Blastocyst Morula Zygote Gastrula Which enzyme is primarily responsible for dissolving the ground substance (hyaluronic acid) of the corona radiata during fertilization? Hyaluronidase Acrosin Pepsin Trypsin During the cleavage of a human zygote, what happens to the overall size of the embryo and the size of the individual blastomeres? Total size remains constant; blastomere size decreases Total size increases; blastomere size remains constant Total size increases; blastomere size increases Total size decreases; blastomere size decreases The 'Acrosome Reaction' in human fertilization is specifically triggered by the influx of which ion into the sperm? Ca 2+ Na + K + Mg 2+ In human embryonic development, the limbs and digits are formed by the end of: Second month of pregnancy First month of pregnancy Third month of pregnancy First trimester The part of the blastocyst that eventually forms the extra-embryonic membranes is the: Trophoblast Inner cell mass Blastocoel Epiblast Which one of the following is not the function of placenta? It (1) Facilitates supply of oxygen and nutrients to embryo. (2) Secretes estrogen. (3) Facilitates removal of carbon dioxide and waste material from embryo. (4) Secretes oxytocin during parturition. The movement of the fetus and appearance of hair on the head are usually observed during which month of pregnancy? Fifth month Fourth month Sixth month Seventh month In the human female, the second polar body is extruded during: The completion of Meiosis II after fertilization The completion of Meiosis I after ovulation The entry of sperm into the fallopian tube The formation of the blastocyst The first polar body formed during oogenesis is extruded from the primary oocyte into the: Perivitelline space Antrum Cytoplasm of the ovum Zona pellucida In cases where the female cannot produce an ovum but can provide a suitable environment for fertilization and development, which ART technique is suggested? GIFT ZIFT IUT ICSI Which of the following prevents polyspermy in humans? Cortical reaction Acrosome reaction Capacitation Fertilization cone In Assisted Reproductive Technology, the method 'GIFT' involves the transfer of: An ovum into the fallopian tube A zygote into the fallopian tube An embryo into the uterus Sperm into the uterus The completion of the second meiotic division of the human secondary oocyte is triggered by: Contact of the sperm with the zona pellucida and entry into the cytoplasm The surge of LH during the middle of the cycle The secretion of estrogen from the Graafian follicle Implantation of the blastocyst in the endometrium The first meiotic division of the primary oocyte is unequal, resulting in the formation of: A large haploid secondary oocyte and a tiny first polar body Two equal-sized secondary oocytes A large diploid secondary oocyte and a tiny polar body Four haploid oocytes Which extra-embryonic membrane in humans acts as the first site of blood cell formation? Yolk sac Amnion Chorion Allantois At which specific stage of Meiosis I is the primary oocyte arrested in a human female from birth until puberty? Diplotene Leptotene Pachytene Zygotene Signals for the onset of parturition originate from : Mother’s hypothalamus Foetus and placenta Mother’s uterus Mother’s pituitary The part of the maternal endometrium that forms the maternal portion of the placenta is the: Decidua basalis Decidua capsularis Decidua parietalis Chorion frondosum Human Placental Lactogen (hPL) acts as a 'diabetogenic' hormone during pregnancy because it: Decreases maternal insulin sensitivity to ensure glucose availability for the fetus Directly increases fetal insulin production Triggers the destruction of maternal beta cells Prevents the absorption of glucose in the mother's intestine The 'Fast Block' to polyspermy in humans is achieved by: Depolarization of the oocyte membrane Release of cortical granules Hardening of the zona pellucida Inactivation of sperm receptors The 'Primitive Streak' in a human embryo appears during which developmental process? Gastrulation Cleavage Implantation Neurulation In humans, the cleavage divisions of the zygote are characterized as: Holoblastic and unequal Meroblastic and equal Holoblastic and equal Meroblastic and unequal The human placenta is described as 'Hemochorial' because: Maternal blood comes into direct contact with the fetal chorion Fetal blood mixes with maternal blood The placenta is formed only from the chorion It allows only the transport of heme-containing proteins Which portion of the blastocyst is specifically involved in the secretion of Human Chorionic Gonadotropin (hCG)? Syncytiotrophoblast Inner cell mass Cytotrophoblast Blastocoel The umbilical cord, which connects the fetus to the placenta, typically contains which of the following blood vessels? Two umbilical arteries and one umbilical vein One umbilical artery and two umbilical veins One umbilical artery and one umbilical vein Two umbilical arteries and two umbilical veins The 'Slow Block' to polyspermy in humans, also known as the cortical reaction, is triggered by the release of which ions? Ca 2+ ions Na + ions K + ions Mg 2+ ions During the 'Hatching' process of the human embryo, the blastocyst escapes from which structure to allow for implantation? Zona pellucida Corona radiata Trophoblast Amnion The amnion of mammalian embryo is derived from mesoderm and trophoblast endoderm and mesoderm ectoderm and mesoderm ectoderm and endoderm The 'Dictyate stage' refers to the prolonged arrest of oogenesis in human females during which phase? Diplotene of Prophase I Metaphase II Prophase II Anaphase I In human females, the 'Thelarche' refers to which milestone of puberty? Development of mammary glands Onset of first menstruation Appearance of axillary hair Growth of pubic hair Seminal plasma in humans is rich in: Fructose, calcium and certain enzymes Glucose and certain enzymes Fructose and sodium Fructose and potassium but poor in calcium Each testis has about how many compartments called testicular lobules? 250 100 500 50 During spermatogenesis, which hormone acts on the Leydig cells and stimulates the secretion of androgens? LH FSH GnRH Inhibin Diaphragms, cervical caps, and vaults are barrier methods that are: Reusable and block the entry of sperm through the cervix Non-reusable and increase phagocytosis of sperm Hormone-releasing and prevent ovulation Inserted into the fallopian tube to prevent fertilization A mature 7-celled embryo sac has how many nuclei in total? 8 7 6 4 Identify the correct sequence of the phases in the human menstrual cycle. Menstrual Follicular Ovulatory Luteal Follicular Menstrual Luteal Ovulatory Menstrual Luteal Follicular Ovulatory Luteal Menstrual Ovulatory Follicular The phenomenon where the pollen tube enters the ovule through the chalazal end is known as: Chalazogamy Porogamy Mesogamy Syngamy The 'World Population Day' is observed on which of the following dates? July 11 May 11 June 11 April 11 Hormones secreted by the placenta to maintain pregnancy are hCG, hPL, progestogens, estrogens hCG, hPL, estrogens, relaxin, oxytocin hCG, hPL, progestogens, prolactin hCG, progestogens, estrogens, glucocorticoids What is the correct sequence of the four wall layers of a typical microsporangium from the outermost to the innermost? Epidermis, Endothecium, Middle layers, Tapetum Epidermis, Middle layers, Endothecium, Tapetum Endothecium, Epidermis, Middle layers, Tapetum Tapetum, Middle layers, Endothecium, Epidermis Pollination carried out by birds is technically referred to as: Ornithophily Entomophily Chiropterophily Malacophily Contraceptive 'Implants' (like Norplant) are typically placed: Subcutaneously under the skin of the upper arm Inside the uterine cavity Deep into the muscular tissue of the thigh Topically as a patch on the abdomen Foetal ejection reflex in human female is induced by Differentiation of mammary glands Pressure exerted by amniotic fluid Release of oxytocin from pituitary Fully developed foetus and placenta Which one of the following is the most likely root cause why menstruation is not taking place in regularly cycling human female ? Retention of well-developed corpus luteum Fertilization of the ovum Maintenance of the hypertrophical endometrial lining Maintenance of high concentration of sex-hormones in the blood stream Select the correct option describing gonadotropin activity in a normal pregnant female : High level of FSH and LH stimulates the thickening of endometrium. High level of FSH and LH facilitate implantation of the embryo. High level of hCG stimulates the synthesis of estrogen and progesterone. High level of hCG stimulates the thickening of endometrium. Fertilization in humans is practically feasible only if:- the sperms are transported into vagina just after the release of ovum in fallopian tube the ovum and sperms are transported simultaneously to ampullary isthmic junction of the fallopian tube the ovum and sperms are transported simultaneously to ampullary - isthmic junction of the cervix the sperms are transported into cervix within 48 hrs of release of ovum in uterus Extrusion of second polar body from egg nucleus occurs : simultaneously with first cleavage after entry of sperm but before fertilization after fertilization before entry of sperm into ovum Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. Assertion A: Endometrium is necessary for implantation of blastocyst. Reason R: In the absence of fertilization, the corpus luteum degenerates that causes disintegration of endometrium. In the light of the above statements, choose the correct answer from the options given below: Both A and R are true and R is the correct explanation of A. Both A and R are true but R is NOT the correct explanation of A. A is true but R is false. A is false but R is true. Find the correct statement : (A) In human pregnancy, the major organ systems are formed at the end of 12 weeks. (B) In human pregnancy the major organ systems are formed at the end of 8 weeks. (C) In human pregnancy heart is formed after one month of gestation. (D) In human pregnancy, limbs and digits develop by the end of second month. (E) In human pregnancy the appearance of hair is usually observed in the fifth month. Choose the correct answer from the options given below : A, C, D and E only A and E only B and C only B, C, D and E only Receptors for sperm binding in mammals are present on : Vitelline membrane Perivitelline space Zona pellucida Corona radiata Match List I with List II related to embryonic development at various months of pregnancy: array llll ; & List-I & ; & List-II A. & The foetus movement starts and hair appears on the head & (I) & 24 weeks of pregnancy B. & The foetus develops limbs and digits & (II) & 20 weeks of pregnancy C. & The foetus develops external genital organs & (III) & 8 weeks of pregnancy D. & The foetus body is covered with fine hair; eyelids separate and eyelashes are formed & (IV) & 12 weeks of pregnancy array A-II, B-IV, C-III, D-I A-II, B-III, C-IV, D-I A-IV, B-II, C-III, D-I A-III, B-II, C-IV, D-I Which of the following hormone is not secreted by human placenta? hCG Estrogen Progesterone LH Twins are born to a family that lives next door to you. The twins are a boy and a girl. Which of the following must be true? They have 75% identical genetic content. They are monozygotic twins. They are fraternal twins. They were conceived through in vitro fertilization. Which hormone is synthesized by the hypothalamus and is primarily responsible for the vigorous contraction of the uterine muscles during parturition? Oxytocin Prolactin Vasopressin Progesterone The deficiency of which of the following hormones during pregnancy can lead to 'Cretinism' (stunted growth and mental retardation) in the baby? Thyroid hormones Growth hormone Parathyroid hormone Glucocorticoids