Description : Fertilisation in humans is practically feasible only if (a) the ovum and sperms are transported simultaneously to ampullary-isthmic junction of the cervix (b) the sperms are transported ... the ovum and sperms are transported simultaneously to ampullary-isthmic junction of the fallopian tube.
Last Answer : (d) the ovum and sperms are transported simultaneously to ampullary-isthmic junction of the fallopian tube.
Description : Extrusion of second polar body from egg occurs (a) simultaneously with first cleavage (b) after entry of sperm but before fertilisation (c) after fertilisation (d) before entry of sperm into ovum.
Last Answer : (b) after entry of sperm but before fertilisation
Description : Explain the events that occur during fertilisation of an ovum in humans. How is it that only one sperm enters the OVUm? -Biology
Last Answer : (i)In humans, the fertilisation of ovum takes place in ampullary-isthmic junction of Fallopian tube. The events that occur during the process of fertilisation are: (a) The sperm reaches the ... that blocks the entry of additional sperms. This ensures that only one sperm can fertilise an ovum
Description : Which one of the following statements about human sperm is correct? (a) Acrosome has a conical pointed structure used for piercing and penetrating the egg, resulting in fertilisation. (b) The ... a sensory structure leading the sperm towards the ovum. (d) Acrosome serves no particular function
Last Answer : (b) The sperm lysins in the acrosome dissolve the egg envelope facilitating fertilisation.
Description : How is the entry of only one sperm ensured into an ovum during fertilisation in humans? -Biology
Last Answer : During fertilisation, a sperm comes in contact with the zona pellucida layer of the ovum and induces changes (depolarisation) in the membrane that blocks the entry of additional sperms. This ensures that only one sperm can fertilise an ovum
Description : What happens during fertilisation in humans after many sperms reach close to the ovum? (a) Secretions of acrosome helps one sperm enter cytoplasm of ovum through zona pellucida. (b) All sperms except ... all the sperms except one. (d) Only two sperms nearest the ovum penetrate zona pellucida.
Last Answer : (a) Secretions of acrosome helps one sperm enter cytoplasm of ovum through zona pellucida.
Description : Capacitation refers to changes in the (a) ovum after fertilisation (b) sperm after fertilisation (c) sperm before fertilisation (d) ovum before fertilisation.
Last Answer : (c) sperm before fertilisation
Description : Identical twins are born when (a) Two sperms fertilise one ovum (b) Two sperms fertilise two ovums simultaneously (c) Open sperm fertilizes the ovum and zygote divides into two separate cells developing independently (d) One sperm fertilises two ovums
Last Answer : Ans:(c)
Description : (i) Mention the event that induces the completion of the meiotic division of the secondary oocyte. (ii) Trace the journey of the ovum from the ovary, its fertilisation and further development until the implantation of the embryo. -Biology
Last Answer : (i)Secondary oocyte completes meiosis-ll only when a sperm enters its cytoplasm. It forms a larger cell, the ootid and a small cell, the second polar body. (ii)The secondary oocyte is ... and inner cell mass.The trophoblast attacheds to endometrium (implantation) and blastocyst gets embedded in it.
Description : (i)Explain the events taking place at the time of fertilisation of an ovum in a human female. (ii)Trace the development of the zygote up to its implantation in the uterus. (iii)Name and draw a labelled sectional view of the embryonic stage that gets implanted. -Biology
Last Answer : (i)In humans, the fertilisation of ovum takes place in ampullary-isthmic junction of Fallopian tube. The events that occur during the process of fertilisation are: (a) The sperm reaches the ... endometrium of the uterus. This is called implantation.(iii) Blastocyst stage implants in the uterus.
Description : The term Test Tube Baby' implies (a) Fertilisation of ovum takes place I the test tube but it develops in uterus (b) Fertilisation of ovum takes place in the test tube and develops in ... uterus but develops in the test tube (d) Fertilisation takes place in uterus and embryo develops in uterus
Last Answer : Ans:(a)
Description : Sex is determined in human beings (a) by ovum (b) at time of fertilisation (c) 40 days after fertilisation (d) seventh to eight week when genitals differentiate in fetus.
Last Answer : (b) at time of fertilisation
Description : The technique called Gamete Intra Fallopian Transfer (GIFT) is recommended for those females (a) who cannot produce an ovum (b) who cannot retain the fetus inside uterus (c) whose cervical ... narrow to allow passage for the sperms (d) who cannot provide suitable environment for fertilisation.
Last Answer : (a) who cannot produce an ovum
Description : The stage transferred into the uterus after induced fertilisation of ovum in the laboratory is (a) embryo at 4 blastomeres stage (b) embryo at 2 blastomeres stage (c) morula (d) zygote.
Last Answer : (c) morula
Description : Which one of the following is the most likely root cause why menstruation is not taking place in regularly cycling human female? (a) Maintenance of the hypertrophical endometrial lining (b) ... the blood stream (c) Retention of well-developed corpus luteum (d) Fertilisation of the ovum
Last Answer : (b) Maintenance of high concentration of sex- hormones in the blood stream
Description : Endosperm is formed during the double fertilisation by (a) two polar nuclei and one male gamete (b) one polar nuclei and one male gamete (c) ovum and male gamete (d) two polar nuclei and two male gametes.
Last Answer : (a) two polar nuclei and one male gamete
Description : In human beings after fertilisation , the structure which gets embedded in the wall of uterus is a) ovum b)embryo c)foetus d)zygote
Last Answer : b)embryo
Description : Which of the following statement about reproductions in human is correct. a) fertilisation takes place externally b) fertilisation takes place in the testes c) during fertilisation egg moves towards sperm d) fertilisation takes place in human female
Last Answer : d) fertilisation takes place in human female
Description : In human beings, normally in which part, does the sperm fertilize the ovum? -Do You Know?
Last Answer : answer:
Description : What are both ovum and sperm ?
Last Answer : : Both ovum and sperm are haploid
Description : Fusion of sperm and ovum is
Last Answer : Fusion of sperm and ovum is A. Amphimixis B. Regeneratin C. Fertilization `rarr` Cleavage `rarr` Zygote ... `rarr` Gastrula. D. None of the above.
Description : Assertion : The nucleus of sperm fuses with the nucleus of ovum , before the formation of ootid . Reason : Diploid nuclear status of organism is essen
Last Answer : Assertion : The nucleus of sperm fuses with the nucleus of ovum , before the formation of ootid . ... . D. If both Assertion & Reason are False.
Description : Assertion : The acrosomal secretions of sperm , help it in entering in the cytoplasm of the ovum . Reason : It contains sperm lysin .
Last Answer : Assertion : The acrosomal secretions of sperm , help it in entering in the cytoplasm of the ovum . ... . D. If both Assertion & Reason are False.
Description : Assertion : Sperm formation continues even in old men but formation of ovum caeses in women around the age of fifty years . Reason : Human male having
Last Answer : Assertion : Sperm formation continues even in old men but formation of ovum caeses in women around the ... D. If both Assertion & Reason are False.
Description : Various changes in mammalian sperm which prepare it to fertilise the ovum are called :
Last Answer : Various changes in mammalian sperm which prepare it to fertilise the ovum are called : A. Capacitation B. Regeneration C. Growth D. None of these
Description : An abnormal human baby with ‘XXX’ sex chromosomes was born due to (a) fusion of two ova and one sperm (b) fusion of two sperms and one ovum (c) formation of abnormal sperms in the father (d) formation of abnormal ova in the mother.
Last Answer : (d) formation of abnormal ova in the mother.
Description : Grey crescent is the area (a) at the point of entry of sperm into ovum (b) just opposite to the site of entry of sperm into ovum (c) at the animal pole (d) at the vegetal pole.
Last Answer : (b) just opposite to the site of entry of sperm into ovum
Description : The second maturation division of the mammalian ovum occurs (a) shortly after ovulation before the ovum makes entry into the fallopian tube (b) until after the ovum has been penetrated by a sperm ... with that of the ovum (d) in the Graafian follicle following the first maturation division.
Last Answer : (b) until after the ovum has been penetrated by a sperm
Description : Meiotic division of the secondary oocyte is completed (a) prior to ovulation (b) at the time of copulation (c) after zygote formation (d) at the time of fusion of a sperm with an ovum.
Last Answer : (d) at the time of fusion of a sperm with an ovum.
Description : human beings, normally in which part, does the sperm fertilize the ovum?
Last Answer : Fallopian tube
Description : The primary mechanism of action of the combined estrogen-progestin oral contraceptive pill is: A. Production of cervical mucus hostile to sperm penetration B. Suppression of FSH and ... Making endometrium unsuitable for implantation D. Enhancing uterine contractions to dislodge the fertilized ovum
Last Answer : B. Suppression of FSH and LH release
Description : 9.Acrosome is important for ----------- . a)ATP production, b)Dissolving membrane of ovum, c)Motility of sperm, d)Nutrition of sperm
Last Answer : b)Dissolving membrane of ovum,
Description : Fertilization of the ovum by the sperm usually occurs in the: a) oviduct b) vagina c) uterus d) ovary
Last Answer : ANSWER: A -- OVIDUCT
Description : Cri-du-chat syndrome in humans is caused by the (a) trisomy of 21st chromosome (b) fertilisation of an XX egg by a normal Y-bearing sperm (c) loss of half of the short arm of chromosome 5 (d) loss of half of the long arm of chromosome 5.
Last Answer : (c) loss of half of the short arm of chromosome 5
Description : In case of a couple where the male is having a very low sperm count, which technique will be suitable for fertilisation? (a) Gamete Intracytoplasmic Fallopian Transfer (b) Artificial Insemination (c) Intracytoplasmic sperm injection (d) Intrauterine transfer
Last Answer : (b) Artificial Insemination
Description : Which of the following approaches does not give the defined action of contraceptive? (a) Hormonal contraceptives Prevent/retard entry of sperms, prevent ovulation and fertilisation (b) ... devices Increase phagocytosis of sperms, suppress sperm motility and fertilising capacity of sperms
Last Answer : (b) Vasectomy Prevents spermatogenesis
Description : In case of a couple where the male is having a very low sperm count, which technique will be suitable for fertilisation ? (1) Gamete intracytoplasmic fallopian transfer (2) Artificial Insemination (3) Intracytoplasmic sperm injection (4) Intrauterine transfer
Last Answer : (2) Artificial Insemination
Description : Which one of the following statements concerning glucose metabolism is correct? (A) The conversion of Glucose to lactate occurs only in the R.B.C (B) Glucose enters most cells by a mechanism in ... ) An elevated level of insulin leads to a decreased level of fructose 2, 6-bisphosphate in hepatocyte
Last Answer : C
Description : Which of the following statements is correct with reference to a test tube baby? (a) Fertilisation of the egg is effected outside the body; the fertilised egg is then placed in the womb of the mother ... . (d) Fertilisation of the egg and growth of the embryo are affected in a large test tube.
Last Answer : (a) Fertilisation of the egg is effected outside the body; the fertilised egg is then placed in the womb of the mother where the gestation is completed.
Description : Fertilization of ovum occur in
Last Answer : Fertilization of ovum occur in A. Fimbriae of oviduct B. Isthmus of oviduct C. Ampulla of oviduct D. None of the above.
Description : Where does fertilisation occur in humans? Explain the events that occur during this process. -Biology
Last Answer : In humans, the fertilisation of ovum takes place in ampullary-isthmic junction of Fallopian tube. The events that occur during the process of fertilisation are: (i) The sperm reaches the junction of ampulla ... and second polar body. (iv)Nucleus of sperm and of ovum fuses to form a diploid zygote.
Description : The duration 19-21 days refers to: (1) incubation period of hen's egg (2) average life-span of a red blood cell in humans (3) the period of menstrual cycle soon after menstruation, during ... to occur (4) period of completion of one schizogony cycle of malarial parasite inside a red blood cell
Last Answer : (3) the period of menstrual cy-cle soon after menstruation, during which fertilisation is most likely to occur Explanation: The menstrual cycle is the scientific term for the physiological changes ... 21 days or more between a woman's shortest and longest cycle lengths is considered very irregular
Last Answer : the period of menstrual cycle soon after menstruation, during which fertilisation is most likely to occur
Description : Which of the following statements about phloem transport is correct? (1) phloem transport occurs unidirectionally (2) gravity influences phloem transport (3) Ca+ is the most abundantcation in phloem sap (4) sugar is transported in phloem as nonreducing sugar
Last Answer : (4) sugar is transported in phloem as nonreducing sugar Explanation: According to most textbooks, only non-reducing carbohydrate species such as sucrose, sugar alcohols, and raffinose family ... probably reflects packaging of carbohydrate in a chemical form which protects it from being metabolized.
Description : Which of the following statements about phloem transport is correct? (1) phloem transport occurs unidirectionally (2) gravity influences phloem transport (3) Ca+ is the most abundantcation in phloem sap (4) sugar is transported in phloem as non-reducing sugar
Last Answer : sugar is transported in phloem as non-reducing sugar
Description : Study the given figure below and answer the question that follow important-questions-for-class-12-biology-cbse-fertilisation-pregnancy-and-embryonic-development-t-33-3 (i)Name the stage of human embryo the ... implantation in the uterus. (iv)Where are the stem cells located in this embryo? -Biology
Last Answer : (i)The stage is blastocyst. (ii) A—Trophoblast. It helps in attachment to endometrium during implantation and provides nourishment to developing embryo. (iii) Inner cell mass acts as precursor to embryo ... into ectoderm and endoderm. (iv) Stem cells are located in inner cell mass of embryo.
Description : What is the work of copper-T? (a) To inhibit ovulation (b) To inhibit fertilisation (c) To inhibit implantation of blastocyst (d) To inhibit gametogenesis
Last Answer : c) To inhibit implantation of blastocyst
Description : (a)Explain how does the exchange of gases occur in plants across the surface of stems, roots and leaves. (b) How are water and minerals transported in plants ? -Biology
Last Answer : a) In plants there are tiny pores called stomata on leaves and lenticels in stem which facilitate the exchange of gases. Carbon dioxide is taken in and oxygen given out {during photosynthesis} and vice ... within the plant, to all parts like the stem, roots, fruits etc. in all directions.
Description : Which one of the following statements regarding post-fertilisation development in flowering plants is incorrect? (a) Ovules develop into embryo sac. (b) Ovary develops into fruit. (c) Zygote develops into embryo. (d) Central cell develops into endosperm
Last Answer : (a) Ovules develop into embryo sac.
Description : Which one of the following statements is wrong? (a) When pollen is shed at two-celled stage, double fertilisation does not take place. (b) Vegetative cell is larger than generative cell. (c) Pollen grains in some plants remain viable for months. (d) Intine is made up of cellulose and pectin.
Last Answer : (a) When pollen is shed at two-celled stage, double fertilisation does not take place.