Human Reproduction Class 12 MCQ Questions With Answers
Human Reproduction Class 12 MCQ Chapter 3 Question 1.
Spot the odd one out from the following structures with reference to the male reproductive system.
(A) Rete testis
(B) Epididymis
(C) Vasa efferentia
(D) Isthmus
Answer:
(D) Isthmus
Explanation :
Rete testis, vasa efferentia and epididymis are parts of male reproductive system whereas isthmus is part of fallopian tube which carries an egg from the ovary to the uterus.
Class 12 Biology Chapter 3 MCQ Question 2.
Which one of the following is not a male accessory gland?
(A) Seminal vesicle
(B) Ampulla
(C) Prostate
(D) Bulbo-urethral gland
Answer:
(B) Ampulla
Chapter 3 Biology Class 12 MCQ Question 3.
The vas deferens receives duct from the seminal vesicle and opens into urethra as
(A) epididymis
(B) ejaculatory duct
(C) efferent ductule
(D) ureter
Answer:
(B) ejaculatory duct
Explanation :
The vas deferens receives duct from the seminal vesicle and opens into urethra as ejaculatory duct. These ejaculatory . ducts which open into the urethra about hnlf way through the prostate gland function to mix Lhc sperm stored in the ampulla with fluids secreted by the seminal vesicles and to transport these substances to the prostate.
Human Reproduction Class 12 MCQ With Answers Question 4.
Urethral meatus refers to the
(A) urinogenital duct.
(B) opening of vas deferens into urethra.
(C) external opening of the urinogenital duct.
(D) muscles surrounding the urinogenital duct.
Answer:
(C) external opening of the urinogenital duct.
Explanation :
Urethral meatus, also known as the external urethral orifice, is the external opening or meatus of the urethra. The urethra originates from the urinary bladder and ex tends through the penis to its external opening called urethral meatus.
MCQ On Human Reproduction Class 12 Pdf Question 5.
Seminal plasma, the fluid part of semen, is on tributed by
(i) Seminal vesicle
(ii) Prostate
(iii) Urethra
(iv) Bulbo-urethral gland
(A) i and ii
(B) i, ii and iv
(C) ii, iii and iv
(D) i and iv
Answer:
(B) i, ii and iv
Explanation :
Secretion of seminal vesicle (paired), prostate gland (unpaired) and bulbo-urethral glands or Cowper’s glands (paired) constitute the seminal plasma. It contains various proteins and fructose as energy suppliers for sperm motility and is also responsible for making the largest proportion of the alkaline buffer.
Biology Class 12 Chapter 3 MCQs Question 6.
Identify the odd one from the following.
(A) Labia minora
(B) Fimbriae
(C) Infundibulum
(D) Isthmus
Answer:
(A) Labia minora
Explanatio:
Fimbriae, infundibulum, isthmus I and ampulla are the parts of fallopian duct I while labia minora is female external genitalia.
Chapter 3 Biology Class 12 MCQs Question 7.
Prostate glands are located below
(A) gubernaculum
(B) seminal vesicles
(C) epididymis
(D) bulbourethral glands
Answer:
(B) seminal vesicles
Explanation:
Prostate gland is the part of male reproductive system that is located just be¬low the bladder. Small and walnut shaped, the prostate surrounds the beginning of the urethra.
Class 12 Biology Ch 3 MCQ Question 8.
Lower narrow end of uterus is called
(A) urethra
(B) cervix
(C) clitoris
(D) vulva
Answer:
(B) cervix
Explanation :
Lower end of uterus is called cervix that opens into vagina. A hollow muscular organ located in front of the rectum and behind the urinary bladder, at the lower end of uterus is called cervix that opens into vagina.
MCQ Class 12 Biology Chapter 3 Question 9.
The third stage of parturition is called “after-birth”. In this stage
(A) excessive bleeding occurs
(B) fetus is born and cervix and vagina contraction to normal condition happens
(C) fetus is born and contraction of uterine wall prevents excessive bleeding
(D) placenta is expelled out.
Answer:
(D) placenta is expelled out.
Explanation:
Third process of parturition is the third and final stage, after the delivery until the placenta or after birth is expelled by powerful uterine contractions. Umbilical cord is cut close to the baby’s navel. It lasts for 10-15 minutes after the birth of child.
Human Reproduction MCQ Chapter 3 Question 10.
Which of the following contains the actual genetic part of a sperm?
(A) Whole of it
(B) Tail
(C) Middle piece
(D) Head
Answer:
(D) Head
Explanation :
Head of the sperm is anterior, broad, flattened and almond shape. It consists of two parts. The head portion is mainly a cell nucleus; it consists of genetic substances and anterior small cap-like acrosome. The nucleus consists of condensed DNA and basic proteins.
MCQs Of Biology Class 12 Chapter 3 Question 11.
Identify the wrong statement from the following.
(A) High levels of oestrogen trigger the ovulatory surge.
(B) Oogonial cells start to proliferate and give rise to functional ova in regular cycles from puberty onwards.
(C) Sperms released from seminiferous tubules are poorly motile/non-motile.
(D) Progesterone level is high during the post-ovulatory phase of menstrual cycle.
Answer:
(B) Oogonial cells start to proliferate and give rise to functional ova in regular cycles from puberty onwards.
Explanation :
Oogenesis is initiated during the embryonic developmental stage when a couple of million gamete mother cell (oogonia) is formed within each foetal ovary (about third month of foetal ovary). Unlike sperm forma¬tion that starts at puberty egg formation begins before birth. No more oogonia are formed and added after birth.
MCQ Questions For Class 12 Biology Chapter 3 Question 12.
The immature male germ cells undergo division to produce sperms by the process of spermatogenesis. Choose the correct one with reference to above.
(A) Spermatogonia have 46 chromosomes and always undergo meiotic cell division.
(B) Primary spermatocytes divide by mitotic cell division.
(C) Secondary spermatocytes have 23 chromosomes and undergo second meiotic division.
(D) Spermatozoa are transformed into spermatids.
Answer:
(C) Secondary spermatocytes have 23 chromosomes and undergo second meiotic division.
Explanation:
Spermatogonia have 46 chromosomes and always undergo mitotic cell division. Primary spermatocytes divide by meiotic cell division. Spermatids are transformed into spermatozoa.
Class 12th Biology Chapter 3 MCQ Question 13.
Spermiation is the process of the release of sperms from
(A) seminiferous tubules.
(B) vas deferens.
(C) epididymis.
(D) prostate gland.
Explanation:
Spermiation is the process by which mature spermatids or spermatozoa are released from Sertoli cells into the seminiferous tubule lumen prior to their passage to the epididymis.
MCQ Of Human Reproduction Class 12 Question 14.
Match between the following representing parts of the sperm and their functions and choose the correct option.
| Column A | Column B |
| A. Head | i. Enzymes |
| B. Middle piece | ii. Sperm motility |
| C. Acrosome | iii. Energy |
| D. Tail | iv. Genetic material |
(A) A-ii, B-iv, C-i, D-iii
(B) A-iv, B-iii, C-i, D-
(C) A-iv, B-i, C-ii, D-iii
(D) A-ii, B-i, C-iii D-iv
Answer:
(B) A-iv, B-iii, C-i, D-
Explanation:
A. Sperm head contains nucleus with densely coiled chromatin fibers surrounded by acrosome. Nucleus transfers the genetic material to next generation.
B. Middle piece of sperm contains large number of mitochondria to provide energy needed for the movement.
C. Acrosome present in the cap of sperm contains hydrolytic enzymes which help sperm to penetrate the egg. These enzymes break down the outer membrane of the ovum, called the zona pellucida, allowing the haploid nucleus in the sperm cell to join with the haploid nucleus in the ovum.
D. Tail of sperm helps in propelling or swimming the sperm cell forwards to meet the egg.
MCQ On Human Reproduction Class 12 Question 15.
Mature Graafian follicle is generally present in the ovary of a healthy human female around stet.
(A) 5-8 days of menstrual cycle.
(B) 11-17 days of menstrual cycle.
(C) 18-23 days of menstrual cycle.
(D) 24-28 days of menstrual cycle.
Answer:
(B) 11-17 days of menstrual cycle.
Explanation:
Mature Graafian follicle is the fol¬licular stage present in the ovary. It is formed after the completion of first mitotic division but before ovulation. It, therefore, contains a 2N diploid oocyte. Graafian follicle is characterized by a large follicular antrum and releases one or more ova into the Fallopian tube and leaves behind the corpus luteum. It is generally present in the ovary of a healthy human female around 11-17 days of menstrual cycle.
Class 12 Human Reproduction MCQ Chapter 3 Question 16.
Which among the following has 23 chromosomes?
(A) Spermatogonia
(B) Zygote
(C) Secondary oocyte
(D) Oogonia
Answer:
(B) Zygote
Explanation :
Secondary oocyte (n = 23). Primary oocyte completes first meiotic division to form secondary oocyte (23 chromosomes) and polar body (23 chromosomes), whereas spermatogonia, zygote and oogonia have 46 chromosomes, hence diploid.
MCQs On Human Reproduction Class 12 Question 17.
The membranous cover of the ovum at ovulation is
(A) corona radiata.
(B) zona radiata.
(C) zona pellucida.
(D) chorion.
Answer:
(A) corona radiata.
Explanation :
Corona radiata is the innermost layer of the cells of the cumulus oophorus and is directly adjacent to the zona pellucida, the outer protective glycoprotein layer of the ovum. Zona radiata is a striated membrane situated next the yolk of an ovum. Chorion is an extra-embryonic fetal membrane which is responsible for the formation of placenta.
Chapter 3 Class 12 Biology MCQ Question 18.
At what stage of life is oogenesis initiated in a human female?
(A) At puberty
(B) During menarch
(C) During menopause
(D) During embryonic development
Answer:
(D) During embryonic development
Explanation :
During embryonic development, the process of formation of haploid ova from diploid germinal cell is called oogenesis and the process occurred in the ovary. Oogenesis begins during embryonic development but is completed only at puberty of the secondary oocyte with the sperm.
Biology Class 12 Chapter 3 MCQ Question 19.
A human female reaches menopause around the age of
(A) 50 years
(B) 15 years
(C) 70 years
(D) 25 years.
Answer:
(A) 50 years
Explanation :
The end of a woman’s fertility is called menopause and the stop of the menstrual cycle. The ovaries stop producing hormones and in humans, the menstrual cycle ceases at around 50 years of age. but sometimes due to health-related problems it varies.
Class 12 Biology Chapter 3 MCQs Biology Question 20.
Layers of an ovum from outside to inside is
(A) corona radiata, zona pellucida and vitelline membrane
(B) zona pellucida, corona radiata and vitelline membrane
(C) vitelline membrane, zona pellucida and corona radiata
(D) zona pellucida, vitelline membrane and corona radiata.
Explanation :
The corona radiata is thick and the outer layer of follicular (granulosa), zona pellucida is inner and thick and non cellular. The zona pellucida surrounds the oocyte and located between the oocyte and the follicular cells. The vitelline membrane is a membrane enclosing an egg that comprises the zona pellucida in mammals.
MCQ Of Chapter 3 Biology Class 12 Question 21.
Choose the incorrect statement from the following.
(A) In birds and mammals internal fertilization takes place.
(B) Colostrum contains antibodies and nutrients.
(C) Polyspermy is prevented by the chemical changes in the egg surface.
(D) In the human female implantation occurs almost seven days after fertilization.
Answer:
(C) Polyspermy is prevented by the chemical changes in the egg surface.
Explanation :
Polyspermy may be defined as the fertilization of an ovum by more than one sperm. During fertilization, a sperm comes in contact with the zona pellucida layer of the ovum and induces changes in the membrane that block the entry of additional sperms. Thus, it ensures that only one sperm can fertilize an ovum.
Question 22.
Acrosomal reaction of the sperm occurs due to
(A) its contact with zona pellucida of the ova.
(B) reactions within the uterine environment of the female.
(C) reactions within the epididymal environment of the male.
(D) androgens produced in the uterus.
Answer:
(A) its contact with zona pellucida of the ova.
Explanation :
Acrosomal reaction of the sperm occurs due to its contact with zona pellucida of the ova. The reaction that occurs in acrosome of sperm is triggered by the release of fertilizin. The main purpose of the acrosomal reaction is to start the fusion of the oocyte membrane with the sperm cell membrane allowing the combination of genetic material contained in both gametes, leading to the fertilization of the oocyte.
Question 23.
Morula is a developmental stage
(A) between the zygote and blastocyst.
(B) between the blastocyst and gastrula.
(C) after the implantation.
(D) between implantation and parturition.
Answer:
(A) between the zygote and blastocyst.
Explanation :
Morula is a developmental stage between the zygote and blastocyst. It is a solid ball of 16-32 blastomeres, produced by a series of cleavage divisions of the early embryo from which a blastula is formed.
Question 24.
Match the following and choose the correct options.
| Column I | Column II |
| A. Trophoblast | i. Embedding of blastoyst in the endometrium |
| B. Cleavage | ii. Group of cells that would differentiate as embryo |
| C. Inner cell mass | iii. Outer layer of blastocyst attached to the endometrium |
| D. Implantation | iv. Mitotic division of zygote |
(A) A-ii, B-i, C-iii, D-iv
(B) A-iii, B-iv, C-ii, D-i
(C) A-iii, B-i, C-ii, D-iv
(D) A-ii, B-iv, C-iii, D-i
Answer:
(D) A-ii, B-iv, C-iii, D-i
Explanation:
A. Trophoblast is the peripheral cells of the blastocyst, which attach the zygote (fertilised ovum) to the uterine wall and become the placenta and the membranes that nour¬ish and protect the developing organism.
B. Cleavage is the repeated mitotic division of cells in the early embryo.
C. Inner cell mass forms within the blastocyst, prior to its implantation within the uterus.
It differentiates to form embryo.
D. Implantation is a process of attachment and invasion of the uterus endometrium by the blastocyst (conceptus).
Question 25.
Which of the following hormones is not secreted by human placenta?
(A) hCG
(B) Estrogens
(C) Progesterone
(D) LH
Answer:
(D) LH
Explanation :
The major hormones secreted by the human placenta are : Human chorionic gonadotropin (hCG), estrogen, progesterone and human placental lactogen. LH (luteinising hormone) is produced by gonadotropic cells in the anterior pituitary gland. This hormone is considered a gonadotrophic hormone because of its role in controlling the function of ova¬ries in females and testes in. males, which are known as the gonads.
Question 26.
The early-stage human embryo distinctly possesses
(A) gills
(B) gill slits
(C) external ear (pinna)
(D) eyebrows.
Answer:
(B) gill slits
Explanation :
Early embryo, organism of vari¬ous vertebrates possesses a dorsal hollow nerve cord, a well developed notochord and a series of gill slits, which represent the fundamental chordate characters.
Question 27.
Gastrula is the embryonic stage in which
(A) cleavage occurs
(B) blastocoel form
(C) germinal layers form
(D) villiform.
Answer:
(C) germinal layers form
Explanation :
Transformation of the blastocyst into gastrula with primary germ layers by rearrangement of the cells is called gastrulation. During gastrulation, the embryo develops three germ layers (endoderm, mesoderm, and ectoderm) The structures derived from ectoderm are
(i) pituitary gland
(ii) cornea
(iii) kidneys
(iv) notochord
(A) (i) and (iii)
(B) (ii) and (iii)
(C) (i) and (ii)
(D) (ii) and (iv).
Answer:
(C) (i) and (ii)
Explanation:
Germ layer Derivatives
Ectoderm -Epidermis, neural tissue, hair, nails, enamel of teeth, etc.
Mesoderm – Blood vessel, joints, connective tissue, skeletal muscles, kidney, etc.
Endoderm – Epithelium of mouth, intestine, liver, etc.
Question 28.
Implantation takes place after fertilization.
(A) 5 days
(B) 6 days
(C) 7 days
(D) 8 days
Answer:
(C) 7 days
Explanation :
When a fertilized egg- travels down the fallopian tube and embedding of the blastocyst into endometrium of uterus is called implantation . Implantation begins about 7th day after fertilisation of ovum and it takes about 3 days for the process to be completed.
Question 29.
Cleavage differs from mitosis in lacking
(A) synthetic phase
(B) growth phase
(C) both (A) and (B)
(D) none of these.
Answer:
(B) growth phase
Explanation :
Cleavage starts after fertilization and it occurs in fallopian tube. It is holoblastic. There is no growth phase, so it differs from mitosis.
Question 30.
In human adult females oxytocin
(A) stimulates pituitary to secrete vasopressin
(B) causes strong uterine contractions during parturition
(C) is secreted by anterior pituitary
(D) stimulates growth of mammary glands.
Answer:
(B) causes strong uterine contractions during parturition
Explanation :
Oxytocin is produced in the hypothalamus and is secreted by the posterior pituitary gland. It causes contraction during parturition and help to bring baby out from the mother’s womb
Assertion and Reason Based MCQs
Directions: In the following questions a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as :
(A) Both assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of assertion (A).
(B) Both assertion (A) and Reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(C) Assertion (A) is true but reason (R) is false.
(D) Assertion (A) is false but reason (R) is true.
Question 1.
Assertion (A): Urethra in human male act as a urinogenital canal.
Reason (R): Urethra carries only urine while sperms are carried by vasa deferentia only.
Answer:
(B) Both assertion (A) and Reason (R) are true but reason (R) is not the correct explanation of assertion (A).
Explanation :
Urethra is the canal through which both urine and semen is discharged therefore it is called urinogenital canal.
Question 2.
Assertion (A) : In human male, testes are extraabdominal and lie in scrotal sacs.
Reason (R): Scrotum protects the testes.
Answer:
(A) Both assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of assertion (A).
Explanation :
The scrotum is a bag-like struc¬ture that helps to protect the testicles. Testicles make sperm and for this, they need to be cooler than the inside of the body. This is why the scrotum is located outside the body.
Question 3.
Assertion (A): The region outside the seminiferous tubules is called interstitial spaces, which contain Leydig’s cells.
Reason (R): Leydig’s cells synthesize and secrete testicular hormones called androgen.
Answer:
(B) Both assertion (A) and Reason (R) are true but reason (R) is not the correct explanation of assertion (A).
Explanation :
Hypothalamus releases GnRH. This hormone stimulates the secretion of LH, which further acts on interstitial cells of Leydig and induces the release of androgen.
Question 4.
Assertion (A): Large members of mitochondria are present in middle piece of sperm.
Reason (R): Numerous mitochondria in the middle piece of sperm produce energy which is required for their movement.
Answer:
(A) Both assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of assertion (A).
Explanation :
Mitochondria is a powerhouse organelle. It stores energy in the form of ATE This energy helps in sperm motility.
Question 5.
Assertion (A): The secretory phase in the human menstrual cycle is also called the luteal phase.
Reason (R): During the luteal phase development of corpus luteum and secretion of progesterone occurs.
Answer:
(A) Both assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of assertion (A).
Explanation :
The luteal phase begins after ovulation. It lasts about 14 days and ends just before a menstrual period. In this, the ruptured follicle closes after releasing the egg and forms the corpus luteum.
Question 6.
Assertion (A): Vasa efferentia develop from rete testis.
Reason (R): Sperm conduction takes place by the ciliary current.
Answer:
(A) Both assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of assertion (A).
Explanation:
Vasa efferentia are short, straight tubes, develop from rete testis. They help in sperm conduction which takes place by the ciliary current.
Question 7.
Assertion (A): The fusion of sperm and ovum to form zygote is called fertilization.
Reason (R): It occurs at ampullary isthmic junction of the fallopian tube.
Answer:
(B) Both assertion (A) and Reason (R) are true but reason (R) is not the correct explanation of assertion (A).
Explanation :
Fertilization in humans occurs at I the ampullary isthmic junction of the fallopian tube. The fusion of sperm and ovum to form a zygote is called fertilization.
Question 8.
Assertion (A): Oxytocin helps in parturition.
Reason (R): Oxytocin acts on uterine muscle and causes expulsion of the fetus.
Answer:
(A) Both assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of assertion (A).
Explanation :
Oxytocin acts on uterine muscles and also increases the production of prostaglandins, which increase the contractions further.
Question 9.
Assertion (A): Endometrium is a mucosal tissue made up of two layers.
Reason (R): It is a inner lining of the uterus. Each month it thickens and renews itself, preparing for pregnancy.
Answer:
(A) Both assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of assertion (A).
Explanation :
It’s two layers-the strata fune rationalize and stratum basalis. If conception takes place, the embryo implants into the endometrium.
Question 10.
Assertion (A): The Leydig cells of testis are present outside the seminiferous tubules.
Reason (R): Testis helps to synthesize and secrete hormones called androgens.
Answer:
(A) Both assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of assertion (A).
Question 11.
Assertion: The gamete formed in males determines the sex of the offspring.
Reason: Sex determination in humans depends upon cumulative effect of some genes of X and Y chromosomes.
Answer:
(A) Both assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of assertion (A).
Explanation :
Sex determination depends either of the chromosomes contributed by male, If a chromosome is contributed in zygote formation the offspring will be male and if Y is contributed then the offspring will be female.
Case-Based MCQs
Attempt any 4 sub-parts from each question. Each sub-part carries 1 mark.
I. Read the following text and answer the following questions on the basis of the same:
During sexual reproduction, the male inserts the sperm into the female reproductive tract, and sperm receive by the ovary and after that sperm fuse with the egg (ovum) in the ampullary region, this process is called fertilization, haploid nucleus of sperm fuse with that of ovum to form Diploid zygote.
Question 1.
The phenomenon of sperm activation in mammals is known as.
(A) Parthenogenesis
(B) Amphimixis
(C) Capacitation
(D) Acrosomal reaction
Answer:
(C) Capacitation
Explanation:
This step is a biochemical event, in which the acrosome reaction occurs so, the reaction can penetrate the zona pellucida of the oocyte and fertilize with the egg (ovum).
Question 2.
Fertilization takes place in
(A) Vagina
(B) Follicle
(C) Uterus
(D) Fallopian tube
Answer:
(D) Fallopian tube
Explanation :
Fusion of sperm with an egg is known as fertilization, most of the time student’s think that this process occurs in ovary but that’s not true it actually occur In the fallopian tube that links an ovary to the uterus fertilized egg successfully travels down the fallopian tube and implants in the uterus.
Question 3.
Egg development without fertilization is known as
(A) Gametogenesis
(B) Parthenogenesis
(C) Metagenesis
(D) Oogenesis
Answer:
(B) Parthenogenesis
Explanation: Parthenogenesis is a method in which a new individual developed without fertilization, and there is no involvement of male gamete, e.g., Honey bee and drosophila, etc.
Question 4.
Site of fusion of sperm with an ovum.
(A) Infundibulum
(B) Ampullary isthmic junction of oviduct
(C) Cervix of uterus
(D) Ovary
Answer:
(B) Ampullary isthmic junction of oviduct
Explanation :
Fallopian tube has three parts first is isthmus second is ampulla (ampullary – isthmic junction) is the most common site for fertilization and the third is infundibulum which is farthest from the uterus, and the first cleavage division of zygote occurs in the ampullary-isthmic junction.
Directions: In the following questions a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as :
(A) Both assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of assertion (A).
(B) Both assertion (A) and Reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(C) Assertion (A) is true but reason (R) is false.
(D) Assertion (A) is false but reason (R) is true.
Question 5.
Assertion (A): All copulations do not lead to the fertilization and pregnancy.
Reason (R): Fertilisation can occur only if the ovum and sperms are transported simultaneously to the ampullary isthmic junction.
Answer:
(A) Both assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of assertion (A).
II. Read the following text and answer the following questions on the basis of the same:
Read the passage and answer any four questions: Implantation is the embedding of the blastocyst into the endometrium of the uterus. Blastocyst is a ball of cells with a large, fluid-filled cavity called the blastocoel. The blastomeres in the blastocyst are arranged into an outer layer called trophoblast and inner cell mass. With the formation of blastocoel, morula is converted to blastula which is called blastocyst in mammals.
Question 1.
State of embryo development, in which implantation occurs in human female is :
(A) Morula
(B) Zygote
(C) Blastocyst
(D) Transient 3-celled stage.
Answer:
(C) Blastocyst
Explanation :
Blastocyst implant in the uterus, normally developing embryo will contain about six to 10 cells,
Question 2.
Which organ is formed during gastrulation?
(A) Gill
(B) Vitelline membrane
(C) Archenteron
(D) Heart.
Explanation :
The primary gut that forms: during gastrulation in the developing zygote is j known as the archenteron.
Question 3.
The process that transforms the embryo into a three-layered stage is called
(A) Blastulation
(B) Cleavage
(C) Gastrulation
(D) Organogenesis.
Answer:
(C) Gastrulation
Explanation :
The process that transforms the embryo into a three-layered stage is called gastrulation (a phase early in the embryonic de¬velopment of most animals).
Question 4.
The ectoderm cells will form the
(A) Skeletal system
(B) Nervous system
(C) Excretory system
(D) Respiratory system
Answer:
(B) Nervous system
Explanation :
Ectodermal cells form the central nervous system.
Directions: In the following questions a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as :
(A) Both assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of assertion (A).
(B) Both assertion (A) and Reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(C) Assertion (A) is true but reason (R) is false.
(D) Assertion (A) is false but reason (R) is true.
Question 5.
Assertion (A): Blastocyst undergoes gastrulation to form three germinal layers.
Reason (R): This involves cell movements (morphogenetic movement) that help to attain new shape and morphology of embryo.
Answer:
(C) Assertion (A) is true but reason (R) is false.
Explanation :
During gastrulation, the blastula reorganizes cells migrate to the interior of the embryo, forming the three germ layers.
III. Study the given diagram and answer any of the four questions given below :
Question 1.
Identify the parts labeled 1, 2, and 3 in the diagram given.
(A) 1-Placental villi, 2-Umbilical cord with its vessels, 3-Yolk sac.
(B) 1- Umbilical cord with its vessels, 2- Yolk sac, 3- Placental villi
(C) 1- Yolk sac, 2- Umbilical cord with its vessels, 3- Placental villi
(D) None of these
Answer:
(A) 1-Placental villi, 2-Umbilical cord with its vessels, 3-Yolk sac.
Explanation :
1. Placental villi having finger-like projections
2. the Umbilical cord is a tube that connects you to your baby during pregnancy.
3. The yolk sac is a membranous sac attached to an embryo.
Question 2.
During embryonic development which of the following is formed first?
(A) Heart
(B) Brain
(C) Skin
(D) Neural tube.
Answer:
(D) Neural tube.
Explanation :
During embryonic development Neural tube formed first, it is the embryonic precursor to the central nervous system.
Question 3.
The signals for parturition originate from :
(A) Placenta only
(B) Placenta as well as fully developed fetus
(C) Oxytocin released from maternal pituitary.
(D) Fully developed fetus only.
Answer:
(B) Placenta as well as fully developed fetus
Explanation :
The signals for parturition originate from Placenta as well as fully developed foetus, which prompt little uterine contraction is known as fetal expulsion reflex
Question 4.
Hormones secreted by the placenta to maintain pregnancy are:
(A) hCG, hPL, progesterone, prolactin
(B) hCG, progesterone, estrogen, glucocorticoid
(C) hCG, hPL, progesterone, estrogen
(D) hCG, hPL, estrogen, relaxin oxytocin.
Answer:
(C) hCG, hPL, progesterone, estrogen
Explanation :
hCG, progesterone, estrogens and human placental lactogen, are secreted by the placenta during pregnancy.
Question 5.
Gestation period in humans is :
(A) 10 weeks
(B) 28 weeks
(C) 32 weeks
(D) 38 weeks
Answer:
(D) 38 weeks
Explanation :
The average length of human gestation is 38 weeks, from the first day of the woman’s last menstrual period.