BIOLOGY 2 Marks Questions

Follicle-stimulating hormones (FSH) and luteinizing hormones (LH) are secreted by gonadotropin releasing hormones from the hypothalamus. These hormones are involved in the regulation of the process of spermatogenesis.
FSH acts on sertoli cells, whereas LH acts on leydig cells of the testis and stimulates the process of spermatogenesis.

Semen (produced in males) is composed of sperms and seminal plasma. The major components of the seminal plasma in the male reproductive system are mucus, spermatozoa, and various secretions of accessory glands. The seminal plasma is rich in fructose, calcium, ascorbic acid, and certain enzymes. It provides nourishment and protection to sperms.

Major functions of male-accessory ducts are:

• Aid in sperm transport.
• Temporary storage of spermatozoa.

Male accessory glands secretions constitute the seminal plasma. These secretions are rich in fructose, ascorbic acid, citrate, calcium, certain enzymes and prostaglandins. These secretions nourish and activate the spermatozoa to swim.

Functions of the Testis:

• They produce male gametes called spermatozoa by the process of spermatogenesis.
• The leydig cells of the seminiferous tubules secrete the male sex hormone called testosterone. Testosterone aids the development of secondary sex characteristics in males.

Functions of the ovary:

• They produce female gametes called ova by the process of oogenesis.
• The growing Graafian follicles secrete the female sex hormone called estrogen. Estrogen aids the development of secondary sex characteristics in females.

Spermiogenesis is the process of transformation of spermatids into mature flagellated spermatozoa (sperms). Spermiation is the process of release of mature spermatozoa. In this spermatozoa are shed into the lumen of seminiferous tubule for transport.

On the sperm head, has enzymes to dissolve the follicles of ovum/facilitate entry of sperm nucleus for fertilisation/help the sperm enter into the cytoplasm of the ovum.

Blastocyst/Blastula.

Fallopian tubes/ (ampulla of) oviduct.

In the seminiferous tubules/testes, nourishes sperms/germ cells.

Meiosis.

Colostrum has abundant antibodies/IgA to develop resistance in newborn babies.

Cervix helps in regulating the passage of sperms into the uterus and forms the birth canal to facilitate parturition.

It is a cap-like structure present in the anterior of the head of a sperm.

Gametogenesis, Insemination, Fertilisation, Implantation, Gestation, Parturition.

Second meiotic division.

Middle of cycle (14th day).

Spermiogenesis.

Gametogenesis → Insemination → Fertilisation → Implantation → Gestation → Parturition.

60,000-80,000

It forms the foetal part of placenta.

Halving of chromosomal number takes place during gametogenesis by meosis and regaining the 2n number occur as a result of fertilisation by fusion of male and female gametes.

Middle myometrium.

A-Fertilisation.
B-Uterus.

Provide energy for the movement of sperm tail.

Uterus.

Zona pellucida.

Ampullary-isthmic junction of the fallopian tube.

Oogenesis starts during embryonic developmental stages of the female foetus while, spermatogenesis starts at puberty.

The outer layer of blastocyst is referred to as trophoectoderm or trophoblast.

They produce male androgen (testosterone).

LH surge is essential for the events leading to ovulation.

Spermatids are produced by meiosis during spermatogenesis. Thus, they possess haploid number of chromosomes.

Umbilical cord transports nutrients and respiratory gases and metabolic wastes to and from mother and foetus.

During fertilisation a sperm head comes in contact with zona pellucida layer of ovum and induces changes in the membrane that block the entry of additional sperms.

Before birth at five months of foetal life, oogonia reach their maximum number.

Six eggs were released by the ovary of a female dog which gave birth to six puppies.

Seminal plasma (secreted by the male reproductive glands) along with the spermatozoa, constitute semen.

Fertilisation takes place in Fallopian tube (W) and implantation takes place in uterus (Y).

The first sign of growing foetus is noticed by listening to the heart sounds through a stethoscope.

In this phase, progesterone stimulates the endometrial glands of the uterus to secrete a nutrient fluid for the foetus hence, also called the secretory phase.

S. No.	Column I	S. No.	Column II
A.	Acrosome	4.	Contains enzymes to dissolve egg envelopes.
B.	Head	3.	Contains the genetic material.
C.	Tail	1.	Motility of sperm towards the egg.
D.	Middle piece	2.	Powerhouse of the sperm; contains a number of mitochondria.

Colostrum.

Perimetrium, Myometrium and Endometrium.

40 chromosomes.

Ciliated epithelial tissue.

If the testes fail to descend to the scrotum, gametogenesis could be inhibited. The process of spermatogenesis requires a marginally lesser ambient temperature than that in the abdominal cavity.

Trophoblast is the outer layer of blastocyst which helps in the attachment of blastocyst to the endometrium of the uterus.