If a germ cell in a female gonad and a germ cell in a male gonad begin undergoing meiosis simultaneously, what will be the ratio of ova and sperms produced ?
1
1:02
2
1:01
3
2:01
4
1:04
Official Solution
Correct Option: (4)
Answer (d) 1 : 4
02
PYQ 2008
medium
biologyID: kcet-200
Notochord, skeletal system and dermis of the skin are the derivatives of
1
All the three layers
2
Mesoderm
3
Endoderm
4
Ectoderm
Official Solution
Correct Option: (2)
Answer (b) Mesoderm
03
PYQ 2008
medium
biologyID: kcet-200
Human egg is
1
Centrolecithal
2
Alecithal
3
Megalecitha!
4
Telolecithal
Official Solution
Correct Option: (2)
Answer (b) Alecithal
04
PYQ 2010
medium
biologyID: kcet-201
In the absence of acrosome, the sperm __________
1
Cannot penetrate the egg
2
Cannot get energy
3
Cannot get food
4
Cannot swin
Official Solution
Correct Option: (1)
Answer (a) Cannot penetrate the egg
05
PYQ 2010
medium
biologyID: kcet-201
Gastrula has a pore which is known as _________
1
Gonophore
2
Blastopore
3
Oospore
4
Zoospore
Official Solution
Correct Option: (2)
Gastrulation is a series of changes that transforms a single-layered blastula into gastrula with primary germ layers rearranged. This involves cell movement which leads to new shape and morphology of the embryo. The morphogenetic movements results in the formation of the cavity called archenteron or primitive gut which opens to outside through blastopore. Through the blastopore yolky endodermal cells are visible. It is present ventrally slightly in front of vegetative pole
06
PYQ 2013
medium
biologyID: kcet-201
Formation of activation calyx in the egg takes place
1
Before fertilization
2
After fertilization
3
At the time of cleavage
4
At the time of amphimixis
Official Solution
Correct Option: (2)
Answer (b) After fertilization
07
PYQ 2014
medium
biologyID: kcet-201
In humans, what is the ratio of number of gametes produced from one male primary sex cell to the number of gametes produced from one female primary sex cell ?
1
1:03
2
4:01
3
1:01
4
1:04
Official Solution
Correct Option: (2)
From a diploid, primary spermatocyte, four haploid spermatozoa are produced through meiosis. While, from a diploid primary oocyte, only one haploid ovum is formed, rest are polar bodies. Hence, the ratio between male gametes and female gametes produced from respective primary sex cells is 4 : 1.
08
PYQ 2014
medium
biologyID: kcet-201
Identify the hormones 'A', 'B' and ' C that are labelled in the given flow chart:
1
A - GnRH, B- ICSH, C- FSH
2
A - GH, B- FSH, C- LH
3
A - GnRH, B - PRL, C - ICSH
4
A - GnRH,B - FSH,C - LH
Official Solution
Correct Option: (4)
Hypothalamus secretes GnRH (Gonadotropin releasing hormone) which stimulates pituitary to release FSH (follicle stimulating hormone) and LH (luteinising hormone). FSH stimulates ovarian follicles to grow while LH (also called interstitial cell stimulating hormone) stimulates Leydig?s cells to secrete testosterone.
09
PYQ 2015
medium
biologyID: kcet-201
In a human foetus the limbs and digits develop after
1
12 weeks
2
First trimester
3
5th month
4
8 weeks
Official Solution
Correct Option: (4)
By the end of second month of pregnancy, the fetus develops limbs and digits.
10
PYQ 2018
easy
biologyID: kcet-201
Identify the odd one from the following.
Official Solution
Correct Option: (1)
11
PYQ 2020
medium
biologyID: kcet-202
A girl after attaining sexual maturity shows development of growing ovarian follicles, development of mammary glands and high pitch of voice. These changes are attributed to ______ hormones.
1
Melatonin
2
Estrogens
3
Progesterone
4
Androgens
Official Solution
Correct Option: (2)
The described changes - ovarian follicle development, mammary gland growth, and high-pitched voice - are all secondary sexual characteristics in females mediated primarily by estrogens. These steroid hormones, produced mainly by the ovaries, regulate female reproductive development and function.
Thus, the correct answer is (B) Estrogens.
12
PYQ 2021
medium
biologyID: kcet-202
Under the influence of oxytocin which layer of the uterus exhibits strong contractions during parturition ?
1
Endometrium
2
Myometrium
3
Perimetrium
4
Both (A) and (C)
Official Solution
Correct Option: (2)
Oxytocin is a hormone that plays a crucial role during labor by stimulating uterine contractions. It exerts its effects on the myometrium, which is the middle and muscular layer of the uterine wall. The myometrium is composed of smooth muscle fibers that contract in response to oxytocin, facilitating the progression of labor and the delivery of the fetus.
The uterine wall consists of three layers:
Endometrium: The innermost lining that thickens during the menstrual cycle and supports embryo implantation.
Myometrium: The thick, muscular middle layer responsible for the powerful contractions during labor.
Perimetrium: The outermost layer that covers and protects the uterus.
During labor, oxytocin binds to receptors in the myometrium, increasing intracellular calcium levels, which leads to muscle contractions. These rhythmic contractions help dilate the cervix and push the baby through the birth canal.
Therefore, under the influence of oxytocin, the myometrium contracts to facilitate childbirth.
The correct answer is (B) : Myometrium.
13
PYQ 2021
medium
biologyID: kcet-202
In the given diagram of human sperm, identify the functions of the labelled parts a,b and c.
1
a → Helps in penetration of sperm into ovum. b → Helps in movement of sperm. c → Provides energy for the movement of sperms into the female reproductive tract.
2
a → Helps in penetration of sperm into ovum. b → Provides energy for the movement of sperm c → Helps in movement of sperm.
3
a → Helps in movement of sperm. b → Helps in penetration of sperm into ovum. c → Provides energy for the movement of sperm.
4
a → Provides energy for the movement of sperm. b → Helps in movement of sperm. c → Helps in penetration of sperm into ovum.
Official Solution
Correct Option: (2)
In the given diagram of a human sperm:
Part a is the acrosome, which contains hydrolytic enzymes that help the sperm penetrate the outer layers of the ovum during fertilization.
Part b is the middle piece, which contains numerous mitochondria. These mitochondria generate ATP, providing the energy required for the movement of the sperm.
Part c is the tail (flagellum), which is responsible for the actual movement or motility of the sperm, propelling it forward toward the ovum.
Therefore, the correct matching is: a → Helps in penetration of sperm into ovum b → Provides energy for the movement of sperm c → Helps in movement of sperm
Correct Answer: B
14
PYQ 2022
easy
biologyID: kcet-202
Identify the odd one from the following.
Official Solution
Correct Option: (1)
15
PYQ 2023
medium
biologyID: kcet-202
With reference to human sperm, match the List-I with List-II.
List-I
List-II
1.
Head
p.
Filled with enzyme
2.
Acrosome
q.
Contains mitochondria
3.
Middle piece
r.
Sperm motility
4.
Tail
s.
Contains haploid nucleus
Choose the correct option from the following :
1
1-r, 2-q, 3-s, 4-p
2
1-s, 2-p, 3-q, 4-r
3
1-s, 2-r, 3-p, 4-q
4
1-q, 2-s, 3-r, 4-p
Official Solution
Correct Option: (2)
1. Head: The head of the sperm contains the haploid nucleus (s).
2. Acrosome: The acrosome is filled with enzymes that help the sperm penetrate the egg (p).
3. Middle piece: The middle piece of the sperm contains mitochondria to provide energy for movement (q).
4. Tail: The tail of the sperm is responsible for sperm motility (r).
The correct answer is (B) : 1-s, 2-p, 3-q, 4-r.
16
PYQ 2026
medium
biologyID: kcet-202
Match items in Column-I with Column-II and choose the correct
1
a - iii, b - i, c - iv, d - ii
2
a - iv, b - ii, c - iii, d - i
3
a - iii, b - ii, c - iv, d - i
4
a - iii, b - iv, c - i, d - ii
Official Solution
Correct Option: (4)
Step 1: Understanding the Concept: A mature mammalian sperm cell is a specialized cell divided into four main functional regions: head, neck, middle piece, and tail. Step 2: Key Formula or Approach: Match the anatomical structure of the sperm with its specific physiological function during fertilization. Step 3: Detailed Explanation:
(a) The Acrosome is a cap-like structure covering the anterior portion of the sperm head. It is filled with hydrolytic enzymes (like hyaluronidase) that help dissolve the egg membranes during fertilization. Thus, a matches with iii.
(b) The Head of the sperm primarily contains the genetic material in the form of an elongated haploid nucleus. Thus, b matches with iv.
(c) The Middle piece is packed with numerous mitochondria, which generate the ATP (energy) required to power the movement of the tail. Thus, c matches with i.
(d) The Tail is a long flagellum that beats in a whip-like motion to propel the sperm forward, facilitating sperm motility. Thus, d matches with ii.
Combining these correct associations, we get: a-iii, b-iv, c-i, d-ii. Step 4: Final Answer: The correct option is (4).
17
PYQ 2026
medium
biologyID: kcet-202
Identify the correct path of milk secretion by the mammary glands.
Step 1: Understanding the Concept: The human mammary gland consists of glandular tissue arranged in lobes and a complex ductal system for the synthesis, storage, and transport of milk. Step 2: Key Formula or Approach: Trace the anatomical pathway of milk from its site of production deep within the gland to its point of exit at the nipple. Step 3: Detailed Explanation: Milk is secreted by the specialized cells of the alveoli, which are clustered in the mammary lobes.
The milk is temporarily stored in the lumen (cavities) of these alveoli.
From the alveoli, the milk passes into smaller ducts called mammary tubules.
The mammary tubules of each lobe join to form a wider collective tube called a mammary duct.
Several mammary ducts then unite to form a dilated, wider structure called the mammary ampulla.
Finally, the ampulla is connected to the lactiferous duct, through which milk is ultimately sucked out from the nipple.
Thus, the correct sequential pathway is: Alveoli mammary tubules mammary duct ampulla lactiferous ducts. Step 4: Final Answer: The correct option is (2).
