Which one of the following statements with regard to embryonic development in humans is correct?
1. | Cleavage divisions bring about a considerable increase in the mass of protoplasm. |
2. | In the second cleavage division, one of the two blastomeres usually divides a little sooner than the second. |
3. | With more cleavage divisions, the resultant blastomeres become larger and larger. |
4. | Cleavage division results in a hollow ball of cells called morula. |
Women who consume the drug thalidomide for relief from vomiting during the early months of pregnancy give birth to children with :
1. | No spleen | 2. | Harelip |
3. | Extra fingers and toes | 4. | Underdeveloped limbs |
A cross-section at the midpoint of the middle piece of a human sperm will show :
1. | centriole, mitochondria, and 9+2 arrangement of microtubules |
2. | centriole and mitochondria |
3. | mitochondria and 9+2 arrangement of microtubules |
4. | 9+2 arrangement of microtubules only |
Which one of the following events is correctly matched with the time period in a normal menstrual cycle?
1. | Release of egg: 5th day |
2. | Endometrium regenerates: 5 - 10 days |
3. | Endometrium secretes nutrients for implantation: 11-18 days |
4. | Rise in progesterone level: 1 - 15 days |
Which of the following is true regarding sperm?
1. Fertilizin : For penetrating egg membrane
2. Hyaluronidase : For penetrating egg membrane
3. Acrosin : Dissolves corona radiata
4. Capacitation : Takes place in penis
How many sperms are formed from a secondary spermatocyte?
1. | 4 | 2. | 8 |
3. | 2 | 4. | 1 |
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Grey crescent is the area
1. at the point of entry of sperm into ovum
2. just opposite to the site of entry of sperm into ovum
3. at the animal pole
4. at the vegetal pole
Which of the following statements is correct?
1. Monkey, apes and humans exhibit estrous cycle.
2. Urine is pale yellow and slightly alkaline.
3. Lots of enzymes are present in bile juice.
4. Ovulation in humans is spontaneous
The 'cells of Rauber' are
1. secretory cells of endometrium in uterus
2. inner cell mass of blastocoel
3. outer cells of trophoblast in contact with uterine wall
4. cells of trophoblast, in contact with inner cell mass of blastocyst.
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): | A moist habitat is almost always required for external fertilization. |
Reason (R): | A moist habitat prevents the drying of gametes and allows sperms to swim to ova. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |