Tag: post fertilization events

Questions Related to post fertilization events

Fraternal twins in humans are produced when

biology reproduction in humans twins reproduction and modern technology post fertilization events

  1. Two sperms fertilize an ovum and the first two blastomeres separate from each other

  2. One sperm fertilizes an ovum and the first two blastomeres separate from each other

  3. Egg develop parthenogenetically and first two blastomeres separate from each other

  4. Two ova are fertilized simultaneously

Show answer
Correct Option: D
Explanation:

Fraternal twins are also called as 'dizygotic'. This means there is fertilization of two seperate eggs(ova) by two individual sperms simultaneously. They are implanted in the uterine wall at the same time. They usually develop in two separate amniotic sacs. They are also called as 'biovular' since two eggs form two zygotes.
So, the correct is answer is 'Two ova are fertilized simultaneously'.

What are identical twins?

biology reproduction in humans twins reproduction and modern technology post fertilization events

  1. Heterozygous

  2. Homozygous

  3. Monozygotic

  4. Dizygotic

Show answer
Correct Option: C
Explanation:

Image result for monozygotic identical twin
Twins are two offsprings produced by the same pregnancy. Twins can either be monozygotic (identical twin), meaning that they develop from one zygote that splits and forms two embryos, or dizygotic (fraternal twin), which are produced from two eggs. Thus, the correct answer is option C.

Which are the two offspring developed in the same uterus but from fertilization of two different ova?

biology reproduction in humans twins reproduction and modern technology post fertilization events

  1. Dizygotic twins

  2. Monozygotic twin

  3. Fraternal twins

  4. Both A and C

Show answer
Correct Option: D
Explanation:

Dizygotic twins may occur if two or more oocytes are released in one cycle. If each is fertilized, dizygotic twins may result. Fertility drugs are a common cause for dizygotic twins, but other factors, like family history, maternal age or weight, can also lead to dizygotic twinning. Thus, the correct answer is option D.

Monozygotic twins develops from

biology reproduction in humans twins reproduction and modern technology post fertilization events

  1. Different zygotes

  2. Different ova

  3. Different sperms

  4. Same zygote

Show answer
Correct Option: D
Explanation:

  • There are two types of twins, Fraternal or dizygotic twins, and monozygotic twins.
  • When the zygote, during the cleavage, separates and forms two different cells and both of them grow individually as embryos, they form the monozygotic twins.
  • Monozygotic twins are of the same sex.
  • When 2 zygotes are fertilized by two different sperms they form the dizygotic twins.
  • They can be of different sex.

So, the correct option should be 'Same Zygote'.

Concordant type of twins are

biology reproduction in humans twins reproduction and modern technology post fertilization events

  1. Free martins

  2. Dizygotic twins

  3. Monozygotic twins

  4. Both B and C

Show answer
Correct Option: C
Explanation:
Monozygotic or identical twins are those twins which are formed by the splitting of one zygote into two embryos. They have almost the same characteristics both phenotypically and genotypically. Dizygotic or fraternal twins are formed when two different eggs are fertilized by two different sperms.
so, the correct option is ' Monozygotic twins'.