Pronucleus

High school (ages 12+)
Science & Technology

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/pronucleus

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. What is the timing of observation?Typically observed around 18 hours post-insemination or ICSI
2. What is the chromosomal number?Each pronucleus is haploid, containing 23 chromosomes in humans
3. Why do we see two pronuclei in a fertilized egg?Because the sperm and the egg each bring one set of chromosomes, and each forms its own pronucleus before they combine into one diploid nucleus.
4. How do the pronuclei become one nucleus?The membranes around each pronucleus dissolve, letting their chromosomes mix and line up together, then they split into two cells.

Syngamy: The fusion of male and female pronuclei to form a diploid zygote nucleus.
Epigenetic Reprogramming: Changes in gene expression that do not involve alterations to the underlying DNA sequence.
Polyspermy: The fertilization of an egg by more than one sperm.