Mitosis gives rise to almost all the cells in the body. A different type of cell division called meiosis gives rise to sperm and eggs. During fertilization the sperm and egg unite to form a single cell called the zygote which contains chromosomes from both the sperm and egg.
What is the main difference between mitosis and meiosis?
Cells divide and reproduce in two ways, mitosis and meiosis. Mitosis results in two identical daughter cells, whereas meiosis results in four sex cells. Below we highlight the keys differences and similarities between the two types of cell division.
How many chromosomes are there when the egg is fertilized?
When an egg and sperm are united during fertilization, the resulting zygote has 23 pairs of homologous chromosomes, one in each pair from the egg and one from the sperm.
What happens during fertilization in meiosis?
Completion of Meiosis
Fertilization establishes the regular diploid number of chromosomes in the zygote. Meiosis occurs over two cycles of cell division, which sperm cells complete before fertilization. … At fertilization, meiosis II resumes and the duplicate copies of each chromosome are pulled apart.
Does meiosis 2 happen after fertilization?
At fertilization, the secondary oocyte completes meiosis II to form a mature oocyte (23,1N) and a second polar body.
Why must meiosis occur prior to fertilization?
Meiosis only occurs in reproductive cells, as the goal is to create haploid gametes that will be used in fertilization. Meiosis is important to, but not the same as, sexual reproduction. Meiosis is necessary for sexual reproduction to occur, as it results in the formation of gametes (sperm and eggs).
Does mitosis happen after fertilization?
The zygote undergoes mitosis to form two identical cells that remain attached. This takes place about 36 hours after fertilization. Mitosis then occurs more frequently.
Why does mitosis happen?
Mitosis is a process where a single cell divides into two identical daughter cells (cell division). … The major purpose of mitosis is for growth and to replace worn out cells.
Is a zygote a baby?
When the single sperm enters the egg, conception occurs. The combined sperm and egg is called a zygote. The zygote contains all of the genetic information (DNA) needed to become a baby. Half the DNA comes from the mother’s egg and half from the father’s sperm.