meiosis Flashcards
what is meiosis?
Meiosis main purpose is to divide sex or gamets. The importance of meiosis is that if the process didn’t happen then the cell wouldn’t divide and it would still have 46 chromosomes but when the organisms go through sexual intercourse and a sperm cell and ova meet they won’t create a human baby. For a human baby to be created the cells should have 23 chromosomes and chromatids each so when they meet up they will have 46 chromosomes all together creating a human baby.Meiosis divides one cell twice meaning one parent cell into 4 daughter cells.
How many stages does it have?
nine
What is crossing over?
When chromosomes line up with their homologues pairs and exchange DNA. Chromosomes shuffle these genetics around which creates a new combination in each gamete.
Which cell does meiosis produce haploid or diploid?
Meiosis produces 4 unique haploid cells whereas mitosis produces two identical diploid cells.
What are haploid and diploid cells?
Haploid cells only have one set of chromosomes like gametes whereas diploid cells have two sets of chromosomes such as body cells.
Explain every stage of mitosis?
Interphase
Cell growth
DNA replication
Growth
Prophase
Meaning before
chromosomes are thickening and condensing
Nucleus is still here
Chromosomes will line up with their homologous pairs meaning they are chromosomes they are of the same height and shape and contain the same genetic information in the same spot.
The pairs will cross over
Crossing over is a way in which the homologous pairs exchange their genetic information with each other and due to this there will be variations.
If there will be no crossing over there will be no variations and me and my sibling will look the same. It is also because the gene will be given directly
Metaphase
Meaning middle. The chromosomes line up in pairs in the middle and the spindles move toward the centromere of the chromosomes.
Anaphase
Meaning away.chromosomes pulled away to the far end of the cell through spindles.The spindles help the chromosomes move to the end of the cell.
Telophase
The cell is divided into two cells but with 46 chromatids and 23 chromosomes. The two new nuclei were formed around the chromosomes and the spindles disassembled.
Cytokinesis
It’s where the cytoplasm of one parent cell divides into two daughter cells.
Prophase2
chromosomes and the spindles starting to form condensing and thickening. And the nuclei disassembles and spindles appear
Metaphase 2
chromosomes line up in the middle in a single line. The spindles move toward the centromere of chromosomes.
Anaphase 2
Instead of chromosomes being pulled away the chromatids are going to be pulled away from one another. And will be taken to the end of cells by spindles.
Telophase2
New cells will be formed so 2 cells have divided in 4 now. The nuclei will form around the chromosomes in the four cells with identical DNA. They will be now left with 23 chromosomes and chromatids.
Tell two processes that ensure there are variations in humans?
meiosis and segregation
