Meiosis Flashcards
Meiosis is
a type of cell division that reduces the number of chromosomes in the parent cell by half and produces four gamete cells.
Meiosis produces
egg and sperm
Prophase I (PRO = before) - Step 1
- Homologous Chromosomes condense and undergo synapsis (gene to gene pairing)
Prophase I - Step 2
- When synapsis is complete, each pair of homologous chromosomes from a bivalent
Prophase I - Step 3
The chromosomes continue to shorten and thicken and the chiasmata between non-sister chromatids become apparent
Prophase I - Step 4
- The nuclear envelope begins to break down.
Each chromosome
consists of ____ sister
chromatids
two
What happens in Prometaphase I?
Spindles attach to kinetochores on chromosomes
What happens in Metaphase I (M = MIDDLE)?
Homologous pairs line up in center of the cell, with bivalents oriented randomly
What happens during Anaphase I (A FOR AWAY)?
Homologous chromosomes are pulled away by spindle fibers, but chromatids do not separate
What happens during Telophase I (T FOR 2) ?
There are two newly formed nuclei, daughter cells are ready to move into prophase II
What happens during Prophase II?
The nuclear envelope breaks down and the chromosomes condense
What happens during Prometaphase II?
Spindles attach to kinetochores on chromosomes
What happens during Metaphase II?
Chromosomes align in the center of the cell
What happens during Anaphase II?
Sister chromatids seperate
What happens during Telophase II and cytokinesis?
The nuclear envelope re-forms and the cytoplasm divides
During Meiosis I, ________ chromatids seperate and during Meiosis II, ________ chromatids seperate
parents , sister
Which of the following statements is NOT true about
gamete formation in mammals?
A. In the female, the separation of cytoplasm is
unequal during meiosis.
B. Only one of the four cells resulting from meiosis
goes on to become an oocyte.
C. The polar bodies formed during meiosis in the
female can participate in fertilization with
sperm.
D. The cytoplasm is diminished during development
of sperm, and a flagellum is formed to give
sperm locomotion.
C. The polar bodies formed during meiosis in the
female can participate in fertilization with
sperm.
What is the “n” number of cells for entering meiosis II?
2n
What is the “n” number of cells after meiosis II?
n
