Question

QUESTION 6 Choose the correct answers to fill in the table below. Choices may be used once, more than once, or not at all. Type of organism Ploidy of cells produced by meiosis what we call the cells produced by meiosis animals (including humans) plants QUESTION 7 Below are several events in meiosis. Identify which phase of meiosis the event occurs in. Crossing over (recombination) occurs between homologous chromosomes. Homologous pairs of chromosomes come together to form tetrads. Homologous pairs of chromosomes align at the center of the cell. Homologous pairs separate and pairs of sister chromatids move toward the poles. Sister chromatids align at the center of the cell. Sister chromatids attach to the spindle, connecting the sisters to opposite poles of the cell. Sister chromatids separate and move toward the poles.

Answer 1

Ans meosis produced haploid cells in both plants and animals . So ploidy of cells is haploid or n. Haploid cells contain only half set of chromosomes from teh parent .

The cells produced by meosis in animals are gametes the sperm and egg cell.

In plants the cells produced are spores .

Crossing over between homologous chromosomes occur in Prophase 1 of meosis 1.

Homologous chromosomes come together to form tetrads in pahchytene phase of prophase 1.

Homologous chromosomes align at the centre of cell in metaphase 1.

Sister chromatids align at centre of cell in metaphase ll.

Sister chromatids attach to spindle connecting the sisters to opposite poles of the cell metaphase ll

Sister chrimatids separate and move towards the pole in anaphase ll

Meosis 1 and 2.

Meosis 1 contains

Prophase 1 has 4 stages leptotene,pachytene zygotene and diplotene.

Leptotene- chromosomes condense and become gradually visible under microscipe .

Zygotene - chromosomes start pairing uo called synapsis . Associated with formation of synaptonemal complex .

Pachytene - complex formed by homologous chromosomes called bivalent or tetrad .in thsi stage recombination nodules appear and crossing over ocurs between two homologous chromosomes.

Diplotene - tetrads separate from each other except at site of crosaovers .

Metaphase l - homologous chromosomes align on the metaphase plate at the centre if the cell. Microtubules from opposite poles attach to homologous chromosomes.

Anaphase l separation of homologous chromosomes but sister chrimatids remain attached at centromere.

Telophase 1 nucleus and membeane reappaers cytokinesis occurs and forms diad of cells.

Meosis 2

Prophase 2 nuclera membrane disapperas and the chromosomal material condense .

Metaphase 2 chromosomes align at centre of cell and microtubules from opposite poles of spindles attach to kinetochores .

Anaphase 2 centromeres of each chromosome splits causing them to move to opposite poles .

Telophase 2- nucleus and membrane reforms,cytokinesis follows and tetrad if cells is formed..