What happens to the chromatin and centromeres during prophase I?
During prophase, the nucleus disappears, spindle fibers form, and DNA condenses into chromosomes ( sister chromatids ). During metaphase, the sister chromatids align along the equator of the cell by attaching their centromeres to the spindle fibers.
What happens to the chromatin during prophase 1?
Prophase I: The nuclear envelope breaks down. The chromatin condenses into chromosomes. Homologous chromosomes containing the two chromatids come together to form tetrads, joining at their centromeres (2n 4c). This is when “crossing over” occurs, which creates genetic variation.
What happens during prophase I?
During prophase I, homologous chromosomes pair and form synapses, a step unique to meiosis. The paired chromosomes are called bivalents, and the formation of chiasmata caused by genetic recombination becomes apparent. Chromosomal condensation allows these to be viewed in the microscope.
Why does chromatin condense in prophase?
Chromatin, a substance that contains genetic material such as DNA, is normally found in a loose bundle inside a cell’s nucleus. During the prophase of mitosis, the chromatin in a cell compacts to form condensed chromosomes; this condensation is required in order for the cell to divide properly.
What happens to chromosomes during prophase?
During prophase, the complex of DNA and proteins contained in the nucleus, known as chromatin, condenses. The chromatin coils and becomes increasingly compact, resulting in the formation of visible chromosomes. … The sister chromatids are pairs of identical copies of DNA joined at a point called the centromere.
What are the 5 stages of prophase 1?
Prophase I is divided into five phases: leptotene, zygotene, pachytene, diplotene, and diakinesis.
Are chromosomes now visible during prophase?
In prophase, the nucleolus disappears and chromosomes condense and become visible.
Which type of chromosome is present in the prophase of cell cycle?
prophase – chromosomes condense; each chromosome consists of a pair of identical sister chromatids joined at the centromere.
What major event occurs during prophase?
During prophase, the chromosomes condense and centrosomes move to opposite sides of the nucleus, initiating formation of the mitotic spindle. Breakdown of the nuclear envelope then allows spindle microtubules to attach (more…)