Question

In which phases is the nuclear envelope ABSENT (for part or all of the phase)?

Check all that apply

• Prometaphase
• Metaphase
• Anaphase
• Telophase

Answer 1

The cells of higher eukaryotes usually undergo open mitosis, which is characterized by breakdown of the nuclear envelope.A unique feature of the nucleus is that it disassembles and re-forms each time most cells divide.

At the beginning of mitosis,the chromosomes condense,the the nucleolus disappears, and the nuclear envelope breaks down, resulting in the release of most of the contents of the nucleus into the cytoplasm.At the end of mitosis, the process is reversed causing the reappearance of nuclear membrane

▪During prophase,the chromosomes condense, the nucleolus disappears, and the nuclear envelope breaks down.

▪Prometaphase is the second phase of mitosis, the process that separates the duplicated genetic material carried in the nucleus of a parent cell into two identical daughter cells. During prometaphase, the physical barrier that encloses the nucleus, called the nuclear envelope, breaks down. The breakdown of the nuclear envelope frees the sister chromatids from the nucleus, which is necessary for separating the nuclear material into two cells.

▪Prometaphase is followed by the third phase of mitosis, known as metaphase.
At metaphase, the condensed chromosomes align on the center of the spindle.

▪During anaphase, the daughter chromosomes then move to opposite poles of the spindle.

▪In telophase , the chromosomes decondense and the nuclei re-form.

The nuclear membrane is disassembled during prophase of mitosis.It remains absent through the duration of mitosis until it begins to reassemble during telophase.The nuclear membrane is thus absent during prophase, pro-metaphase metaphase, and telophase.

The nuclear membrane is present and essential during all periods of interphase.