AP BIOLOGY

CELL DIVISION

THE CELL CYCLE

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
A cell spends 90% of its time in which stage?
A
Interphase
B
M Phase
C
Cytokinesis
D
S Phase
Explanation: 

Detailed explanation-1: -During interphase, the cell undergoes normal growth processes while also preparing for cell division. It is the longest phase of the cell cycle, cell spends approximately 90% of its time in this phase. In order for a cell to move from interphase into the mitotic phase, many internal and external conditions must be met.

Detailed explanation-2: -A cell spends the longest in Interphase due to the following reasons: Cell growth takes place during this period. DNA synthesis takes place which is in preparation for pre-mitotic division. Replication of chromosomes takes place.

Detailed explanation-3: -Prophase I can occupy 90% or more of the time taken by meiosis. Although it is traditionally called prophase, it actually resembles the G2 phase of a mitotic cell division. The nuclear envelope remains intact and disappears only when the meiotic spindle begins to form, as prophase I gives way to metaphase I.

Detailed explanation-4: -However, mitosis and cytokinesis last only about an hour, so approximately 95% of the cell cycle is spent in interphase-the period between mitoses. During interphase, the chromosomes are decondensed and distributed throughout the nucleus, so the nucleus appears morphologically uniform.

Detailed explanation-5: -In fact, interphase takes up about 90% of a cell’s life. That leaves just 10% for mitosis! Cell before mitosis showing the location of the centrioles, microtubules, nuclear membrane, nucleolus, and DNA (Let’s Talk Science using an image by Aldona via iStockphoto). Interphase has three stages: G1, S and G2.

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