2007-01-17 01:21:16 · 5 answers · asked by Zman 1 in Science & Mathematics ➔ Biology
Yes, chromosomes are always present in cells - but what you may be thinking is if they are visible under a normal light microscope. Interphase is the period between cell division, but when metaphase occurs they chromosomes beging to condense, making them visible through microscopes.
2007-01-17 01:29:17 · answer #1 · answered by djessellis 4 · 0⤊ 0⤋
Surely, chromosome is present in the cell all the time. What you need to understand is what happens to the chromosome during interphase. During interphase, cells grow and replicate their chromosomes. Interphase consists of three parts: gap 1 (G1), synthesis (S), and gap 2 (G2).
G1 last from the birth of a new cell to the onset of chromosome replication; for the genetic material, it is a period when the chromosomes are neither duplicating nor dividing.
Synthesis (S) is the time when the cell duplicates its genetic material by synthesizing DNA. During duplication, each chromosome doubles to produce identical sister chromatids that will become visible when the chromosomes condense at the beginning of mitosis. The two sister chromatids remain joined to each other at the centromere.
Gap 2 (G2) is the interval between chromosome duplication and the beginning of mitosis. During this time, the cell may grow; it also synthesizes proteins that are essential to the subsequent steps of mitosis itself.
In addition, during interphase an array of fine microtubules crucial for many interphase processes becomes visible outside the nucleus. The microtubules radiate out into the cytoplasm from a single organizing centre known as the centrosome, usually located near the nuclear envelope.
2007-01-17 02:05:56 · answer #2 · answered by Aldro 2 · 0⤊ 0⤋
Yes. Chromosomes are always present throughout the entire life cyle of a cell. The only time they change at all is when they split to form a new cell or are corrupted/diseased (or exposed to radiation) and dissolve. (I think the stage that they split is Anaphase, so you would have just a centramere with two "legs" or chromatids, but it is still considered a chromosome)
2007-01-17 01:28:46 · answer #3 · answered by Royal R 2 · 0⤊ 0⤋
Yes chromosomes are present at all times.
2007-01-17 01:28:38 · answer #4 · answered by Em 3 · 0⤊ 0⤋
Chromosomes are present at all times unless they are disintegrated.
2007-01-17 01:24:55 · answer #5 · answered by PIPI B 4 · 0⤊ 0⤋