Answer: prophase
Chromosomes become visible during _____.
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. Most eukaryotic chromosomes include packaging proteins called histones which aided by chaperone proteins bind to and condense the DNA molecule to maintain its integrity. These chromosomes display a complex three-dimensional structure which plays a significant role in transcriptional regulation.
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. Most eukaryotic chromosomes include packaging proteins called histones which aided by chaperone proteins bind to and condense the DNA molecule to maintain its integrity. These chromosomes display a complex three-dimensional structure which plays a significant role in transcriptional regulation. Chromosomes are normally visible under a light microscope only during the metaphase of cell division (where all chromosomes are aligned in the center of the cell in their condensed form). Before this happens each chromosome is duplicated (S phase) and both copies are joined by a centromere resulting either in an X-shaped structure (pictured above) if the centromere is located equatorially or a two-arm structure if the centromere is located distally. The joined copies are now called sister chromatids. During metaphase the X-shaped structure is called a metaphase chromosome which is highly condensed and thus easiest to distinguish and study. In animal cells chromosomes reach their highest compaction level in anaphase during chromosome segregation. Chromosomal recombination during meiosis and subsequent sexual reproduction play a significant role in genetic diversity. If these structures are manipulated incorrectly through processes known as chromosomal instability and translocation the cell may undergo mitotic catastrophe. Usually this will make the cell initiate apoptosis leading to its own death but sometimes mutations in the cell hamper this process and thus cause progression of cancer. Some use the term chromosome in a wider sense to refer to the individualized portions of chromatin in cells either visible or not under light microscopy. Others use the concept in a narrower sense to refer to the individualized portions of chromatin during cell division visible under light microscopy due to high condensation.
The word chromosome ( /ˈkroʊməˌsoʊm -ˌzoʊm/ ) comes from the Greek χρῶμα (chroma “colour”) and σῶμα (soma “body”) describing their strong staining by particular dyes . The term was coined by the German anatomist Heinrich Wilhelm Waldeyer referring to the term chromatin which was introduced by Walther Flemming the discoverer of cell division .
The word chromosome ( /ˈkroʊməˌsoʊm -ˌzoʊm/ ) comes from the Greek χρῶμα (chroma “colour”) and σῶμα (soma “body”) describing their strong staining by particular dyes . The term was coined by the German anatomist Heinrich Wilhelm Waldeyer referring to the term chromatin which was introduced by Walther Flemming the …
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. Most eukaryotic chromosomes include packaging proteins called histones which aided by chaperone proteins bind to and condense the DNA molecule to maintain its integrity. These chromosomes display a complex three-dimensional structure which plays a significant role in transcriptional regulation.
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. Most eukaryotic chromosomes include packaging proteins called histones which aided by chaperone proteins bind to and condense the DNA molecule to maintain its integrity. These chromosomes display a complex three-dimensional structure which plays a significant role in transcriptional regulation. Chromosomes are normally visible under a light microscope only during the metaphase of cell division (where all chromosomes are aligned in the center of the cell in their condensed form). Before this happens each chromosome is duplicated (S phase) and both copies are joined by a centromere resulting either in an X-shaped structure (pictured above) if the centromere is located equatorially or a two-arm structure if the centromere is located distally. The joined copies are now called sister chromatids. During metaphase the X-shaped structure is called a metaphase chromosome which is highly condensed and thus easiest to distinguish and study. In animal cells chromosomes reach their highest compaction level in anaphase during chromosome segregation. Chromosomal recombination during meiosis and subsequent sexual reproduction play a significant role in genetic diversity. If these structures are manipulated incorrectly through processes known as chromosomal instability and translocation the cell may undergo mitotic catastrophe. Usually this will make the cell initiate apoptosis leading to its own death but sometimes mutations in the cell hamper this process and thus cause progression of cancer. Some use the term chromosome in a wider sense to refer to the individualized portions of chromatin in cells either visible or not under light microscopy. Others use the concept in a narrower sense to refer to the individualized portions of chromatin during cell division visible under light microscopy due to high condensation.
The word chromosome ( /ˈkroʊməˌsoʊm -ˌzoʊm/ ) comes from the Greek χρῶμα (chroma “colour”) and σῶμα (soma “body”) describing their strong staining by particular dyes . The term was coined by the German anatomist Heinrich Wilhelm Waldeyer referring to the term chromatin which was introduced by Walther Flemming the discoverer of cell division .
The word chromosome ( /ˈkroʊməˌsoʊm -ˌzoʊm/ ) comes from the Greek χρῶμα (chroma “colour”) and σῶμα (soma “body”) describing their strong staining by particular dyes . The term was coined by the German anatomist Heinrich Wilhelm Waldeyer referring to the term chromatin which was introduced by Walther Flemming the …