chromosomes deeply detail
Answers
Answered by
0
A chromosome is a deoxyribonucleic acid (DNA) molecule with part or all of the genetic material (genome) of an organism. Most eukaryotic chromosomes include packaging proteins which, aided by chaperone proteins, bind to and condense the DNA molecule to prevent it from becoming an unmanageable tangle.
Chromosomes are normally visible under a light microscope only when the cell is undergoing the metaphase of cell division(where all chromosomes are aligned in the center of the cell in their condensed form).[3]Before this happens, every chromosome is copied once (S phase), and the copy is joined to the original by a centromere, resulting either in an X-shaped structure (pictured to the right) if the centromere is located in the middle of the chromosome or a two-arm structure if the centromere is located near one of the ends. The original chromosome and the copy are now called sister chromatids. During metaphase the X-shape structure is called a metaphase chromosome. In this highly condensed form chromosomes are easiest to distinguish and study.In animal cells, chromosomes reach their highest compaction level in anaphase during chromosome segregation.
Chromosomes are normally visible under a light microscope only when the cell is undergoing the metaphase of cell division(where all chromosomes are aligned in the center of the cell in their condensed form).[3]Before this happens, every chromosome is copied once (S phase), and the copy is joined to the original by a centromere, resulting either in an X-shaped structure (pictured to the right) if the centromere is located in the middle of the chromosome or a two-arm structure if the centromere is located near one of the ends. The original chromosome and the copy are now called sister chromatids. During metaphase the X-shape structure is called a metaphase chromosome. In this highly condensed form chromosomes are easiest to distinguish and study.In animal cells, chromosomes reach their highest compaction level in anaphase during chromosome segregation.
Attachments:
Answered by
1
In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.
Chromosomes are not visible in the cell’s nucleus—not even under a microscope—when the cell is not dividing. However, the DNA that makes up chromosomes becomes more tightly packed during cell division and is then visible under a microscope. Most of what researchers know about chromosomes was learned by observing chromosomes during cell division.
Each chromosome has a constriction point called the centromere, which divides the chromosome into two sections, or “arms.” The short arm of the chromosome is labeled the “p arm.” The long arm of the chromosome is labeled the “q arm.” The location of the centromere on each chromosome gives the chromosome its characteristic shape, and can be used to help describe the location of specific genes.
The parts of a chromosome are the Centromere, the Kinetochores, the Telomeres and a pair of sister Chromatids. The chromatids are each divided into a "p" arm and a "q" arm. (The p arm is the shorter one).
The centromere is the part that connects the two chromatids together in an X shape. The telomeres are the materials that hold the ends of each arm together. The chromatids are a molecule of DNA wrapped tightly around histones.
A Kinetochore attaches to microtubules for separation of the sister chromatids by the mitotic spindle during the anaphase part of cell division.
Structure and Function of the Centromere
Centromeres consist of a complex combination of proteins and DNA. They are essential to the division of cells and ensure the accurate segregation of chromosomes. Studies have demonstrated that chromosomes without centromeres segregate randomly and are eventually lost from cells. In contrast, chromosomes that have multiple centromeres can be subject to fragmentation.
Metacentric Chromosomes
Metacentric chromosomes have the centromere in the center, such that both sections are of equal length. Human chromosome 1 and 3 are metacentric.
Submetacentric Chromosomes
Submetacentric chromosomes have the centromere slightly offset from the center leading to a slight asymmetry in the length of the two sections. Human chromosomes 4 through 12 are submetacentric.
Acrocentric Chromosomes
Acrocentric chromosomes have a centromere which is severely offset from the center leading to one very long and one very short section. Human chromosomes 13,15, 21, and 22 are acrocentric.
Telocentric Chromosomes
Telocentric chromosomes have the centromere at the very end of the chromosome. Humans do not possess telocentric chromosomes but they are found in other species such as mice.
Chromosomes are not visible in the cell’s nucleus—not even under a microscope—when the cell is not dividing. However, the DNA that makes up chromosomes becomes more tightly packed during cell division and is then visible under a microscope. Most of what researchers know about chromosomes was learned by observing chromosomes during cell division.
Each chromosome has a constriction point called the centromere, which divides the chromosome into two sections, or “arms.” The short arm of the chromosome is labeled the “p arm.” The long arm of the chromosome is labeled the “q arm.” The location of the centromere on each chromosome gives the chromosome its characteristic shape, and can be used to help describe the location of specific genes.
The parts of a chromosome are the Centromere, the Kinetochores, the Telomeres and a pair of sister Chromatids. The chromatids are each divided into a "p" arm and a "q" arm. (The p arm is the shorter one).
The centromere is the part that connects the two chromatids together in an X shape. The telomeres are the materials that hold the ends of each arm together. The chromatids are a molecule of DNA wrapped tightly around histones.
A Kinetochore attaches to microtubules for separation of the sister chromatids by the mitotic spindle during the anaphase part of cell division.
Structure and Function of the Centromere
Centromeres consist of a complex combination of proteins and DNA. They are essential to the division of cells and ensure the accurate segregation of chromosomes. Studies have demonstrated that chromosomes without centromeres segregate randomly and are eventually lost from cells. In contrast, chromosomes that have multiple centromeres can be subject to fragmentation.
Metacentric Chromosomes
Metacentric chromosomes have the centromere in the center, such that both sections are of equal length. Human chromosome 1 and 3 are metacentric.
Submetacentric Chromosomes
Submetacentric chromosomes have the centromere slightly offset from the center leading to a slight asymmetry in the length of the two sections. Human chromosomes 4 through 12 are submetacentric.
Acrocentric Chromosomes
Acrocentric chromosomes have a centromere which is severely offset from the center leading to one very long and one very short section. Human chromosomes 13,15, 21, and 22 are acrocentric.
Telocentric Chromosomes
Telocentric chromosomes have the centromere at the very end of the chromosome. Humans do not possess telocentric chromosomes but they are found in other species such as mice.
Similar questions