what are chromosomes made of ? [Must read this]

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if your question is what are chromosomes made of ?Chromosomes are thread-like structures within which deoxyribonucleic acid is tightly prepackaged among the nucleus. deoxyribonucleic acid is rolled around proteins known as histones, which give the structural support. Chromosomes facilitate make sure that deoxyribonucleic acid is replicated and distributed suitably throughout biological process. every body incorporates a bodily structure, that divides the body into 2 sections – the p (short) arm and also the alphabetic character (long) arm. The bodily structure is found at the cell’s constriction purpose, which can or might not be the middle of the body.


Source: National Human Genome Research Institute

At the tip of every body may be a repetitive ester sequence cap known as a end. In vertebrates, the end may be a TTAGGG sequence continual to just about fifteen,000 base pairs. These deoxyribonucleic acid regions serve a important role of conserving the genomic sequence by protective the ordination from degradation, and inhibiting body fusion and recombination. These regions also are concerned in body organization among the nucleus.

In humans, forty six chromosomes ar organized in twenty three pairs, as well as twenty two pairs of chromosomes known as autosomes. Autosomes ar labeled 1-22 for reference. every body try consists of 1 body hereditary from the mother and one from the daddy.

In addition to the twenty two numbered autosomes, humans even have one try of sex chromosomes known as associate allosome. rather than labeling these body pairs with numbers, allosomes ar labeled with letters like XX and XY. Females have 2 copies of the sex chromosome (one hereditary from the mother and one from the father). Males have one copy of the sex chromosome (inherited from the mother) and one copy of the Y chromosome (inherited from the father).

Arranged on the chromosomes ar genes. Genes ar fabricated from deoxyribonucleic acid and contain the directions for building proteins and ar integral in creating and maintaining the shape.

Locating a sequence

The genetics location, a uniform means of describing a gene’s location on the body, consists of a mix of numbers and letters and is created from 3 components:

Number or letter of the body (1-23, X or Y)

Arm of the body (p or q)

Position of the sequence on the arm (cytogenetic bands). The position relies on the sunshine and dark bands that seem on the body once stained and is expressed as a two-digit range (one digit represents region and one represents band). typically the digits ar followed by a mathematical notation and one or additional digits. These extra digits represent the space from the bodily structure (increasing numeric worth indicates farther distance from centromere). “Cen”, “ter”, and “tel” also are wont to describe the position of the sequence on the arm.

Cen – getting ready to the bodily structure
Ter (terminus) – getting ready to finish of either the p or alphabetic character arms
Tel (telomere) – getting ready to finish of either the p or alphabetic character arms

Gene: dysplasia cancer enzyme receptor
Chromosomal location: 2p23
Location description: body two, p arm, position twenty three

Chromosome vs. molecular locations

Chromosome location, or genetics location, is a technique to explain the situation of sequence on a body. in our own way to spot the situation of a sequence is by exploitation the molecular location. The sequencing of the bottom pairs describes the molecular location of the sequence on a body. The molecular location is additional precise; but, tiny variations within the address might occur between analysis teams as a results of varied ordination sequencing ways.

For example, in humans, the body location of the EGFR sequence is 7p12, whereas the molecular location is body seven, NC_000007.14 (base pairs fifty five,019,032 to 55,207,338).

Mitosis vs. meiosis

Cells divide through 2 processes: cell division and meiosis. In each processes, diploid cells (containing 2 sets of chromosomes, or forty six chromosomes) divide. In mitosis, the diploid “parent” cell divides and produces 2 diploid “daughter” cells. However, in meiosis, the parent cell produces four haploid girl cells (each containing 1/2 the parent cells chromosomes, or twenty three chromosomes).

The important distinction between cell division and meiosis is that cell division produces 2 genetically identical girl cells, whereas meiosis produces four genetically totally different girl cells.

The phases of biological process are similar for each cell division and meiosis, and each processes end in organic process (cytoplasmic division of the girl cells). However, in meiosis, the cycle happens doubly (meiosis I and meiosis II) before the four haploid girl cells ar made.

Another distinction between the stages of cell division and meiosis is that in meiosis, homologous chromosomes try up throughout metaphase rather than chromatids. in an exceedingly homologous try, one body comes from the mother, and one body comes from the daddy. Homologous chromosomes ar terribly similar, however they’re not identical. They carry a similar genes (eg, hair or eye color), however they will not code for a similar attribute (eg, blonde hair or brown eyes).

Stages of biological process

Interphase – Replication of deoxyribonucleic acid. Most of a cell’s time is spent in interphase. happens before biological process. Consists of 3 stages: Gap one (growth), S part (DNA replication) and Gap two (continues growth, prepares for cell division).

Prophase – Chromosomes condense. Mitotic spindle forms.

Metaphase – Chromosomes line up within the middle of the cell.

Anaphase – Chromatids break free each other and ar pull toward opposite sides of the cell.

Telophase – Division of the cell contents into 2 new cells happens (cytokinesis).




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