Where are chromosomes present and what are their functions

Chromosomes are thread-like structures of proteins and nucleic acids obtained from the nucleus of living cells. The structure carries genetic details of living systems in the form of genes. A chromosome structure is made out of DNA and proteins organised into one’s genes. The deoxyribonucleic acid or DNA coils around proteins known as histones. Thus, chromosomes assist DNA in replication and distribution during cell division. Although, replication and distribution are primary functions of chromosomes in living organisms. The thread-like structure of chromosomes subdivides into two parts, i.e., the p arm and the q arm. Consequently, the cells containing 23 chromosomes inherit one pair of chromosomes with the mother and one pair with the father. Meaning of Chromosomes • Chromosomes refer to the staining ability of specific dyes, often meant with the coloured body. Theodor Boveri and Walter Sutton defined chromosome structure as information carriers of genes in eukaryotic cells in 1902. • Often the number of chromosomes varies in different living species. For instance, plants and animals have 8-50 chromosomes in somatic cells. Humans have 23 chromosomes in cells of which 22 are autosomes, and 1 is a sex chromosome. Similarly, nematode consists of 2 chromosome cells, and the protozoan consists of 1600 chromosome cells. • Scientists adopt Karyotyping technique to analyse and find abnormalities in the structure of chromosome cells. Structure of Chromosomes • Chromosomes are pres...

Chromosomes are thread-like, systematized structures that are made up of a combination of DNA and protein, found in the nuclei of cells. The chromosomes are wide in variety and vary among different organisms. In humans, each cell contains 23 pairs of chromosomes — one of each pair taken from each parent. Of these 23 pairs, 22 pairs, or 44 chromosomes, are non-sex chromosomes — also known as autosomes, and a single pair makes up a sex chromosome. In females, the sex chromosome is made up of a double X sequence, whereas male sex chromosomes are made up of an XY sequence. This forms the most basic difference between males and females at the cellular level. The DNA present in the chromosome contains most of the genetic information and also controls the hereditary transference. Structure of Chromosomes In prokaryotes, or cells that do not contain a nucleus — like bacteria, the chromosome is generally, circular in structure. In place of a nucleus, prokaryotes contain what is referred to as a nucleoid, which contains the DNA. In eukaryotes, or cells that contain a nucleus, the chromosome is linear in structure. Chromosomes can exist in duplicated, or unduplicated stages. When unduplicated, it appears as a single strand, whereas duplicated chromosomes consist of two strands, which are linked by a centromere. Each of the two strands make up the sister chromatids. Duplicated chromosomes have a typical structure, likened to an asymmetrical version of the letter X, with the two chroma...

23 Chromosomes and Their Functions Chromosomes A chromosome is a nucleoprotein structure that generally appears like a rod-shaped structure during nuclear division. These chromosomes are tightly packed inside the nucleus of a cell and are made of DNA molecules. This DNA is responsible for carrying the hereditary information. Thus chromosomes as a whole play an important role in inheritance. Gene is typically a unit of DNA that is located on the chromosome in a linear fashion. The occurrence of different genes on the same chromosome is called linkage. Furthermore, all genes located physically on a given chromosome are termed a ‘linkage group’. Human Chromosomes In humans, 23 such chromosomes occur in pairs and thus totalling 46 chromosomes. These 23 pairs can be divided into autosomes and allosomes. The first 22 pairs come under autosomes, and the 23rd pair is the allosome or sex chromosome. Also Read: Genetic Mapping Geneticists use ‘map unit’ to measure the distance between linked genes. It is a diagrammatic graphical representation that displays the exact arrangement, location and combination of genes in a linkage group of Genetic mapping is also adopted to construct linkage maps for fungi, Drosophila, maize, garden pea, etc. 23 Chromosomes and Their Functions The major function of chromosomes is to carry the hereditary information from one cell generation to the next. DNA is the only permanent component of the chromosome and is the sole genetic material of eukar...

Overview DNA is in every cell in your body. Chromosomes are found carrying your DNA in the nucleus of your cells. DNA looks like a spiral staircase (double helix). The rungs are base pairs and the rails are sugar and phosphate molecules. What is DNA? Deoxyribonucleic acid (DNA) is the material that exists in every cell in your body that holds your genetic code. It makes up your body’s instruction manual. What is DNA made of? DNA has a language that it uses to write your instruction manual (a code). Four chemical bases make up your DNA language including: • Adenine (A). • Cytosine (C). • Thymine (T). • Guanine (G). These four bases arrange themselves in order to form “words” in your instruction manual. DNA constantly replicates itself by making hand-written copies of your body’s instruction manual using the chunks of bases that form the words. There are an estimated 3 billion bases in a human’s body. About 99% of those bases are the same in every person. The remaining 1% is what makes you unique. What are genes? Genes are the building blocks for your body. Some genes give the instructions to make proteins. A protein’s job is to tell your body what types of physical characteristics you should have, like your hair and eye color. Some genes code for RNA, which does other jobs. How do I get genes? You can’t buy genes from a department store. You inherit your genes from your parents. You receive one copy of a gene from each parent (one from the egg and one from the sperm). Once ...

When a cell divides, one of its main jobs is to make sure that each of the two new cells gets a full, perfect copy of genetic material. Mistakes during copying, or unequal division of the genetic material between cells, can lead to cells that are unhealthy or dysfunctional (and may lead to diseases such as cancer). Physically speaking, DNA is a long string of paired chemical units (nucleotides) that come in four different types, abbreviated A, T, C, and G, and it carries information organized into units called genes. Genes typically provide instructions for making proteins, which give cells and organisms their functional characteristics. In eukaryotes such as plants and animals, the majority of DNA is found in the nucleus and is called nuclear DNA. Mitochondria, organelles that harvest energy for the cell, contain their own mitochondrial DNA, and chloroplasts, organelles that carry out photosynthesis in plant cells, also have chloroplast DNA. The amounts of DNA found in mitochondria and chloroplasts are much smaller than the amount found in the nucleus. In bacteria, most of the DNA is found in a central region of the cell called the nucleoid, which functions similarly to a nucleus but is not surrounded by a membrane. A cell’s set of DNA is called its genome. Since all of the cells in an organism (with a few exceptions) contain the same DNA, you can also say that an organism has its own genome, and since the members of a species typically have similar genomes, you can also ...

chromosome number, precise number of An organism with any multiple of the diploid number of chromosomes is said to be polyploid. Solanum tuberosum), the African clawed Xenopus laevis), and the plains viscacha rat ( Tympanoctomys barrerae; also called red vizcacha rat). In most animals, however, any change from the typical chromosome number for a species may be accompanied by changes—sometimes drastic—in the organism. For instance, in humans,

23 Chromosomes and Their Functions Chromosomes A chromosome is a nucleoprotein structure that generally appears like a rod-shaped structure during nuclear division. These chromosomes are tightly packed inside the nucleus of a cell and are made of DNA molecules. This DNA is responsible for carrying the hereditary information. Thus chromosomes as a whole play an important role in inheritance. Gene is typically a unit of DNA that is located on the chromosome in a linear fashion. The occurrence of different genes on the same chromosome is called linkage. Furthermore, all genes located physically on a given chromosome are termed a ‘linkage group’. Human Chromosomes In humans, 23 such chromosomes occur in pairs and thus totalling 46 chromosomes. These 23 pairs can be divided into autosomes and allosomes. The first 22 pairs come under autosomes, and the 23rd pair is the allosome or sex chromosome. Also Read: Genetic Mapping Geneticists use ‘map unit’ to measure the distance between linked genes. It is a diagrammatic graphical representation that displays the exact arrangement, location and combination of genes in a linkage group of Genetic mapping is also adopted to construct linkage maps for fungi, Drosophila, maize, garden pea, etc. 23 Chromosomes and Their Functions The major function of chromosomes is to carry the hereditary information from one cell generation to the next. DNA is the only permanent component of the chromosome and is the sole genetic material of eukar...

When a cell divides, one of its main jobs is to make sure that each of the two new cells gets a full, perfect copy of genetic material. Mistakes during copying, or unequal division of the genetic material between cells, can lead to cells that are unhealthy or dysfunctional (and may lead to diseases such as cancer). Physically speaking, DNA is a long string of paired chemical units (nucleotides) that come in four different types, abbreviated A, T, C, and G, and it carries information organized into units called genes. Genes typically provide instructions for making proteins, which give cells and organisms their functional characteristics. In eukaryotes such as plants and animals, the majority of DNA is found in the nucleus and is called nuclear DNA. Mitochondria, organelles that harvest energy for the cell, contain their own mitochondrial DNA, and chloroplasts, organelles that carry out photosynthesis in plant cells, also have chloroplast DNA. The amounts of DNA found in mitochondria and chloroplasts are much smaller than the amount found in the nucleus. In bacteria, most of the DNA is found in a central region of the cell called the nucleoid, which functions similarly to a nucleus but is not surrounded by a membrane. A cell’s set of DNA is called its genome. Since all of the cells in an organism (with a few exceptions) contain the same DNA, you can also say that an organism has its own genome, and since the members of a species typically have similar genomes, you can also ...

Overview DNA is in every cell in your body. Chromosomes are found carrying your DNA in the nucleus of your cells. DNA looks like a spiral staircase (double helix). The rungs are base pairs and the rails are sugar and phosphate molecules. What is DNA? Deoxyribonucleic acid (DNA) is the material that exists in every cell in your body that holds your genetic code. It makes up your body’s instruction manual. What is DNA made of? DNA has a language that it uses to write your instruction manual (a code). Four chemical bases make up your DNA language including: • Adenine (A). • Cytosine (C). • Thymine (T). • Guanine (G). These four bases arrange themselves in order to form “words” in your instruction manual. DNA constantly replicates itself by making hand-written copies of your body’s instruction manual using the chunks of bases that form the words. There are an estimated 3 billion bases in a human’s body. About 99% of those bases are the same in every person. The remaining 1% is what makes you unique. What are genes? Genes are the building blocks for your body. Some genes give the instructions to make proteins. A protein’s job is to tell your body what types of physical characteristics you should have, like your hair and eye color. Some genes code for RNA, which does other jobs. How do I get genes? You can’t buy genes from a department store. You inherit your genes from your parents. You receive one copy of a gene from each parent (one from the egg and one from the sperm). Once ...

chromosome number, precise number of An organism with any multiple of the diploid number of chromosomes is said to be polyploid. Solanum tuberosum), the African clawed Xenopus laevis), and the plains viscacha rat ( Tympanoctomys barrerae; also called red vizcacha rat). In most animals, however, any change from the typical chromosome number for a species may be accompanied by changes—sometimes drastic—in the organism. For instance, in humans,