Genetic Material: Genes, DNA, RNA & Chromosomes

sinaumedia Literacy – Genetic material or heredity factors are information possessed by every living cell that can be passed on to their offspring. In a sequence of DNA there are instructions that affect the nature or determine the characteristics of living things (called genes).

Meanwhile, genetic factors are a condition of the body that can occur due to the influence of our previous ancestors who belong to the family lineage. This genetic factor can actually happen to us, for example if there is our family (parents, grandparents, and so on) who have diabetes, then we are most likely to get diabetes too.

In general, all of the genetic information that determines the characteristics of living things is stored in DNA which is located in the cell nucleus. DNA becomes a fairly long strand. In order to assemble inside the cell’s tiny nucleus, DNA strands are wrapped around proteins called histone proteins.

In studying genetic information there is a branch of biology known as Genetics. The book entitled Genetics by Ramadhani Chaniago ,  Agus Hery Susanto ,  Desak Made Citrawathi & Sanusi Mulyadiharja discusses genes, DNA and chromosomes.

With histone proteins, the DNA coils form chromatin threads. When a cell divides, these chromatin threads form chromosomes. The genetic material itself consists of chromosomes, genes, DNA, and RNA. Check out the full discussion below, Sinaumed’s.


Genes are the smallest units of genetic material that control the heredity of organisms. Genes consist of DNA spun by histone proteins and arranged in a linear and orderly sequence at loci on chromosomes.

Each chromosome has hundreds of loci, so that in a cell, there are thousands of genes.

For example, it is estimated that there are 26,000 to 40,000 genes in the human body with 46 chromosomes. This also causes one individual to have thousands of traits. There are three kinds of components that make up a gene, namely cistrons (components consisting of hundreds of nucleotides), rekons (components that are smaller than a gene and consist of one or two pairs of nucleotides), mutons (components that are larger than rekons and consist of one or two nucleotides). nucleotide pairs). There are two things that determine the types of genes, namely their nature and role.

Regulatory genes that regulate structural gene expression. In eukaryotic cells, the gene consists of a transcription initiation regulatory domain, which consists of the GCCACACCC series, ATGCAAAT, GC box, CCAAT box and TATA box, then Introns, Exons, (Protein codification areas that can be transcribed overlapping or nonoverlapping. For example , in a code with three nucleotide sequences (triplet codons) AUU GCU CAG, it can be read nonoverlapping as AUU GCU CAG or overlapping as AUU UUG UGC GCU CUC CAG.

Although around 1961 it was known that amino acids are coded by codons in a nonoverlapping manner, it has been found that different proteins are transcribed by shifting overlapping codons.

In studying the genes that make up us, life, character, and one’s destiny, Sinaumed’s can read the book Genes from Siddhartha Mukherjee which discusses this matter.

Gene Expression

Gene expression is the process by which information codes contained in genes are converted into proteins that operate only within the cell.

Gene expression consists of two stages, namely:

  1. Transcription, the process of making an RN copy
  2. Translation, the process of synthesizing a specific polypeptide in the ribosome.

The process of transcription of DNA into mRNA and translation of mRNA into a polypeptide is called the central dogma. The central dogma applies to both prokaryotes and eukaryotes. However, in eukaryotes there is an additional stage that occurs in between transcription and translation which is called the pre-mRNA stage.

The pre-mRNA stage is to select the mRNA to be sent out of the nucleus for translation at the ribosome. Exons are mRNAs that will be sent out of the nucleus for translation, while introns are mRNAs that will remain in the nucleus because it is possible that the mRNA will form a protein that is not functional (useless) when translated.

The introns will then break down again to form new mRNA chains. Also know that some mistakes called mutations can occur in this process of gene expression.

Gene Scope

The concept of genetics developed from the science that discusses how traits are passed on to a wider scope, namely the study of genetic material. Broadly speaking, genetics discusses:

  • The structure of the genetic material, including genes, chromosomes, DNA, RNA, plasmids, episomes, and transposable elements.
  • Reproduction of genetic material, including cell reproduction, DNA replication, and others.
  • Genetic material work, covering the scope of genetic material, transcription, genetic code and others.
  • Changes in genetic material, including mutations and recombination
  • Genetics in populations
  • Genetic material engineering


Chromosomes are fine objects like threads that easily absorb color and function as hereditary carriers. In a diploid cell, the chromosomes appear in pairs. A pair of chromosomes is called a homologous chromosome, which is a chromosome that has the same shape, size and gene sequence.

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While the chromosomes that are not their partner are called nonhomologous chromosomes. Each chromosome has parts such as the centromere, chromosome arms, matrix, chromonema, chromomeres, telomeres, and satellites. Based on the location of the centromere, there are four types of chromosomes, namely: metacentric type, submetacentric type, acrocentric type, telocentric type. The following is a picture of the chromosome and its parts. Chromosome Heredity – Capture1 Well, Quipperian, in humans, the number of chromosomes in a diploid cell is 46 pieces or 23 pairs.

The chromosomes consist of 44 pieces or 22 pairs of body chromosomes (autosomes) and a pair of sex chromosomes (gonosomes), namely XX in females and XY in males. In haploid cells such as egg cells or sperm cells, there are 23 chromosomes consisting of 22 autosomes and a gonosome. Egg cells have 22 autosomes and 1 X, while sperm have 22 autosomes and 1 X or 1 Y.

Chromosome functions include as a place to store genetic information that will be passed from parent to child to form the characteristics and characteristics of that individual. Plays an important role in the process of cell division.

Determines the sex of an individual. The structure of the Chromosome Section includes:

  • Centromere The central part of a chromosome which is usually round in shape. At the centromere there is a kinetochore which has an important function during cell division. It is at this point that the spindle threads attach to each of the opposite poles.
  • Chromatids are one of the two arms of the replicated chromosome. On the chromosome arm there is a chromonema, which is a spiral-shaped band. On chromonema you can see thickening in the form of beads called chromomeres. Usually chromeres are difficult to observe, but they can be seen clearly in chromosomes that have done a lot of replication. Kromonema is covered by a special substance called matrix. Chromatids are attached to each other at the centromere.
  • Telomeres are the term used to denote the ends of chromosomes. Telomeres function to keep DNA at the ends unraveled and prevent one arm from meeting with the other chromosome arm. Telomeres also function to protect chromosomes from environmental threats.
  • Chromomeres are bead-shaped structures that are accumulations of chromatin material that are sometimes seen during interphase. Chromomeres are very clearly visible on polytene chromosomes (chromosomes with DNA that has been replicated many times without separation and are located side by side until the chromosomes form like wires).
  • Satellites are part of the chromosomes that are circular in shape and are located at the ends of the chromatid arms. Satellites are formed due to secondary constriction in that area.

Chromosome Arrangement

Chromosomes in prokaryotic organisms are in the form of RNA only. This can be found in the mosaic virus (tobacco). Chromosomes can also be just DNA, for example in the T virus, and can also contain both DNA and RNA, as in the Escherichia coli bacteria.

Chromosomes contain structures consisting of thin, coiled threads. Along these threads are regularly located structures called genes. Each gene occupies a specific place in the chromosome. The location of a gene on a chromosome is called a gene locus. So it is this gene that actually functions to regulate the traits that will be passed on from parents to offspring. In addition, genes also regulate the development and metabolism of individuals. Genes are made up of DNA (Nucleic acid).

A number of genes lined up on each chromosome have a special job. There are genes that regulate flower color, hair height, nose shape, hair type, hair color, blood type, coat color and so on. The number of chromosomes in each organism is different in different types of organisms. The size of the chromosomes also varies greatly from one type of organism to another.

In every cell of the body, chromosomes are in pairs. Paired chromosomes that have the same shape, size and composition are called homologous chromosomes. Each pair of homologous chromosomes is different from other pairs of homologous chromosomes. The chromosomes of body cells are in pairs (allelic) so that the body’s chromosomes consist of two sets. The two sets of chromosomes in the body cell are diploid (2n). In sex cells (gametes) there are no pairs or only one set of chromosomes. One set of chromosomes in sex cells is haploid (n).

Chromosome Building Materials

The building blocks of chromosomes are chromatin threads which consist of DNA (deoxyribonucleic acid), RNA as a result of transcription and protein (histones or acids and non-histones or bases). Each chromatid carries a DNA molecule whose structure is in the form of a double strand so that in both chromatids there are two DNA molecules.

In humans, it includes at least 7 proteins making up the chromosomes, while other proteins do not get a place in the chromosomes. One of the proteins, CENP-A, Chromosomes in eukaryotic organisms are composed of the following parts: DNA-DNA makes up about 35% of the total number of chromosomes. RNA RNA makes up about 5% of the chromosomes.

Protein This protein consists of histones which are basic and nonhistones which are acidic. These two types of proteins function to roll up the chromosome threads so that they become faded and act as DNA doubling enzymes and DNA copying.

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DNA or deoxyribonucleic acid is a nucleic acid which is a constituent of genes in the cell nucleus. DNA stores all the biological information of every living thing and some viruses. DNA consists of two polynucleotide chains arranged in a double helix. Each nucleotide consists of three components, namely a phosphate, deoxyribose sugar, and a nitrogenous base.

There are two kinds of nitrogenous bases that make up DNA, namely purine bases consisting of adenine (A) and guanine (G) bases and pyrimidine bases consisting of thymine (T) and cytosine (S) bases. Well, these two DNA chains are bonded to each other on the nitrogenous bases connected by hydrogen bonds. Nitrogen base A binds to T, while G binds to S. Between A and T are connected by 2 hydrogen bonds, while between G and S are connected by 3 hydrogen bonds. Functions of DNA include:

  • DNA Serves as a Carrier of Genetic Information The unique nature of DNA material makes researchers interested in learning more about DNA. The results of DNA can be used to help identify a murder case, even the death of someone whose identity is unknown. DNA also helps law enforcement work, because it can identify or find out information about who is the perpetrator or who is the victim through a DNA test.
  • Plays a Role in Self-Duplication and Inheritance DNA is bundled into 46 chromosomes. Humans have 23 each derived from male and female germ cells. This can happen through a complex process. To be clear, germ cells, spermatozoa from males and eggs or ova from females each supply half of your DNA. This is what makes DNA play a role in self-duplication and inheritance.
  • Expression of Genetic Information DNA is the basis of life. It is a complex molecule made up of four types of bases, cross-connected like a ladder, and twisted into a spiral. All four proteins are each connected to one another. And the order of all the pairs forms the genes that define who you are as well as all other organisms on earth. DNA also contains all the genetic coding used to control the function, behavior and development of an organism.
  • Functions of DNA for Forensics Forensic scientists can use DNA found in blood, sperm, skin, saliva, and hair left at crime scenes to identify possible suspects. This identification is usually called genetic fingerprinting or DNA profiling.
  • Functions of DNA in Computing DNA has an important role in computer science, for research and also as an example of a form of computational method. For example, database theory. Database theory was also influenced by DNA research, which had the particular problem of storing and manipulating DNA sequences. The database devoted to DNA research is the genomic database.


RNA nitrogenous bases consist of purine bases, namely adenine (A) and guanine (G) and pyrimidine bases, namely uracil (U) and cytosine (S). The four nitrogenous bases will form pairs A – U and G – S. Adenine and uracil are connected by 2 hydrogen bonds, while guanine and cytosine are connected by 3 hydrogen bonds. RNA can be divided into two types, namely genetic RNA and nongenetic RNA. Genetic RNA is RNA that plays a role in inheritance. This RNA is only found in RNA viruses. Nongenetic RNA is RNA that plays a role in protein synthesis. Well, RNA is divided into three kinds, namely mRNA, tRNA, and rRNA. What’s the difference?

Kinds of RNA


mRNA is a single and long chain RNA formed by DNA through the process of transcription in the cell nucleus. The nitrogenous bases along the mRNA chain constitute the genetic code called codons. mRNA functions as a carrier of the genetic code (codons) from the cell nucleus to the cytoplasm.


tRNA is a short, single-stranded RNA formed by DNA in the cell nucleus and transported to the cytoplasm. tRNA functions as a codon translator. The trick is to carry amino acids from the cytoplasm to the ribosome and attach these amino acids according to the codon sequence on the mRNA. tRNA has two important attachment ends, namely the end for the attachment of the codon on the mRNA or called the anticodon and the end for the attachment of amino acids.


rRNA is RNA that is contained in ribosomes, but is formed by DNA in the cell nucleus. rRNA functions as a polypeptide assembly machine in protein synthesis that moves in one direction along the mRNA chain.

Thus, the discussion of genetic material that has been discussed above. After reading this article to the end, we hope that Sinaumed’s can understand and add insight into genes, chromosomes, DNA and RNA.