[Biology Class Notes] on Difference Between Gene and DNA Pdf

Genes are units of heredity transferred from one generation to the next generation and are held to determine some characteristics of the offspring. The Word “ gene” was coined by Danish botanist Wilhelm Johnson in 1909. Gregor Mendel discovered that genes come in pairs and are inherited as distinct units. Genes are found on tiny structures called Chromosomes. Chromosomes are found inside the cells of our body. There is an important role of genes in determining physical traits. Information is carried by genes like whether a person has curly hairs or straight hairs, short legs or long legs. Most of these things are passed on from parents to their offspring.

Working of Genes

Chromosomes are found in matching pairs or sets of two. There are hundreds or sometimes thousands of genes in just one chromosome. The chromosomes and genes are made up of DNA (deoxyribonucleic acid). Specific instructions are spelt out by DNA. DNA is just a cookbook recipe for the synthesis of proteins in the cells.  Most of the things in our body are made up of proteins such as bones, teeth, hairs, earlobes, blood, muscles. Hence, they are considered as building blocks of the body. Proteins are essential for our body to work properly, the growth of our body, and to stay healthy. It is estimated by scientists that each gene makes as many as 10 different proteins in the body. It goes up to 300,000 proteins. The working of a gene can be explained with an example – Neera’s mother has one gene for brown hair and one for red hair. She passed the brown hair gene to Neera. Neera’s father has two genes for brown hair. Neera ended up with two genes for brown hair, one from each of her parents. 

Gene Expression 

The information encoded in a gene is used in the synthesis of a functional product like protein, and the process is known as Gene expression. While in non-protein-coding genes such as tRNA or small nuclear RNA genes result in the formation of a functional RNA as a product. DNA is transcribed into RNA, and this transcribed RNA is then translated into proteins. This is known as central dogma.

Stages of Gene Expression 

Structural genes are those genes that code for the amino acid sequences.  There are two stages involved in the process of gene expression.

Transcription

It is the process hatch that leads to the production of messenger RNA and the processing of the resulting mRNA molecule by using enzyme RNA polymerase.

Translation

It is the process in which mRNA is used to direct protein synthesis and also for the subsequent post-translational processing of the protein molecule. Other forms of RNA that play a role in transcription can also be produced by some genes. There are a number of components included in structural genes which are mentioned below.

• Exons:  Amino acids are coded by exons and they thoroughly determine the amino acid sequence of the protein product. Exons are the portions of genes that are represented in the final mature mRNA molecule. 

• Introns:  These portions of the genes do not code for amino acids and are spliced (removed) from the mRNA molecule before translation.

What is DNA?

DNA, or deoxyribonucleic acid, is a complicated molecule that includes all of the information needed to construct and sustain an organism. It is a double-helix molecule that carries genetic instructions for all known species and many viruses’ formation, functioning, growth, and reproduction. It is a mixture of two polynucleotides. This polynucleotide coils around itself, forming a double helix. All living organisms’ cells contain DNA. In fact, practically every cell in a multicellular organism contains the whole set of DNAs needed for that organism. The whole set of your DNA is called your genome. There are 3 billion bases, 20,000 genes, and 23 chromosome pairs in it. Nucleotides constitute the DNA molecule. Each nucleotide is composed of three components: a sugar, a phosphate group, and a nitrogen base.

Structure of DNA

The DNA structure may be compared to a twisted ladder, and this structure is known as a double helix. It is a nucleic acid, and nucleotides are the building blocks of all nucleic acids. The DNA molecule is made up of units called nucleotides, and each nucleotide is made up of three separate components: sugar, phosphate groups, and nitrogen bases. The majority of DNA is contained inside a cell’s nucleus, where it creates the chromosomes. Histones are proteins that attach to DNA on chromosomes. DNA is made up of two strands that twist together to form a spiral ladder known as a helix. DNA is composed of four nucleotide building blocks: adenine (A), thymine (T), guanine (G), and cytosine (C).  Hydrogen bonds connect the complementary base pairs of guanine and cytosine, and adenine and thymine, respectively. The two strands of a DNA helix are held together by hydrogen bonds between complementary nucleotides. Each base has the ability to make hydrogen bonds with the outside world, such as water. In addition, the hydrogen bonds formed by each nucleotide’s phosphate groups engage, causing two strands of DNA to create a helical helix. Genes are small strands of DNA that contain distinct genetic information. DNA contains the genetic information required for heredity, as well as for instructions and life processes. Vertical gene transfer transmits the instruction from parent to child.

The backbones of DNA and RNA are made up of phosphodiester links. When two of the hydroxyl groups in phosphoric acid react with hydroxyl groups on other molecules to generate two ester bonds, this is called a phosphodiester bond. This relationship is part of the “bond.” C-O-PO2−-O-C. Although phosphodiesters are most commonly associated with DNA and RNA, they may also be found in other biomolecules, such as acyl carrier proteins. 

Difference Between Genes and DNA

Deoxyribonucleic Acid (DNA) 

• DNA is the genetic material of organisms and it is located in the nucleus and nucleoid.

• The information necessary for development, function, ng, and reproduction is stored in DNA.

• A monomer that contains DNA is the nucleotide which consists of three groups, pentose sugar, a nitrogenous base, and a phosphate group. Phosphate and nitrogenous base are attached to pentose sugar. 

• DNA is stable even in alkaline conditions.

Gene

• Gene is a specific nucleotide sequence.

• Genes help to encode an amino acid sequence of a specific protein.

• Genes are made up of DNA but few may have RNA.

Difference Between
Genes and DNA