DNA, RNA, PROTEIN.pptx

DNA, RNA AND PROTEIN (INTRODUCTION, STRUCUTRE AND FUNCTIONS )

1. DNA, RNA AND PROTEINS –INTRODUCTION, STRUCTURE AND FUNCTIONS PRESENTED BY D. JASMINE PRIYA, B.Sc., DCA., M.Sc., PGDCLT. DR. NGP ARTS AND SCIENCE COLLEGE COIMBATORE

2. DNA

3. What is DNA? “DNA is a group of molecules that is responsible for carrying and transmitting the hereditary materials or the genetic instructions from parents to off springs.” Full-Form of DNA DNA is known as Deoxyribonucleic Acid. It is an organic compound that has a unique molecular structure. It is found in all  prokaryotic cells and eukaryotic cells.  Who Discovered DNA? DNA was first recognized and identified by the Swiss biologist,  Johannes Friedrich Miescher  in 1869 during his research on white blood cells. The double helix structure of a DNA molecule was later discovered through the experimental data by James Watson and Francis Crick . Finally, it was proved that DNA is responsible for storing the genetic information in living organisms.

4. DNA STRUCTURE

5. Structure of DNA The DNA molecule is composed of units called nucleotides, and each nucleotide is composed of three different components, such as sugar, phosphate groups and nitrogen bases.  The basic building blocks of DNA are nucleotides, which are composed of a sugar group, a phosphate group, and a nitrogen base.  The sugar and phosphate groups link the nucleotides together to form each strand of DNA. These 4 Nitrogenous bases pair together in the following way: These base pairs are essential for the DNA’s double helix structure, which resembles a twisted ladder. Adenine (A) Thymine (T) Guanine (G) Cytosine (C) are four types of nitrogen bases. A  with  T C  with  G . 

6. Among the three components of DNA structure, sugar is the one which forms the backbone of the DNA molecule. It is also called deoxyribose. The nitrogenous bases of the opposite strands form hydrogen bonds, forming a ladder-like structure. The DNA molecule consists of 4 nitrogen bases, namely adenine (A), thymine (T), cytosine (C) and Guanine (G) which ultimately forms the structure of a nucleotide. The A and G are purines and the C and T are pyrimidines. The two strands of DNA run in opposite directions. These strands are held together by the hydrogen bond that is present between the two complementary bases. The strands are helically twisted, where each strand forms a right-handed coil and ten nucleotides make up a single turn. The pitch of each helix is 3.4 nm. Hence, the distance between two consecutive base pairs (i.e., hydrogen-bonded bases of the opposite strands) is 0.34 nm.

7. DNA Function DNA is the genetic material which car­ries all the hereditary information.  Apart from storing genetic information, DNA is involved in: Replication process: Transferring the genetic information from one cell to its daughters and from one generation to the next and equal distribution of DNA during the cell division Mutations: The changes which occur in the DNA sequences Transcription Cellular Metabolism DNA Fingerprinting Gene Therapy

8. RNA

9. What is RNA ? RNA is a ribonucleic acid that helps in the synthesis of proteins in our body. This nucleic acid is responsible for the production of new cells in the human body. It is usually obtained from the DNA molecule. RNA resembles the same as that of DNA, the only difference being that it has a single strand unlike the DNA which has two strands and it consists of an only single ribose sugar molecule in it. Hence is the name Ribonucleic acid. RNA is also referred to as an enzyme as it helps in the process of chemical reactions in the body.

10. Basic Structure of RNA The basic structure of RNA is shown in the figure below- The ribonucleic acid has all the components same to that of the DNA with only 2 main differences within it. RNA has the same nitrogen bases called the adenine, Guanine, Cytosine as that of the DNA except for the Thymine which is replaced by the uracil. Adenine and uracil are considered as the major building blocks of RNA and both of them form base-pair with the help of 2 hydrogen bonds. RNA resembles a hairpin structure and like the nucleotides in DNA, nucleotides are formed in this ribonucleic material(RNA). Nucleosides are nothing but the phosphate groups which sometimes also helps in the production of nucleotides in the DNA.

11. RNA Types There are various types of RNA, out which most well-known and most commonly studied in the human body are : 1. tRNA – Transfer RNA The transfer RNA is held responsible for choosing the correct protein or the  amino acids  required by the body in-turn helping the ribosomes. It is located at the endpoints of each amino acid. This is also called as soluble RNA and it forms a link between the messenger RNA and the amino acid.

12. 2. rRNA-Ribosomal RNA The rRNA is the component of the ribosome and are located within the in the cytoplasm of a cell, where ribosomes are found. In all living cells, the ribosomal RNA plays a fundamental role in the synthesis and translation of mRNA into proteins. The rRNA is mainly composed of cellular RNA and are the most predominant RNA within the cells of all living beings

13. 3. mRNA – Messenger RNA This type of RNA functions by transferring the genetic material into the ribosomes and pass the instructions about the type of proteins, required by the body cells. Based on the functions, these types of RNA is called the messenger RNA. Therefore, the mRNA plays a vital role in the process of transcription or during the protein synthesis process.

14. Functions of RNA The ribonucleic acid – RNA, which are mainly composed of nucleic acids, are involved in a variety of functions within the cell and are found in all living organisms including bacteria, viruses, plants, and animals. These nucleic acid functions as a structural molecule in  cell organelles  and are also involved in the catalysis of biochemical reactions. The different types of RNA are involved in various cellular process. The primary functions of RNA: Facilitate the translation of DNA into proteins Functions as an adapter molecule in  protein synthesis Serves as a messenger between the DNA and the ribosomes. They are the carrier of genetic information in all living cells Promotes the ribosomes to choose the right amino acid which is required in building up of new proteins in the body.

15. PROTEIN

16. What are proteins? Proteins are made up of many building blocks, known as amino acids. Our body needs dietary  protein  to supply amino acids for the growth and maintenance of our cells and tissues. Our dietary protein requirement changes throughout life. The European Food Safety Authority (EFSA) recommends adults consume at least 0.83 g of protein per kg body weight per day (e.g. 58 g/day for a 70 kg adult). Plant and animal-based proteins vary in their  quality  and  digestibility , but this is not usually a concern for most people if their total protein meets their needs. We should aim to consume protein from a variety of sources that benefits both our health and the planets.

17. What are proteins made of? Proteins are made up of many different amino acids linked together. There are twenty different of these amino acid building blocks commonly found in plants and animals. A typical protein is made up of 300 or more amino acids and the specific number and sequence of amino acids are unique to each protein. Rather like the alphabet, the amino acid 'letters' can be arranged in millions of different ways to create 'words' and an entire protein 'language’. Depending on the number and sequence of amino acids, the resulting protein will fold into a specific shape. Amino acids are classified as either essential or non-essential. As the name suggests, essential amino acids cannot be produced by the body and therefore must come from our diet. Whereas, non-essential amino acids can be produced by the body and therefore do not need to come from the diet.

18. Essential amino acids Non-essential amino acids Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine Alanine Arginine* Asparagine Aspartate Cysteine* Glutamate Glutamine* Glycine* Proline* Serine Taurine* Tyrosine*

19. What do proteins do for the body? Our bodies are made up of thousands of different proteins, each with a specific function. They make up the structural components of our cells and tissues as well as many  enzymes ,  hormones  and the active proteins secreted from  immune cells  . These body proteins are continually being repaired and replaced throughout our lives. This process (known as ‘protein synthesis’) requires a continuous supply of amino acids. Although some amino acids can be recycled from the breakdown of old body proteins, this process is imperfect. This means we must eat dietary protein to keep up with our body’s amino acid demand. As protein is essential for  cell  and tissue growth,  adequate intake  of protein is particularly important during periods of rapid growth or increased demand, such as  childhood, adolescence ,  pregnancy , and breastfeeding.

20. Functions of proteins in the body