Evolution and Heredity | DNA, Mutation | Chromosomes | Edu d study

Heredity and Evolution bring changes in DNA via genes. Chromosomes consist of DNA that has genes, a certain type of compound, carry codes.  

What component of the cellular nucleus of living being carried hereditary characters?

What do we call the process of transfer of physical and mental characters from one generation to the next?

What is mean Heredity?

DNA ( Deoxyribonucleic Acid ) - Introductions for Life

The nucleus cell carries a set of unique codes for making new cells to build and maintain the body. These instructions are called genes. They are made of a substance called DNA.  chromosomes are made of 46 tiny structures inside the cell nucleus. These are made of tightly coiled strands of DNA that contain all the information the cell needs to make a new and identical to itself. Every time a cell divides by the process of mitosis and meiosis so the body can grow or repair itself. A DNA strand "unzips" down the middle. It rebuilds itself into a new DNA strand, carrying all the same codes.

Introduction of  Major Scientists:

1) Johann Gregor Mendel ( July 22, 1822-Jan. 6, 1884 ): Johann Mendel is a pioneer of modern genetics and is called the "Father of Genetics". He was the first one to say that the characters are transmitted from one generation to the next through genes. A priest, Mendel invented the basic principles of heredity through experiments in his garden of the monastery. His experiments depicted that the inheritance in pea plants follows particular patterns which becomes the basis of modern genetics and leading to the study of heredity. He published his work "Experiments in plant hybridization."

Other important scientists as Hugo de Vries; Walter and Sutton(study the paired chromosomes of grasshopper) and the trio of scientists Ostwald Avery, Mclyn McCarthy, and Colin MacLeod, etc. are leading scientist proved that all living beings have DNA as a genetic material except viruses. Dr. Har Govind Khorana discovered the triplet codons for 20 amino acids. 

20 amino acids are:

1) Glycine 2) Serine 3) Asparagine 3) Histidine 4) Alanine 5) Threonine 6) Glutamic acid 7) Phenylalanine 8) Valine 9) Cysteine 10) Glutamine 11) Tyrosine 12) Leucine 13) Methionine 14) Arginine 15) Tryptophan 16) Isoleucine 17) Aspartic acid 18) Lysine 19) Proline 20) Cystine

What is Mendelism?

It is the epoch-making work of Mendel in which he performed experiments on garden pea in a scientific manner and proposed principles are known as Mendel's Law of Inheritance.

Some of the concepts which are very important to know for understanding Genetics are given below:

Concepts :

1) Heredity:

"Heredity is the transfer of biological characters from one generation to another via genes".

"Heredity is defined as the transmission of characters from one generation to the next."

2) Transcription : 

The construction process of the mRNA molecule uses a DNA molecule resulting transfer of genetic information to the mRNA. This process of RNA synthesis is called transcription.

3) Translation:

The process of forming a protein molecule at a chromosomes site of protein synthesis from information contained in messenger RNA. There are three types of RNA: mRNA, tRNA, rRNA. Each mRNA is made up of thousands of triplet codons. Amino acids are supplied by the tRNA as per the message on mRNA and tRNA has 'anticodon having a complementary sequence to the codon on mRNA is called  Translation. 

4) Translocation:

Transfer of a chromosome's part in a different position especially on a non-homologous chromosome. tRNA brings in the amino acids are bonded together by peptide bonds with the help of rRNA. In this process, the ribosome keeps on moving from one end of mRNA to another end by the distance of one triplet codon called 'translocation'. 

5) Central Dogma:

The genes present in the form of DNA participate in the functioning of the cell with the help of RNA and thereby control the structure and the functioning of the body.  protein synthesis information is stored in the DNA and synthesis of appropriate proteins as per requirement is necessary for the body. these proteins are synthesized by DNA through the RNA and are called Central Dogma.

6) Triplet Codon:

The mRNA formed in the nucleus comes in the cytoplasm with a coded message from DNA which contains the codes for amino acids and the code for each amino acid consists of three nucleotides is called a triplet codon.

7) Mutation:

Any nucleotide of the gene that changes its position that causes minor change is called Mutation. The mutation may cause genetic disorders like sickle cell anemia.

Evolution:

Life exists on the earth and crores of plants and animals with diversity present on the earth. Evolution is the gradual change occurring in living organisms' overall long duration. It is said that formation of new species because of the changes in specific characters of several generations of living organisms as a response to natural selection is called evolution. Evolution is the progressive development of plants and animals from one generation to the next having different structural and functional organizations. We generally accept the theory of "Gradual development of living organisms" in which the first living material is called protoplasm formed in the ocean. With time, unicellular organisms and multicellular organisms were formed. Theories implied that evolution is the everlasting process of changes and to prove it the various proofs are available in the support of the theory in which the following evidence is given: 

1. Morphological evidence:
2. Anatomical evidence:
3. Vestigial organs:
4. Paleontological evidence:
5. Connecting links: 
6. Embryological evidence:

1) Morphological evidence:

There are some similarities in the living organisms like the structure of the mouth, the position of eyes, the structure of nostrils, and ear pinna, and the equally distributed hairs on the body in the case of animals whereas leaf shape, leaf venation, leaf petiole, etc. In the case of plants; and their origin must be the same and have common ancestors as dogs, fox, etc. These are called morphological evidence.