Category Class 12

Translation

Translation It is the process of protein synthesis by reading the mRNA codons. It occurs in cytoplasm. Ribosomes are the sites for protein synthesis in a cell. Process of Translation Charging of tRNA: Binding of specific amino acid to the tRNA…

Transcription

Transcription Transcription is the process where genetic information from a strand of DNA is copied to form the RNA. The RNA is formed as a complementary strand to the DNA strand. Here during the addition of bases in RNA, adenine…

DNA Replication

DNA Replication DNA replication is a process where two identical copies of DNA are produced from a single DNA molecule. It involves the separation of the two strands of a DNA helix to form two new DNA molecules. Out of…

Hershey-Chase Experiment

Hershey-Chase Experiment Alfred Hershey and Martha Chase (1952) gave proof that DNA is the genetic material. In the experiment, bacteriophages (viruses that infect bacteria) were used. They grew some bacteriophages on a medium that contained radioactive phosphorus and some others on a sulphur-containing radioactive medium. The bacteriophages grown…

Griffith’s experiment

Griffith’s experiment Rough strain of Streptococcus was injected into the mouse. The mouse lived. Smooth strain of Streptococcus was injected into the mouse. The mouse died. When heat-killed smooth strain of Streptococcus was injected into the mouse, the mouse lived. In the last set of experiments,…

Molecular Basis Of Inheritance-Summary

Molecular Basis Of Inheritance – A good summary makes the whole chapter easy. 1 DNA, RNA and Search for Genetic Material The DNA DNA (Deoxyribonucleic acid) is a double-stranded, helical molecule. Its structure was cracked by Watson and Crick based on the X-ray crystallography results provided…

Application of human genome project

Application of human genome project 1. Disorders: More than 1200 genes are responsible for common human cardiovascular diseases, endocrine diseases (like diabetes), neurological disorders (like Alzheimers disease), cancers and many more. 2. Cancers: Efforts are in progress to determine genes that will…

Reverse transcription

Reverse transcription 1. Reverse transcription is the synthesis of DNA from an RNA template. 2. A class of RNA viruses, called retroviruses, are characterized by the presence of an RNA-dependent DNA polymerase (reverse transcriptase). 3. For example, the virus that causes AIDS, is…

Wobble hypothesis

Wobble hypothesis 1. Wobble hypothesis explains the phenomena of multiple codons coding for the code for a single amino acid. 2. According to this theory the base in the first position of the anticodon on tRNA is an abnormal base which…

Enzymes required for DNA replication

Enzymes required for DNA replication 1. DNA Polymerase – Elongates a new DNA strand at a replication fork. Adds nucleotides one by one to the new and growing DNA strand. 2. DNA ligase – Joins sugar-phosphates of Okazaki fragments. Okazaki fragments…

Clover -leaf model of t-RNA

Clover -leaf model of t-RNA 1. The structure of RNA was explained by cloverleaf in the cloverleaf model.2. It helps in providing the anticodon to the m-RNA template.3. They have several loops like aminoacyl binding loop, anticodon loop and ribosomal binding loop…

Nucleosome model

Nucleosome model 1. Woodcock stated that chromatin appears as a chromatin beads.2. These beads like structure were referred to as nucleosome.3. This nucleosome is composed of DNA and histone proteins.4. The central core is made up core histones H2A, H2B, H3,…

Molecular Basis Of Inheritance-Concept

Molecular Basis Of Inheritance – A quick revision tool for the grip on the chapter. 1 Nucleosome model 1. Woodcock stated that chromatin appears as a chromatin beads.2. These beads like structure were referred to as nucleosome.3. This nucleosome is composed…

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