The process of makingmRNAfrom DNA is called transcription, and it occurs in the nucleus. ThemRNAdirects the synthesis of proteins, which occurs in the cytoplasm.mRNA formedin the nucleus is transported out of the nucleus and into the cytoplasm where it attaches to the ribosomes.

Messenger RNACarries the Instructions for Making Proteins

mRNA is “messenger” RNA. mRNA is synthesized in the nucleus using the nucleotide sequence of DNA as a template. This process requires nucleotide triphosphates as substrates and is catalyzed by the enzymeRNA polymerase II. The process of making mRNA from DNA is calledtranscription, and it occurs in the nucleus. The mRNA directs the synthesis of proteins, which occurs in the cytoplasm. mRNA formed in the nucleus is transported out of the nucleus and into the cytoplasm where it attaches to theribosomes. Proteins are assembled on the ribosomes using the mRNA nucleotide sequence as a guide. Thus mRNA carries a “message” from the nucleus to the cytoplasm. The message is encoded in the nucleotide sequence of the mRNA, which is complementary to the nucleotide sequence of the DNA that served as a template for synthesizing the mRNA. Making proteins from mRNA is called

the mena formed in nucleus comes in cyytoplasm

The process of makingmRNAfrom DNA is called transcription, and it occurs in the nucleus. ThemRNAdirects the synthesis of proteins, which occurs in the cytoplasm.mRNA formedin the nucleus is transported out of the nucleus and into the cytoplasm where it attaches to the ribosomes

mRNA is synthesized in the nucleus using the nucleotide sequence of DNA as a template. This process requires nucleotide triphosphates as substrates and is catalyzed by the enzyme RNA polymerase II. The process of making mRNA from DNA is called transcription, and it occurs in the nucleus. The mRNA directs the synthesis of proteins, which occurs in the cytoplasm. mRNA formed in the nucleus is transported out of the nucleus and into the cytoplasm where it attaches to the ribosomes. Proteins are assembled on the ribosomes using the mRNA nucleotide sequence as a guide. Thus mRNA carries a “message” from the nucleus to the cytoplasm. The message is encoded in the nucleotide sequence of the mRNA, which is complementary to the nucleotide sequence of the DNA that served as a template for synthesizing the mRNA. Making proteins from mRNA is called translation.

CONTENTS

1DNA, RNA and protein synthesis

2DNA replication

2.1Mistakes in DNA replication

3Transcription

3.1Formation of pre-messenger RNA

3.2RNA splicing

3.3Alternative splicing

3.4Reverse transcription

4Translation

5Transfer RNA

6The Genetic code

6.1An exercise in the use of the genetic code

7The Wobble hypothesis

DNA, RNA AND PROTEIN SYNTHESIS

The genetic material is stored in the form of DNA in most organisms. In humans, the nucleus of each cell contains 3 × 109base pairs of DNA distributed over 23 pairs of chromosomes, and each cell has two copies of the genetic material. This is known collectively as the human genome. The human genome contains around 30 000 genes, each of which codes for one protein.

Large stretches of DNA in the human genome are transcribed but do not code for proteins. These regions are calledintronsand make up around 95% of the genome. The nucleotide sequence of the human genome is now known to a reasonable degree of accuracy but we do not yet understand why so much of it is non-coding. Some of this non-coding DNA controls gene expression but the purpose of much of it is not yet understood. This is a fascinating subject that is certain to advance rapidly over the next few years.

HOW IS MRNA FORMED

mRNA is formed due to translation process occurs in cytoplasm..