abida Archive

MUTATIONS

The changes in the genetic makeup of a cell are Called mutations. The mutations alter the structure of chromosomes. Sometimes, a point mutation occurs in a gamete, or in a cell. This cell gives rise to gametes. Thus the mutation is transmitted to offsprihg

Control of Gene Expression in Eukaryotes

The expression of gene can be controlled at different levels in the eukaryotes Transcriptional Control of Gene Expression The RNA synthesis depends on RNA polymerase enzymes. Numerous proteins called transcription factors help in the action of these enzymes. The RNA polymerase and transcription factor

TRANSLATION

The synthesis of protein at the ribosomes form mRNA is called translation. Role of tr.n:;, in transcription Transfer RNA (tRNA) plays an important role in translation. It reads codes on the mRNA and brings different amino acids. Thus a polypeptide chain is formed. The

GENES IN ACTION

A sequence of bases in DNA that .codes for the synthesis of One polypeptide is called gene. The genes must transmit their information from the nucleus to the cytoplasm. Therefore, protein synthesis occurs in cytoplasm. The synthesis of an RNA molecule from DNA is

DNA Replication in Eukaryotes

Following steps take place in the replication of DNA in Eukaryotes: Origin of replication The replication of a DNA molecule begins at special sites called origins of replication. The eukaryotic DNA contains thousand of such replication origins. A rotein initiates DNA replication. It recognizes

OBJECTIVES OF CHROMOSOME AND GENE LINKAGE

Multiple Choice Questions MCQs Four options are given at the end of each statement. You should encircle one option from them. Which of the followings is linker protein? (a) H1                           (b) H2A,                      (c) I-12B                     (d) H3 Which of the following proteins is absent is

DEFINITIONS AND KEY POINTS OF CHROMOSOME AND GENE LINKAGE

TERMS DEFINITIONS Cell cycle The highly dispersed state of chromosomes is called chromatin. Mitosis The   highly folded form during division of cell              is called Nucleosothe Four types of Histone protein form a core particle called nucleosome. Heterochromatic Heterochromatic        region      are      inactive       portions       of Euchromatic