Answer to Question #101218 in Cell Biology for Abhishek

Question

(a) Describe the structure and function of nuclear envelope.

(b) Explain the molecular theory of recombination.

Answer 1

STRUCTURE:

The nuclear envelope is known as the nuclear membrane which is made up of two lipid bilayer that is inner and outer nuclear membranes to surrounds the nucleus so that can encase the genetic material. The space between the membranes is called the perinuclear space. It is usually about 20–40 nm wide. The outer nuclear membrane is continuous with the endoplasmic reticulum, nuclear envelope has many nuclear pores that allow materials to move between the cytosol and the nucleus. Intermediate filament protein form a structure called the nuclear lamin on the inner aspect of the inner nuclear membrane and gives structural support to the nucleus.

FUNCTION:

Nuclear envelop separates the contents of the nucleus from the rest of the cell such as from the cell organelles which is found in both animal and plant cells.

The cell performs man building proteins, converting molecules into energy, and removing waste products which is found in both animal and plant cells.

MOLECULAR THEORY OF RECOMBINATION

Recombination is a process by which pieces of DNA are broken and recombined to produce new combinations of alleles. This recombination process creates genetic diversity at the level of genes that reflects differences in the DNA sequences of different organisms.The recombining DNA molecules have homologus sequences. The DNA molecules align or pair with each other and undergo crossing over and homologous recombination. The recombinant DNA has new genetic constitution. Bacteria can acquire DNA of other closely related bacterial species and can become transformed.