Decidua : pregnant endometrium

Decidua:

Definition : Deciduas means gravid endometrium

Decidua reaction:

 i) cells of the endometrium polyhedral and loaded with glycogen and  lipids

  ii) intercellular spaces are filled with extravasate

  iii) the tissues is edematous

At first it occur at the site of implantation but soon spread throughout the endometrium
 

Parts of deciduas : it is divided into three parts

1.      decidua basalis : parts of decidua deep to the developing embryo which contributes to the development of placenta

2.      decidua capsularis : part of decidua which surround the embryo and it is separated from the uterine cavity

3.      decidua parietalis : rest of the decidua excluding decidua basalis and decidua capsularis

Easy summary of RNA

RNA: the nucleic acid which is found mainly in the nucleolus and ribosome

Composition of RNA : it is formed by single stand nucleotide . Each nucleotide contain pentose suger , phosphate, four nitrogenous bases :  (A), cytosine (C), guanine (G), or uracil  (U). Adenine

There are three types of RNA: 1. mRNA  2. tRNA  3.rRNA

Messenger RNA (mRNA): it transfers genetic information from the nucleus to the ribosomes in the cytoplasm and also acts as a template for the synthesis of polypeptides.

Transfer RNA: transfers activated amino acids from the cytoplasm to messenger RNA.

Ribosomal RNA :  (rRNA) is responsible for the translation of mRNA to protein.

itis the RNA component of the ribosome which is essential for protein synthesis in all living organisms. rRNA is the predominant RNA in most cells, composing around 80% of cellular RNA. Ribosomes are approximately 60% rRNA and 40% protein by weight.

Easy summary of barr body

Barr body 

The condensed, inactive, single X-chromosome , appearing as a densely staining mass, that is found in the nuclei of somatic cells of female mammals. It is named after its discoverer, Murray Barr.

 The number of Barr bodies is thus one less than the number of X-chromosomes. 

The Lyon hypothesis states that in cells with multiple X chromosomes, all but one are inactivated during mammalian embryogenesis 

A genotypical human female has only one Barr body per somatic cell, while a genotypical human male has none.

This happens early in embryonic development at random in mammals  except in marsupials and in some extra-embryonic tissues of some placental mammals, in which the father's X chromosome is always deactivated.

The human abnormalities called Kleinefelter's syndrome and Turner's syndrome both result from an unnatural presence or absence of a Barr body. 

Kleinefelter's syndrome(47XXY genetically male but contain Barr body  and

 Turner's syndrome (45X0 genetically female but contain no Barr body .

Easy summary of Mendel’s law

Mendel’s law:  

Gregor Mendel describes the inheritance of traits passed from one generation to the next.

The mendel‘s law has three parts: 

1.      The Law of Dominance

Mendel's law of dominance states that one gene (dominant gene) is dominant or powerful can mask the expression of other gene (recessive gene).  

Single dominant gene can express the character

Two dose of recessive genes can express the character  

2.      The Law of Segregation

Mendel's second law, the law of segregation, states that two alleles of a gene segregated or separated during formation of gametes.  

So one copy of parent gene  only pass  to their offspring for a particular trait .

 Offspring gets second copy of gene from another parent. 

These  segregation or separation occur during meiosis. 

3.      The Law of Independent Assortment

 During gamete formation alleles of genes located on different chromosomes are assorted or distributed independently. The transmission of one character does not influence the transmission of other character.