Biology Questions

Endocrine glands are glands of the endocrine system that secrete their products, hormones, directly into the blood rather than through a duct.

The major glands of the endocrine system include:

pineal gland,

pituitary gland,

pancreas,

ovaries,

testes,

thyroid gland,

parathyroid gland,

hypothalamus and

adrenal glands.

Hemopoiesis begins in the red bone marrow, with hemopoietic stem cells that differentiate into myeloid and lymphoid lineages.

Myeloid stem cells give rise to all the other formed elements, including the erythrocytes; megakaryocytes that produce platelets; and a myeloblast lineage that gives rise to monocytes and three forms of granular leukocytes: neutrophils, eosinophils, and basophils.

There are two kingdoms of bacteria. They are

1. Eubacteria  and 

2. Archaea

The members of these two kingdoms appear similar in shape and appearance, even under the extreme magnification of the electron microscope . However, they are very different from each other in a number of molecular and biochemical aspects. It is these differences that have resulted in the microorganisms being grouped into separate kingdoms.

For example, eubacteria contain the rigid, stress-bearing network known as the peptidoglycan . The only exceptions are the bacteria from the genera Mycoplasma and Chlamydia. Archaebacteria do not contain peptidoglycan. Instead, they contain a different structure that is called pseudomurein.

The common bacteria belongs to Eubacteria kingdom.