Cell Biology and Structure

Stem cells are the cells which can form different cells which can differentiate and perform different functions. The pluripotent stem cells are the cells which can generate all the cells in the body of an organism. The multipotent stem cells are cells which can form more than one type of cell. The totipotent cells are the cells which can differentiate to form all the type of cells in the body as well as the extraembryonic structures like the placenta. 

Stem cells are found in all organisms and are capable of dividing to form new cells which can be differentiated into various types of specialised cells. The progenitor cells have the capability to differentiate into one type of cell. Due to this property, they are also known as unipotent stem cells. The pancreatic progenitor cells can from the cells in the pancreas. 

Autologous adult stem cells can be harvested from both adipose tissue (fat) and bone marrow. Therefore, both A and C are valid sources.

The pericytes are the stem cells which are found in the adult tissues. These cells are generally found in the outer layer of the blood vessels. These cells can be used for transplantation in the individual who suffers from muscular dystrophy. Muscular dystrophy is a genetic disorder which results in weakening and wasting of the muscle tissues. The pericytes are the stem cells which can help in the production of the new muscle tissues.

SCNT stand for somatic cell nuclear transfer. It is a laboratory technique for creating an ovum with a donor nucleus. It can be used in embryonic stem cell research, or in regenerative medicine.

Stem cells are undifferentiated (a), can differentiate into various cell types (b), and can multiply (c). Statement d is false because they can transform into cardiac/nerve cells, and e is false because they are not limited to reproductive progeny.

There are different types of transplantations in which the donor from which the stem cells are received differs. In the case of the syngeneic stem cell transplantation, the stem cells are obtained from the identical twin. There are very fewer chances of graft versus host reaction and rejection in these type of transplantation.

A neuron is a nerve cell that is the basic building block of the nervous system. Neurons are similar to other cells in the human body in a number of ways, but there is one key difference between neurons and other cells. Neurons are specialized to transmit information throughout the body. Nerve cell or neuron possess a cell body with a long, thin hair like axon. A nerve cell can be up to a metre long. 

• An erythrocyte is a cell containing large amounts of hemoglobin and specialized for oxygen transport. In mammals, erythrocytes are round and biconcave in shape. 
• They are devoid of nucleus and other membrane-bound organelles. They derive energy through glycolysis and serve as tiny packets of hemoglobin.

The cell is the structural unit of life with various shapes and size. The size of the cell ranges from 0.5 micrometers to 100 micrometers. Mycoplasma gallicepticum, a parasitic bacterium is thought to be the smallest known organisms with the size from 0.2 to 0.3 micrometer, capable of independent growth and reproduction. Later, the name for mycoplasma was pleuropneumonia-like organisms or PPLO.

The tissues which cover or protect the body are called epithelial tissues. Cells of the epithelial tissues are tightly packed and have a small amount of cementing material in between them. These are small cells covering the organs and cavities of the body.  
Mast cells are a type of cells belonging to areolar connective tissues. It fills the space around the organs. 
Kupffer cells are star-shaped macrophages present in the liver lining. 
Nerve cells possess a cell body and one or many thin fiber-like axons. Some nerve cells possess axons as long as 1 meter and thus, are the largest cell in the human body. It is also known as the longest cell in the human body. Thus, the correct answer is option A.