Stem cells and totipotency

Question 1

what are stem cells?

Answer 1

• stem cells are undifferentiated dividing cells that have the ability to divide to form an identical copy of themselves in a process called self renewal
• once cells have matured and specialized they can no longer develop into other cells so in mature mammals, only a few cells are stem cells

Question 2

What are the types of stem cells?

Answer 2

• totipotent stem cells: -found in the early embryo and can differentiate into any type of cell
• pluripotent stem cells: -found in embryos and can differentiate into almost any type of cell
• multi potent stem cells: -found in adults and umbilical cords and can differentiate into a limited number of specialized cells
• found in adult stem cells and umbilical cord stem cells
• unipotent stem cells: -can only differentiate into a single type of of cell
• derived from multi potent stem cells and are made in adult tissue

Question 3

what is specialization?

Answer 3

-the cells of multi cellular organisms are each adapted in different ways to perform a particular role

Question 4

how are genes prevented from expressing themselves?

Answer 4

• preventing transcription

- preventing translation

Question 5

What are induced pluripotent stem cells?

Answer 5

• induced pluripotent cells are produced by unipotent stem cells (normal body cells) which are genetically altered in a lab to make them pluripotent by using transcription factors to switch genes on or off
• they express some genes that are capable of self renewal so they can divide indefinitely
• these can be used to regrow tissues that have been damaged in some way by disease or in accidents

Question 6

What is cell differentiation?

Answer 6

-the process by which each cell develops into a specialized structure suited to the role that it will carry out is known as cell differentiation