book 5 (stem cells)

Question 1

describe the general features of stem cells

Answer 1

1. self-renewal ability - it can divide via mitosis to produce new stem cells
2. undifferentiated and unspecialized - cells do not have any cell-specific structures to carry out specific functions
3. daughter cells have the ability to differentiate by turning on/off expression of specific genes

Question 2

describe the unique features and function of zygotic stem cells

Answer 2

1. totipotent - they are able to differentiate into any cell type to form a whole organism, including the extra-embryonic tissues
2. stem cells are derived from the cells of a morula
3. functions for the development of whole organisms

Question 3

describe the features and function of embryonic stem cells

Answer 3

1. pluripotent - they are able to differentiate into almost any cell type to form any organ or type of cells, except those of the extra-embryonic tissues
2. stem cells are derived from the inner cell mass of the blastocyst
3. functions to give rise to various organs in organisms, or multiple specialized cell types that make up the heart, lung, skin and other tissues in the developing foetus

Question 4

describe the features and function of adult stem cells

Answer 4

1. multipotent - they are able to differentiate into a limited range of cell type to produce only cells of a single lineage
2. derived from the specialized tissues eg myeloid and lymphoid stem cells are derived from the bone marrow
3. it’s function of adult stem cells is to provide growth, tissue repair and tissue maintenance
4. it can also generate a continuous supply or terminally differentiated cells through asymmetric division

Question 5

state the functions of myeloid and lymphoid stem cells

Answer 5

1. myeloid stem cells differentiate into red blood cells, platelets as well as various types of white blood cells - monocytes, neutrophils, basophils
2. lymphoid stem cells differentiate into 3 types of white blood cells - B and T lymphoid and natural killer cells, for the daily replacement of worn out blood cells from normal wear and tear, for fighting infections in diseases and from injuries