Slide 1 of 30 Copyright Pearson Prentice Hall 7-4 The Diversity of Cellular Life

Slide 2 of 30 Copyright Pearson Prentice Hall 7-4 The Diversity of Cellular Life The differences among living things arise from the ways in which cells are specialized to perform certain tasks and the ways in which cells associate with one another to form multicellular organisms.

7-4 The Diversity of Cellular Life Slide 3 of 30 Copyright Pearson Prentice Hall Multicellular Organisms Organisms that are made up of many cells are called multicellular. There is a great variety among multicellular organisms.

7-4 The Diversity of Cellular Life Slide 4 of 30 From single cell to me! Cell Differentiation

7-4 The Diversity of Cellular Life Slide 5 of 30 How did that happen? ESSENTIAL QUESTIONS: A pancreas cell, eye cell and nerve cell in your body: Are these cells genetically identical to each other (same # of chromosomes)? Does an eye cell have the gene to make insulin? Why are they different in form and function?

7-4 The Diversity of Cellular Life Slide 6 of 30 What is cell differentiation? Differentiation means that one cell performs a different function and has a specialized form than another cell, depending on where it is in your body.

7-4 The Diversity of Cellular Life Slide 7 of 30 When does cell differentiation occur? Cell differentiation occurs as cells become specialized when an embryo grows and develops. STEM CELLS

7-4 The Diversity of Cellular Life Slide 8 of 30 What are stem cells? Stem cells are unspecialised cells that have the ability to reproduce and differentiate into a diverse range of specialised cells.

7-4 The Diversity of Cellular Life Slide 9 of 30 Types of stem cells Embryonic Adult

7-4 The Diversity of Cellular Life Slide 10 of 30 Embryonic stem cells Embryonic stem cells are derived from an embryo about 4–5 days old (bastocyst). These cells have the ability to differentiate into all of the cell types that make up an organism.

7-4 The Diversity of Cellular Life Slide 11 of 30 Adult (tissue) stem cells Adult or tissue stem cells are found in small numbers in the tissues and organs of adults and children, including the brain, bone marrow, skeletal muscle and skin. These cells give rise to a much more limited range of cell types and will tend to develop into cell types that are closely related to the tissue in which they are found. These cells replenish differentiated cells that need replaced in the tissues in which they are found.

7-4 The Diversity of Cellular Life Slide 12 of 30 Other types of stem cells Stem cells can also be taken from the umbilical cord of new babies. Like adult stem cells, these cells can differentiate into a limited range of specialised cells.

7-4 The Diversity of Cellular Life Slide 13 of 30 Early embryogenesis of the Seastar at the 2-cell and 4-cell stages (top). The cells divide asymmetrically to form the morula (bottom left) and then differentiate into a swimming larva after gastrulation (bottom right).

7-4 The Diversity of Cellular Life Slide 14 of 30 MRI technology has allowed detailed 3D images of mouse and quail development.