Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Cell growth wikipedia , lookup
Extracellular matrix wikipedia , lookup
Cell culture wikipedia , lookup
Cell encapsulation wikipedia , lookup
Tissue engineering wikipedia , lookup
List of types of proteins wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Stem-cell therapy wikipedia , lookup
5.5 Multicellular Life KEY CONCEPT Cells work together to carry out complex functions. 5.5 Multicellular Life Objectives • Describe the specialization in multicellular organisms. • Identify different types of stem cells. 5.5 Multicellular Life Vocabulary • Tissue – Group of cells that work together to perform a similar function. • Organ – Group of different types of tissues that work together to perform a specific function or related functions. • Organ System – Two or more organs that work in a coordinated way to carry out similar functions. 5.5 Multicellular Life Vocabulary • Cell Differentiation – Processes by which unspecialized cells develop into their mature form and function. • Stem Cell – Cell that can divide for long periods of time while remaining undifferentiated. 5.5 Multicellular Life Multicellular organisms depend on interactions among different cell types. CELL TISSUE leaf stem vascular tissue ORGAN lateral roots primary root root system • Tissues are groups of cells that perform a similar function. • Organs are groups of tissues that perform a specific or related function. • Organ systems are groups of organs that carry out similar functions. shoot system SYSTEMS 5.5 Multicellular Life Specialized cells perform specific functions. • Cells develop into their mature forms through the process of cell differentiation. • Cells differ because different combinations of genes are expressed. • A cell’s location in an embryo helps determine how it will differentiate. Outer: skin cells Middle: bone cells Inner: intestines 5.5 Multicellular Life Stem cells are unique body cells. • Stem cells have the ability to – divide and renew themselves – remain undifferentiated in form – develop into a variety of specialized cell types 5.5 Multicellular Life • Stem cells are classified into three types. – totipotent, or growing into any other cell type – pluripotent, or growing into any cell type but a totipotent cell – multipotent, or growing into cells of a closely related cell family 5.5 Multicellular Life • Stem cells come from adults and embryos. – Adult stem cells can be hard to isolate and grow. – The use of adult stem cells may prevent transplant rejection. – The use of embryonic stem cells raises ethical issues – Embryonic stem cells are pluripotent and can be grown indefinitely in culture. First, an egg is fertilized by a sperm cell in a petri dish. The egg divides, forming an inner cell mass. These cells are then removed and grown with nutrients. Scientists try to control how the cells specialize by adding or removing certain molecules. 5.5 Multicellular Life • The use of stem cells offers many currently realized and potential benefits. – Stem cells are used to treat leukemia and lymphoma. – Stem cells may cure disease or replace damaged organs. – Stem cells may revolutionize the drug development process. 5.5 Multicellular Life Question/Answer • Why is regulation of the differentiation process during the early stages of development so critical? – The early stages of differentiation lead to the development of progressively more specialized tissues and organs. Distribution of cell differentiation in the early stages could cause severe abnormalities in an organism’s body structure. 5.5 Multicellular Life Question/Answer • List treatment benefits and risks of both types of stem cells. – Adult stem cells taken from a patient’s body are less likely to be rejected. However, they can be difficult to isolate and grow, and have limited potential as far as what tissue can develop. Embryonic stem cells can develop into almost any cell type. However, they may be rejected by a patient’s body.