Specialization and Stem cells

Why Specialize?? A single celled organism performs all required functions all in one cell. Ex. An Amoeba

Why Specialize?? Multicellular organisms are much more complex. Allocated cells , tissues and organs perform certain bodily functions. Ex. Supply food and nutrients, transport materials, remove waste and fight infections

Specialized Cells The structure matches the function!!

Stem Cell Stem cell: an unspecialized cell Scientists study stem cells to learn more about specialization and differentiation Stem cells can be used to treat injuries and diseases by regenerating organs Stem cells can differentiate into any cell type of a plant or animal such as nerve, blood, or muscle cells of humans Every cell in you body originally came from a small group of stem cells These stem cells specialize when exposed to certain conditions such as hormones or can remain unspecialized and actively dividing for long periods of time

Animal Stem Cells Animal stem cells - two types Embryonic stem cells can differentiate into other cell types http://www.hhmi.org/biointeractive/stemcells/human_emb_dev.html Adult stem cells are mature specialized cells mostly involved in replacement of damaged tissue

Plant Stem Cells Called meristematic cells Found in growing tips of roots and stems Meristematic cells in an onion root tip (magnification 25x)

Regeneration Cell Regeneration: the process of replacing or regrowing a body tissue or organ Salamanders - have unique ability to not only to regrow limbs that have been amputated but also tails, lenses in eyes, and parts of the heart. http://www.dnatube.com/video/504/Newt-Limb-Regeneration Humans - the liver is the only organ that has the ability to naturally regenerate, and in young children, fingertips can also regenerate.

The axoloti is a type of salamander that can regrow amputated limbs Regeneration of a newt’s limb over 6 to 8 weeks. The newt is a type of salamander. The axoloti is a type of salamander that can regrow amputated limbs videos.howstuffworks.com/science-channel/29246-kapow-superhero-science-limb-regeneration-video.htm?sort=most_watched&page=2

Current Research Pig extracellular matrix applied to severed fingertip of human stimulates regrowth http://news.bbc.co.uk/2/hi/health/7354279.stm http://news.bbc.co.uk/2/hi/health/7354458.stm Creation of body parts in the lab – success seen with: Regrown bladder (picture) Blood vessels Heart valves Image from: http://news.nationalgeographic.com/news/2006/04/0404_060404_bladders.html

Specialized Cells and Tissues Its all about team work! Tissue: groups of cells that function together to perform specialized tasks.

Animal Tissues 4 types of specialized tissues: Epithelial Tissue: Lines body cavities and outer surface of body Protects structures Forms glands that produce hormones, enzymes and sweat Connective Tissue: Supports and protects structures Forms blood Stores fat Fills empty space

Animal Tissues Muscle Tissue: Nervous Tissue: Allows for movement Responds to stimuli Transmits and stores information

Plant Tissues 4 types of specialized tissues Epidermal Tissue: Forms the protective outer covering Allows the exchange of materials and gases into and out of the plant through guard cell stomata Vascular Tissue: 2 types of vascular tissue Xylem: moves substances from roots to the leaves Phloem: transports sugars from leaves to other areas

Plant Tissues Ground Tissue: Meristematic Tissue: In the stem: provides strength and support In the roots: stores food and water In the leaves: photosynthesis Meristematic Tissue: Unspecialized tissue capable of dividing by mitosis Found in several locations in the plant Responsible for growing new parts of the plant

Plant Tissues