Cell Specialization

What is cell differentiation? Living organisms can be made of one single cell(unicellular) or multicellular Plants, animals and fungi are multicellular Unicellular organisms, like bacteria, are able to perform all life functions within one single cell.

Multicellular Organisms Multicellular organisms need many different types of cells to carry out the same life processes. Each of these special types of cells has a different structure that helps it perform a specific function. Humans have many different types of cells with different jobs. Cell diferentiation- is the process by which cells become specialized in order to perform different functions. Ex: Blood cells – carry oxygen

Multicellular organisms begin as just one single cell—a fertilized egg. Then they grow from one single cell to trillions of specialized cells that perform different functions is a process that happens with the regulation of DNA and RNA. Nerve cell – transmits signals to all parts of the body

Roles of DNA and RNA in Cell Differentiation DNA controls the way cells function – it determines what type of specialized cells will be made Stem cells are cells that have the ability to become any type of specialized cell in the body. After an egg cell and sperm cell unite to begin forming a new organism, all of the DNA in each cell of that organism will be virtually identical. If every part of the DNA in each cell is the same, then how do cells become different types of cells? DNA is wound tightly into chromosomes. Different regions of the chromosome code for every different function and cell type. Not all sections of a chromosome are turned on, or expressed, at the same time. Only the regions that are needed to perform a specific function are expressed in each cell.

These regions are often depicted as bands or stripes on a drawing of a chromosome. These bands are called genes, and whether or not a gene is expressed(turned on) determines what type of cell will be created. This process by which information from a gene is used to make the structures of a cell is called gene expression. For example: genes that are expressed (turned on) in a nerve cell are different from the genes that are expressed in a muscle cell. Both cells have the same DNA, but expressing different genes generates different cell types.

Environmental Factors Influence Gene Expression Environmental factors can also influence gene expression and cell differentiation. For example: available nutrients, salinity, and temperature are all factors that can influence gene expression in organisms.

Specialized Plant Cells In plants, cells are specialized for the roles they play in the plant’s survival. Three of the many specialized cell types in plants include the cells of the roots, stems, and leaves. They are full of chloroplasts ready to capture energy from the sun and turn it into chemical energy.

Muscle Cells Muscle cells are long, fibrous cells that have the ability to contract. They allow animals to move and allow their organs to function in circulation as well as digestion. Muscle cells are made up of two special types of proteins called actin and myosin. Because of actin and myosin, muscle strands are able to slide past each other. This sliding action allows muscle cells to contract. Since a lot of energy is needed in your muscle cells, you will find more mitochondria in them than is found in most cells.

What is a tissue? A tissue is a group of cells that have a similar shape and function. Different types of tissues can be found in different organs.

4 types of Tissues connective epithelial muscular nervous

Connective tissue Types: fat tissue, dense fibrous tissue Cartilage, bone and blood Connective tissue is the most abundant and the most widely distributed of the tissues. Functions: support and protection Stores nutrients Attached muscles to bone etc.

Epithelial Tissue Functions Protection - ex: skin Locations : Body coverings Body linings Glandular tissue The skin is an organ made up of epithelial tissue which protects the body from dirt, dust, bacteria and other microbes that may be harmful. Functions Protection - ex: skin Absorption – ex: stomach lining absorbs and digests food Filtration – ex: kidneys filter blood Secretion – forms glands that secret chemical substances.

Muscle Tissues There are three types of muscle tissue: skeletal, smooth, and cardiac. Skeletal muscle is a voluntary type of muscle tissue that is used in the contraction of skeletal parts. Smooth muscle is found in the walls of internal organs and blood vessels. It is an involuntary type. The cardiac muscle is found only in the walls of the heart and is involuntary in nature.

Nervous Tissue Nerve tissue is composed of specialized cells which not only receive stimuli but also conduct impulses to and from all parts of the body. Nerve cells or neurons are long and string-like.