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Quietly Do the Following: Observe the wood frogs and spotted salamander eggs at front table Take a paper and create a diagram of the development of a frog. Spotted Salamander. Frog egg develop video link.
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Quietly Do the Following:Observe the wood frogs and spotted salamander eggs at front table Take a paper and create a diagram of the development of a frog.
The fertilized egg gives rise to a large number of cells through cell division (mitosis), but the process of cell division alone could only lead to increasing numbers of identical cells.
Task : • List as many different types of cells in your body as you can. • Do any of the types of cells you listed have specialized jobs? If so...write down it’s job
Structure and Function • Different Structure = Different Function Video: Specialized Cells and Tissues • In class mini assignment.
Using only a pair of scissors and a 3-inch-by-5-inch card, you can make a loop large enough to step into and pull over your head! It has to be continuous (NO BREAKS IN THE PAPER AT ALL)
Objectives • In the development of most multicellular organisms, a single cell (fertilized egg) gives rise to many different types of cells, each with a different structure and corresponding function. • As cell division proceeds, the cells not only increase in number but also undergocell differentiationbecoming specialized in structure and function.
KEY CONCEPT Gene Regulation allows cells to differentiate so that our cells can work together to carry out complex functions.
SYSTEMS leaf shoot system stem vascular tissue CELL TISSUE ORGAN root system lateral roots primary root Multicellular organisms depend on interactions among different cell types. • The various types of cells (such as blood, muscle, or epithelial cells) arrange into tissues which are organized into organs that perform a specific function, and, ultimately, into organ systems.
Inner: intestines Outer: skin cells Middle: bone cells 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.
During the process of cell differentiation a cell becomes specialized in order to perform a specific function. When this process occurs only specific parts of the DNA are activated to make a functional product (protein synthesis). • The parts of the DNA that are activated determine the function and specialized structure of a cell, this is referred to as gene expression.
Gene expression plays a critical role in the changes that take place in a developing embryo and fetus and in the differentiation cells to form specialized cells that make up our organs and organ systems. The DNA in all of our cells is the same. Different regions of the chromosome code for every different function and cell type by turning on or off different sections of the gene, cells become differentiated to create specialized cells. Example: genes that are expressed (turned on) in a nerve cell are different from the genes that are expressed in a muscle cell
Other factors affect Gene Expression: • Environmental factors influence gene expression: For example, a tadpole in a pond will go through many physical changes as it responds to the environment. Look at the pictures below. Tadpole A will spend about 16 weeks of its life undergoing metamorphosis before becoming an adult frog. Tadpole B is living in an area of drought, and in response to its environment, it will release hormones to speed up the process of metamorphosis. Tadpole B will spend about 10 weeks of its life undergoing metamorphosis before becoming an adult frog. Both tadpoles will survive to become adult frogs, but their cell differentiation is controlled at different rates.
Other factors affect Gene Expression: • In Himalayan rabbits and Siamese cats, genes that code for fur color are turned on and off depending on temperature. In warm parts of the body (anything warmer than 35°C), gene expression is turned off, and the fur color is white. Cooler parts of the body (anything cooler than 35°C) turn on the gene, creating black fur.
Because all cells contain the same DNA, all cells initially have the potential to become any type of cell. • Once a cell differentiates, the process can not be reversed. • Stem cellsare unspecialized cells that continually reproduce themselves and have, under appropriate conditions, the ability to differentiate into one or more types of specialized cells.
Embryonic cells, which have not yet differentiated into various cell types, are called embryonic stem cells. • Stem cells found in adult organisms, for instance in bone marrow, are called adult stem cells.
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 (liver cells, heart cells, bone cells, nerve cells, etc.)
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 Stem cells are classified into three types.
Stages of Embryogenesis The fertilized egg (day 1) undergoes cell division to form a 2-cell embryo, followed by 4-cell, etc. until a ball of cells is formed by the fourth day. The ball becomes hollow, forming the blastocyst. This is the stage at which pluripotent embryonic stem cell lines are generated to make various organs. Following the blastocyst stage, the tissues of the embryo start to form and the cells become multipotent. Blastocyst inner mass cells 8-cell stage blastocyst
Can you explain the following? NGSS Core Concepts: Explain how instructions in DNA lead to cell differentiation and result in cells specialized to perform specific functions in multicellular organisms. Explain the process of cell differentiation as the basis for the hierarchical organization of organisms (including cells, tissues, organs, and organ systems).
Diagram Prompt: In multicellular organisms individual cells grow and then divide via a process called mitosis, thereby allowing the organism to grow. ... Cellular division and differentiation produce and maintain a complex organism, composed of systems of tissues and organs that work together to meet the needs of the whole organism.
Your diagram should have a separate paragraph that describes how cells differentiate and organisms develop into complex organisms. This should unify all concepts to cell differentiation and incorporate the following terms - mitosis, gene expression, stem cells, blastocyst, and various organs/organ systems) _______________ (insert concept) is thoroughly described and you connected it to cell differentiation.
