Cell Differentiation What makes cells so different but

Cell Differentiation What makes cells so different, but still the same.

What do you find in plant cells that you do not find in animal cells? What do you find in animal cells that you do not find in plant cells?

Not all cells are created equal… • We know the difference between a plant and animal cell, but are all plant cells and animal cells exactly the same?

Why Not?

What is cell differentiation? • Cellular Differentiation is the process by which cells become specialized and take on specific roles in an organism

Why differentiate cells? • Because the various cells of plant and animals need to perform different functions! – Differentiation dramatically changes a cell's size, shape, membrane potential, metabolic activity, and responsiveness to signals.

MULTICELLULAR ORGANISM don’t just contain many cells. They have different kinds of cells doing different jobs

Cells in a multi-cellular organism become SPECIALIZED by turning different genes on and off (they are regulated by DNA!!) Cell Specialization =DIFFERENTIATION

How do cells differentiate? • Cellular differentiation almost never involves a change in the DNA sequence itself. • These changes are largely due to highly controlled modifications in gene expression of specific genes.

What is a stem cell? an undifferentiated cell that has the ability to differentiate into other kinds of cells because of different patterns of gene expression

• Mitosis - stems cells divide to make identical copies of themselves • Differentiation – the DNA tells the cells which specific gene to express (show) causing them to look different and perform different functions (jobs), but still have identical DNA • Grow and Develop – the organism then grows and develops, each new type of cell going through mitosis to make identical copies of itself and expressing the same specific genes

SPECIALIZED ANIMAL CELLS Muscle cells Cheek cells Red blood cells

Specialized Plant cells Guard cells Xylem cells Pollen