Specialized Cells

How does the body of a multicellular organism compare to a large city – the city needs roads, waste disposal, police force, energy companies?

The cells in a complex organism are not all identical. (ie The cells in a complex organism are not all identical. (ie. An eye cell looks different than a skin cell).

Our body, just like a large city, needs energy, transportation, waste disposal, etc. Every cell cannot digest food, fight disease and coordinate movements. Specialized cells have differences that allow them to perform one job very well

We all started out as one cell We all started out as one cell. How did we get so many kinds of different cells??

Specialized cell – a cell that can perform a specific function.

Stem Cells Unspecialized cells that have no distinct shape or function

Cellular differentiation – the process that produces specialized cells Cellular differentiation – the process that produces specialized cells. It is directed by the genetic information inside the cell.

Stem Cells All animals and plants start from a single cell called a zygote. As the zygote divides and grows into more distinct looking cells they begin to look different.

Stem Cells – a cell that can differentiate into many different cell types.

Stem Cells Each time the stem cell divides in mitosis, the part of the DNA instructions that are switched on, will determine the type of cell that is produced.

The two types of stem cells are: Embryonic which can differentiate into any kind of cell. Tissue stem cells which can only differentiate into certain types of cells. Ex. Tissue stem cells found in bone marrow can differentiate into white blood cells, red blood cells, or platelets.

Cord Blood Cell Banking Umbilical cords contain a rich source of stem cells which can be harvested during birth and ‘banked’ in case it is needed later in the child’s life. They can be used as treatment for leukemia.

Stem Cell Transplantation Used to treat leukemia patients.

Cells types

Red Blood Cells Carry oxygen in the blood. These cells are smooth so that they can easily pass through blood vessels

Skin Cells Layers of skin cells fit together tightly Covers the outside of the body to protect the inside cells and reduce water loss What features would make a good skin cell?

Muscle Cells Arranged in bundles called fibres They can contract which makes the fibre shorter and causes the bone to move

Nerve Cells Long, thin and have many branches They conduct electrical impulses to coordinate body activity

Fat Cells They have a large vacuole in which to store fat molecules The cells stores chemical energy this way.

Homework Read pages 58- 60 Answer questions 1-6