Unit B: Cells and Systems Topic 5: Cell Specialization and Organization

Cells are Specialized in Multicellular Organisms Specialized according to the need they meet. Unicellular cells have to perform all the jobs needed to stay alive. A cell in a human being is like an ant in an ant colony. Soldier ants are given the job of protecting the colony. They are bigger than worker ants and carry out their job until they die.

A cell’s shape is based on its job Just like with the soldier ant, a cell’s structure is determined by what job it has to do. A muscle cell is stretchy and flexible. A nerve cell has many connections so that signals can be sent quickly to other nerve cells.

Efficiency of Multicellular organisms versus unicellular organisms Because multicellular organisms have different kinds of cells performing different jobs, they are much more adaptable to their environment. They have a better chance at surviving in different environments than unicellular organisms.

Tissues and Cells Tissues are groups of the same kind of cell doing the same kind of job. A muscle tissue helps move the bones in your body, causing you to move. Bone tissue gives you the support and strength you need to live.

Organs Are distinct structures in your body that perform special functions in your body that are VITAL in keeping you alive. (eg. heart pumps blood, brain regulates your body’s activities) Having organ damage is much more critical than general tissue damage.

Systems A system is a group of tissues and organs working together to perform related activities. Because a plant only needs sunlight, water, and some minerals to survive, it only needs three systems to survive and reproduce. Animals have a greater challenge in getting food and reproducing, and surviving so they need more systems.