1 Review What is cellular specialization Explain How do cellular junctions and receptors

help an organism maintain homeostasis2 Description Use an area in your life- school sports,

etc…, to construct an analogy that explains why specialization and communication are necessary for you to function well.

CH 7 CELL STRUCTURE AND FUNCTION7.4 Homeostasis and Cells

Homeostasis

Relatively constant internal physical and chemical conditions

To keep constant unicellular organisms grow, respond to the environment, transform energy, and reproduce.

Unicellular organisms are most numerous Eukaryotes may also be unicellular.

Multicellular Organisms

Cells are independent but work together Cells specialize Cells communicate.

Levels of Organization

Tissue Group of similar cells that performs a particular

function.

Levels of Organization

Organ Groups of tissues that work together.

Levels of Organization

Organ system Group of organs that work together to perform a

specific function.

Cellular Communication

Use chemical signals between cells Cells can form cellular junctions

For holding cells together or to allow messages to pass

Receptor Receives the chemical message.

Mitochondria Distribution

Scientists studied several organs in the mouse to see how many mitochondria were found in each.

They described the amount of mitochondria as a percentage of total cell volume (the greater the volume=the greater number of mitochondria)

The graph is on the next slide.

Interpret Graphs What approximate percentage of cell volume is composed of mitochondria?Calculate Approximately how much more cellular volume

is composed of mitochondria in the left ventricle than in the pituitary gland?

Infer There are four chambers in the mouse heart, the tight and left ventricle, and the left and right atria. Based on the data given, which chamber- the left or right ventricle, do you think pumps blood from the heart to the rest of the body- Explain?