BIOLOGY

Unit 2 Notes:Living

Organization

(1) Living Organization• All living things are made of cells and

atoms/molecules.

• Levels of Organization:– Atoms – Cells (Basic units of life.)– Tissues (Similar cells working on a common function.)– Organs (Different tissues working on a common function.)– Organ Systems

(Different organs working on a common function.)– Organism (All organ systems maintaining homeostasis.)

(2) Cell Processes• All living systems are made of atoms.

• All living things contain at least the following biological elements:Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur

• All cellular processes are driven by energy exchange and the movement and reacting of different molecules.

(3) Homeostasis• Involuntary processes and reactions are in place to

maintain Homeostasis within cells.

• Homeostasis = Internal stability / balance.

(4) Cell Specialization• When cells are “specialized” this means that they

have a unique shape and a unique function.

• In our bodies we have many specialized cells, which each complete a specific function, to maintain overall homeostasis.

(5) Human Organs• Humans have a lot of different organs to keep us

living and healthy.

• Some Main Internal Organs:– Brain– Heart– Lungs– Liver– Stomach– Small and Large Intestine– Kidneys

(6) Organ Functions• Brain: Controls all other organ systems and allows

us to respond.

• Heart: Pumps and circulates blood.

• Lungs: Bring in oxygen gas, and get rid of carbon dioxide gas.

• Liver: Detoxifies chemicals and breaks down drugs in blood.

Organ Functions Continued• Stomach: Breaks down food into molecular

components.

• Small Intestine: Finish breaking down food and absorb useful nutrients.

• Large Intestine: Absorb water, and excrete food waste.

• Kidneys: Filter blood and maintain blood homeostasis.