[Chapter 2 Notes]


Most Frequent Elements Found in Organisms

Element Name

% Composition by Body Weight

Importance

Oxygen

65%

a. Used in cellular respiration.

b. Component of water.

c. Component of organic molecules

Carbon

18.5%

a. Backbone of organic molecules

Hydrogen

9.5%

a. Electron carrier.

b. Component of water.

c. Important component of organic molecules.

 

Other Important Elements Found in Living Organisms

Element Name

Importance of Element

Nitrogen

a. Important component of all proteins.

b.Important component of all nucleic acids.

Calcium

a. Component of bones & teeth.

b. Involved in muscle contraction.

Phosphorus

a. Important component of nucleic acids.

b. Involved in energy transfers within cells.

Iron

a. Component of hemoglobin (in blood).

Sodium

a. Main positive ion outside cells.

b. Important in nerve impulse transmission.

 


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