Question

unit topic: biology basics
science, chemistry of life, and the four biologi
concept 2:
chemistry of life
objectives

1. list the six elements necessary for life and give examples of three molecules that contain those elements.
2. list the levels of organization of that make up an organism, starting with an atom and ending with an organism.
3. differentiate between polar and nonpolar molecules.
4. explain the properties of water that make it such a unique molecule.

Explanation:

1. The six elements necessary for life are carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), and sulfur (S). Examples of molecules: glucose ($C_6H_{12}O_6$) contains C, H, O; amino - acids (e.g., glycine $C_2H_5NO_2$) contain C, H, O, N; DNA contains C, H, O, N, P.
2. The levels of organization starting from an atom are: atom, molecule, organelle, cell, tissue, organ, organ - system, organism.
3. Polar molecules have an uneven distribution of charge due to differences in electronegativity, like water ($H_2O$) where oxygen is more electronegative than hydrogen. Non - polar molecules have an even distribution of charge, such as oxygen gas ($O_2$) or methane ($CH_4$).
4. Properties of water: high specific heat (resists temperature changes), cohesion (water molecules stick to each other), adhesion (sticks to other substances), and it is a universal solvent (dissolves many substances).

Answer:

1. Six elements: carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur. Molecules: glucose, glycine, DNA.
2. Atom, molecule, organelle, cell, tissue, organ, organ - system, organism.
3. Polar: uneven charge distribution (e.g., $H_2O$). Non - polar: even charge distribution (e.g., $O_2$, $CH_4$).
4. High specific heat, cohesion, adhesion, universal solvent.