Chemical Compounds in Living Things

Main Components of the Atom Proton p + Electron e - Neutron n 0 (Nucleus- p + and n 0 )

Atomic Terminology Atomic Number - # of protons in the atom Atomic Weight – equals the # of protons and the # of neutrons Isotopes – atoms with the same # of protons, but a different # of neutrons

Electron Shells/Clouds – layers surround the nucleus where electron exist Electron Cloud/Energy Level Number of Electrons Needed to Fill the level Picture 1st Energy level 2 nd Energy Level 3 rd Energy Level Atoms/elements are more stable if their outer shell is full.

Atoms forming Chemical Bonds Strongest Bond: Covalent bonds -.

2 nd Strongest Bond: Polar Covalent Bonds

3 rd Strongest Bond: Ionic Bond

Weakest Bond: Hydrogen Bond (Does not form a new substance)

Weak Hydrogen Bonds When hydrogen atoms bonded in a compound are attracted to other molecules or compounds

Chemical Compounds in Living Things About 24 elements are found in living organisms and four,__________, _________, ________, __________make up 96% of the body’s weight. (water is ~62%) Two groups of compounds »organic (contain carbon) biotic »inorganic (everything else) abiotic

Special Characteristics of Water 1. Water is a polar molecule (a positive end and a negative end) which easily forms Hydrogen bonds with other itself and other compounds.

2. Water works its way between other ionic and polar covalent compounds thereby dissolving them. 3. Water’s hydrogen bonds create a strong cohesive force, thus water has high surface tension. 4. Water can absorb a lot of energy/heat before increasing in temperature. 5. Water’s structure creates a solid form that is less dense than its liquid form, thus ice floats.

Carbon Organic – living Use: Carbon forms strong covalent bonds allowing it to create stable structures. Life forms can also use structures with carbon for energy because a large amount of energy is released when carbon’s covalent bonds are broken.

The Four Most Common Types of Bio- compounds

Carbohydrates Examples – Sugars – Starch – Glycogen – Cellulose – Composed of: C:H:O 1:2:1 ratio Use: for energy

Lipids Examples – Fat – Wax – Oil – Composed of: C:H:O-but less O than carbohydrates – Use: Insulation (warmth), energy storage, makes up cell membrane.

Proteins Examples – Meat – Dairy (milk, cheese, eggs, nuts) – Composed of: C:H:O:N Use: muscle contraction, transport oxygen, provides immunity, carry out chemical reactions (enzymes and hormones).

Nucleic Acids Examples – DNA – RNA – Composed of: – H:O:N:C+Phosphorus DNA use: genetic code RNA use: instruct the cell to make proteins.