1. Chemistry of life
Chapter 2

2. Atom An atom is the smallest particle of an element that has the characteristics of that element
Atoms are made of 3 particles:
Protons (positively charged)
Neutrons (neutrally charged)
Electrons (negatively charged)

3. Atoms
Protons & Neutrons are found in the nucleus of an atom (in the center).
Electrons are found moving around in a “cloud” that surrounds the nucleus.

4. Atom
The Proton gives the atom its character. Normally atoms have the same number of neutrons and electrons as they do protons.
Atoms can have different numbers of Neutrons and are called isotopes.
There are some isotopes that are unstable called radioactive isotopes that tend to break apart.
The Electrons are involved in bonding.

5. Subatomic Particles
Location
Charge
Mass
Function
Proton
Nucleus + 1
Identification
Neutron
Isotopes
Electron
Electron Cloud -
Bonding

6. Elements A pure substance made of only one atom.
Everything is made of elements (rocks, trees, people…)
There are 90 elements that occur naturally
Only about 25 of the natural elements are essential to living organisms.
More than 96% of the mass of the human body is made of Carbon, Hydrogen, Oxygen, and Nitrogen.

7. Elements in the Human Body
Percentage of Body Weight
Element
Usage
65%
Oxygen
This element is obviously the most important element in the human body. Oxygen atoms are present in water, which is the compound most common in the body, and other compounds that make up tissues. It is also found in the blood and lungs due to respiration.
18.6%
Carbon
Carbon is found in every organic molecule in the body, as well as the waste product of respiration (carbon dioxide). It is typically ingested in food that is eaten.
9.7%
Hydrogen
Hydrogen is found in all water molecules in the body as well as many other compounds making up the various tissues.
3.2%
Nitrogen
Nitrogen is very common in proteins and organic compounds. It is also present in the lungs due to its abundance in the atmosphere.
1.8%
Calcium
Calcium is a primary component of the skeletal system, including the teeth. It is also found in the nervous system, muscles, and the blood.
1.0%
Phosphorus
This element is common in the bones and teeth, as well as nucleic acids.
0.4%
Potassium
Potassium is found in the muscles, nerves, and certain tissues.
0.2%
Sodium
Sodium is excreted in sweat, but is also found in muscles and nerves.
Chlorine
Chlorine is present in the skin and facilitates water absorption by the cells.
0.06%
Magnesium
Magnesium serves as a cofactor for various enzymes in the body.
0.04%
Sulfur
Sulfur is present in many amino acids and proteins.
0.007%
Iron
Iron is found mostly in the blood since it facilitates the transportation of oxygen.
0.0002%
Iodine
Iodine is found in certain hormones in the thyroid gland.
There are many other elements found in the human body, but their presence is largely insignificant when compared to these

8. Isotopes Have the same number of protons and a different number on neutrons
Ex. Radioactive carbon is used for carbon dating.

9. Compounds and bonding
Compound - Atoms of different elements chemically combined. Water (H2O) is a compound.
Atoms often become more stable when they combine or bond with other atoms to get eight electrons in their outer shell of electrons.

10. Why Do Atoms Bond?
Notice the “empty” space to hold up to the eight electrons in all the outer levels of each element except Hydrogen.

11. Bonding The electrons are given away, taken, or shared by other atoms.
Covalent bonds - occur when atoms share electrons. Atoms held together with a covalent bond are called Molecules.
Water has a covalent bond.
Count the electrons around both O and H

12. Bonding
Ionic bonds - occur when an atom gains electrons and becomes a negatively charged ion or loses electrons to another atom and becomes positively charged ion.
The opposite charges attract.

13. Salt Notice the transfer of the electron
Which is the positive ion and the negitive ion?

14. Cohesion and Adhesion
Cohesion is an attraction between molecules of the same substance.
Adhesion is an attraction between molecules of different substances.
cohesion
adhesion

15. Mixtures & Solutions
Mixture is a combination of substances which both retain their own properties.
Solution is a special type of mixture where one or more substances (solutes) are dissolved in another (solvent).

16. Mixtures & Solutions
A solute is the substance being dissolved; table salt for example
A solvent is the substance in which the solute dissolves; water for example.

17. Acids and Bases pH is the measure of how acidic or basic a solution is using a scale of 0 -14
Acid - a substance that forms hydrogen ions (H+) in solution. Examples: Stomach acid, Soft Drinks, Tomatoes
Base - a substance that forms hydroxide ions (OH-) in solution. Examples: Detergent, Ammonia, Hair Remover, Oven cleaner
Base
OH-
Acid H+
H+OH = H2O
Neutral

18. Water Makes up 70 to 95 % of most living things
Makes essential solutions
Examples: salt water or sugar water or blood or digestive juices
Has high surface tension - because water is polar (has a positive and a negative side). It “sticks” together.

19. Water
Cohesion

20. WATER
Creeps up small tubes. Such as the veins in trees. This is adhesion.
Takes a lot of energy to evaporate. That is why it cools you when you sweat.
Is resistant to temperature change. Oceans and lakes are slow to get hot in the summer and cold in the winter.
It expands when frozen

21. Organic Chemistry Carbon element is essential for life.
Carbon is the basic element in Plants, Animals, Paints, Pills, Plastics, Glue, and Dye
Carbon can bond in a variety of ways (single, double, triple)
Carbon can make long chains by itself or with other elements
Isomer same simple formula different 3d structure
Polymer large molecule formed with many smaller molecules

22. Organic Compounds Carbohydrate organic compound formed of CHO
Ratio 2 hydrogen (H) and 1 oxygen (O)
Monosaccharide- one sugar (glucose)
Disaccharide- 2 sugar (sucrose)
Polysaccharide -many sugars (starch, cellulose, glycogen)
starch- plant food storage
cellulose- cell wall of plant
glycogen - animal food storage

23. Organic Compounds Lipids organic compounds with CHO
Ratio of bonds less than that of carbohydrates (Much less O)
Carbohydrate C6H12O6
Lipid C56H110O6
Lipids are fats and oils and waxes
Used for long term storage, insulation, protective coatings
Made of 3 fatty acids and 1 glycerol

24. Organic Compounds
Protein large polymer made of CHON (sometimes sulfur)
Building block is amino acid (AA)
Bond between AA is a peptide bond
Proteins are important for muscles, hair, nails, and enzymes
Enzymes protein that speeds up chemical reactions

25. Organic Compounds Nucleic acid stores information in cells
Nucleic acids are made of nucleotides
DNA contains a nucleic acid called deoxyribonucleic acid
RNA contains a nucleic acid called ribonucleic acid
DNA is an organism’s master copy of their genetic code!!

26. Organic Compounds Compound Building block Elements Examples
Carbohydrates
Glucose
CHO
Sugar, Starches, Glycogen, Fiber
Lipids
3 Fatty Acids
1 Glycerol
Fats, Oils, Waxes
Proteins
Amino Acids
CHON
Muscles, Hair, Nails, Enzymes
Nucleic Acids
Nucleotides
CHONP
Deoxyribonucleic Acid (DNA)
Ribonucleic Acid (RNA)