Download substances which cannot be broken down into

The Chemistry of Life
SOL 1d; 3b-c
Obj. 1. TSW be able to demonstrate an understanding of the properties of atoms.
2. TSW be able to diagram the structure of water and describe the hydrogen
bonding between water molecules.
I. The Nature of Matter
A. Structure of the Atom – smallest part of element that has characteristic of that element
1. Center of atom is the nucleus
a. Nucleus consists of protons and neutrons
b. Protons are positive
c. Neutrons are neutral
2. Surrounding nucleus is an electron cloud.
a. Electrons have a negative charge.
b. Travel around nucleus in energy levels
1. 1st level holds a maximum of 2 electrons
2. 2nd level holds a maximum of 8 electrons
3. 3rd level holds a maximum of 18 electrons
Ex
1. atomic # is the number of protons in the nucleus
2. Mass # is the number of protons and neutrons in the nucleus
3. The number of protons equal the number of electrons
Particles
Location
Charge
Symbol
B. Elements and Isotopes
1. Elements – substances which cannot be broken down into simpler substances.
2. Isotope – same # protons but different # of neutrons
- Ex Li, Be, B, F
C. Chemical Bonds
-Atoms combine by forming bonds– stable when 8 electrons are in the outer energy level
1. Ionic Bond
- gain or loss of electrons in its outer shell
Ex NaCl
2. Covalent Bond
-two atoms share electrons
Ex. H2O (Figure 2-4)
II. Properties of water
A. The water molecule
- blood is mostly water; water makes up 80-95% of most organisms
Let’s review water molecule composed of which 2 atoms? What type of bond?
1. Polar
a. molecule with unequal distribution of charge
b. each molecule has positive (hydrogen end) and negative (oxygen end)
Ex water is able to dissolve many substances because of its polarity
2. Hydrogen bonds
- attraction of opposite charges between hydrogen atom on one water molecule
and the oxygen atom on another water molecule to form a weak bond
3. Water resists temperature change
4. Water expands when it freezes
- ice is less dense that water , that’s why it floats
B. Solutions and Suspensions
1. Mixtures – material composed of two or more elements or compounds that
are physically mixed but not chemically combined
a. Solutions - type of mixture in which 1 or more substances are evenly distributed
- consist of solute and solvent
1. solute – substances being dissolved
2. solvent – substance which does the dissolving
Ex Kool-Aid, sugar water, salt water
Neither the solute nor the solvent change chemically, but they are
recovered by evaporation.
C. Acids, Bases, and pH
1. pH scale
2. Acid definition3. Base definition* Normal pH is between 6.5 and 7.5
Sol 3
Obj TSW examine carbohydrates, lipids, proteins, and nucleic acids
I. Carbohydrates
A. Function – to store and release energy
B. Structure
- compound of carbon, hydrogen and oxygen
- ratio C:H:O
1:2:1
C. Types
1. Monosaccharides
- simplest type called simple sugar
Ex glucose, fructose, galactose
2. Disaccharides
-2 monosaccharides linked together
Ex
Glucose + glucose
maltose
Glucose + fructose
sucrose
Glucose + galctose
lactose
3. Polysaccharides
- largest carbohydrate molecule that consist of polymers (many
Monosaccharides)
Ex. Starch – glucose polymer used for food storage by plants
Cellular – glucose polymer that forms the cell wall
Glycogen – glucose polymer used for food storage by animals
II. Lipids
A. Function
- long-term energy storage, insulation, protection
B. Structure
1. large amount of carbon and hydrogen ; little oxygen
2. subunits are glycerol and fatty acids
Ex animal fat and vegetable oils
III. Proteins
A. Function – carry out cell metabolism; muscle contraction; chemical reactions,
enzymes
B. Structure
1. large complex polymer composed of carbon, hydrogen, oxygen, nitrogen and
sometimes sulfur.
2. Basic building blocks are amino acids
3. There are 20 different amino acids
4. Amino acids are linked by condensation
Look at Fig 7.17 page 180
C. Example of protein
- Enzymes are proteins that speed up a chemical reaction
IV. Nucleic acids
A. Function – store information in cells
B. Structure
1. polymer made of nucleotides hydrogen, oxygen, nitrogen, and
phosphorus arranged in 3 groups ---- base, sugar, and phosphate group.
Ex DNA , RNA