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Chemistry in BIOLOGY ???

Why do biologists need to know about chemistry?

I. Matter- made of mass and volume
   A. Atoms- smallest unit of matter
        
        1. Nucleus- center of atom
             a. Neutrons- neutral charge, 1 amu
             b. Protons- positive charge, 1 amu
         
        2. Electrons- orbit the nucleus, have a negative charge, 0 amu
             a. Electrons are located around the nucleus and arranged in energy levels (shells)
 
  - In an atom, the number of protons equals the number of electrons and therefore, the atom is neutral
  
   B. Elements-  a pure substance, made of the same kind of atom, there are approximately 110 elements; only about 12 are commonly used in Biology
         
         1. Symbols- shorthand of elements - Examples - C, H, O, N, P
      
   C. Isotopes-  elements that have the same number of protons but different number of neutrons
         -Atomic Mass- weight of the atom, the number of protons plus the number of neutrons
         -Atomic Number- the # of protons of an element
         1. Radioisotopes are isotopes that have unstable nuclei
              a. Emit particles or energy from the nucleus
                    - Radiation from certain isotopes can be used to help treat cancer or kill bacteria
         2. Tracers- the use of isotopes to study biochemical reactions
                    - follow the movement of substances within organisms (radioactive dye)
 
   D. Compounds - 2 or more kinds of atoms that are chemically combined
     
II. Chemical Bonding
   
   A. Ionic Bonds
         1. Ion- an atom that has lost or gained electrons (to complete the outer shell) and now has a charge (charged particle)
         2. An ionic bond forms through the transfer of electron(s) from one atom to another to form a neutral compound (NaCl, CaCl)          
   B. Covalent Bond- a compound formed from the sharing of electrons
      1. Diatomic molecules- a bond formed from 2 atoms of the same element (H2 ,O2)
 
   C. van der Waals force - a slight attraction that occurs between oppositely charged regions of molecules that are close together
              - this is how geckos can grip smooth surfaces
 
III. Mixtures- made up of substances that are not chemically combined; therefore, they retain their own individual properties (salad, salt water)
   A. Solutions- homogeneous mixture (same phase), particles do not settle out
      1. Solvent- dissolving agent
      2. Solute- substance being dissolved
   B. Suspensions- substances settle out of the liquid (mud)
   C. Colloids- a suspension in which the particles do not settle out (foam, cream, mayonnaise)
IV. Acids- compounds that donate a hydrogen ion (H+), they contain a higher concentration of hydrogen atoms than water
   A. Sour taste, corrosive
   B. In H2O, acids separate into its ions
V. Bases- compounds that accept H+, contain a hydroxyl group (OH), they have a lower concentration of hydrogen ions compared to water
   A. Bitter taste, slippery (lye)
   B. In H2O, bases separate into it ions

VI. Neutralization- when solutions of acids and bases are mixed, water and salt are formed
   A. Buffers are weak acids and bases which are combined with strong acids and bases to prevent sudden changes in pH

VII. pH Scale- a scale based from 1-14
   A. 1-6.9 acids (lower numbers being stronger acids)
   B. 7 neutral (water)
   C. 7.1-14 bases (higher numbers being stronger bases)

 

Chemical Compounds of Life - Biochemistry

Background Since we are studying life, we must understand the basic components of life. Everything (living & nonliving) on this earth is made of approximately 110 elements. Most of these elements form organic chemicals which are the basic structures of organisms.

I. Inorganic Compounds- compounds that do not contain carbon

A. Water (H2O) is the most abundant inorganic compound in your entire body = 70%

II. Organic Compounds- compounds that contain carbon (C), four groups of organic molecules are listed below.

A. CARBOHYDRATES- organic compounds of C, H, O in which the H:O ratio is 2:1

1. Monosaccharides- are the simplest carbohydrates C6H12O6- glucose
2. Sugars are used by the body for energy (all carbohydrates are used as energy)
3. sugar + oxygen-----> energy + carbon dioxide + water

C6H12O6 + O2-----> 36 ATP + CO2 + H2O

4. Dehydration- removing of water
5. Synthesis- putting together

Dehydration Synthesis- putting molecules together by removing water; such as

monosaccharide + monosaccharide ------> disaccharide
C6H12O6 + C6H12O6 ------> C12H22O11 + H2O

6. Polymers (macromolecules) of Carbohydrates- which are polysaccharides- long chains of monosaccharides; examples

Glycogen- animals only, not in plants
Starch- plants store excess glucose in this form
Cellulose- found in cell walls of plants
Chitin- special starch that makes up the exoskeleton of an animal, beetle, grasshopper

7. Hydro- refers to water
8. lysis- means to split

Hydrolysis (or digestion)- breaking down large complex molecules into small simple molecules; this process involves putting the H2O molecule back into the place it was removed from during dehration synthesis, such as

disaccharide + H2O ------> monosaccharides + monosaccharide
(maltose) C12H22O11 + H2O ------> C6H12O6 + C6H12O6

B. LIPIDS- organic compounds of C, H, O; do NOT have 2:1 ratio of H:O

1. Glycerol + 3 Fatty Acids are the building blocks for lipids (fats)
2. glycerol- (type of alcohol); fatty acid- a long chain of carbon & hydrogen atoms with a carboxyl group at one end
3. Saturated Fats

- all single bonds between Carbon & Hydrogen
- increase cholesterol levels, can lead to hardening of the arteries, which can cause heart attacks

4. Unsaturated Fats

- some have double or triple bonds between Carbon & Hydrogen
- are better for your diet

5. Function of Lipids:

a. used to make cell structures [example: cell membrane]
b. stored energy
c. 2 times as much energy in one gram of fat then in one gram of carbohydrate

6. Polymers of Lipids- which are long chains combined glycerol + fatty acids

Cholesterol
Steroids
Waxes

C. PROTEINS- organic compounds of C, H, O, N; sometimes S

1. basic builing blocks are AMINO ACIDS [20 kinds of amino acids]
2. Protein Synthesis- occurs at ribosomes (organelle inside cell)

Dehydration Synthesis- putting molecules together by removing water; such as

amino acid + amino acid ------> dipeptide + water

3. Polymers of Proteins- which are long chains amino acids which are attached by peptide bonds

Hormones- chemical messengers produced by glands, insulin was the first protein to be determined
Antibodies- protect against disease
Pigments (color)- blood, skin, & eyes
Enzymes- enable chemical reations to take place in the body

4. Enzymes-

a. speed up chemical reactions WITHOUT being used up so they can work over & over
b. are Organic Catalysts (make it possible for chemical reactions to take place), they are NOT reactants, nor products
c. Substrate- substance enzyme works on, "Lock + Key Method"
d. 3 things that affect enzyme action

1. Temperature (37 degrees Celsius = 98.6 degrees Fahrenheit)
2. pH- hydrogen concentration
3. Concentration- of enzymes

e. enzymes are named by the substate they work on & adding "-ase"

 Enzyme

Substate
maltase maltose
sucrase sucrose
amylase amylose
lipase lipids
protease proteins

D. NUCLEIC ACIDS- organic compounds of C, H, O, P

1. basic builing blocks are NUCLEOTIDES which have 3 parts

a. Phosphate group
b. five carbon sugar
c. nitrogenous base

2. Polymers of nucleotides are

DNA (deoxyribonucleic acid)- hereditary material
RNA (ribonucleic acid)- 3 types used to make proteins
 
III. Chemical Reactions

   A. Chemical formulas- every compound consists of atoms in definite proportions
      1. Molecular formula- shows the symbol of elements and how many atoms of each are present (H2O , C6H12O6 , water and glucose)
      2. Empirical formula- show the symbol and atoms in lowest ratio (CH2O)

   B. Chemical Equations- chemical bonds are broken and new products are formed
      1. The number of atoms of each kind of the reactants must equal the number of atoms of each kind on the product side

IV. Indicators- a substance that changes color when the pH goes above or below a certain value
ex) blue litmus paper, red litmus paper, methyl orange, phenolphthalein
 

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