Download Cell Chemistry

Chapter 2:
Objectives:
Chemistry Comes Alive
1. Describe matter and the states in which it exists.
2. Define chemical element and list the four elements that form the bulk of body matter.
3. Describe the composition of an atom.
4. Distinguish between a compound and a mixture
5. Differentiate between ionic and covalent bonds. Contrast these bonds with hydrogen
bonds.
6. Compare and contrast polar and nonpolar compounds.
7. Describe synthesis, decomposition, and exchange reactions.
8. Describe the bonding characteristics of carbon found in organic compounds.
9. Explain the importance of water and salts to body homeostasis.
10. Define acid and base, and explain the concept of pH.
11. Explain the role of dehydration synthesis and hydrolysis in the formation and
breakdown of organic molecules.
12. Describe and compare the building blocks, general structures, and biological
functions of carbohydrates, lipids, proteins, and nucleic acids.
13. Explain the role of ATP in cell metabolism.
Matter: made of atoms, all things made of matter. It is anything that has mass and takes up space.
Forms or states of matter: solid, liquid, gas
Atom: smallest unit of an element, composed of a nucleus (protons, neutrons), and an electron cloud
(electrons)
Element and four elements of living things: Carbon, Hydrogen, Oxygen, Nitrogen
(CHON). Elements are the smallest unit of matter, made of the same type of atoms
Trace elements: Mg, K, Na, Ca, S, P, etc (abt. 25)
Molecules: when two or more atoms combine chemically, molecules are formed.
Compound: when two or more different atoms bind together to form a molecule, a compound is
formed. Compounds require a chemical change to occur. The new compound has chemical
characteristics that differ from those of the atoms that formed it.
Bonding
I. Ionic: atoms donate electrons to create ions that are then attracted to one another to form molecules
(NaCl or sodium chloride).
II. Covalent: atoms share electron between atoms to form molecules
A. Polar: unequal sharing of electrons that creates positively and negatively charged ends to a
molecule. Water is a common polar compound, also phosphates in cell membrane
B. Nonpolar: evenly shared electrons; CO2, hydrocarbons in cell membrane.
C. Hydrogen: hydrogen atoms are attracted to the negative end of another polar covalent
molecule; “rungs” of DNA molecule.
Chemical Reactions
I. Synthesis: A + B  AB. An anabolic reaction found in rapidly growing tissues.
II. Decomposition: AB  A + B. A catabolic reaction, ex., glycogen to glucose.
III. Exchange: AB + C  AC + B, AB + CD  AC + BD
Oxidation-reduction reactions
Cellular respiration and photosynthesis:
Inorganic Compounds
I. Water: has properties due to its polar covalent bond
A. High Heat Capacity: allows subtle changes in temperature
B. High Heat of Vaporization: allows evaporative cooling (sweating)
C. Polar solvent properties: acts as a transport medium for substances in the body (wastes,
nutrients, gases), especially those that are also polar.
D. Reactivity: involved in chemical reactions; ex. Water added in hydrolysis for digestion
E. Cushioning: protects organs (brain, fetus) from physical trauma
II. Salts: required for nerve impulse transmission (NaCl), harden bones and teeth (Ca), transport
oxygen (Fe).
Acids and Bases
I. Acids: release H+ in water, ex. carbonic acid, acetic acid, HCl
II. Bases: release OH- in water or take up H+, ex. bicarbonate, ammonia, proteins, phosphates
III. pH and neutralization: concentration of H+ or OH- in solution. 0-14 is pH scale, 7 is neutral. 06.9 is acidic, 7.1-14 is basic
IV. Buffers: resist large and abrupt swings of pH in the body. Bicarbonate, phosphate, proteins are the
main three.
Dehydration Synthesis: removal of a molecule of water from two molecules will allow them to
covalently bond with one another. Ex. formation of organic molecules (polymers) from monomers
Hydrolysis: the addition of water between two molecules breaks them apart. Ex. the splitting of
polymers into monomers
Organic Compounds
I. Carbohydrates
A. Monosaccharides: glucose, ribose in DNA and RNA
B. Disaccharides: maltose and sucrose
C. Polysaccharides: starch (glycogen) and cellulose
D. Functions: short term energy storage, structural molecules, used for immediate energy
II. Lipids: monomers are glycerol and fatty acids (saturated and unsaturated)
A. Neutral fats: triglycerides in adipose cells
B. Phospholipids: phosphate, glycerol, and two fatty acids in cell membrane
C. Steroids: cholesterol and sex hormones
D. Functions: longterm energy storage in adipose tissue, forms sex hormones, found in cell
membrane
III. Nucleic Acids: polymers are DNA and RNA
A. Nucleotides: monomers of a sugar, phosphate, and nitrogenous base of either adenine,
guanine, cytosine, or thymine
B. Functions: hereditary information, blueprint for proteins
IV. Proteins
A. Amino acids: monomers of proteins, come in 20 different types with a common structure:
R

NH2  C  COOH

H
B. Functions: enzymes, receptors, buffers, structure, transport, defense
C. Four levels of protein structure
i. Primary: polypeptide chain of amino acids
ii. Secondary: alpha helix or beta pleated sheet
iii. Tertiary: “scribble” shape due to various bonds between R groups
iv. Quaternary: two or more proteins, fibrous or globular
D. Denaturation: breakage of bonds in protein, results in loss of function. High temperature and low
pH (acidity) often denature proteins.