Chapter 3 The Chemical Basis of Life II:
Organic Molecules
What element is found in all forms of life? - ANS Carbon
Define organic molecules - ANS A carbon-containing molecule, so named because such molecules were
first discovered in living organisms
Define macromolecules - ANS Many molecules bonded together to form a polymer. Important
macromolecules found in living organisms consist of carbohydrates, proteins, lipids, and nucleic acids.
What is organic chemistry? - ANS The study of carbon-containing molecules
What is vitalism? - ANS When the study of organic molecules were once considered a fruitless endeavor.
This concept was once held that organic molecules were created by, and therefore imparted with, a vital
force that was contained within a plant or animals body.
People who believed this argued that chemists could not synthesize organic compounds because they
could only arise through the intervention of mysterious qualities associated with life.
How was vitalism debunked? - ANS Vitalism was disproved by Friedrich Wohler by creating urea through
a chemical process (reaction between ammonia and chancing acid) that produced urea, an organic
compound found in urine
What is a key property of Carbon? - ANS It's ability to form four covalent bonds with other atoms, to
include other carbon atoms
Why can Carbon have four covalent bonds at once? - ANS Because carbon has four electrons and
requires another four for the outer shell to be full
,In living organisms, what does carbon most typically bond with? - ANS Carbon, oxygen, nitrogen,
hydrogen, and sulfur atoms
How many bonds can be formed between two carbon atoms? - ANS Single, double, or triple bonds
How many bonds can be formed between carbon, oxygen, and nitrogen? - ANS single or double bonds
Up to how many bonds can there be between carbon and nitrogen? - ANS Up to a triple bond
What are the benefits of Carbon atoms? - ANS The variation in bonding of carbon with carbon and other
atoms allows a vast number of organic compounds to be formed with only a few chemical elements
What shapes can carbon bonds with other atoms take on? - ANS - Linear
- Ringlike
- Highly Branched
How does the molecular shape influence an atom? - ANS It influences the function - such molecular
shapes can produce molecules with a variety of functions
Are carbon-carbon and carbon-hydrogen bonds polar or non polar? - ANS Since they have similar
electronegativities, they are nonpolar
What are hydrocarbon atoms? - ANS Molecules with predominately hydrogen-carbon bonds
Are hydrocarbons soluble in water? - ANS Due to their nonpolarity, hydrocarbons are hydrophobic and
extremely insoluble in water
,Are carbons bonded with oxygen and nitrogen soluble in water? - ANS Due to the electronegativity
difference, when carbon is bonded to one of these two atoms, they are polar and are hydrophilic and
soluble in water due to its attraction to water molecules,
How is carbon the backbone for the variety of important molecules in living organisms? - ANS The ability
to form both polar and nonpolar covalent bonds
Why is carbon important to living organisms (related to temp)? - ANS Carbon bonds are stable and can
withstand large ranges of temperatures associated with life
Why are carbon atoms so stable and can withstand large temp ranges? - ANS Due to their small size, the
bonds formed are much shorter, and therefore much stronger and more stable
What affect does the stable carbon atom have on living organisms? - ANS Carbon atoms are compatible
with what we observe about life forms today;; namely, living organisms can inhabit environments with a
range of temperatures
What are functional groups? - ANS A group of atoms with a characteristic chemical structure that
exhibits particular properties. Each functional group exhibits the same properties in all molecules in
which it occurs
What are most organic molecules and macromolecules composed of? - ANS functional groups
Where are amino groups found? - ANS In proteins and other types of organic molecules
Describe the functional group Amino. - ANS (-NH2)
Found in amino acids (proteins)
Weakly basic (can accept H+), polar, forms part of peptide bonds
, Describe the functional group Carbonyl. - ANS (-CO)
Found in steroids, waxes, and proteins
Polar, highly reactive, forms hydrogen bonds
Describe the functional group Aldehyde. - ANS (-CHO)
Found in linear forms of sugars and some odor molecules
Polar, highly reactive, forms hydrogen bonds
Describe the functional group Carboxyl - ANS (-COOH)
Found in amino acids and fatty acids
Acidic (gives up H+ in water), forms part of peptide bonds
Describe the functional group Hydroxyl - ANS (-OH)
Found in steroids, alcohol, carbohydrates, and some amino acids
Polar, forms hydrogen bonds with water
Describe the functional group Methyl - ANS (-CH3)
Can be attached to DNA, and found in proteins and carbohydrates
Nonpolar
Describe the functional group Phosphate - ANS (-PO4^2-)
Found in nucleic acids, ATP, and phospholipids
Polar, weakly acidic and negatively charged at typical pH of living organisms
Describe the functional group Sulfate - ANS (-SO4^1-)