Brenda Hall
Biological
Molecules
Steroi
ds
Eicosan
4 Classes in Living
Systems
Phospholi
Triglyceri
des
Prote
ins
Lipi
Carbohydr
Monosacchar
Disaccharid
Fatty
Acids
Saturated,
Polysaturat
ed, &
Unsaturdat
Glucose
,
Glycoge
n, &
Fructos
Sucrose
,
Lactose
,&
Nucle
ic
Acids
Polysacch
arides
Cellulos
e&
Starch
Amino
Acids
Nucelotide
DN
A&
RN
Summary:
The Biological Molecules have four classes in Living Systems. Each are Representative
Molecules of Functional Groups (Hydroxyl, Carboxyl, Amine, and Phosphate).
1. Lipids
2. Carbohydrates
3. Nucleic Acids
4. Proteins
To begin, Lipids are a very diverse group of fatty, water-insoluable molecules that
function as stored energy, components of cellular membranes, and hormones. There are four
primary classes of Lipids.
1. Triglycerides: are the most common form of lipids in living things. Used for long-term
energy storage and adipose connective tissue and for structural support, cushioning,
and insulation of the body.
a. They are formed from a glycerol molecule and three fatty acids. (Glycerol is
also in Phospholipids**)
i.
Fatty Acids may differ in length and in number position of double bonds
between the carbons in the chain.
ii.
There are three types of chains:
1. Saturated: if lacks double bonds- every carbon has maximum
number of hydrogen atoms bound to it
2. Unsaturated: has one double bond
3. Polyunsaturated: has two or more double bonds
2. Phospholipids: amphipathic molecules that form chemical barriers of cell membranes,
including plasma membranes that form the outer barrier of a cell.
a. Structural component of cell membrane
b. One end of Glycerol has a polar phosphate group with organic molecules
attached to it rather than a fatty acid (Triglycerides**)
i.
Hydrophilic (polar) head: glycerol, phosphate, and organic groups are
polar
ii.
Hydrophobic: two fatty acids attached to glycerol
3. Steroids: composed of hydrocarbons arranged in a distinct multiringed structure
a. Has four attached carbon rings
b. Physiological regulators and component of cell membranes
4. Eicosanoids: modified 20-carbon fatty acids that are obtained from the phospholipids of
plasma membranes.
Carbohydrates are next in line meaning, hydrated carbon. Both are hydrated with an equivalent
water molecule…-H & -OH. Carbohydrates are broken up into, Monosaccharides,
Diasaccharides, and Polysaccharides.
1. Monosaccharides: simple sugar monomers
a. Glucose is the most common = 6-carbon carbohydrate
b. Fructose = 6-carbon sugar
2. Diasaccharides: two simple sugars bound together by dehydration. Formed from two
monosaccharides.
a. Sucrose
b. Lactose
c. Maltose
3. Polysaccharides: three or more sugars. Function as storage and cell surface markers.
a. Cellulose most common in plants
b. Plant Starch is a major nutritional source of glucose in humans.
Nucleic Acids: Store and transfer genetic information and determine the types of proteins
synthesized within the cells.
1. Nucleotides: building blocks of nucleic acids
a. Has three components: a sugar, a phosphate functional group, and a nitrogenous
base.
b. Three types of Nucleic Acids:
i.
DNA: is a double-stranded nucleic acid; can be found as a component of
chromosomes within the nucleus and mitochrondia
1. Deoxyribose sugar, phosphate, and one of four nitrogenous bases
a. AGCT
i.
T:A
ii.
G:C
ii.
RNA: single-stranded nucleic acid lovated both within the nucleus and the
cytoplasm
1. Ribose sugar, phosphate, and one of four nitrogenous bases
a. AGCU
iii.
ATP (adenosine triphosphate): composed of the nitrogenous base
adenine, a ribose sugar, and three phosphate groups covalently linked.
1. Central molecule in the transfer of chemical energy within cells.
2. “ENERGY CURRENCY” of a cell
3. Produced continuously and stored in limited amounts within cell
Proteins: have a variety of functions →
1.
2.
3.
4.
5.
6.
7.
Serve as catalysts
Act in defense
Aid in transport
Contribute to structural support
Cause movement
Perform regulation
Provide storage
Proteins are polymers composed of one or more linear strains of amino acid monomers that
may number in the thousands.
a. Twenty standard amino acids are normally found in the proteins of living organisms.
i.
Each amino acid has an anime functional group -NH2
ii.
And an carboxylic acid -COOH functional group
1. Both are linked to same carbon atom, which accounts for the general
name “amino acid”.
2. Made up of peptide bonds: during dehydration synthesis reaction
between amine of one amino acid and a carboxyl of another amino acid.
a. Oligopeptide: 3-20 amino acids
b. Polypeptide: 21-199 amino acids
iii.
If more than 200 amino acids are linked it is termed a protein!