CARBOHYDRATES

- A carbohydrate is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen
atom ratio of 2:1 (as in water) and thus with the empirical formula Cm (H2O)n (where m may be different from n)
- Mainly sugars and starches, together constituting one of the three principal types of nutrients used as energy sources (calories) by the
body.
- The body breaks down most sugars and starches into glucose, a simple sugar that the body can use to feed its cells. Complex
carbohydrates are derived from plants. Dietary intake of complex carbohydrates can lower blood cholesterol when they are substituted
for saturated fat.
- where it is a synonym of saccharide. The word saccharide comes from the Greek word σάκχαρον (sákkharon), meaning "sugar".

CHEMICAL GROUPS
1. MONOSACCHARIDES – “one” unit of sugar

- building blocks (monomers) of all carbohydrates

Common monosaccharaides (C6H12O6)

GLUCOSE – energy source for cells / cellular respiration

FRUCTOSE – sugar in fruit

GALACTOSE – sugar in milk

2. DISACCHARIDES – “two” units of sugar

- two mono units joined by glycosidic linkages/bond

MALTOSE – “malt sugar” [Glucose and Glucose]

SUCROSE – “table sugar” [Glucose and Fructose]

LACTOSE – “milk sugar” [Galactose and Glucose}

3. OLIGOSACCHARIDES

TRISACCHARIDES – contains 3 monosaccharide units

Fructose + Galactose + Glucose (ex. Raffinose)

TETRASACCHARIDES – contains 4 monosaccharide units

2 (Galactose) + Glucose + Fructose (ex. Stachyose)

PENTASACCHARIDES – contains 5 monosaccharide units

3 (Galactose) + Glucose + Fructose (ex. Verbascose)

4. POLYSACCHARIDES – “many” units of sugar

- can be straight or branched chains

STARCH – how plants store energy

- amylose

- Amylopectin

GLYCOGEN – how human and animals store energy

Other Polysaccharides for structural molecules

CELLULOSE – found in cell walls of plants

CHITIN – forms exoskeleton in insects and crustaceans

PEPTIDOGLYCAN – found in cell walls of bacteria

Lipids
- Lipids are a class of organic compounds that are insoluble in water. Simply put, lipids are non-polar and so cannot mix with water.
However, lipids are soluble in other lipids and some organic solvents like chloroform, benzene, and ether. Lipids are hydrophobic
[hydro means “water” and phobic means “fear of”].
- Lipids are molecules that contain hydrocarbons and make up the building blocks of the structure and function of living cells.
Examples of lipids include fats, oils, waxes, certain vitamins, hormones and most of the non-protein membrane of cells.
Function of Lipids
- Energy storage - Insulation - Hormone precursors
- Protection - Lubrication - Cell membrane

CATEGORIES OF LIPIDS

1. TRIGLYCERIDES
FATS – solid at room temperature; used by animals
OILS – liquid at room temperature; used by plants

The neutral fat polymer is called a triglyceride. Dehydration synthesis bonds 3 fatty acid chains to the glycerol
molecule and removes 3 water molecules. Just like the other classes of organic compounds, triglycerides are reduced to glycerols and
fatty acids again through hydrolysis.

SATURATED FATTY ACIDS UNSATURATED FATTY ACIDS TRANS – FATTY ACIDS

2. PHOSPHOLIPIDS
A phospholipid is similar in structure to a
triglyceride. There is a glycerol backbone, two
fatty acid chains bonded to the glycerol. But instead
of a third fatty acid chain in the mix, there is a phosphate
group. Now phosphate is a polyatomic ion: basically a
negatively charged molecule made of a phosphorus atom
surrounded by oxygen atoms.
A phospholipid is unique among lipids. One part of the
molecule is like a typical fat, non-polar. The other part is
charged and will bond to polar molecules like water. So the
phosphate group end is called the hydrophilic region (“water
loving”) and the fat end is called the hydrophobic region
(“water fearing”).

3. STEROIDS
Steroids are found in animals within something called hormones. The basis of a steroid molecule is a four-ring structure: one ring
with five carbons and three rings with six carbons. You may have heard of steroids in the news. Many bodybuilders and athletes have
used anabolic steroids to build muscle mass. The steroids make their bodies add more muscle than they would normally be able to.
Those anabolic steroids help bodybuilders wind up stronger and bulkier (but not faster). Steroids are also used in necessary medicines.
Some help people with acne, while others are used as muscle relaxers for injuries. Steroids have a structure that is very different from
triglycerides or phospholipids. The core of every steroid is four fused carbon rings. One steroid is different from each other is the side
chains that arise from this central core. Most hormones are proteins but there are steroid hormones, like sex hormones (testosterone,
estrogen, progesterone), and glucocorticoid hormones. Secreted by the adrenal glands, glucocorticoids such as cortisol and aldosterone
help regulate metabolic activity, (like the oxidation of glucose) reduce inflammation, and maintain the water balance of the body.
4. WAXES
Waxes are esters of fatty acids with long chain monohydric alcohols (one hydroxyl group). Natural waxes are often mixtures of such
esters, and may also contain hydrocarbons. The formulas for three well known waxes are given below, with the carboxylic acid moiety
colored red and the alcohol colored blue.

Spermaceti beeswax carnuba wax

CH3(CH2)14CO2-(CH2)15CH3 CH3(CH2)24CO2-(CH2)29CH3 CH3(CH2)30CO2-(CH2)33CH3

Waxes are widely distributed in nature. The leaves and fruits of many plants have waxy coatings, which may protect them from
dehydration and small predators. The feathers of birds and the fur of some animals have similar coatings which serve as a water
repellent. Carnuba wax is valued for its toughness and water resistance.

PROTEINS
- Proteins are molecules made up of sequences of amino acids bound by a peptide bond.
- The genetic code specifies twenty different amino acids that can compose proteins. Therefore, there are numerous combinations of
amino acids that can form polypeptide chains, and for this reason, protein molecules can be hugely diverse.
- Proteins play a fundamental role in nearly all biological processes. Due to their diversity, they can take on many different
configurations and can play varied roles in cells and tissues.
Some protein functions
- they have a structural function (cell membrane proteins, cytoskeleton proteins, connective tissue proteins)
- an enzymatic function (enzymes are proteins)
- an energy storage function (proteins can be broken down into acetyl-CoA to "feed" the Krebs cycle),
- an osmotic regulation function (albumin)
- a transportation function (membrane channels, respiratory pigments)
- an immune protection function (antibodies)
- a movement function (contractile proteins)
- an endocrine integration function (hormones)
- an informative function (membrane receptors, intracellular signalers)

-The units that make up proteins are amino acids. - The peptide molecule is the molecule formed by the bonding of
amino acids through the peptide bond. An oligopeptide is a
- A carboxyl group –COOH, an amine group – NH₂, an
peptide composed of few amino acids (oligo = few). Polypeptides
hydrogen atom –H and a variable radical -R are
are peptides that contain many amino acids (poli = many), in
necessarily bound to the central carbon atom of an amino
general more than 50.
acid.

- There are twenty different known amino acids that form proteins related to the genetic code of the living organisms. There are still
many other amino acids that are not yet known

STRUCTURE OF PROTEIN

The primary structure of a protein is the linear sequence of amino

acids that form the molecule.
The primary structure is the basis of identity of the protein.
Modification of only one amino acid in the primary structure creates a
different protein. This different protein can be inactive or can even have
other biological function

The secondary structure of a protein is generated by the way in

which its amino acids interact through the intermolecular bond. These
interactions create a spatial conformation of the polypeptide chain. The
two most studied secondary conformations of proteins are the alpha-helix
and the beta-sheet.

The tertiary structure of a protein is a spatial conformation in

addition to the secondary structure, in which the alpha-helix or the beta-
sheet folds itself up. The forces that maintain the tertiary structure are
generally interactions between the –R groups of the amino acids, other parts
of the protein and the water molecules of the solution.
The main types of tertiary structure of proteins are globular
proteins and fibrous protein.

The quaternary structure of a protein is the spatial conformation

caused by interactions between the polypeptide chains that form the
protein.
Only proteins made up of two or more polypeptide chains have a
quaternary structure. Insulin (two chains), hemoglobin (four chains) and
immunoglobulins (antibodies, four chains) are some examples of protein
with a quaternary structure.

NUCLEIC ACIDS
- Nucleic acids are molecules that code for hereditary traits by controlling the production of protein.
 Basis of Comparison DNA RNA
Description It contains the genetic instruction It is responsible for the
used in the development and template in the synthesis
functioning of all living organisms of proteins which in turn
control the operation of
the cell

Function Long – term storage and Transfer the genetic

transmission of genetic information for the
information creation of proteins from
the nucleus to the
ribosomes
Number of Strand 2 1
Location in the Cell nucleus cytoplasm
Type of Sugar deoxyribose ribose
Nitrogenous bases Adenine (A) Adenine (A)
Thymine (T) Uracil (U)
Cytosine (C) Cytosine (C)
Guanine (G) Guanine (G)
Major Types mRNA
rRNA
tRNA
Pairing Adenine – Thymine Adenine – Uracil
Cytosine - Guanine Cytosine - Guanine

- Made up of monomers called nucleotide

PHOSPHATE

SUGAR (DEOXYRIBOSE/RIBOSE)

NITROGENOUS BASE (CYTOSINE;

GUANINE; ADENINE; THYMINE
(URACIL)