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Name: _________________________________________________ Period: ___________ Date: ________________ Macromolecules Guided Notes

Do you have ever read a nutrition facts ticket on the back of your lunch items? If so, you might have a look at the

carbohydrates, protein and lipids or fat content. Now, you may be identified different macromolecules we will discuss in

this lesson. These large biomolecules providing you with a building block that make and maintain your body.

The Carbon role in life

The carbon atom has four electrons in its valence shell that available for bonding. To become a stable atom, the carbon

tends to form four covalent bonds to fill the outer energy level. The carbon atom usually has an ability to bond with

other carbon atoms, as well as bonding with other elements. When two carbon atoms form a covalent bond, each atom

could share one electron to form single bond, share two electrons and form double bond or share three electrons to

form triple bond.

The carbon atoms bond to each other in many ways to form various compounds such as, straight chains, branched

chains, or rings. Actually, these compounds can have any number of carbon atoms and may contain atoms of many

other elements, so a huge number of carbon compounds can be synthesized in our body.

Monomers and Polymers

Carbon compounds vary greatly in size so, some compounds may contain just one or two carbon atoms while others

may contain hundreds or thousands of atoms. Cells synthesize biomolecules by bonding small molecules together. These

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Name: _________________________________________________ Period: ___________ Date: ________________ Macromolecules Guided Noteslarge biomolecules are called polymers that can be defined as long chain of repeating subunits or small molecules that

called monomers such as amino acids that made up protein.

Condensation reaction (dehydration synthesis)

How these polymers formed from the monomers? Generally, polymers are synthesized by a chemical reaction that

called condensation. In this reaction, the monomers that are attached together to make the biomolecule have a

hydrogen atom (–H) and a hydroxyl group (–OH) group which are removed to release water. These subunits become

bonded by a covalent bond, as a water molecule released. These polymers can be broken apart by hydrolysis.

This figure above showing the condensation of two glucose molecules to form one maltose molecule and formation of

covalent bond between the glucose units as well as releasing of water molecule.

Carbohydrates

One of the most abundant macromolecules in the living cell are the carbohydrates and considered as the fuel source for

living cells. The carbohydrate is defined as the biomolecule that contains carbon, hydrogen, oxygen atoms. The ratio of

these atoms is approximately two hydrogen atoms and one oxygen atom per one carbon atom.

Carbohydrate molecules have various chain lengths. There are three categories of biologically important carbohydrates:

monosaccharides, disaccharides, and polysaccharides.

1. Monosaccharides

Monosaccharides (mono- = “one”; sacchar- = “sugar”) are the simplest type of carbohydrates and typically

contains from 3 to 7 carbon atoms. The most common examples of this category are the isomers glucose and

fructose.



2. Disaccharides

Disaccharides (di- = “two”) is a two-sugar molecule that formed when two monosaccharides join via a

condensation reaction or dehydration synthesis.

For example, when glucose and fructose link together by a dehydration synthesis, a molecule of sucrose which is

known as table sugar, is produced.

3. Polysaccharides

Polysaccharide (poly- = “many”) is the largest carbohydrate molecule and defined as long chain of

monosaccharides linked by covalent bonds. These biomolecules usually have a high molecular weight. Starch,

glycogen, cellulose, and chitin are examples of polysaccharides that is very important in living organisms.

a. Starch molecule consists of branched chains of glucose molecules and is utilized as energy storage by

plants.

b. Glycogen is a highly branched glucose polymer that function as energy store in the mammal's liver.

c. Cellulose is another glucose polymer that typically found in the plant cell walls and serve as structural

support.



Lipids

Lipids are the second group of large biomolecules that are typically consists of carbon and hydrogen associated with a

small amount of oxygen atoms. lipids are used to store energy, serve as insulation, forming cell membranes, and provide

building blocks for hormones like testosterone. Fats, oils, waxes, and steroids are the most common examples of lipids.

This group of macromolecules is insoluble in water because they have a nonpolar part that are not attracted by water

molecules.

The lipid molecules are made of glycerol which is a three carbons molecule that serves as a backbone in which the fatty

acids attached to form a lipid molecule. A fatty acid is a long chain of carbon and hydrogen. If the carbon atoms in the

chain is bonded to other carbons by single bonds, the fatty acid is called a saturated fatty acid. When a double bond is

existing in the chain, the fatty acid is called unsaturated fatty acid. The fatty acids which contain more than one double

bond are called polyunsaturated fatty acids.



Proteins

Proteins is one of the most abundant macromolecules in living system that essential to all life forms. A single living cell

contains thousands of proteins that perform unique functions such as contraction of muscle tissue, transportation of

oxygen in the bloodstream, providing immunity, regulating other proteins, and carrying out chemical reactions. A

protein can be defined as a large, complex polymer that made of carbon, hydrogen, oxygen, nitrogen, and may also

contains sulfur.

Amino acids are monomers that form building blocks of protein molecule. There are about 20 natural occurring amino

acids that in various combinations, produce thousands of proteins. The typical amino acid is composed of a central

carbon atom to which are attached a hydrogen atom, carboxyl group (–COOH), an amino group (–NH2), and a variable

group (–R) that makes each amino acid different.



Amino acids are bounded together by a covalent bond that called a peptide bond. The peptide bond is formed when an

–H atom from the amino group of one amino acid and an –OH group from the carboxyl group of another amino acid are

removed to release a water molecule.

Precisely, a protein molecule is made up of one or more linear chains of amino acids that is called a polypeptide chain.

Proteins are very diverse in shapes and sizes. The number and sequence of amino acids that make up a protein are

important in determining its shape because there are different types of amino acids such as acidic, basic, and neutral

amino acids.


Name: _________________________________________________ Period: ___________ Date: ________________ Macromolecules Guided NotesThese different chemical properties of amino acids cause them to attract and repel each other in different ways. Several

proteins include of two or more amino acids that are bounded together by hydrogen bonds. The three-dimensional (3D)

shape of the protein is very important to the functioning of the protein and if the sequence of amino acids in the protein

is changed, the protein might fold differently and lose its ability to perform its function.

The most common examples of proteins are the enzymes and hormones.

1. Enzymes are extremely important proteins which found in living cells and changes the rate of a biochemical

reaction such as salivary amylase.

2. Hormones are considered as biochemical signals that released by endocrine cells and control specific processes,

such as growth, development, metabolism, and reproduction. Insulin is one of the most common example of

hormones.

Nucleic acids

Nucleic acids are another type of macromolecules that is extremely important to any living creatures. The nucleic acids

are the genetic material that store cellular information. The nucleic acids are polymers that made of small building

blocks which called nucleotides. Nucleotides composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus atoms

arranged in three attached molecules that are nitrogenous base, ribose sugar, and three phosphate groups.



The two naturally occurring varieties of nucleic acids are: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

DNA (Deoxyribonucleic acid)

DNA is the main copy of an organism’s information code that consists of two strands of nucleotides. This double-

stranded molecule contains the instructions used to create enzymes and structural protein. Consequently, DNA

molecules are the genetic code which regulates how an organism looks and acts. The DNA’s instructions copy is passed

on every cell division and from one generation of an organism to the offspring.

RNA (Ribonucleic acid)

RNA is another important nucleic acid molecule that forms a message or a copy of DNA that utilized to making proteins.

Unlike the DNA molecule the RNA is usually single-stranded molecule. There are four major types of RNA: messenger

RNA (mRNA), ribosomal RNA (rRNA), transfer RNA (tRNA), and regulatory RNAs.


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