Structure: Monosaccharides consist of a single chain of molecules.
Function: Monosaccharides, such as glucose, are the primary energy source for cells. Ribose and deoxyribose are the major components of DNA and RNA as well.

Structure: Disaccharides are formed when two monosaccharides are linked together through the process of dehydration synthesis during which a water molecule is given off.
Function: Disaccharides often serve as forms of energy storage.

Structure: Polysaccharides are formed when many monosaccharides are linked together through many dehydration synthesis reactions in which many water molecules are released. 
Starch: A fairly straight chain glucose polymer which may have a few side chains (joined by alpha 1/4 bonds).
Glycogen: A highly branched polymer of glucose (joined by alpha 1/4 bonds). 
Cellulose: A straight chain polymer of glucose (joined by beta 1/4 bonds).

Examples:
Why are carbohydrates called carbohydrates?
Carbohydrates are called carbohydrates since the ratio of hydrogen to oxygen is 2:1 as it is in water.
What is the function of glycogen?
Glycogen is the major form in which the monosaccharide glucose is stored in animals.

So What? 
Carbohydrates are important because they are sugars and starches– some of the building blocks of life. They are also used by the body as sources of energy, structural components of DNA and RNA, and it makes proteins. Moreover, carbohydrates are vital for the human diet. Most animals, including humans, have enzymes that can hydrolyze plant starch, making glucose available as a nutrient for cells. Foods such as potatoes, wheat, and corn are the major sources of starch in the human diet too. In other words, both animals and humans need carbohydrates to maintain energy.

Lipids contain mostly carbon, hydrogen, and oxygen, but may also contain other elements such as nitrogen and phosphorus. Lipids are usually non polar, therefore relatively insoluble in water. 

Neutral Fat (Triglycerides):

Structure:

Triglycerides are composed of one fat and three fatty acid chains which are combined by three dehydration synthesis reactions in which three water molecules are given off. 

• saturated fatty acids (solid at room temperature):

These fats are saturated with hydrogen and have no double bonds between carbon atoms, and are typical of animal fats. 

Example: butter, lard

• unsaturated fatty acids (liquid at room temperature):

Because of a deficiency of hydrogen atoms, these fats have double bonds between some of the carbon atoms, and are typical of plant fats. 

Example: canola oil, olive oil

 Function:

Triglycerides function as long term energy storage, insulates against the cold, and protects major organs.

Phospholipids:
Structure:
The structure of phospholipids are very similar to that of triglycerides except that the third fatty acid is replaced by a phosphate group, which in turn is often linked to a nitrogen-containing group. Due to the presence of the phosphate group, part of this molecule is polar (the "head" of the phospholipid), whereas the other two fatty acids are non-polar and are referred to as the "tail" of the phospholipid.
Function:
Phospholipids function as a major component of the cell membrane.

Steroids:
Structure:
The structure of steroids is very similar to cholesterol since they're derived from cholesterol. Steroids consist of three 6-carbon rings and one 5-carbon ring with one or more side chains.

Function:
Steroids function as sex hormones (Ex. progesterone, estrogen, testosterone), and cholesterol is often found in cell membranes which it helps to stabilize and strengthen. Also, the steroid aldosterone is a hormone which helps to control blood flow levels.

Example:
What is the key feature which helps to identify lipids?
The key feature that helps to identify lipids is that they are hydrophobic, meaning they are insoluble in water.
How does the structural difference between a triglyceride from an animal and a plant affect the physical properties of these neutral fats?
It affects the physical properties of these fats because unsaturated fats are liquid at room temperature, and the double bonds in unsaturated fatty acids will lower the melting point. As for saturated fatty acids, they are solid at room temperature.

So What?
Lipids are important because they play an extremely vital role in the human body. For instance, triglycerides act as a long term storage energy and 1 gram of fat stores more than two times the energy of 1 gram of carbohydrate. They also insulate against the cold and protects major organs. Moreover, phospholipids are the major component of the cell membrane. Lastly, steroids act as sex hormones, and cholesterol helps to stabilize and strengthen as well. 

Examples:
What is the difference between the terms "polypeptide" and "protein"?
A polypeptide is a polymer of many amino acids linked by peptide bonds, whereas a protein is an organic macromolecule composed of one or several polypeptides.
What does the structure of an amino acid consist of?
The structure of an amino acid consists of an amino group, an R group (side chain), and an acid group (carboxyl).

So What?
Proteins are important because they are important building blocks of various parts of the human body. For instance, keratin (hair and nails), collagen (tendons and ligaments), and muscles are made up of proteins. Moreover, proteins also function as transportation (eg. hemoglobin transports oxygen and carbon dioxide in the blood), hormones (eg. insulin helps regulate sugar levels in the blood) and catalysts (enzymes) make possible chemical reactions at body temperature. Proteins also protect humans from getting sick because the antibodies produced by proteins protects the body against pathogens. 

Initiation: A complex forms in this sequence: a small ribosomal subunit + mRNA + large ribosomal unit + initiator tRNA (with anticodon AUG)
Elongation: A series of tRNA's delivers specific amino acids in sequence by codon-anticodon matching; a peptide bond joins each amino acid to the next sequence.
Termination: A stop codon is reached, and the polypeptide chain is released into the cytoplasm or enters the cytomembrane system for further processing.

Roles of Molecules Involved in Protein Synthesis:
1. DNA contains the code or "blueprint" for the protein to be synthesized.
2. mRNA carries a transcribed copy of the DNA code from the nucleus to the ribosomes in the cytoplasm.
3. tRNA carries a specific amino acid to the ribosome for assembly into polypeptides.
4. rRNA together with proteins forms ribosomes, which are the site of protein synthesis (translation).
5. Amino acids are the building blocks that are linked together by peptide (covalent) bonds to form polypeptides.
6. Various enzymes.

Examples:
Given the tRNA anticodon sequence: UCA GGU CCA AAA AGU
...determine
a.) the complementary mRNA codons:
AGU CCA GGU UUU UCA
b.) the polypeptides (amino acids):
serine, proline, alanine, phenylalanine, serine
c.) the original DNA code:
AGT CCA GGT TTT TCA

So What?
Protein synthesis is important because the proteins created during this process control the activities of the cells. It also forms the enzymes that catalyze the production of organic biomolecules that are essential for life. Therefore, many of the processes in the body would fail or work improperly without these proteins. The DNA in each cell contains the instructions on the formation of protein as well, which is why every cell in the body must have a copy of the DNA.

Duodenum: The duodenum consists of the first 25cm of the small intestine. Ducts from the gallbladder and pancreas join then empty into the duodenum. 

Jejunum and Ileum: The jejunum and ileum are the sites of the majority of chemical digestion and absorption. The long length of the jejunum and ileum also provides time for digestion to occur. Its walls 

Large Intestine/Colon: At the junction which joins the small intestine to the large intestine, there's a bind sac called the cecum which has an appendix. Furthermore, the colon includes three regions called the ascending colon, the transverse colon, and the descending colon. Moreover, various bacteria such as E. colin live in the colon and help to break down materials that cannot be digested by humans such as cellulose/fibre and produce some vitamins (i.e. Vitamin K) which we absorb and use. 

 
Roles of the Liver:
The liver has a number of functions which include:
1. Removes and metabolizes toxic substances (i.e. alcohol) from the blood.
2. Uses amino acids from the blood to produce proteins (i.e. prothrombin and fibrinogen, which are used in blood clotting).
3. Stores iron and the fat soluble vitamins A, D, K, and B12.
4. Converts the toxic amino acid breakdown product ammonia into urea which is less toxic.

Examples:
1. a.) Name the two digestive enzymes which are classified as proteases.
Trypsin and pepsin.
b.) Explain why these enzymes are classed as proteases.
These enzymes digests long polypeptides into short polypeptides.

So What?:
The small intestine is important because it contains bile (in the duodenum), which helps in preparation for chemical digestion. It also contains pancreatic juice, which has NaHCO3 and helps to neutralize the acid chyme, causing the pH of the small intestine to be slightly basic. Along with their role in chemical digestion, the jejunum and ileum are also the main sites of absorption of nutrients and water from the digestive tract into the blood and lymph. Whereas for the large intestine/colon, all three parts of the colon are involved in the absorption of water, salts, and some vitamins. Lastly, the liver helps to maintain homeostasis in the blood.