Topic 3.2: Carbohydrates, Lipids, and Proteins

Assessment Statements• 3.2.1: Distinguish between organic and inorganic compounds• 3.2.2: Identify amino acids, glucose, ribose and fatty acids from

diagrams showing their structure• 3.2.3: List three examples each monosaccharides, disaccharides,

and polysaccharides• 3.2.4: State one function of glucose, lactose, and glycogen in

animals, and of fructose, sucrose, and cellulose in plants• 3.2.5: Outline the role of condensation and hydrolysis in the

relationships between monosaccharides, disaccharides and polysaccharides; between fatty acids, glycerol and triglycerides; and between amino acids and polypeptides

• 3.2.6: State three functions of lipids• 3.2.7: Compare the use of carbohydrates and lipids in energy

storage

Introduction to carbohydrates, lipids, proteins, and nucleic acids

Molecule Subcomponents

Carbohydrates Monosaccharides

Lipids Glycerol and fatty acids

Protein (polypeptides) Amino acids

Nucleic acids Nucleotides

Common biochemical's and their structure

• Molecules can be classified as being either inorganic or organic– All organic molecules contain the element carbon,

although not all carbon-containing molecules are organic• CO2

Common biochemical's and their structure

Category Subcategory Example molecules

Carbohydrates Monosaccharides Glucose, galactose, fructose

Disaccharides Maltose, lactose, sucrose

Polysaccharides Starch, glycogen, cellulose

Protein Enzymes, antibodies

Lipids Triglycerides, phospholipids

Nucleic acids DNA, RNA

Molecule StructureAmino Acids

Glucose

Ribose

Molecule Structure

Fatty Acids

Functions of carbohydrates in animals and plants

• Carbohydrates exist in different sizes

• Monosaccharides

• Dissaccharides

• Polysacchrides

Functions of carbohydrates in animals and plants

• All of these carbohydrates serve many functions in living organisms

• Animals:Name Type One Function

Glucose Monosaccharide Chemical fuel for cell respiration

Lactose Disaccharide Makes up some of the solutes in milk

Glycogen Polysaccharides Stores glucose in liver and muscles

Functions of carbohydrates in animals and plants

• Plants

Name Type One Function

Fructose Monosaccharide Found in many fruits (makes them sweet)

Sucrose Disaccharide Often transported from leaves of plants to other locations in plants by vascular tissue

Cellulose Polysaccharide One of the primary components of plant cell walls

Role of Lipids

• Lipids are biochemically important molecules that serve many functions.

• Triglyceride lipids– Solid form as fats– Liquid form as oils

• If you eat more food than you burn, your body will store much of the excess as fat in adipose cells– Adipose cells get smaller or larger depending on how

much lipids is being stored

Role of Lipids

• Lipids are very efficient molecules for storing energy– Glycogen is a carbohydrate used by animals to

store energy– Starch is a carbohydrates used by plants to store

energy• Equal mass of carbohydrates and lipids, the

lipid stores approximately twice as much chemical energy as the carbohydrates

Role of Lipids

• Lipids are also important for thermal insulation– Blubber!!!

Condensation and hydrolysis reactions

• A condensation reaction is responsible for building large molecules. An enzyme catalyzes the reaction between alcohol groups on adjacent monomer units (eg. glucose). This results in the production of a polymer and a molecule of water.

• A-H + B-OH --> A-B + H2O

Condensation and hydrolysis reactions

• A hydrolysis reaction is responsible for breaking down large molecules (eg. digestion). An enzyme weakens the bond between two parts of a polymer, allowing for the insertion of a water molecule into the bond. This results in the production of monomers.

• A-B + H2O --> A-H + B-OH

Condensation and hydrolysis reactions

• Digesting Food– Food are chemically digested in your alimentary

canal• Digestive enzymes that accomplish this are hydrolysing

enzymes• Each reaction requires a molecule of water as a

reactant