Biological Molecules & Carbohydrates

• Biological molecules are large, essential molecules built from smaller organic molecules
• Biological molecules are composed of carbon, hydrogen, and oxygen, with some containing nitrogen, phosphorus, and sulfur (CHONPS)
• There are four main types of biological molecules: nucleic acids, carbohydrates, lipids, and proteins
• Nucleic acids' building blocks are nucleotides
• Carbohydrates' building blocks are monosaccharides
• Lipids' building blocks are fatty acids
• Proteins' building blocks are amino acids

Carbohydrates

• Carbohydrates function as short-term energy storage in cells
• Carbohydrates are also structural components of cell walls and cytoskeletons
• Carbohydrates are found inside vacuoles or dissolved in the cytoplasm
• Carbohydrates are polymers of monosaccharides
• Carbohydrates are made of carbon, hydrogen, and oxygen (CHO)
• Chloroplasts produce carbohydrates during photosynthesis
• Monosaccharides consist of 3, 5, or 6 carbons
• Triose's major examples are glyceraldehyde
• Pentose's major examples are ribose and deoxyribose
• Hexose's major examples are glucose, fructose, and galactose
• Disaccharides are made by binding two monosaccharides together via a glycosidic bond Glucose + glucose = maltose (grains)
• Glucose + galactose = lactose (milk)
• Glucose + fructose = sucrose (table sugar)
• Polysaccharides are built from hundreds or thousands of monosaccharides, typically glucose
• Cellulose is the most abundant natural biopolymer
• Chitin is a long-chain polymer of N-acetylglucosamine, creating arthropod exoskeletons and fungi cell walls

Lipids

• Lipids are a diverse group of nonpolar compounds, some containing phosphorus (CHOP)
• Lipids serve as long-term energy storage, form biological membranes, produce hormones, and provide insulation The main lipid types are fats, oils, phospholipids, steroids, waxes, and carotenoids
• Fats and oils consist of fatty acids (long chains of carbon and hydrogen) and a glycerol molecule
• Fatty acids are either saturated (single bonds only) or unsaturated (one or more double bonds)
• Fats are animal lipids, solid at room temperature, and usually saturated
• Oils are vegetable lipids, liquid at room temperature, and usually unsaturated
• Fats are stored within adipose cells in animals and insulate against cold temperatures
• Oils are found in seeds
• Required dietary lipids or made in the body
• Omega-3 and omega-6 fatty acids are essential
• Phospholipids are composed of glycerol, two fatty acids, and a phosphate group
• Phospholipids are amphiphilic molecules, containing both hydrophilic and hydrophobic portions
• Phospholipids are major components of biological membranes Steroids are lipids with 4 fused rings
• They are part of membranes, form hormones, and are derived from cholesterol
• Cholesterol can both be produced by the liver and ingested
• Cholesterol is a component of bile and a precursor to vitamin D
• Waxes are long chains of carbon and hydrogen with an alcohol group in the middle
• Waxes are highly hydrophobic, preventing water from sticking on the surface
• Waxes cover aquatic bird feathers and plant leaf surfaces
• Carotenoids are lipids produced by organisms and act as pigments
• Carotenoids involve photosynthesis and vision by absorbing light wavelengths
• Carotenoids are precursors of vitamin A (retinol) They need to be ingested to increase the absorption when ingested with other lipids

Proteins

• Proteins are polymers of amino acids that are made of carbon, hydrogen, oxygen, nitrogen and sometimes sulphur (CHONS)
• The ribosomes produces protein
• Proteins act as enzymes, receptors, signal molecules, transport, hormones, contractile, and defense.
• Some amino acids are produced by the body, but others must be ingested
• Amino acids all have the same structure: a central carbon (α C), amino group, carboxyl group, a hydrogen and a radical (R)
• Amino acids are bound together by a peptide bond
• Few amino acids together form a peptide (e.g., glutathione)
• Hundreds of amino acids together form a polypeptide (e.g., titin)

Nucleic Acids

• Nucleic acids are polymers of nucleotides made of carbon, hydrogen, oxygen, nitrogen and phosphorous (CHONP)
• They carry the genetic blueprint and the instructions for the functioning of the cell
• In eukaryotic cells, nucleic acids present in the nucleus, can also be found in the nucleoid of prokaryotes that are in the cytoplasm
• Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA) are two types of nucleic acids
• Nucleotides are made of Phosphate group, Pentose and Nitrogenous base
• Pentose include Ribose → RNA, and Deoxyribose → DNA
• Nitrogenous base are Adenine (A), Thymine (T) , Guanine (G), Cytosine (C) and Uracil (U) → only in RNA
• Adenine, Thymine, Guanine base code for DNA
• The sequence of bases in the DNA is used to make a protein
• Bases can be paired with each other to join two strands of nucleic acids

Biochemical Food Tests Summarized

• Vitamin C presence can be tested with DCPIP solution with the purple substance turning colorless when the acid is present
• A Starch Test requires placing food on a white tile and adding drop of lodine to the food, colour change will indicate presence
• A Protein Test is done by adding Biuret's to the suspension tested, colour change will indicate presence
• A Reducing Sugar Test is done by adding Benedict's to the test tube with food within, heat the test-tube to look for a colour change
• A Lipid Emulsion test first requires adding the the food to ethanol test-tube; Then add water, cover the test tube and shake

Explore biological molecules and their building blocks: nucleic acids, carbohydrates, lipids, and proteins. Focus on carbohydrates, their function as short-term energy storage, structural components, and composition of monosaccharides. Learn about the role of chloroplasts in carbohydrate production during photosynthesis.