Understanding Macromolecules and Carbohydrates

• Macromolecules contain a significant number of atoms and are vital for biological functions.
• The most important macromolecules are carbohydrates, lipids, proteins, and nucleic acids.
• Macromolecules are composed of smaller units known as monomers, which serve as building blocks.

Carbohydrates

• Carbohydrates consist of carbon, hydrogen, and oxygen atoms, serving as a primary energy source.
• Carbohydrates come in the variations of monosaccharides, also known as simple sugars, and polysaccharides.
• Monosaccharides cannot be broken down into smaller sugar molecules.
• Common monosaccharides include glucose, fructose, and galactose.
• Polysaccharides are complex carbohydrates made of many monosaccharide molecules linked.
• Polysaccharides break down into individual sugar molecules during digestion.
• Polysaccharides act as long-term energy storage and provide structural support.
• Starch is a polysaccharide found in plants, working as the primary storage form of energy.
• Glycogen is the storage form of glucose in animals, stored in the liver and muscles.
• Cellulose is a polysaccharide in plant cell walls which humans cannot digest, but it is essential as dietary fiber.
• Carbohydrates break down into glucose during digestion and are absorbed in the small intestine.
• Glucose is transported from intestinal epithelial cells into the bloodstream via the GLUT2 transporter.
• The liver regulates blood sugar levels, storing excess glucose as glycogen or releasing glucose into the bloodstream when needed.

Lipids

• Lipids are composed of glycerol and fatty acid chains, essential for energy storage, insulation, cushioning, and cell membranes.
• Lipids exist as phospholipids, steroids, and triglycerides.
• Phospholipids form the basic structure of cell membranes with a hydrophilic head and hydrophobic tails.
• Steroids act as messengers and regulators, with cholesterol being a key component for cell membranes and hormones.
• Triglycerides consist of three fatty acid molecules attached to a glycerol molecule.
• Fatty acids are the building blocks of fats and can be saturated or unsaturated.
• Saturated fatty acids are bonded with hydrogen atoms, solid at room temperature, and commonly associated with cardiovascular disease.
• Unsaturated fatty acids have carbon atoms connected by double bonds, liquid at room temperature.
• Glycerol is a simple polyol compound and a component of many lipids, including triglycerides.
• Triglycerides are a major source of energy and are broken down into fatty acids and glycerol during digestion.
• Excess calories are converted into triglycerides and stored in fat cells.
• Healthy triglyceride levels are crucial for overall health.

Proteins

• Proteins are polymers of amino acids that perform essential functions.
• Proteins build and repair tissues and facilitate bodily processes.
• Muscles are made of proteins that repair and strengthen muscle fibers after exercise.
• Protein-rich foods are broken down into amino acids, which rebuild damaged muscle tissues.
• Enzymes are a type of protein act as catalysts, speeding up chemical reactions.
• Amino acids contain nitrogen and are the building blocks of proteins.
• Organisms break proteins into amino acids, which plants and animals assimilate to build their own proteins.
• Plants convert nitrogen compounds into amino acids through enzymatic reactions.
• There are 20 types of amino acids, where nine are essential amino acids that must come from food.

Nucleic Acids

• Nucleic acids store and transmit genetic information, existing as DNA and RNA.
• DNA holds the blueprint of our bodies.
• RNA takes instructions from DNA and helps build proteins.