Biology Class: Digestion & Macromolecules

The Function of Digestion

• Digestion is crucial for providing nutrients for energy and growth.
• Appropriate terminology related to animal anatomy is used.
• The anatomy of the digestive system is explained.

Macromolecules & Living Systems

• The three main fluid compartments in the body are cytoplasm (inside cells), interstitial fluid (between cells), and blood plasma.
• These compartments contain thousands of inorganic ions and molecules like water, phosphates, hydrogen ions, and sodium ions.
• Fluids move freely in and out of cells in both directions.
• Cells (25L), Interstitial fluid (12L), and Plasma (3L) make up the fluid compartments of the body.

Diffusion

• Diffusion is the movement of molecules from an area of high concentration to an area of low concentration, important in biological processes.

Macromolecules

• Macromolecules are organic molecules containing carbon and hydrogen bonds, which can also be bonded to other atoms like oxygen, nitrogen, and sulfur.
• Larger and more complex assemblies of organic molecules are also known as nutrients.
• Nutrients provide energy, regulate cellular activities, and build and repair tissues.

Macromolecules in Organisms

• Some carbohydrates store energy for future needs.
• Lipids are key structural components of cell membranes.
• Nucleic acids store and transfer hereditary information, and guide protein production.
• Proteins are structural supports and perform specific jobs in cells, like catalyzing reactions and transmitting signals.

The Digestive System

• All cells in the human body need energy from food to function.
• Heterotrophs, like humans, rely on consuming other organisms to obtain nutrients.

Food for Energy

• Nutrients provide energy for all biological processes and physical activity.
• All organisms require chemical energy for basic life functions.

Cellular Respiration

• Cellular respiration is the process of breaking down glucose and oxygen to produce carbon dioxide, water, and ATP (energy).
• The chemical equation for this process is C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP

Nutrients

• Macronutrients (carbohydrates, proteins, and lipids) are needed in large quantities.
• Micronutrients (vitamins and minerals) are needed in small quantities.
• Water is also essential for many bodily functions.

Metabolism

• Metabolism is a set of chemical reactions in living organisms to maintain life.
• Catabolism breaks down large molecules into smaller ones (e.g., digestion).
• Anabolism builds larger molecules from smaller ones (e.g., building muscle).

Biomolecules

• Carbohydrates, lipids, proteins, and nucleic acids are the four main biomolecules.

Breaking Down Macronutrients

• Macronutrients come in the form of polymers (made of monomers).
• The digestive system breaks down polymers into monomers the body can use.

Carbohydrates

• Carbohydrates are the main source of energy, made of carbon, hydrogen, and oxygen.
• Examples include glucose, fructose, lactose, maltose, starch, glycogen, and cellulose.

Carbohydrates and Diet

• About 55% of daily calories should come from carbohydrates.
• Good sources include grains, fruits, and vegetables.
• Excessive carbohydrates can lead to high blood sugar and weight gain.

Proteins

• Proteins are large, complex molecules made of amino acids.
• The type, sequence, and folding of a protein determine its unique properties.
• There are 20 amino acids, 11 produced by the body, and 9 that must come from the diet.
• Proteins are important for structure, enzymes, hormones, transportation, and antibodies.

Proteins in Diet

• Good sources of protein include animal products (eggs, meat, fish, cheese) and plant products (beans, lentils, seeds, nuts).
• Protein should make up 10-30% of a person's daily energy intake.

Lipids

• Lipids (fats and oils) are made of fatty acids bonded to a glycerol molecule (triglyceride).
• Saturated fats are usually solid at room temperature (e.g., meat, butter).
• Unsaturated fats are liquid at room temperature (e.g., avocado, olive oil, fish oil).

Lipid Functions

• Lipids are crucial for long-term energy storage, cell membrane structure, hormone production, and insulation.

Lipids in Diet

• Some essential fatty acids must be obtained from the diet, specifically omega-3 fatty acids.
• Lipids are important for health, preventing heart disease and arthritis.
• Sources include fish, oil, and nuts.

Micronutrients (Vitamins)

• Vitamins are organic substances needed for growth and function, but they don't provide calories.
• Fat-soluble vitamins (A, D, E, K) are stored in tissues
• Water-soluble vitamins (B, C) are not stored in the body.

Micronutrients (Minerals)

• Minerals are inorganic elements found in both plants and animals, crucial for various bodily functions.
• Examples include calcium for strong bones, potassium for fluid balance, and iron for red blood cells.

Water

• Water makes up about 60% of the human body.
• Water is essential for many chemical reactions, maintaining blood volume, regulating temperature, and hydrolysis.

Functions of the Digestive System

• Ingestion is taking food and water into the body.
• Digestion breaks down food into useable macronutrients via mechanical and chemical means.
• Absorption moves nutrients from the digestive system to the bloodstream.
• Elimination removes undigested material