Nutrients and Their Functions

Nutrients and Their Functions

• Proteins build and repair body tissues, especially muscles
• Good sources of proteins are eggs, chicken, fish, tofu, and legumes
• Carbohydrates provide quick energy to the body
• Simple carbohydrates include glucose and sucrose which provides fast energy
• Complex carbohydrates include starch and whole grains which provides longer-lasting energy
• Fiber aids digestion but isn't a direct energy source
• Lipids (fats) provide long-term energy, help with vitamin absorption, and insulation
• Healthy fats are found in nuts, avocado, and olive oil
• Unhealthy fats are found in deep-fried food, butter, and bacon
• Vitamin C boosts the immune system and is found in citrus fruits
• Vitamin D, strengthened by sunlight, strengthens bones.
• Calcium and phosphorus are important minerals for bone health
• Magnesium prevents muscle cramps and is found in leafy greens
• Zinc supports the immune system
• Potassium is necessary for nerve function and is found in bananas
• Sodium regulates water/fluid balance in the body
• Water is essential for all body processes and is included in the base of the food pyramid

Recommended Energy and Nutrient Intake (RENI)

• The Recommended Energy and Nutrient Intake (RENI) provides guidelines for daily nutrient needs
• The recommendations vary based on age, gender, and activity level
• RENI is used to promote health and prevent nutrient deficiency

The Food Pyramid

• The base of the food pyramid consists of water and healthy beverages, which should be consumed the most
• The top of the food pyramid consists of fats, oils, and sweets, which should be consumed the least

Digestive System and Nutrient Absorption

• Enzymes help break down food into nutrients
• Nutrients can't be absorbed properly without enzymes
• Healthy Digestive Practices include eating fiber-rich foods, drinking enough water, staying physically active, and avoiding fried/processed foods
• The digestive system works with the circulatory system to transport nutrients throughout the body

Nutrient-Related Scenarios

• Feeling tired despite eating may be due to consuming too much sugar or junk food, leading to a lack of sustained nutrients
• Difficulty focusing in class could be due to skipping breakfast, resulting in a missed energy boost
• Muscle cramps may be caused by low magnesium levels
• Weak bones can result from low calcium and vitamin D levels
• A weak immune system can be due to low vitamin C or zinc levels

Extra Nutritional Facts

• Macronutrients are needed in large amounts and include carbohydrates, fats, and proteins
• Micronutrients are needed in small amounts and include vitamins and minerals
• Lactose is a disaccharide from glucose + galactose and is found in milk
• Maltose is made of glucose + glucose

Digestive System Overview

• The digestive system breaks down food into smaller molecules
• It absorbs nutrients into the bloodstream
• It eliminates solid waste

Major Processes in Digestion

• Mechanical digestion physically breaks food into smaller pieces
• Mechanical digestion begins in the mouth (chewing by teeth, movement by tongue) and continues in the stomach through churning
• Chemical digestion uses enzymes and acids to break food into molecules the body can absorb
• Chemical digestion begins in the mouth with saliva and continues in the stomach and small intestine

Organs and Their Functions

• The mouth is the site of both mechanical (chewing) and chemical (saliva) digestion
• Saliva contains amylase, which begins carbohydrate digestion
• The tongue helps to move food for chewing and swallowing and pushes food toward the pharynx (throat) for swallowing
• Teeth mechanically break food into smaller pieces for easier digestion
• Saliva moistens food and contains amylase that chemically digests starch into sugars
• The esophagus is a muscular tube that transports food from mouth to stomach using peristalsis, and no digestion occurs here
• The stomach churns food (mechanical digestion) and releases gastric juices like pepsin to digest proteins (chemical digestion)
• The small intestine is the main site for chemical digestion and nutrient absorption
• The small intestine works with enzymes from the pancreas and bile from the liver and nutrients are absorbed through villi into the bloodstream
• The large intestine absorbs water and forms and stores waste before elimination
• The liver produces bile, which helps digest fats (by emulsifying them)
• Bile is not an enzyme, but it helps enzymes break down fats
• The pancreas produces digestive enzymes (e.g., lipase, amylase, trypsin) sent to the small intestine
• The digestive enzymes help break down fats, carbohydrates, and proteins
• The gallbladder stores bile from the liver, and it is released into the small intestine when needed for fat digestion
• The rectum stores undigested waste before elimination and does not participate in digestion

Enzymes in Digestion

• Amylase, found in saliva and the pancreas, breaks starch into sugars (carbs)
• Pepsin, found in the stomach, breaks proteins into amino acids
• Enzymes are proteins that act as catalysts for chemical digestion

Sequence of Digestion (Pathway of Food)

• Digestion follows this sequence: Mouth → Esophagus → Stomach → Small Intestine → Large Intestine → Rectum → Anus

Summary: Digestion in Action

• The mouth's main role in digestion is mechanical (chewing) and chemical (saliva) digestion
• The tongue moves food for chewing and swallowing
• The esophagus moves food to the stomach
• The stomach churns and digests proteins
• The small intestine is the main site of absorption and final digestion
• The large intestine absorbs water and forms feces
• The liver produces bile to help digest fats
• The gallbladder stores bile until needed
• The pancreas produces enzymes for chemical digestion
• The rectum stores waste before elimination

What is Taxonomy?

• Taxonomy is the branch of biology that deals with classifying and naming organisms
• Taxonomy helps scientists understand relationships between species
• Systematics is a related term and refers to the broader science of classifying organisms and studying evolutionary relationships

Binomial Nomenclature

• Binomial nomenclature was developed by Carolus Linnaeus, known as the "Father of Taxonomy"
• It uses two names: Genus (first word, always capitalized) and Species (second word, lowercase)
• Both names are italicized (or underlined when handwritten)

Taxonomic Hierarchy (from Broadest to Most Specific)

• The taxonomic hierarchy: Kingdom → Phylum → Class → Order → Family → Genus → Species
• A mnemonic is: King Philip Came Over For Great Spaghetti
• Kingdom is the broadest and includes the most organisms
• Species is the most specific and refers to a single kind of organism
• The scientific name of the lion is Panthera leo: Panthera = Genus, leo = Species

Domains and Kingdoms

• According to the Three-Domain System (by Carl Woese): Bacteria are single-celled with no nucleus, Archaea are single-celled, live in extreme environments, with no nucleus, and Eukarya are cells with a nucleus (includes plants, animals, fungi, protists)
• The Six Kingdoms of Life include: Plantae (e.g., Zea mays, Mangifera indica), Animalia (e.g., humans, Canis familiaris = dog), Fungi, Protista, Bacteria, and Archaea

Classification Approaches

• Artificial classification is based on external features (e.g., color, size)
• Phylogenetic classification is based on evolutionary relationships
• Scientists use DNA evidence, structure, and ability to reproduce to determine species

Species Concept and Biodiversity

• A species is a group of organisms that can interbreed and produce fertile offspring
• Organisms that look alike are not necessarily the same species
• Biodiversity refers to the variety of life in an ecosystem
• The benefits of biodiversity include: Stability of ecosystems, Natural resource availability, and Medical and agricultural advances
• Loss of biodiversity makes ecosystems more vulnerable and not stronger

Study Tips for Mastering Science

• Understand, don’t just memorize: Focus on why things happen, not just what happens
• Use mnemonics for lists such as King Philip Came Over For Great Spaghetti which is used for the taxonomic ranks of Kingdom, Phylum, Class, Order, Family, Genus, Species
• Make flashcards, write terms on one side (e.g., Amylase) and functions on the back (e.g., breaks down starch in the mouth); quiz yourself or a friend regularly
• Use diagrams and flowcharts to label parts of the digestive system and draw arrows showing how food moves or create a classification tree for common animals and plants
• Explaining topics to a classmate, sibling, or even to yourself out loud helps you retain information better
• Apply real-life connections, link facts to real-world experiences and when you eat rice, remember amylase starts digesting it in your mouth
• Study in short bursts using the Pomodoro Technique for 25 minutes, take a 5-minute break, and after 4 rounds, take a longer 15–20 minute break to help avoid burnout and boost focus
• Practice with quizzes, create mock tests from your reviewers, and Use multiple choice or matching types based on your digest
• Stay relaxed and positive, don’t cram the night before, and Get enough sleep, drink water, and eat nutritious food especially before an exam