Biology: Digestion and Macromolecules

Macromolecules

• Types: Carbohydrates, Proteins, Lipids, Nucleic acids
• Functions: Energy storage, structural components, enzymes, information transfer
• Energy storage: Carbohydrates (short-term), lipids (long-term)

Human Digestive System

• Stages of digestion: Ingestion, digestion, absorption, assimilation, egestion
• Digestive organs: Mouth, esophagus, stomach, small intestine, large intestine, liver, pancreas, gallbladder

Ingestion

• Mechanical digestion: Chewing breaks down food into smaller pieces
• Chemical digestion: Saliva contains amylase that begins starch digestion

Digestion

• Digestive enzymes: Proteases (proteins), lipases (lipids), amylases (carbohydrates)
• Peristalsis: Wave-like muscle contractions that move food through the digestive tract

Absorption

• Villi in small intestine: Increase surface area for nutrient absorption
• Liver: Processes absorbed nutrients, detoxifies harmful substances, produces bile

Respiration and Breathing

• Breathing: Physical process of inhaling and exhaling
• Respiration: Chemical process of producing energy from glucose

Organs Involved in Ventilation

• Lungs: Main organ of gas exchange
• Diaphragm: Muscle that contracts to allow air into the lungs
• Chest and rib muscles: Assist in expanding and contracting the chest cavity

Requirements for Gas Exchange

• Respiratory surface: Alveoli provide a large surface area for gas exchange
• Moisture: Keeps alveolar surface moist to facilitate gas diffusion
• Concentration gradient: Maintained by continuous blood flow and breathing

Anaerobic vs. Aerobic Respiration

• Aerobic respiration: Uses oxygen, produces more energy (ATP), byproducts are CO2 and H2O
• Aerobic respiration equation: Glucose + Oxygen → Carbon dioxide + Water + Energy
• Anaerobic respiration: Does not use oxygen, produces less energy, byproducts include lactic acid (in muscles)
• Anaerobic respiration equation: Glucose → Lactic acid + Energy

Transport in Organisms - Cardiovascular System

• Features of arteries: Thick-walled, carry blood away from the heart
• Features of veins: Thin-walled, carry blood to the heart, have valves
• Features of capillaries: Microscopic, thin walls for exchange of substances with tissues

Heart Anatomy

• Path of blood flow: Right atrium → right ventricle → lungs → left atrium → left ventricle → body
• Cardiac cycle: Sequence of events in one heartbeat

Blood Composition

• Components: Red blood cells (oxygen transport), white blood cells (immune defense), platelets (clotting), plasma (transport medium)

Transport in Organisms - Plants

• Transport: Xylem (water and minerals), Phloem (sugars)
• Leaf anatomy: Mesophyll (photosynthesis), stomata (gas exchange)

Transpiration

• Process: Loss of water vapor from the plant, mainly through stomata
• Factors: Light, temperature, humidity, wind

Photosynthesis

• Rate and limiting factors: Light intensity, carbon dioxide concentration, temperature
• Equation: Carbon dioxide + Water + Light energy → Glucose + Oxygen