Lecture: Life Processes

Introduction

• Importance: Essential for board exams.
• Tools Needed: Notebooks, pens, textbooks, pencil.
• Focus: Nutrition, Respiration, Transportation, Excretion.

Nutrition

Definition

• Nutrition: Mode of intake and utilization of food.

Types of Nutrition

• Autotrophic: Self-prepared food (e.g., green plants via photosynthesis).
• Heterotrophic: Dependent on other organisms.
  • Saprophytic: Feeds on dead and decaying matter (e.g., fungi).
  • Parasitic: Depend on host organisms (e.g., ticks).
  • Holozoic: Ingestion of solid food (e.g., humans).

Photosynthesis

• Conversion of carbon dioxide and water into glucose and oxygen using sunlight and chlorophyll.
• Steps: Absorption of sunlight, splitting of water molecules, reduction of carbon dioxide.
• Equation: 6CO2 + 6H2O → C6H12O6 + 6O2.

Human Digestion

• Five Steps: Ingestion, Digestion, Absorption, Assimilation, Egestion.
• Digestive System: Buccal cavity, esophagus, stomach, small intestine, large intestine, rectum, anus.
• Accessory Glands: Salivary glands, liver, pancreas.

Enzymes in Digestion

• Salivary Amylase, Pepsin, Pancreatic Juices.

Respiration

Definition

• Respiration: Breakdown of glucose to release energy, known as cellular respiration.
• Types: Aerobic (with oxygen), Anaerobic (without oxygen).

Aerobic Respiration

• Occurs in mitochondria.
• Glucose separated into pyruvate (cytoplasm), then into carbon dioxide and water with energy (mitochondria).
• ATP: Energy currency of the cell.

Anaerobic Respiration

• Occurs in the absence of oxygen.
• In humans: Produces lactic acid and energy in muscles.
• In yeast: Produces ethanol and CO2 (fermentation).

Human Respiratory System

• Components: Nostrils, nasal cavity, pharynx, larynx, trachea, bronchi, lungs, alveoli.
• Mechanism of Breathing: Inhalation and exhalation involving diaphragm and rib cage movements.

Transportation

In Plants

• Xylem: Transports water and minerals from roots to aerial parts.
• Phloem: Transports food (glucose) from leaves to other parts.
• Transpiration: Loss of excess water, creating transpirational pull.
• Translocation: Movement of food via phloem using energy (ATP).

In Animals

Human Circulatory System

• Blood: Plasma (fluid) and cells (RBC, WBC, platelets).
• Blood Vessels: Arteries (away from heart), veins (towards heart), capillaries (exchange of gases).
• Heart: Four-chambered (atria and ventricles), allows double circulation (systemic and pulmonary circuits).

Excretion

In Plants

• Removal of wastes via transpiration, excretion of resins and gums, shedding of leaves, etc.

In Humans

• Excretory System: Kidneys (main organ), ureter, urinary bladder, urethra.
• Nephrons: Structural and functional units of kidneys.
• Urine Formation: Ultra-filtration in glomerulus, reabsorption in tubules.

Conclusion

• Recap: Life processes include Nutrition, Respiration, Transportation, and Excretion.
• Importance: Essential for exam preparation and understanding basic biological functions.