Life Processes

Introduction

• Life processes are essential for maintaining and repairing organisms.
• All living things are made up of cells, which require maintenance and repair through life processes.
• Two main functions of life processes:
  • Supply of new materials
  • Removal of waste materials
• Four primary life processes:
  1. Nutrition
  2. Respiration
  3. Transportation
  4. Excretion

Nutrition

In Plants

• Plants prepare their own food through photosynthesis using water, carbon dioxide, and sunlight.
• Photosynthesis Definition: Process where plants produce oxygen and glucose.
• Photosynthesis occurs in chloroplasts within plant leaves.
• Steps of Photosynthesis:
  1. Chlorophyll in chloroplasts absorbs sunlight.
  2. Water molecules split into hydrogen and oxygen.
  3. Hydrogen reacts with carbon dioxide to form glucose.
• Proteins are formed in plants using nitrogen from the soil.

In Human Beings

• Begins in the mouth, ends at the anus.
• Digestive System Components:
  • Mouth: Food is chewed and mixed with saliva, containing salivary amylase.
  • Esophagus: Moves food to stomach through peristaltic movements.
  • Stomach: Uses gastric juice (containing pepsin, hydrochloric acid, mucus).
  • Small Intestine: Enzymes from pancreas and liver complete digestion. Nutrients absorbed by villi.
  • Large Intestine: Absorbs water, excretes waste.

Respiration

• Releases energy from glucose.

Aerobic Respiration

• Requires oxygen.
• Occurs in mitochondria, produces ATP.
• ATP: „Cell currency", provides energy for cellular activities.

Anaerobic Respiration

• Does not require oxygen.
• Less ATP produced.
• Occurs in bacteria, yeast, muscle cells under oxygen-deprived conditions (produces lactic acid).

Transportation

In Humans

• Involves heart, blood, and blood vessels.
• Heart:
  • Pumps deoxygenated blood from body to lungs.
  • Pumps oxygenated blood from lungs to body.
• Blood Vessels:
  • Arteries: Carry oxygenated blood.
  • Veins: Carry deoxygenated blood.
  • Capillaries: Connect arteries and veins.
• Lymphatic System:
  • Transports lymph, absorbs fats, returns extracellular fluid to bloodstream.

In Plants

• Energy requirement is lower, transport is slower.
• Xylem: Transports water (via roots, stems, leaves).
• Phloem: Translocates food materials (glucose) upwards and downwards using ATP.

Excretion

In Humans

• Removes nitrogenous wastes (urea, uric acid).
• Excretory system components:
  • Kidneys: Filter blood through nephrons.
  • Ureters: Transport urine to bladder.
  • Bladder: Stores urine.
  • Urethra: Excretes urine.
• Nephrons filter blood, reabsorb nutrients, excrete waste as urine.

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These notes summarize key points about life processes, as covered in the lecture.