Respiration and Energy Production

Respiration: An Introduction

• Breathing is inhaling and exhaling air.
• Breathing brings oxygen into contact with specialized tissue, maximizing oxygen transfer.
• Oxygen is crucial for creating energy for the cells.

Aerobic Cellular Respiration

• Obtaining energy from glucose and oxygen reactions.
• This process occurs in the mitochondria.
• The chemical equation is: C₆H₁₂O₆ + 6 O₂ + 36ADP + 36Pi → 6CO₂ + 6 H₂O + 36ATP.
• Breaking down glucose with oxygen produces ATP, vital for cell functions like growth, reproduction, and movement.
• Most energy is lost as heat, and ~36% is used to create ATP.
• ATP is made using energy from glucose breakdown.
• This energy drives the phosphorylation of ADP into ATP.
• ADP + a phosphate group forms ATP.

Gas Exchange

• Exchange of carbon dioxide and oxygen between the external environment and the internal environment (blood in capillaries).
• In single-celled organisms, and simple multicellular organisms, oxygen diffuses into cells and carbon dioxide diffuses out.
• Complex multicellular organisms rely on specialized tissue for gas exchange to maximize oxygen and carbon dioxide diffusion.
• Oxygen enters the lungs, absorbed by red blood cells, transported throughout the body, dissolving into interstitial fluid, and diffusing into cells to produce ATP.
• Carbon dioxide follows a reverse path, exiting the body via the lungs .

Ventilation

• Movement of air in and out of the lungs.
• The process involves inspiration (inhaling) and expiration (exhaling).

Human Gas Exchange Structures

• Nasal Cavity: Contains 3 bony plates (conchae) lined with mucus membrane, trapping debris with hair and mucus, and warming and moistening air.
• Pharynx: Common passageway for air and food, leading to the trachea and esophagus.
• Epiglottis: Flap of tissue that prevents food and liquid from entering the trachea.
• Larynx: Contains vocal chords, producing sound when air passes through them.
• Trachea: Tube from the larynx to the lungs; consists of cartilage rings to prevent collapse during breathing. Includes cilia, hair-like extensions, to move mucus and trapped particles towards the pharynx.
• Bronchi: Tubes from trachea to lungs, containing cartilage rings for support and cilia for debris removal.
• Bronchioles: Microscopic tubes branching within the lungs, leading to alveoli and lacking cartilage rings.
• Alveoli: Microscopic air sacs in the lungs (approximately 300 million) with thin walls, enabling efficient O2 and CO2 exchange via capillaries.
• Lungs: Two lobes in the left lung and three lobes in the right lung, enclosed by the pleural membranes.
• Diaphragm: Thin sheet of muscle below the lungs, crucial for breathing by changing the volume of the thoracic cavity.
• Ribs: Protect the thoracic cavity and aid in breathing by expanding the thoracic cavity using intercostal muscles between them.

This quiz covers the basics of respiration, including the processes of inhaling and exhaling air, aerobic cellular respiration, and gas exchange. Understand how oxygen is vital for energy production in cells and the biochemical reactions involved. Get ready to test your knowledge on these essential biological concepts!