Biology Chapter: Diffusion and Factors

Diffusion

• Movement of particles occurs from higher concentration to lower concentration, termed as moving down a concentration gradient.
• Movement against the concentration gradient occurs from lower to higher concentration.
• Key reasons for diffusion include the random kinetic movement of molecules and the presence of a concentration difference.

Factors Affecting Rate of Diffusion

• Temperature: Higher temperatures increase kinetic energy, thereby increasing diffusion rates (e.g., holding an alcohol-filled tube increases its diffusion rate).
• Distance of Diffusion: Longer distances lead to slower diffusion, while shorter distances facilitate quicker diffusion.
• Air Current: Favorable air currents can enhance diffusion rates when they align with the direction of diffusion.
• Stirring: Agitation boosts diffusion by increasing molecular kinetic energy.
• Molecule Size: The rate of diffusion is inversely proportional to the size of molecules; larger molecules diffuse slower.
• Surface Area to Volume Ratio: A higher surface area relative to volume enhances diffusion rates.

Active Transport

• Active transport involves moving particles into or out of cells against their concentration gradient, requiring energy from respiration.
• Utilizes carrier proteins located in cell membranes that bind to specific particles.

Factors Affecting Active Uptake

• Mitochondria Count: More mitochondria increase energy availability through aerobic respiration, enhancing active transport.
• Oxygen Concentration: Increased oxygen levels elevate the rate of aerobic respiration, impacting active uptake.
• Carrier Protein Availability: The number of carrier proteins in the membrane directly influences the rate of active transport.

Diffusion

• Movement of particles occurs from higher concentration to lower concentration, termed as moving down a concentration gradient.
• Movement against the concentration gradient occurs from lower to higher concentration.
• Key reasons for diffusion include the random kinetic movement of molecules and the presence of a concentration difference.

Factors Affecting Rate of Diffusion

• Temperature: Higher temperatures increase kinetic energy, thereby increasing diffusion rates (e.g., holding an alcohol-filled tube increases its diffusion rate).
• Distance of Diffusion: Longer distances lead to slower diffusion, while shorter distances facilitate quicker diffusion.
• Air Current: Favorable air currents can enhance diffusion rates when they align with the direction of diffusion.
• Stirring: Agitation boosts diffusion by increasing molecular kinetic energy.
• Molecule Size: The rate of diffusion is inversely proportional to the size of molecules; larger molecules diffuse slower.
• Surface Area to Volume Ratio: A higher surface area relative to volume enhances diffusion rates.

Active Transport

• Active transport involves moving particles into or out of cells against their concentration gradient, requiring energy from respiration.
• Utilizes carrier proteins located in cell membranes that bind to specific particles.

Factors Affecting Active Uptake

• Mitochondria Count: More mitochondria increase energy availability through aerobic respiration, enhancing active transport.
• Oxygen Concentration: Increased oxygen levels elevate the rate of aerobic respiration, impacting active uptake.
• Carrier Protein Availability: The number of carrier proteins in the membrane directly influences the rate of active transport.

Explore the principles of diffusion, including movement across concentration gradients and the factors affecting the rate of diffusion. Understand how temperature, distance, air currents, stirring, and molecule size influence diffusion dynamics in biological systems.