Biology Chapter: Diffusion and Factors

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Questions and Answers

What does 'down a concentration gradient' refer to?

Movement without any concentration difference

Movement from higher to lower concentration (correct)

Movement against the flow of particles

Movement from lower to higher concentration

Which factor does NOT affect the rate of diffusion?

Pressure (correct)

Temperature

Molecular size

Distance of diffusion

How does temperature impact the rate of diffusion?

Has no effect on diffusion rate

Increases kinetic energy, hence increases diffusion rate (correct)

Only affects diffusion rate in liquids

Decreases kinetic energy, leading to slower diffusion

What movement is characteristic of active transport?

Requires energy to move against a concentration gradient Signup and view all the answers

Which of the following enhances the rate of active transport?

Increase in the number of carrier proteins Signup and view all the answers

What effect does stirring have on diffusion?

Increases the rate of diffusion Signup and view all the answers

What is the relationship between molecular size and rate of diffusion?

Larger molecules diffuse more slowly Signup and view all the answers

Which process describes the use of energy to move particles into a cell against their concentration gradient?

Active uptake Signup and view all the answers

What effect does surface area to volume ratio have on diffusion?

Directly proportional to diffusion rate Signup and view all the answers

Which of the following factors affects aerobic respiration in relation to active transport?

Concentration of oxygen Signup and view all the answers

What is the primary reason for the movement of particles in diffusion?

Random movement of particles due to thermal energy Signup and view all the answers

Which factor leads to an increase in the rate of diffusion?

Decreasing distance between particles Signup and view all the answers

What role do carrier proteins play in active transport?

They specifically bind and force particles against their concentration gradient Signup and view all the answers

How does the concentration of oxygen impact active transport?

Increased oxygen concentration enhances aerobic respiration and, therefore, active transport Signup and view all the answers

Which statement about the factors affecting diffusion is true?

Higher temperatures generally increase the rate of diffusion Signup and view all the answers

Study Notes

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.

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Description

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.