Biology Chapter: Cell Membranes and Transport

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Questions and Answers

How does cholesterol contribute to the fluidity of cell membranes in varying temperatures?

Cholesterol maintains membrane fluidity by preventing lipids from freezing in cold temperatures and slowing them down in heat to limit movement.

What is diffusion and how does it occur with a real-life example?

Diffusion is the movement of particles from a high concentration area to a low concentration area, like the spreading smell of cake in a room.

Describe the process of osmosis in relation to plant roots and soil.

Osmosis is the movement of water from a dilute solution to a higher concentration area, such as water moving into plant roots from moist soil.

What impact does cholesterol have on membrane stability?

<p>Cholesterol enhances membrane stability by preventing them from unraveling and ensuring proper fluid balance.</p> Signup and view all the answers

Explain the difference between diffusion and osmosis with examples.

<p>Diffusion involves the spread of particles like a smell in a room, while osmosis specifically refers to the movement of water, such as water entering plant roots.</p> Signup and view all the answers

Flashcards

Cholesterol's role in membrane fluidity

Cholesterol helps maintain the fluidity of cell membranes by preventing them from becoming too stiff or too fluid.

What is diffusion?

The movement of particles from an area of high concentration to an area of low concentration.

What is the difference between diffusion and osmosis?

Diffusion is the movement of particles from a region of high concentration to a region of low concentration, while osmosis is the movement of water across a semi-permeable membrane from a region of high water concentration to a region of low water concentration.

What is osmosis?

The movement of water across a semi-permeable membrane from a region of high water concentration to a region of low water concentration.

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How does osmosis work in plants?

The absorption of water from the soil by plant roots is an example of osmosis. The soil has a lower concentration of water than the plant roots, so water moves into the roots.

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Study Notes

Cholesterol's Role in Cell Membranes

Cholesterol maintains membrane fluidity.
In cold temperatures, cholesterol prevents lipids from becoming rigid and immobile.
In warm temperatures, cholesterol prevents excessive fluidity by restricting lipid movement.
Cholesterol stabilizes the membrane structure, preventing its breakdown.

Diffusion

Diffusion is the net movement of particles from an area of high concentration to an area of low concentration.
Example: The scent of a freshly baked cake spreading throughout a room.

Osmosis

Osmosis is the movement of water across a semipermeable membrane from a region of high water concentration (dilute solution) to a region of lower water concentration (concentrated solution).
Example: Plant roots absorbing water from the soil. The soil solution has a higher water concentration than the root cells, causing water to flow into the roots.