Biology Chapter on Passive Transport

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Questions and Answers

What is the primary energy source used in active transport mechanisms?

Glucose

ATP (correct)

FADH2

NADH

How many sodium ions are transported outside the cell for every two potassium ions transported inside by the sodium-potassium pump?

3 (correct)

Which process is characterized by the cell membrane enveloping a large particle to form a vesicle?

Exocytosis

Pinocytosis

Facilitated diffusion

Phagocytosis (correct)

What is formed during pinocytosis when the cell membrane folds around liquid material?

Pinocytic vesicle Signup and view all the answers

In what type of cells does exocytosis primarily occur?

Secretory cells Signup and view all the answers

What is the primary characteristic of passive processes in membrane transport?

They do not require cell assistance to move substances. Signup and view all the answers

Which process involves the movement of water across a selectively permeable membrane?

Osmosis Signup and view all the answers

What mechanism allows large molecules like glucose to pass through the cell membrane without using energy?

Facilitated diffusion Signup and view all the answers

In which situation would active transport be necessary for the cell?

When moving glucose from low to high concentration Signup and view all the answers

What are integral proteins primarily responsible for in facilitated diffusion?

Serving as carriers for larger molecules Signup and view all the answers

Which of the following statements is true regarding diffusion?

It continues until equilibrium is reached. Signup and view all the answers

What is the role of ATP in active processes of membrane transport?

To provide energy for moving substances against their concentration gradient. Signup and view all the answers

Which of the following processes would be categorized as an active transport mechanism?

Exocytosis Signup and view all the answers

What is osmosis primarily concerned with in terms of molecular movement?

The net movement of water molecules across a membrane Signup and view all the answers

What type of solution causes a cell to swell due to water influx?

Hypotonic solution Signup and view all the answers

What happens to the osmotic pressure when solute concentration increases?

Osmotic pressure increases Signup and view all the answers

Which process involves the movement of solvents due to hydrostatic pressure?

Filtration Signup and view all the answers

What is the primary role of dialysis?

To separate large molecules from small molecules Signup and view all the answers

In which scenario would a cell lose water rapidly?

In a hypertonic solution Signup and view all the answers

What type of membrane is required for osmosis to occur?

Selectively permeable membrane Signup and view all the answers

Which of the following accurately describes filtration?

It is driven by pressure differences across a membrane Signup and view all the answers

Study Notes

Passive Transport

Diffusion: Movement of molecules from high to low concentration.
- Types:
  - Lipid soluble: Molecules dissolve in the lipid bilayer (e.g., oxygen, carbon dioxide, fatty acids, alcohol).
  - Channel mediated: Water and ions move through membrane protein channels (e.g., Na+, K+, Cl-).
- Equilibrium: Movement continues until the concentration gradient is equal on both sides.
Facilitated diffusion: Movement of larger molecules through membrane proteins that act as carriers.
- Example: Glucose transport.
- No energy required: Moves from high to low concentration.
Osmosis: Water movement across a selectively permeable membrane from a region of high water concentration to a region of low water concentration.
- Driven by: Water potential (concentration gradient).
- Types of solutions:
  - Isotonic: Same solute concentration inside and outside the cell.
  - Hypotonic: Lower solute concentration outside the cell, causing water to move into the cell (swelling).
  - Hypertonic: Higher solute concentration outside the cell, causing water to move out of the cell (shrinking).
Filtration: Movement of water and small solutes across a membrane due to pressure difference.
- Example: Kidney filtration where blood pressure forces water and small molecules like urea through blood vessel membranes.
Dialysis: Diffusion of solutes across a selectively permeable membrane that allows small molecules to pass while retaining larger ones.

Active Transport

Active Transport: Movement of substances against their concentration gradient, requiring energy (ATP).
- Example: Sodium-potassium pump, which moves Na+ out of the cell and K+ into the cell, creating an electrical potential across the membrane.
Endocytosis: Taking in large molecules or particles.
- Phagocytosis: "Cell eating" where the cell membrane engulfs solids and forms a phagocytic vesicle.
- Pinocytosis: "Cell drinking" where the cell membrane engulfs liquids and forms a pinocytic vesicle.
Exocytosis: The release of substances from the cell by reverse endocytosis.
- Secretion: Examples are hormones and neurotransmitters.

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Description

Test your understanding of passive transport mechanisms, including diffusion, facilitated diffusion, and osmosis. This quiz covers the types of molecules involved, how they move across cell membranes, and concepts like equilibrium and water potential. Ideal for biology students looking to consolidate their knowledge in this area.