Biology Chapter on Diffusion and Osmosis

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Questions and Answers

How many potassium ions does the sodium-potassium pump move into a cell if it moves six sodium ions out of the cell?

eight

four (correct)

six

two

Which process allows proteins and polysaccharides that are too large to diffuse into a cell?

channel proteins

exocytosis

the sodium-potassium pump

endocytosis (correct)

What mechanism is used to remove large molecules from a cell?

exocytosis (correct)

diffusion

osmosis

endocytosis

What term describes the process of removing materials from a cell in vesicles?

exocytosis Signup and view all the answers

Which statement accurately describes hormones?

signal molecules distributed throughout the body Signup and view all the answers

Signal molecules attach to which type of proteins in order to transmit messages into a cell?

receptor proteins Signup and view all the answers

What is diffusion?

Movement of a substance from high to low concentration Signup and view all the answers

What occurs at the cell membrane when a signal molecule binds to a transport protein?

permeability change Signup and view all the answers

Which type of endocytosis allows a cell to target and uptake specific substances?

receptor-mediated endocytosis Signup and view all the answers

Which process is exemplified by the dispersal of ink in a beaker of water?

Diffusion Signup and view all the answers

What type of proteins serve as channels for specific substances through the lipid bilayer?

Channel proteins Signup and view all the answers

Which method is characterized by a cell engulfing large particles?

phagocytosis Signup and view all the answers

Which epithelium type is responsible for sweeping out bacteria and dust from the nasal cavity?

ciliated epithelium Signup and view all the answers

How do sugar molecules typically cross the cell membrane?

Via facilitated diffusion Signup and view all the answers

Which process does not require energy?

Osmosis Signup and view all the answers

How do ions move through ion channels?

Passive transport Signup and view all the answers

What is the term for the diffusion of water into or out of a cell?

Osmosis Signup and view all the answers

Osmosis is classified as what type of transport?

Passive transport Signup and view all the answers

Which of the following correctly describes an isotonic solution in relation to a cell?

The solution has the same solute concentration as the cytoplasm. Signup and view all the answers

What is a key difference between active transport and passive transport?

Active transport moves substances against their concentration gradient. Signup and view all the answers

Study Notes

Diffusion and Movement Across Membranes

Diffusion refers to the movement of substances from areas of high concentration to low concentration.
Ink dispersing in water illustrates diffusion in action.
Channel proteins create tunnels within the lipid bilayer for specific substances to pass through.
Sugar molecules utilize facilitated diffusion to cross cell membranes.

Transport Mechanisms

Diffusion and osmosis do not require energy; they occur passively.
Active transport requires energy to move substances against their concentration gradient.
Ions move through ion channels via passive transport, enabling selective permeability.
The movement of water into or out of cells is termed osmosis, a type of passive transport.

Water Passage through Membranes

Water can pass through the cell membrane using specialized channel proteins designated for water transport.
Isotonic solutions maintain equal solute concentrations with the cytoplasm, preventing net water movement into or out of the cell.

Active vs. Passive Transport

Active transport, unlike passive transport, involves the use of energy (ATP) and typically involves carrier proteins.
The sodium-potassium pump is a well-known example of active transport, moving sodium out and potassium into cells.

Sodium-Potassium Pump

The pump moves two potassium ions into cells for every three sodium ions it ejects.
The sodium-potassium pump is vital for maintaining cellular function and volume.

Transport of Large Molecules

Proteins and polysaccharides too large for diffusion or active transport enter cells via endocytosis.
Exocytosis allows cells to remove large molecules, utilizing vesicles to transport them out.

Hormones and Signal Molecules

Hormones act as signal molecules that affect specific target cells rather than all cells indiscriminately.
Signal molecules bind primarily to receptor proteins to enact cellular responses.
Binding of signal molecules can lead to permeability changes due to activation of transport proteins.

Endocytosis Types

Pinocytosis is the process where cells drink large dissolved molecules, while phagocytosis involves engulfing large particles (e.g., bacteria by white blood cells).
Receptor-mediated endocytosis enables cells to specifically take in target substances, such as cholesterol from the blood, through receptor binding.

Epithelial Tissue Functions

Epithelial tissue serves crucial roles in protection, absorption, secretion, and sensation.
Different types, such as ciliated and columnar epithelium, have specialized functions; for instance, ciliated epithelium clears dust and bacteria from the respiratory tract.

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Description

Test your understanding of diffusion and osmosis in biological systems with this quiz. Explore key concepts such as movement through membranes and the behavior of substances in different concentrations. Perfect for biology students looking to reinforce their knowledge.