Cell Biology Unit 4 Assessment

Questions and Answers

How does the plasma membrane help maintain homeostasis in a cell?

The plasma membrane filters what substances go in and out of the cell, disposes of excess substances, and allows needed substances in through selective permeability.

How does the inside of a cell remain separate from its environment?

With the phospholipid bilayer.

What are the major components of a plasma membrane?

Phospholipid bilayer, cholesterol, proteins, and carbohydrates.

Which membrane component provides basic membrane structure?

Phospholipid bilayer. Signup and view all the answers

Which membrane component provides cell identity?

Carbohydrates. Signup and view all the answers

Which membrane component enables the membrane to have fluidity?

Cholesterol. Signup and view all the answers

Which membrane component enables a cell to transport materials across the membrane?

Proteins. Signup and view all the answers

Why is selective permeability important in a plasma membrane?

It is important to prevent harmful substances from entering the cell. Signup and view all the answers

Why is it important for a cell to maintain homeostasis?

Homeostasis keeps the cell functioning properly. Signup and view all the answers

Which organelle is primarily responsible for maintaining homeostasis in a cell?

Plasma membrane. Signup and view all the answers

Explain what a mosaic is.

A place where different parts of the membrane float in a fluid-like shape. Signup and view all the answers

How does the orientation of the phospholipids in the bilayer allow a cell to interact with its internal and external environment?

The hydrophilic heads face outward toward the water, while the hydrophobic tails face inward, providing a barrier that is semi-permeable. Signup and view all the answers

What happens during equilibrium?

When the particles continue to move randomly but no further change in concentration will occur. Signup and view all the answers

What would happen to a cell placed in a strong salt solution?

The cell membrane would start to shrink or shrivel. Signup and view all the answers

What would happen to a cell placed in pure water?

The cell will start to take in the water and swell, and it could possibly burst. Signup and view all the answers

How are cells able to get dissolved materials inside?

Through facilitated diffusion. Signup and view all the answers

What are 3 examples of passive transport?

Osmosis, diffusion, and facilitated diffusion. Signup and view all the answers

Are osmosis and diffusion examples of active or passive transport?

Passive transport. Signup and view all the answers

What are 3 examples of active transport?

Exocytosis, endocytosis, and transport proteins. Signup and view all the answers

What does a transport protein do?

They carry molecules across the membrane using ATP. Signup and view all the answers

How would a large particle enter a cell?

Endocytosis. Signup and view all the answers

How is facilitated diffusion different from active transport?

Active transport uses energy, and facilitated diffusion does not. Signup and view all the answers

Summarize how cellular transport helps maintain homeostasis within a cell.

A cell seeks to maintain homeostasis by adjusting water concentration through osmosis. Signup and view all the answers

Study Notes

Plasma Membrane and Homeostasis

The plasma membrane regulates what enters and exits a cell, helping maintain internal balance.
Selective permeability allows the membrane to remove excess substances and intake necessary ones.
This process is crucial for eliminating waste and sustaining metabolic needs.

Cell Structure and Components

The plasma membrane consists mainly of a phospholipid bilayer, cholesterol, proteins, and carbohydrates.
Phospholipid bilayer provides the foundational structure of the membrane.
Carbohydrates function in cell identity, acting as markers for recognition.
Cholesterol contributes to the fluidity of the membrane, enhancing flexibility.

Mechanisms of Transport

Proteins within the membrane facilitate the transport of materials across it.
Selective permeability prevents harmful substances from entering the cell, crucial for cell survival.
To ensure proper function, cells must maintain homeostasis, which involves constant regulatory actions from the plasma membrane.

Understanding Membrane Dynamics

The term "mosaic" describes the diverse components of the membrane that float and move in a fluid manner.
Orientation of phospholipids is critical; hydrophilic heads face outward, and hydrophobic tails face inward, maintaining a protective barrier.

Passive vs. Active Transport

Passive transport does not require energy and includes diffusion, osmosis, and facilitated diffusion.
Active transport, however, requires energy (ATP) and includes processes like endocytosis, exocytosis, and transport proteins.
Facilitated diffusion simplifies the movement for larger or charged molecules across the membrane without energy.

Osmosis and Concentration Dynamics

Equilibrium occurs when particle movements remain random, with no net change in concentration.
A cell placed in a strong salt solution will shrivel due to water loss, while in pure water, the cell may burst from excess intake.
Hypotonic solutions lead to water influx; cells adjust concentrations to maintain balance.

Transport Mechanisms

Cells utilize facilitated diffusion to transport dissolved materials efficiently.
Endocytosis allows large particles to enter cells, while exocytosis helps expel materials.
Transport proteins are essential in moving molecules actively across membranes using energy.

Impacts of Environment on Cells

Organisms in hypertonic environments, like the Great Salt Lake, might develop adaptations to survive osmotic pressure.
Knowledge of cellular transport mechanisms is fundamental for understanding how cells interact with their surroundings and maintain homeostasis.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz focuses on the plasma membrane's role in maintaining homeostasis in cells. It covers concepts of selective permeability and how cells regulate their internal environment. Test your understanding of these critical biological processes.