Biology Chapter on Cell Membrane and Cell Wall

Questions and Answers

What is the primary function of the plasma membrane in a cell?

To provide energy for cellular processes

To regulate the movement of materials in and out of the cell (correct)

To synthesize proteins

To store genetic information

Which organelle is responsible for photosynthesis in plant cells?

Chloroplasts (correct)

Mitochondria

Nucleus

Golgi apparatus

What structure enables plant cells to withstand hypotonic environments without bursting?

Nucleus

Central vacuole

Plasma membrane

Cell wall (correct)

How do prokaryotic cells differ from eukaryotic cells?

Prokaryotic cells lack membrane-bound organelles Signup and view all the answers

What is the role of the Golgi apparatus in a cell?

Modification, packaging, and storage of substances Signup and view all the answers

Which type of plastid is primarily responsible for storage in plant cells?

Leucoplasts Signup and view all the answers

What would most likely happen if the Golgi apparatus were not present in a cell?

The cell would not be able to modify or package proteins properly Signup and view all the answers

What is the purpose of the large central vacuole in plant cells?

To maintain turgidity and store important substances Signup and view all the answers

What property of the plasma membrane allows it to control the movement of substances in and out of the cell?

It is selectively permeable. Signup and view all the answers

Which of the following correctly describes the cell wall of plant cells?

It is primarily composed of cellulose. Signup and view all the answers

What happens to plant cells placed in a hypotonic solution?

They swell and build pressure against the cell wall. Signup and view all the answers

Which part of the cell does not absorb water by osmosis when it is dead?

Protoplast Signup and view all the answers

In what way does the cell wall help plant cells in a dilute environment?

It helps maintain cell shape and prevents bursting. Signup and view all the answers

Which of the following substances is capable of moving through a selectively permeable plasma membrane?

Water Signup and view all the answers

What is the effect of placing an onion peel in iodine solution during observation?

It enhances the visibility of the starch within the peel. Signup and view all the answers

Why is the ability to absorb water through osmosis crucial for living cells?

It helps maintain turgor pressure for structural integrity. Signup and view all the answers

What occurs when a cell is placed in an isotonic solution?

There is no net movement of water across the membrane. Signup and view all the answers

What happens to a cell in a hypertonic solution?

The cell will lose water and shrink. Signup and view all the answers

Which of the following accurately describes osmosis?

The movement of water across a selectively permeable membrane. Signup and view all the answers

What role does the plasma membrane play in a cell?

It is selectively permeable and controls substance entry and exit. Signup and view all the answers

What is the primary component of the plasma membrane?

Lipids and proteins. Signup and view all the answers

What does endocytosis allow a cell to do?

Engulf food and other materials from outside. Signup and view all the answers

Why do unicellular freshwater organisms tend to gain water?

Through normal osmosis process. Signup and view all the answers

Which type of transport requires energy for molecules to move in and out of the cell?

Active transport. Signup and view all the answers

Study Notes

Cell Structure and Function

Plasma membrane composed of lipids and proteins encloses all cells, regulating material movement between the cell and its environment.
In plant cells, a protective cell wall made mainly of cellulose supports the cell and prevents bursting in hypotonic solutions.
Eukaryotic cells possess a nucleus, which is encased in a double-layered membrane and regulates cell life processes.

Organelles and Their Functions

The endoplasmic reticulum (ER) serves as an intracellular transport passage and a manufacturing site for proteins and lipids.
The Golgi apparatus comprises stacks of membrane-bound vesicles responsible for storing, modifying, and packaging substances manufactured by the cell.
Plant cells typically contain plastids, including:
- Chloroplasts: Contain chlorophyll for photosynthesis.
- Leucoplasts: Primarily function in storage of nutrients.

Vacuoles and Prokaryotes

Most mature plant cells contain a large central vacuole that maintains turgidity and stores essential substances, including waste.
Prokaryotic cells lack membrane-bound organelles, have smaller ribosomes, and their chromosomes consist only of nucleic acid.

Osmosis and Selective Permeability

The plasma membrane is selectively permeable, facilitating specific movement of substances like water and CO2 across the membrane.
Osmosis allows water to enter or exit cells based on external solute concentration, affecting cell size and pressure.
- In isotonic solutions, water movement into and out of the cell is balanced.
- Hypotonic solutions lead to cells gaining water and increasing pressure against the cell wall.
- Hypertonic solutions result in water loss, causing cell shrinkage.

Importance of the Plasma Membrane

The membrane’s flexibility allows for processes like endocytosis, where the cell engulfs food and other materials from the environment.
Electron microscopy provides detailed insight into the structure of the plasma membrane, which consists of organic molecules essential for its function.

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Description

Explore the fundamental concepts of cell membranes and cell walls in this quiz. Discover how the plasma membrane regulates material movement and the role of the cell wall in plant cells. Test your knowledge about the structural components and functions crucial to cellular biology.