Problem 4 - Campbell Biology Concepts & Connections

Question

A plant cell placed in distilled water will ____; an animal cell placed in distilled water will ____. a. burst ... burst b. become flaccid... shrivel c. become turgid... be normal in shape d. become turgid ... burst

Step-by-Step Solution

Answer

d. become turgid... burst

Step 1: Understanding Plant Cells in Distilled Water

Distilled water is a hypotonic solution. Plant cells, when placed in distilled water, will absorb water due to osmosis. The cell wall provides structural support, preventing them from bursting. As a result, plant cells become turgid.

Step 2: Understanding Animal Cells in Distilled Water

Animal cells do not have a cell wall. In a hypotonic solution like distilled water, animal cells will take in water by osmosis, leading to an increase in volume. Without a cell wall to provide support, they eventually burst.

Step 3: Combining Both Insights

Based on the understanding of how plant and animal cells respond to hypotonic solutions, we can conclude that a plant cell placed in distilled water will become turgid, while an animal cell placed in distilled water will burst.

Key Concepts

hypotonic solution

A hypotonic solution is one where the concentration of solutes outside the cell is lower than inside the cell. This causes water to move into the cell through the process of osmosis. Osmosis is the movement of water across a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration.
When plant or animal cells are placed in a hypotonic solution like distilled water, water enters the cell. This happens because cells are trying to balance solute concentrations on both sides of their membranes.
Understanding this helps to predict how cells will react in such environments.

turgid plant cells

Turgid plant cells are the result of water entering the cells and filling up the vacuoles. The pressure inside the plant cell increases, causing the cell membrane to push against the cell wall. This pressure is known as turgor pressure.
The cell wall ensures that the cell does not burst, providing structural integrity. This makes the plant cell firm and gives plants their upright structure.
In a turgid state, plants look healthy and robust because their cells are filled with water. This is important for maintaining the plant's structural stability.

burst animal cells

Animal cells don’t have a cell wall, unlike plant cells. When placed in a hypotonic solution like distilled water, water flows into the cell by osmosis.
As the cell takes in more water, it swells and eventually bursts because there’s no cell wall to counteract the internal pressure. This process is called lysis.
Animal cells can only regulate their internal water balance up to a certain point without a cell wall, so they are more vulnerable to bursting in hypotonic solutions.

cell wall

The cell wall is a rigid, protective layer that surrounds plant cells. It is mainly composed of cellulose and serves multiple functions.
One of the primary functions is to provide structural support. It helps plants maintain their shape and prevents cells from bursting when they absorb water.
The cell wall also helps plants grow upright and withstand various environmental conditions. Without it, plant cells would be much more fragile in hypotonic environments.