What salty or fresh water does to plant and animal cells
Grade 9 Science Worksheet
Circle the best answer.
Read this first
Use this
Beaker drawing (model data, not to scale). One beaker holding one plant cell, drawn as a stiff wall with the membrane just inside it.
Ari's class views an onion skin cell that holds 2% solute in 7% salt water. How is the solution described?
- Hypertonic, because 7% is more solute than the cell's 2%
- Hypotonic, because the cell's 2% is less than 7%
- Hypertonic, because salt moves into the cell
- Isotonic, because both sides of the membrane contain some solute
An Elodea leaf cell holds 3% solute. Bo puts it in circle water with 0.2% solute. How is the water described?
- Isotonic, because no water moves in or out
- Hypertonic, because the cell's 3% is more than 0.2%
- Hypotonic, because water moves toward less solute
- Hypotonic, because 0.2% is less than the cell's 3%
A teacher's shell-less egg holds 10% solute. Esme sees it in a 10% sugar solution. How is the solution described?
- Isotonic, because the solution matches the egg's 10%
- Isotonic, because no water moves in or out
- Hypertonic, because the egg holds 10% solute
- Hypotonic, because sugar can move into the egg
Kira puts a celery piece in fresh water. What happens to its cells?
- Water leaves, so the cells go limp and soft
- Salt enters until the cells are firm and full
- Water enters until the wall resists, and they turn firm
- Water enters until the cells swell and burst
Luz puts a crisp lettuce leaf in 8% salt water. What happens to its cells?
- Water enters and the cells burst open, so the leaf tears
- Water enters the cells, so the leaf turns crisper
- Nothing changes, because the wall blocks water from moving
- Water leaves, the membrane pulls from the wall, the leaf wilts
Use the table
Lab card for one potato strip (model data, a class reads about a teacher's test)
Salt in the solution (%) Start mass (g) End mass (g) 10 5.0 4.0 Percent change = (end mass - start mass) / start mass x 100.
Milo reads the card for one potato strip. What is the percent change in mass, and what moved?
- A 25% decrease, because water left the strip
- A 20% decrease, because water left the strip
- A 1% decrease, because water left the strip
- A 20% increase, because salt moved into the strip
Noah reads the card for a teacher's shell-less egg in plain water. What is the percent change in mass, and why?
- A 9.1% increase, because water entered the egg
- A 10% increase, because water entered the egg
- A 10% decrease, because water moved toward less solute
- A 6% increase, because water entered the egg
Pia reads the card for one celery strip. What is the percent change in mass, and what does it show?
- A 0% change, because equal amounts of water cross each way
- A 4% change, because the solution is 4% salt
- A 0% change, because no water crosses the membrane
- A 0% change, because salt moved in as water moved out
Ren reads a graph of potato strips soaked in salt solutions. At about what salt percent is the solution isotonic to the potato cells?
- 10%, where the line ends
- 0%, where the strips gained the most
- 4%, where the change in mass is 0
- 4%, where no water moves in or out
Tala uses the graph of potato strips. What happens to the cells in the 1% salt solution, and why?
- Water leaves, because water moves toward less solute
- Water enters, because the 1% solution is hypotonic to the cells
- Water enters, because the cells are hypotonic to the 1% solution
- Salt enters, which raises the mass by 10%