chapter 8

Cell membranes are said to be selectively permeable. Which statement best explains what selectively permeable means?

• The cell membrane prevents any harmful substance from entering the cell.
• The cell membrane lets certain substances enter the cell and keeps certain substances out of the cell.
• The cell membrane allows only large molecules to diffuse into the cell.
• The cell membrane has pores that let only water and glucose into the cell and carbon dioxide out.

Tags

NGSS.MS-LS1-2

Base your answer to the question on the diagram below and on your knowledge of biology. The diagram represents two solutions, A and B, separated by a selectively permeable membrane. Which statement best describes the outcome after 20 minutes?

• Solution A will contain approximately the same number of glucose molecules as solution B.
• Solution A will contain all of the water molecules.
• Solution B will remain unchanged.
• Solution B will lose all of the glucose molecules to solution A.

The diagram below represents a cell in water.  Formulas of molecules that can move freely across the cell membrane are shown.  Some molecules are located inside the cell and others are in the water outside the cell.

Based on the distribution of these molecules, what would most likely happen after a period of time?

• The concentration of O₂ will increase inside the cell.
• The concentration of CO₂ will remain the same inside the cell.
• The concentration of O₂ will remain the same outside the cell.
• The concentration of CO₂ will decrease outside the cell.

Tags

NGSS.HS-LS1-7

NGSS.HS-LS2-3

A substance is most likely to diffuse into a cell when

• it is a large organic food molecule such as protein or starch
• it is enclosed in an organelle such as a vacuole
• the concentration of the substance is greater outside the cell than inside
• the pH of the substance is greater than the pH of the cellListen

Tags

NGSS.MS-LS1-2

The diagram below shows the relative concentration of molecules inside and outside of a cell.

Which statement best describes the general direction of diffusion across the membrane of this cell?

• Glucose would diffuse into the cell.
• Protein would diffuse out of the cell.
• Oxygen would diffuse into the cell.
• Carbon dioxide would diffuse out of the cell.

Tags

NGSS.MS-LS1-2

In the diagram below; the dark dots indicate small molecules. These molecules are moving out of the cells as indicated by the arrows. The number of dots inside and outside of the two cells represents the relative concentrations of the molecules inside and outside of the cells. ATP is being used to move the molecules out of the cell by

• Cell A 
• Cell B 
• both Cell A and B
• neither Cell A or B

Tags

NGSS.MS-LS1-2

The picture below is an example of _________________.

• osmosis
• isotonic
• diffusion
• active transport

Tags

NGSS.MS-LS1-1

What is diffusion?

• when molecules move 
• when molecules move from a high concentration to a low.
• no movement 
• molecules move everywhere

What is diffusion?

• when molecules move 
• when molecules move from a high concentration to a low.
• no movement 
• molecules move everywhere

When both inside and outside of a cell have the same amount of water it is said that the cell has reached a state of

• Osmosis
• Diffusion
• Equilibrium