IB membrane structure and transport

The cell membrane contains channels and pumps that help move materials from one side to the other. What are these channels and pumps made of?

• carbohydrates
• lipids
• bilipids
• proteins

During diffusion, when the concentration of molecules on both sides of a membrane is the same, the molecules will

• move across the membrane to the outside of the cell.
• stop moving across the membrane.
• continue to move across the membrane in both directions.
• move across the membrane to the inside of the cell.

Which means of particle transport is shown in this diagram?

• diffusion
• osmosis
• facilitated diffusion
• active transport

Look at the cross section of a cell membrane of a eukaryotic cell. H+ ions are being pumped from a low concentration to a high concentration. 
How do you describe this type of transport across the cell membrane?

• active transport
• passive transport
• facilitated diffusion
• co-transport 

Osmosis occurs when there is a different concentration of solute molecules on each side of the membrane. The drawing below shows a beaker containing a 30% salt solution and a suspended cell containing a 10% salt solution. What statement best describes the cell after 20 minutes?

• Water will move from the cell into the beaker, resulting in a smaller cell.
• Water will move from the beaker into the cell, resulting in a larger cell.
• Salt will move from the cell into the beaker, resulting in a smaller cell.
• Salt will move from the beaker into the cell, resulting in a larger cell.

Tags

NGSS.MS-LS1-2

An osmosis investigation was conducted using chicken eggs to represent cells with semi permeable membranes. The mass of each egg was measured to determine how much water diffused into or out of the eggs. The eggs were first soaked in vinegar to dissolve the shell. Each egg was then placed in one of three different solutions for 24 hours. The table below shows the results of the investigation.
Based on this experiment, which of the following should be inferred about cells with semi permeable membranes?

• Substances other than water may also cross the cell membrane.
• Water enters the cell when placed in environments of high water concentration.
• Substances other than water may block pores in the cell membrane.
•  Water leaves the cell when placed in environments with a low concentration of solutes

Tags

NGSS.HS-LS1-3

A beaker is divided into two halves, A & B, by a membrane that is freely permeable to the water and NaCl but not to protein. Side A is half-filled with a solution of 8% protein, while side B is half filled with a 2% protein solution. Predict what would happen to side A after a few hours. 

• The number of protein molecules has increased.
• The number of water molecules has decreased.
• The number of water molecules has increased.
• The percentage of water has decreased. 

In an emergency trauma room, a doctor accidentally gives a patient a large transfusion of distilled water directly into one of his veins instead of blood. Predict what might happen if distilled water was given to the patient instead of blood. 

• have no unfavorable effect as long as the water was sterile
• have serious, perhaps fatal effects because there would be too much fluid for the heart to pump.
• have serious, perhaps fatal effects because the red blood cells would tend to shrivel
• have serious, perhaps fatal effects because the red blood cells would tend to burst

Tags

NGSS.HS-LS1-3

Carrot sticks that are left in a dish of freshwater for several hours become stiff and hard. Similar sticks left in a saltwater solution become limp and soft. From this we can deduce that the freshwater is ______ and the saltwater is ________ to the cells of the carrot sticks.

• hypotonic, hypertonic
• hypotonic, hypotonic
• hypertonic, hypertonic
• hypertonic, hypertonic

Tags

NGSS.MS-LS2-4

In pure water, a red blood cell from an animal will swell and burst, but a leaf cell from a plant will not. Which structure in the leaf cell is responsible for this difference?

• cell membrane
• cell wall
• mitochondrion
• nucleus