Transport

Cells need to bring in molecules to carry out cellular processes. Often, this requires moving the molecules across the cell membrane against the concentration gradient. How do these molecules get into the cell?

• passive transport by diffusion
• active transport using ATP 
• passive transport by osmosis
•  osmosis

A person with swollen gums rinses his mouth with warm salt water, and the swelling decreases. Which of the following has occurred?

• The swollen gums have absorbed the saltwater solution.
• The saltwater solution lowers the temperature of the water in the gums.
• The salt in the solution has moved against the concentration gradient.
• The water in the gums has moved out due to the high concentration of salt in the solution. 

The cell membrane of the red blood cell will allow water, oxygen, and carbon dioxide to pass through. Because other substances are blocked from entering, this membrane is called

• perforated
• semi-permeable
• non-conducive
• permeable

 Look at the diagram of a cross-section of a cell membrane below. The cell membrane controls movement of materials into and out of the cell. The following particles are moving from high concentration to low concentration and are using a carrier protein. How would you describe this type of movement across the membrane? 

• simple osmosis
• active transport
• simple diffusion
• facilitated diffusion

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

 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

The diagram below represents a cell and some molecules in its environment. Which molecule would require the use of energy in order to be brought into the cell?

• 1
• 2
• 3
• 4

Which activity can occur without the use of energy?

• contraction of muscle tissue
• protein synthesis in a cell
• active transport of minerals
• movement of water across a membrane

The diffusion of water across a selectively permeable membrane is called 

• active transport
• facilitated diffusion
• osmosis
• phagocytosis

During diffusion molecules tend to move 

•    up the concentration gradient
•  from an area of lower concentration to an area of higher concentration
•  in a direction that doesn’t depend on concentration
•  down the concentration gradient