Cell Structure and Function

Which of the following processes requires ATP?

• Simple diffusion
• Osmosis
• Facilitated diffusion
• Active transport

What is the main function of the middle lamella?

• To store starch
• To synthesize proteins
• To divide the cell
• To glue adjacent cells together

In which direction does water move during osmosis?

• From lower to higher water concentration
• Randomly
• Only in the presence of light
• From higher to lower water concentration

Which of the following is a characteristic of active transport?

• Occurs only in plant cells
• Moves molecules down the gradient
• Is always faster than passive transport
• Requires energy input

Which of the following statements about plasmodesmata is true?

• They are found in animal cells
• They prevent cell-to-cell contact
• They are impermeable channels
• They allow communication between plant cells