Movement of Substances Across The Cell Quiz

What is the primary function of carbon dioxide in photo-autotrophs?

• To provide energy

• To assist in photosynthesis

• To absorb nutrients

• To store water

What is the process called that removes waste products produced through metabolism?

• Digestion

• Excretion

• Respiration

• Circulation

Where is carbon dioxide excreted by simple diffusion?

• Into the stomach

• Into the alveoli in the lungs

• Into the kidneys

• Into the liver

Explain the difference between exocytosis and endocytosis.

What is the primary function of the cell membrane?

• To produce energy for the cell

• To control the exchange of materials between the cell's internal and external environments

• To store genetic information

• To synthesize proteins

What is the basic framework of a cell membrane according to the fluid-mosaic model?

• A single layer of phospholipids

• A bilayer of phospholipids with embedded proteins

• A layer of carbohydrates

• A layer of nucleic acids

​ (a)   imbedded in the cell membrane ​ (b)   the diffusion of selected materials between the cell and the extracellular environment. ​ (c)   is a passive process with materials diffusing ​ (d)   the concentration gradient. There are two types of transport proteins in membranes: channel proteins and ​ (e)   .

• Transport proteins
• facilitate
• Facilitated diffusion
• down
• carrier proteins
• Active transport
• Endocytosis
• Exocytosis

Where are the phospholipid 'heads' positioned in the bilayer?

• In the center of the bilayer

• On the outer and inner edges of the bilayer

• Outside the cell membrane

• Inside the cytoplasm

Diffusion, osmosis, and facilitated diffusion are all ​ (a)   and no ​ (b)   is required to facilitate the diffusion of materials down the concentration gradient. ​ (c)   uses carrier proteins to facilitate the diffusion of materials across a membrane in the opposite direction to the ​ (d)   . Most cells have hundreds of carrier proteins per micrometre that are involved in transporting one or more materials ​ (e)   . Active transport requires an input of ATP and is described as an active process.

• passive processes
• ATP
• Active transport
• concentration gradient
• across the membrane
• energy-consuming methods
• chemical reactions
• electrolytic processes

What must the cell membrane be able to do to achieve its function?

• Control which substances enter and leave the cell

• Generate electrical impulses

• Replicate DNA

• Produce hormones