Ch. 5 Exploring Membrane Structure and Transport

Which of the following is a primary component of the phospholipid bilayer in cell membranes?

• Cellulose

• Phospholipids

• Glycogen

• Starch

What is the main function of cholesterol in animal cell membranes?

• Energy storage

• Stabilizing membrane fluidity

• Protein synthesis

• DNA replication

Which type of transport requires energy input from the cell?

• Simple diffusion

• Facilitated diffusion

• Active transport

• Osmosis

What is the term for the movement of water across a selectively permeable membrane?

• Diffusion

• Osmosis

• Endocytosis

• Exocytosis

Which of the following proteins spans the entire membrane and is involved in transporting substances?

• Peripheral protein

• Integral protein

• Glycoprotein

• Enzyme

Which process describes the synthesis of membrane lipids in eukaryotic cells?

• Occurs in the nucleus

• Occurs in the smooth endoplasmic reticulum

• Occurs in the Golgi apparatus

• Occurs in the mitochondria

Which of the following best describes facilitated diffusion?

• Movement of molecules against their concentration gradient

• Movement of molecules through a membrane protein down their concentration gradient

• Movement of water only

• Movement of molecules using vesicles

A red blood cell placed in a hypotonic solution will:

• Shrink

• Swell and possibly burst

• Remain unchanged

• Undergo plasmolysis

Which statement best explains why membranes are described as "fluid mosaics"?

• They are solid and unchanging

• Proteins and lipids can move laterally within the layer

• They are made only of proteins

• They are made only of lipids

Which of the following would most likely increase the fluidity of a cell membrane?

• Increasing the proportion of saturated fatty acids

• Increasing the proportion of unsaturated fatty acids

• Removing cholesterol

• Adding more proteins