The picture shows a contractile vacuole of a unicellular freshwater organism. The contractile vacuole regulates the flow of water into and out of the cell in an aquatic environment. What conditions cause the vacuole to fill with water?

• the concentration of the water is greater outside of the cell that inside of the cell

• the temperature of the water in the vacuole is higher than the temperature of its environment

• the concentration of water inside the cell is the same as the concentration outside the cell

• the temperature of water in the vacuole is lower than the temperature of its environment

The diffusion of water across a permeable membrane is called

• facilitated diffusion

• osmosis

• active tranport

• simple diffusion

Which cellular process takes place in the ribosomes that are bound to the endoplasmic reticulum?

• the breakdown of waste material

• the conversion of radiant energy to glucose

• the synthesis of new proteins

• the replication of nucleic acids

Which group of organelles is directly responsible to produce new molecules within a cell?

• ribosomes

• lysosomes

• vacuoles

• cell membrane

The diagram shows cellular activity across a cell membrane. Which two processes does this diagram most directly model?

• energy conversions and synthesis of new molecules

• synthesis of new molecules and homeostasis

• transport of molecules and energy conversions

• homeostasis and transport of molecules

Which cell component is responsible for maintaining homeostasis in the cell?

• cell membrane

• vacuole

• lysosomes

• ribosomes

Some students used vinegar to dissolve away the shells of three eggs and used these eggs as models of human red blood cells. The students observed the changes in the eggs when they were place in different solutions. Which statement best describes the role of the cell membrane in this model?

• the cell membrane is an impermeable barrier that prevents water from entering the cell

• the cell membrane allows solutes to enter the cell, which causes the cell to shrink

• the cell membrane allows water to enter and leave the cell

• the cell membrane removes solutes from the environment