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What type of transport moves substances from an area of high concentration to low concentration without using cellular energy?
Passive transport
What type of transport requires cellular energy in the form of ATP?
Active Transport
What structure forms the main boundary of the cell and controls what enters and leaves?
Plasma membrane / cell membrane
What process brings large particles or substances into the cell using vesicles?
Endocytosis
If you put a drop of food coloring into water, why does the color eventually spread throughout the water?
Diffusion
What is the movement of molecules directly through the phospholipid bilayer from high to low concentration called?
Simple diffusion
Active transport usually moves substances against what?
The concentration gradient
What part of the phospholipid is attracted to water?
Hydrophilic head
What process releases materials from the cell using vesicles?
Exocytosis
Why does a plant wilt when it loses too much water?
Water leaves plant cells by osmosis, causing the cells to lose turgor pressure.
Oxygen and carbon dioxide can easily cross the cell membrane because they are small and nonpolar. What transport mechanism allows this?
Simple diffusion
What membrane protein uses ATP to move substances across the membrane?
Protein pump
What membrane proteins form channels that allow specific substances to cross the membrane?
Channel proteins
What type of endocytosis involves the cell engulfing large particles, such as bacteria?
Phagocytosis
A student eats very salty food and becomes thirsty. How can osmosis help explain this?
The high solute concentration causes water to move out of cells, triggering thirst.
A cell is placed in a solution with a higher solute concentration outside the cell. Water moves out of the cell. What process is occurring?
Osmosis
The sodium-potassium pump moves 3 Na⁺ out of the cell and 2 K⁺ into the cell. Is this passive or active transport?
Active transport
A molecule cannot pass directly through the phospholipid bilayer but can cross using a membrane protein without ATP. What process is this?
Facilitated diffusion
A white blood cell surrounds and engulfs a bacterium. What process is occurring?
Phagocytosis
A patient receives an IV solution. Why must the solution have an appropriate concentration relative to blood cells?
To prevent excessive water movement that could cause cells to swell or shrink.
A red blood cell is placed in distilled water. Predict what will happen to the cell and explain why.
Water enters the cell by osmosis, causing it to swell and possibly burst (hemolysis).
A cell has a lower concentration of glucose inside than outside, but it still moves glucose into the cell using ATP indirectly through another ion gradient. What type of transport is this?
active transport
Two substances are moving through different membrane proteins. Substance A moves from high to low concentration, while Substance B moves from low to high concentration using ATP. Identify the transport mechanisms.
A: Facilitated diffusion; B: Active transport
A pancreatic cell produces digestive enzymes and releases them outside the cell in vesicles. What transport mechanism is responsible? Explain.
Exocytosis; vesicles fuse with the plasma membrane and release their contents outside the cell.
A cell is placed in a solution. After several minutes, the cell becomes smaller, but the solute cannot cross the membrane. What can you conclude about the solution outside the cell? Explain.
The solution is hypertonic because water moved out of the cell by osmosis.