STAAR Blitz - Cell Transport

STAAR Blitz - Cell Transport

By Kendall Smith

Cell Membrane

The cell membrane is the border that determines what enters and exits the cell.; made of LIPIDS

The cell membrane is selectively permeable, or semipermeable, meaning only certain molecules can pass through​

The movement of molecules occurs by either passive or active transport.​

Cell Transport ​

One of the most important cell processes = homeostasis.

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Homeostasis is a balance between the internal physical & chemical conditions. This occurs by regulating the movement of molecules from one side of the membrane to the other.​

Movement of molecules from a HIGH to LOW concentration WITHOUT energy (ATP)​

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Passive Transport

Diffusion

Movement of particles from areas of high concentration to areas of low concentration. (i.e. oxygen and carbon dioxide)

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This is called diffusion.​​

Count the dots!!​

Passive Transport

Facilitated Diffusion

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The movement of large molecules using special protein channels is known as facilitated diffusion. This does NOT require energy!

Count the dots!!​

Passive Transport

Osmosis

​Osmosis is the diffusion of water across the cell membrane from HIGH concentrations to LOW concentrations.​

Passive Transport

HYPER = HIGHER Solute concentration; water moves OUT

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HYPO = LOWER solute concentration; water moves IN

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ISO = EQUAL solution concentration; water moves IN and OUT​

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Osmosis (cont.)

Movement of molecules from a LOW to HIGH concentration WITH energy (ATP)​

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Active

Transport

Multiple Choice

The diagram illustrates the movement of molecules through a cell membrane.

What process is being used by the cell to move the molecules?

• osmosis

• endocytosis

• active transport

• facilitated diffusion

Multiple Choice

A student used a microscope to observe Elodea submerged in a solution. The student observed the cell cytoplasm pull away from the cell wall and clump together in the center of the cell.

What statement best explains why this occurred?

• The cell was submerged in a pure water solution

• The cell was submerged in a solution with a higher water concentration than the inside of the cell.

• The cell was submerged in a solution with an equal water concentration to the inside of the cell.

• The cell was submerged in a solution with a lower water concentration than the inside of the cell.

Multiple Choice

Review the chart above. Under which condition will the cell experience the greatest flow of water into the cell from the environment?

• Condition 1

• Condition 2

• Condition 3

• Condition 4

Multiple Choice

Cell have several mechanisms for regulating their internal environments. Which of these mechanisms involved in maintaining homeostasis requires energy?

• osmosis

• diffusion

• active transport

• passive transport

Multiple Choice

Which cellular structure in an animal cell helps maintain homeostasis by controlling the transportation of substances into and out of the cell?

• vacuole

• cell membrane

• mitochondrion

• cell wall

Multiple Choice

Shira is analyzing samples of red blood cells using a microscope. Her observations are shown.

Shira observes that the shape of cell A appears normal, while Cell B appears swollen and Cell C is shrunken. The shrinking of Cell C indicates that the cell is reacting to what?

• lower solute concentration outside the cell than inside

• an anaerobic environment outside the cell

• higher solute concentration outside the cell than inside

• more oxygen inside the cell than what can be used

Multiple Choice

The diagram illustrates the use of energy by a nerve cell to expel a sodium ion from inside the cell.

Which best explains why energy is necessary to complete this function?

• The ion is being transported against a concentration gradient.

• The ion has more kinetic energy than surrounding molecules.

• The ion is a waste product that is digested by the cell membrane.

• The ion is too large to pass through the cell membrane by diffusion.

Multiple Choice

In cells, transport of nutrients and waste across membranes is accomplished through the process of facilitated diffusion. In which of the following ways does facilitated diffusion differ from simple diffusion?

• Facilitated diffusion requires that a protein channel be present before crossing the membrane.

• Simple diffusion requires that a protein channel be present before crossing the membrane.

• Facilitated diffusion requires that nutrients or wastes travel from a higher concentration to a lower concentration.

• Simple diffusion requires that nutrients or wastes travel from a higher concentration to a lower concentration.

Multiple Choice

Active transport and facilitated diffusion in cells both result in the movement of nutrients or wastes across a membrane. Which of the following comparisons between active transport and facilitated diffusion is not true?

• Facilitated diffusion requires proteins and active transport does not.

• Active transport requires the input of energy and facilitated diffusion does not.

• Facilitated diffusion requires a concentration gradient across the membrane and active transport does not.

• Active transport requires the presence of a semipermeable membrane and facilitated diffusion does not.