LS 1.7 Cell Transport Post Assessment

Deer mice rely on other organisms for many nutrients. The food deer mice consume is broken down into smaller particles, absorbed, and distributed throughout their bodies. Once of these particles is glucose. Glucose requires specialized molecules such as the GLUT4 Transporter to enter cells. Once glucose is in a cell, it can be broken down further to provided energy for the growth, metabolism, and maintenance of individual deer mice. Glucose entering a cell by way of GLUT4 is shown in the model above.

A researcher claims that glucose is moved into cells by facilitated diffusion through the GLUT4 transporter. Based on the model, which statement best supports the researcher’s claim?

• The movement of glucose across the membrane does not require ATP.

• Glucose moves from an area of low concentration to an area of high concentration.

• The glucose molecules diffuse freely through the membrane without a protein channel.

• Glucose provides energy for the protein channel to transport materials across the membrane.

Other particles consumed by deer mice, such as calcium, have to move into cells by active transport. Which diagram correctly shows the movement of particles into the cell by active transport?

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When glucose is broken down, carbon dioxide is produced, which results in more carbon dioxide inside the cell than outside the cell. The carbon dioxide then diffuses out of the cell. Which statement best describes the movement of carbon dioxide by diffusion?

• The carbon dioxide can move through the plasma membrane by moving down the concentration gradient.

• Water molecules are needed to move the carbon dioxide across the plasma membrane.

• Peripheral proteins help move the carbon dioxide across the plasma membrane.

• The transport of carbon dioxide through the plasma membrane requires energy from ATP.

Students created flowcharts to show select types of transport that occur across the plasma membrane. Which flowchart correctly shows the types of plasma membrane transport?

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The diagram below represents a cell and some molecules in its environment. Which molecule would require the use of energy in order to be brought into the cell?

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Answer explanation

Molecules diffuse High to Low

... with the flow

Which form of active transport is being shown?

• Facilitated Diffusion
• Exocytosis
• Endocytosis
• Protein Pumps

Mature mammalian red blood cells, called erythrocytes, have no nucleus, ribosomes, or mitochondria. The cytoplasm of erythrocytes is rich in hemoglobin, the protein that carries oxygen. The large amount of hemoglobin allows the red blood cells to carry the large amount of oxygen cells need for the high rate of metabolism in mammals. Erythrocytes have a biconcave shape, meaning they are thinner in their center than along their edges as shown in the model. Based on the structure of erythrocytes, how do red blood cells help to maintain homeostasis in mammalian organisms?

• Oxygen enters and leaves red blood cells against a concentration gradient through protein pumps to maintain homeostasis. The biconcave shape of erythrocytes provides an increased surface area on the cells for active transport to occur.

• Oxygen diffuses into and out of red blood cells to maintain homeostasis. The biconcave shape of erythrocytes provides an increased surface area on the cells for diffusion to occur.

• Oxygen enters red blood cells via endocytosis and exits red blood cells via exocytosis to maintain homeostasis. The biconcave shape of erythrocytes provides an increased surface area on the cells for bulk transport to occur.

• Red blood cells synthesize hemoglobin to increase absorption of oxygen to maintain homeostasis. The biconcave shape of erythrocytes provides an increased surface area on the cells for protein synthesis to occur.

Tags

NGSS.HS-LS1-3

Lionel places red blood cells in a beaker of pure water, and then he observes their activity under a microscope. Which is the MOST likely result that Lionel will observe?

• Water diffuses into the red blood cells by osmosis, and the cells eventually burst.

• Water diffuses out of the red blood cells by osmosis, and the cells shrink to about half their normal size.

• Water diffuses both in and out of the red blood cells, and the cells remain approximately the same size.

• Water diffuses both in and out of the red blood cells, and the cells alternately expand and shrink.

• Water diffuses into the cell membrane but not the cell interior, causing the cell membrane to swell

Simple diffusion is the movement of molecules from

• an area of equilibrium to an area of high concentration.
• an area of low concentration to an area of high concentration.
• an area of high concentration to an area of high concentration.
• an area of high concentration to an area of low concentration until equilibrium is reached.

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-4

In the diagram above, the concentration of sugar inside the cell is higher than it is outside the cell. Yet the sugar enters the cell by diffusion. How does the diagram illustrate the role of the active transport pump in moving the sugar into the cell?

• The pump generates energy by releasing three sodium ions, which transfer the energy to the sugar when they bind with the sugar.

• The pump lowers the concentration of sodium inside the cell so the sugar can hitch a ride on a sodium ion that enters by diffusion.

• The pump lowers the concentration of sugar inside the channel protein so the sugar can diffuse into the cell with no added energy.

• The pump releases sodium ions, one of which binds to a membrane protein and opens a channel, enabling the sugar to pass through.