4.9 B: Basic Cell Communication in Organ Systems Quiz ...

4.9 B: Basic Cell Communication in Organ Systems Quiz

PROCTOR VERSION

1. All normal, healthy body cells have MHC-1 proteins on their cell surfaces. A natural killer (NK) cell

is produced by the immune system and has inhibitory receptors that bind to MHC-1 proteins. When an NK cell binds to a normal body cell, it recognizes the MHC-1 protein, "turns off," and does not destroy the cell. If, however, the NK cell binds to a cell lacking the correct MHC-1 protein, the NK cell is "turned on." Different receptors on the NK cell then search for other proteins that indicate that the cell is in distress or damaged. If these other proteins are detected, the NK cell will release cytotoxic substances that destroy the distressed or damaged cell. The diagrams below show how an NK cell interacts with a normal body cell and with a cancer cell (damaged body cell).

Which condition most likely results in an autoimmune disorder that would cause NK cells to attack and destroy normal, healthy body cells? (A) A mutation makes the MHC-1 receptor on NK cells unable to "turn on" after the NK cells bind

to MHC-1 proteins on normal body cells. Distractor Rationale: This answer suggests the student may understand that NK cells must be "turned on" before they destroy a distressed or damaged cell, but does not understand that binding to the MHC-1 sites keeps NK cells inactive ("turned off"). (B) Body cells are unable to produce MHC-1 proteins on the surface and have unique surface proteins that cause NK cells to bind to them and "turn on."

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4.9 B: Basic Cell Communication in Organ Systems Quiz

PROCTOR VERSION

Rationale: This answer suggests the student understands that NK cells "turn on" and destroy distressed or damaged cells that lack MHC-1 proteins and have unique surface proteins indicating distress or damage.

(C) Body cells display abnormal MHC-1 proteins on their surface and NK cells have a mutation that blocks their ability to produce cytotoxic substances. Distractor Rationale: This answer suggests the student may understand that NK cells will "turn on" when they bind to cells that lack MHC-1 proteins, but does not understand that NK cells need to make cytotoxins in order to destroy a distressed or damaged cell.

(D) A mutation prevents the MHC-1 receptors on NK cells from recognizing MHC-1 proteins and prevents them from making receptors to detect other proteins. Distractor Rationale: This answer suggests the student may understand that NK cells will "turn on" when they bind to cells that lack MHC-1 proteins, but does not understand that NK cells need to detect other proteins before they destroy a distressed or damaged cell.

Aligned to: LO 4.9 CA 4.9: Predict Effects of Changes to Biological Systems

2. The diagram below shows two pathways by which hormone A and hormone B are transported

from a secretory cell to a target cell.

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4.9 B: Basic Cell Communication in Organ Systems Quiz

PROCTOR VERSION

Which statement best explains why the two hormones are transported by different methods from the secretory cell to the target cell?

(A) Hormone B can easily pass through the target cell's membrane because it is a small molecule, and hormone A must be transported through the target cell's membrane because it is a large molecule. Distractor Rationale: This answer suggests the student may understand that small molecules can pass more easily through cell membranes than large molecules, but does not understand that hormone A cannot be transported across the cell membrane because it is a water-soluble hormone that cannot diffuse through the hydrophobic lipid membrane.

(B) Hormone A is a peptide because it binds to a surface protein on the target cell, and hormone B is a nucleic acid because it travels into the nucleus and interacts with a gene. Distractor Rationale: This answer suggests the student may understand that hormone A could be a peptide because it binds to surface receptors and that hormone B interacts with a gene in the nucleus, but does not understand that hormone B could not be a nucleic acid because nucleic acids are not a type of hormone, or that hormone B is lipid-soluble and can pass through the lipid bilayer.

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4.9 B: Basic Cell Communication in Organ Systems Quiz

PROCTOR VERSION

(C) Hormone B is moved through the blood via carrier proteins because its receptor is in the target cell's nucleus, and hormone A travels freely through the blood to the target cell because its receptor is on the target cell's membrane. Distractor Rationale: This answer suggests the student may understand that hormone B binds to receptors in the nucleus and must be transported by a protein, but does not understand that hormone B is lipid-soluble and needs a carrier protein for transport in the blood, or that hormone A is water-soluble and cannot diffuse across the target cell's hydrophobic membrane.

(D) Hormone A does not need a carrier protein because it is a water-soluble hormone, and hormone B must be transported through the blood via carrier proteins because it is a lipidsoluble hormone. Rationale: This answer suggests the student understands that hormone A is water-soluble and cannot diffuse across the target cell's hydrophobic membrane because the plasma membrane is made of lipids, and that hormone B is lipid-soluble and can diffuse across the plasma membrane but must be carried via transport proteins through the blood.

Aligned to: LO 4.9 CA 4.9: Predict Effects of Changes to Biological Systems

3. Macrophages are large white blood cells that can engulf foreign substances called antigens. Both

macrophages and lymphocytes, such as T cells, appear together at the site of infection. Which statement best explains how macrophages initiate an immune response when a new antigen is first encountered?

(A) Macrophages incorporate the antigen into their genetic material and produce a large number of identical macrophages that are programmed to destroy that specific antigen. Distractor Rationale: This answer suggests the student may understand that cells programmed to identify specific antigens are copied in an immune response, but does not understand that B cells identify antigens and produce plasma cells that release antibodies to destroy the antigen.

(B) Macrophages present the antigen directly to a memory B cell that produces antibodies programmed to destroy that specific antigen.

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4.9 B: Basic Cell Communication in Organ Systems Quiz

PROCTOR VERSION

Distractor Rationale: This answer suggests the student may understand how an immune response would occur with a previous exposure, but does not understand that memory B cells would not be present upon a first exposure to an antigen.

(C) Macrophages present the antigen to helper T cells, which activate memory B cells to produce plasma cells, and the plasma cells release antibodies that identify and destroy that specific antigen.

Rationale: This answer suggests the student understands how macrophages work with helper T cells to initiate an immune response by activating B cells to produce plasma cells, which release antibodies that destroy the specific antigen.

(D) Macrophages present fragments of the antigen to other macrophages, which are then able to seek out and destroy the antigen by releasing helper T cells that engulf that specific antigen.

Distractor Rationale: This answer suggests the student may understand how macrophages break down antigens and present them to the immune system, but does not understand that macrophages present antigen fragments to helper T cells, which activate B cells, and that B cells produce plasma cells that release antibodies to destroy the antigen.

Aligned to: LO 4.9 CA 4.9: Predict Effects of Changes to Biological Systems

4. Nerve cells communicate with one another via chemical messengers called neurotransmitters.

Endorphins are a type of neurotransmitter that decrease pain signals by interacting with the sodium (Na+) channels and potassium (K+) channels in a postsynaptic nerve cell. Which statement describes how an endorphin most likely interacts with a postsynaptic neuron in a pain signal pathway?

(A) Endorphins bind to and temporarily close sodium (Na+) channels in the postsynaptic neuron, which prevents depolarization of the neuron.

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