Download All normal, healthy body cells have MHC

4.9 B: Basic Cell Communication in Organ Systems Quiz
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.
(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.”
(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.
(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.
Page 1 of 4
4.9 B: Basic Cell Communication in Organ Systems Quiz
2.
The diagram below shows two pathways by which hormone A and hormone B are transported
from a secretory cell to a target cell.
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.
(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.
(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.
(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.
Page 2 of 4
4.9 B: Basic Cell Communication in Organ Systems Quiz
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.
(B) Macrophages present the antigen directly to a memory B cell that produces antibodies
programmed to destroy that specific 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.
(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.
Page 3 of 4
4.9 B: Basic Cell Communication in Organ Systems Quiz
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.
(B) Endorphins bind to and temporarily open potassium (K+) channels in the postsynaptic
neuron, which represses all neural activity.
(C) Endorphins bind to and permanently open sodium (Na+) channels in the postsynaptic
neuron, which decreases the membrane potential of the neuron.
(D) Endorphins bind to and permanently disable the potassium (K+) channels in the
postsynaptic neuron, which prevents the neuron from reaching an action potential.
Page 4 of 4