AP Biology : Understanding Neural Cells

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #81 : Types Of Cells And Tissues

Which of the following is a differentiating feature of the two photoreceptors—rods and cones—in the human retina?

Possible Answers:

Rods transduce signals through depolarization; cones do not

Cones use sodium ion channels to transmit light signals; rods use glutamate as a neurotransmitter to bipolar cells

Cones provide color vision; rods do not

Only cones use rhodopsin to absorb light

Correct answer:

Cones provide color vision; rods do not

Explanation:

Rods and cones are contained in the human retina, but they differ in shape and function.  

The functional difference between the two is that rods are more sensitive to light, but do not distinguish colors. Comparatively, cones are able to sense color and are less sensitive to distinctions fo light and dark. There are three different types of cone photoreceptors that have different sensitivity across the visible spectrum, with optimal responses to red, blue and green light, respectively. 

Both types of receptors use rhodopsin as the visual pigment that is activated when exposed to light. This initiates a signaling cascade that causes cellular depolarization through sodium ion channels and the release of the neurotransmitter glutamate by bipolar neuron cells to further transmit the visual signal.

Example Question #11 : Understanding Neural Cells

Which of the following is the correct sequence of events of for the initial signaling in response to light detection by photoreceptors in the eye?

Possible Answers:

Light activates rhodopsin; sodium channels close and the photoreceptor become hyperpolarized, initiating the release of glutamate

Light activates rhodopsin; sodium channels open and the photoreceptor become depolarized, initiating the release of glutamate

Light activates rhodopsin; sodium channels open and the photoreceptor become depolarized, halting the release of glutamate

Light activates rhodopsin; sodium channels close and the photoreceptor become hyperpolarized, halting the release of glutamate

Correct answer:

Light activates rhodopsin; sodium channels close and the photoreceptor become hyperpolarized, halting the release of glutamate

Explanation:

The signaling cascade in response to light  in the human eye is caused by two types of photoreceptors present in the retina—rods and cones. Rods provide dark and light vision (black and white) and cones are capable of discerning color along the visible spectrum.

Rhodopsin is the visual pigment in photoreceptors and is made up of a light-absorbing vitamin-like molecule (retinal) that is bound to a cell membrane protein called opsin. The absorbtion of light by rhodopsin results in chemical bond shifting and a change in the molecule's shape. This causes rhodopsin to activate. The active rhodopsin initiates a G-protein cascade that causes sodium channels on the receptor's cell membrane to close. This prevents sodium ions from entering the cell, resulting in a build-up of ions in the extracellular space in comparison to the cell interior. The membrane potential is directly related to this difference in concentration; a higher concentration of positive ions outside the cell will result in hyperpolarization.

In response to being in a hyperpolarized state, the photoreceptor cell will stop its release of the neurotransmitter glutamate across the cell synapse with retinal neurons. Glutamate is an inhibitory neurotransmitter; halting the release of glutamate will leave the neurons capable of stimulation by visual signals.

Example Question #81 : Types Of Cells And Tissues

Which of the following best describes the role of nervous tissue in the human body?

Possible Answers:

Protection

Transmission of electrical impulses

Support for tissues and organs

Skeletal movement

Correct answer:

Transmission of electrical impulses

Explanation:

Nervous tissue is responsible for the transmission of electrical impulses throughout the human body. This transmission occurs in nerve cells called neurons. It regulates sensory input, muscle control, homeostasis, and mental activity.

Example Question #81 : Types Of Cells And Tissues

Which of the following best describes the peripheral nervous system (PNS)?

Possible Answers:

It is composed of nerves outside of the central nervous system

It includes the somatic and autonomic nervous system

All of these

It is exposed to toxins

Correct answer:

All of these

Explanation:

The PNS is the part of the nervous system that is comprised of all the nerves located outside of the central nervous system. The PNS nerves are not protected by bone; therefore, they are susceptible to toxins and injury. The PNS can be further divided into the somatic and autonomic nervous systems.

Example Question #13 : Understanding Neural Cells

Which of the following is not a function of glial cells?

Possible Answers:

Transmit electrical signals to the brain

Supply nutrients and oxygen to neurons

Hold neurons in place

Insulate neurons

Correct answer:

Transmit electrical signals to the brain

Explanation:

Glial cells are important in maintaining nervous system homeostasis. The major functions of glial cells include insulating neurons, holding them in place, and supplying them with nutrients and oxygen. Glial cells also degrade pathogens and dead neurons.

Example Question #84 : Types Of Cells And Tissues

Which of the following best represent features of neuron cells?

Possible Answers:

Axons

Axons and sarcoplasmic reticulum

Axons and dendrites

Sarcoplasmic reticulum

Correct answer:

Axons and dendrites

Explanation:

Neuron cells are functional units of nervous tissue that transmit electrical signals. Neurons typically are composed of a soma, dendrites, and an axon. The soma is the body of the cell, the dendrites are branched projections that receive signals, and the axon conducts signals away from the cell body.

Example Question #611 : Cellular Biology

Which of the following is not true regarding the function of axons in nerve cells?

Possible Answers:

Axons have nodes of Ranvier

Axons can be myelinated or unmyelinated

They receive electrical signals from other neurons

They transmit electrical signals away from the cell body 

Correct answer:

They receive electrical signals from other neurons

Explanation:

Axons are the parts of neurons that transmit electrical signals away from the cell body and to other neurons. The axon branches off of the soma and is long with a constant radius. Parts of the axon are myelinated, meaning that it is insulated to allow for salutatory conduction. Gaps in insulation are referred nodes of Ranvier.

Example Question #11 : Understanding Neural Cells

Which of the following is the term used to describe the rapid rise and fall in membrane potential required for signal transmission in neurons?

Possible Answers:

Threshold potential

Membrane potential

None of these

Action potential

Correct answer:

Action potential

Explanation:

In neurons and many other cells, electrical signal transmission requires action potential. Action potential can be defined as the rapid rise and fall of membrane potential that allows for signal propagation. In the case of neurons, reaching action potential allows the electrical signal to travel down to axon, which permits signal transduction.

Example Question #11 : Understanding Neural Cells

What makes up the central nervous system (CNS)?

Possible Answers:

Peripheral nerves

Spinal cord

Brain and spinal cord

Brain

Correct answer:

Brain and spinal cord

Explanation:

The CNS is composed of the brain and spinal cord. It receives and regulates information from within the body.

Example Question #611 : Cellular Biology

Which of the following best describe “ganglia”?

Possible Answers:

The part of a neuron that transmits electrical signals to other nerve cells

Clusters of nerve cells

The neuron cell body 

Specialized neurons located only in the heart

Correct answer:

Clusters of nerve cells

Explanation:

Ganglia are described as clusters of nerve cells that are found in the autonomic nervous system.

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