Question 1

Tastes and smells are distinct kinds of environmental information where ________.

Accepted Answer

Neural projections from taste receptors and olfactory receptor go to different parts of the brain, so the brain can distinguish between tastes and smells based on the location of activation in the brain.

Question 2

It can be very difficult to select an angle for sneaking up to a grasshopper to catch it because grasshoppers have ________.

Accepted Answer

The answer of It can be very difficult to select...

Question 3

In a mammalian visual system, visual information is integrated at ________.
I. the lens
II. the retina
III. the optic nerve
IV. the visual cortex

Accepted Answer

Visual information is primarily integrated at the retina, where photoreceptors convert light into neural signals that are sent to the brain via the optic nerve. However, further integration and processing of visual information occurs in the visual cortex, which is responsible for higher-level aspects of visual perception such as object recognition and depth perception. The lens does not play a direct role in visual information integration, as its primary function is to focus light onto the retina. Therefore, choices I and III can be eliminated.

Question 4

Corneal surgery is now routinely performed to change the shape of the cornea and improve vision. This surgery is beneficial because it ________.

Accepted Answer

Corneal surgery, such as LASIK or PRK, involves reshaping the cornea to improve its ability to focus light onto the retina, which can improve vision. It does not affect the circulation of nutrients to the eye, the amount of light entering the eye, or the sensitivity of the photoreceptors.

Question 5

Lateral inhibition via horizontal cells in the mammalian retina ________.

Accepted Answer

Lateral inhibition via horizontal cells in the mammalian retina enhances visual contrast by inhibiting the activity of neighboring cells, thus making the signal from the activated cells more distinct.

Question 6

In the odorant cells of mammals, specific odorants are detected by binding to ________.

Accepted Answer

Odorants are detected by binding to G protein-coupled receptors in the odorant cells of mammals. Binding of the odorant to the receptor triggers a signal transduction pathway that results in the generation of an action potential in the olfactory nerve.

Question 7

Sensory transduction of light in the vertebrate retina is accomplished by ________.

Accepted Answer

Rods and cones are the photoreceptor cells in the retina that transduce light into electrical signals, which are then processed by bipolar cells and transmitted to ganglion cells, ultimately leading to visual perception. Amacrine cells play a modulatory role in this process, but they do not directly transduce light.

Question 8

Hair cells in the vertebrate ear are responsible for transducing sound pressure waves. Ion channels in the hair cell membrane open when ________.

Accepted Answer

Ion channels in the hair cell membrane open when the membrane is distorted mechanically, which occurs when sound pressure waves cause movement of structures in the ear such as the tympanic membrane and ossicles. This movement results in the bending of the stereocilia on the hair cells, which in turn causes ion channels to open and an influx of ions to occur, ultimately leading to the generation of electrical signals that are transmitted to the brain.

Question 9

Compared to viewing a distant object, a human viewing an object held within five centimetres of the eye requires a lens that ________.

Accepted Answer

When viewing an object held within five centimetres of the eye, the ciliary muscles contract to increase the curvature of the lens, making it more spherical. This allows for greater refraction of light, which is necessary for focusing on objects closer to the eye. Therefore, the correct choice is B.

Question 10

Rods exposed to light will ________.

Accepted Answer

When rods are exposed to light, the pigment rhodopsin breaks down into retinal and opsin, triggering a series of events that ultimately leads to the closure of sodium channels in the photoreceptor cell membrane. This results in hyperpolarization of the cell and a decrease in the release of neurotransmitter, which in turn leads to the signaling of the brain about the presence of light. Therefore, the correct choice is B, hyperpolarise due to the closing of sodium channels.

Question 11

What structures would neurobiologists look for if they are interested in determining if an animal can see in colour?

Accepted Answer

Neurobiologists would look for opsin proteins in the animal's retina to determine if it has the ability to see in color. Opsins are the photoreceptor proteins responsible for detecting light and transmitting signals to the brain, and different types of opsins are sensitive to different wavelengths of light, allowing for color vision. The other options (electroreceptors, pupil, and lens) do not specifically relate to color vision.

Question 12

Umami perception would be stimulated by ________.

Accepted Answer

Umami is one of the five basic tastes, and it is the taste of glutamate, which is often found in meaty and savory foods such as beef. Therefore, a slice of roast beef would stimulate umami perception.

Question 13

How could you genetically modify an animal so that it would distinguish more shades of green?

Accepted Answer

Introducing genes for additional opsins that respond to different wavelengths in the green region of the spectrum would allow the animal to distinguish more shades of green. This would increase the sensitivity of the animal's vision and allow it to distinguish more subtle differences in green hues. Inducing genes to produce more cone cells would not necessarily increase the animal's ability to distinguish shades of green, as each cone cell is typically specialized to respond to a specific range of wavelengths. Similarly, producing green fluid in the eyeball would not necessarily improve the animal's color vision, as the fluid would likely absorb some wavelengths of green light. Inducing increased production of cGMP would affect the function of photoreceptors, but would not necessarily be targeted specifically to green wavelengths.

Question 14

The blind spot in the human retina is the location that has the collected axons of ________.

Accepted Answer

The blind spot in the human retina is the location where the optic nerve exits the eye. The optic nerve carries visual information from the retina to the brain, and it is made up of the axons of ganglion cells. Therefore, the collected axons in the blind spot are those of ganglion cells.

Question 15

Experiments with genetically altered mice showed that the mice would consume abnormally high amounts of bitter-tasting compounds in water after their ________.

Accepted Answer

The answer of Experiments with genetically altered mice showed that...

Question 16

Which of the following sensory receptors is correctly paired with its category?

Accepted Answer

Hair cells are specialized mechanoreceptors found in the inner ear that perceive sound vibrations and head movements. Muscle spindles, on the other hand, are also mechanoreceptors that detect changes in muscle length and tension. Taste receptors are chemoreceptors that respond to different chemical molecules in food. Rods and cones in the retina of the eye are photoreceptors that detect light stimuli, not chemical molecules, making D incorrect.

Question 17

Methyl jasmonate is a plant-derived compound that blocks mosquito carbon dioxide receptors. What would you expect to happen if you applied this compound to your skin and then exposed yourself to a swarm of mosquitos?

Accepted Answer

Methyl jasmonate blocks mosquito carbon dioxide receptors, which are an important sensory cue for finding a host. Therefore, if applied to the skin, the compound would make it harder for the mosquitos to find a host and be less likely to bite. However, it is important to note that this does not completely repel mosquitos, and other sensory cues such as visual cues and body heat are still important for them to find a host.

Question 18

The umami receptor in the sense of taste detects ________.

Accepted Answer

The umami receptor in the sense of taste specifically detects monosodium glutamate (MSG) which is a type of amino acid responsible for the savory taste in foods. Glucose, potassium ions, and hydrogen ions are not detected by the umami receptor.

Question 19

Two students studying physiology taste a known "bitter" substance, and both report sensing bitterness. They then sample another substance. Student A reports sensing both a bitter taste and a salty taste, but student B reports only a salty taste. What is the most logical explanation?

Accepted Answer

Student A's ability to detect both bitter and salty tastes suggests that they have intact taste buds for both flavors. However, student B's inability to detect the bitter taste suggests that they lack the protein receptor necessary to detect the bitter molecule. This is a genetic difference, not an allergic reaction or a result of differences in saliva.

Question 20

Most of the chemosensory neurons arising in the nasal cavity have axonal projections that terminate in the ________.

Accepted Answer

Most of the chemosensory neurons in the nasal cavity project their axons to the olfactory bulb, which is responsible for processing odor information.

Quiz 50: Sensory and Motor Mechanisms