Knpe 125 Unit 1 Test

The correct order of events in translation is initiation, elongation, and termination. Initiation is the first step in translation where the ribosome binds to the mRNA and the start codon is recognized. Elongation follows initiation, where amino acids are added to the growing polypeptide chain. Termination is the final step, where the ribosome reaches a stop codon and the polypeptide chain is released.

Increasing the lanes of traffic from 1 to 3 on a highway represents an increase in conductance. Conductance refers to the ease with which a substance or flow can pass through a given medium. In this case, increasing the number of lanes on a highway allows for a greater flow of traffic, indicating an increase in conductance.

Increasing the transcription of mitochondrial genes would lead to an increase in the production of mitochondrial proteins. These proteins are essential for energy production in the cells, particularly during endurance exercise. More mitochondrial proteins would enhance the capacity of the mitochondria to generate ATP, the energy currency of the cell. As a result, increasing the transcription of mitochondrial genes would improve the efficiency of energy production, leading to better endurance exercise performance.

The correct equation for the physiological flow model is Flow = Gradient (P) x Conductance. This equation represents the relationship between flow, pressure gradient, and conductance. It states that the flow of a substance is equal to the pressure gradient across a system multiplied by the conductance of that system. Conductance represents the ease with which a substance can flow through a system, and the pressure gradient represents the difference in pressure between two points. Therefore, this equation accurately describes the relationship between flow, pressure, and conductance in the physiological flow model.

Once an afferent neuron enters the spinal column, it travels towards the brain via the dorsal column. The dorsal column is a pathway in the spinal cord that carries sensory information from the body to the brain. It is located towards the back (dorsal) of the spinal cord and consists of two main tracts, the fasciculus gracilis and the fasciculus cuneatus. These tracts relay sensory information such as touch, pressure, and proprioception to the brain for processing and interpretation. Therefore, the correct answer is the dorsal column.

The rate of flow for water through a hose can be calculated using the formula: Flow rate = Pressure gradient / Conductance. In this case, the pressure gradient is given as 200 mmHg and the conductance is given as 2 L/mmHg/min. Plugging these values into the formula, we get: Flow rate = 200 mmHg / 2 L/mmHg/min = 100 L/min. Therefore, the correct answer is 100 L/min.

If the mass of substance y is increasing, it means that more of substance y is entering the system. In order for more substance y to enter the system, the conductance for inflow must be increasing. This implies that there is a higher rate of flow or easier movement of substance y into the system. The other options, such as P for inflow decreasing or P for outflow increasing, do not necessarily indicate an increase in the mass of substance y.

During depolarization, the membrane potential becomes more positive because sodium (Na+) channels open.

An exergonic reaction is a chemical reaction that releases energy. In the given examples, only the firecracker exploding in mid-air can be defined as exergonic because it involves a rapid release of energy in the form of heat, light, and sound. Metabolism producing ATP from ADP and an inorganic phosphate is an endergonic reaction as it requires energy input. A tree using photosynthesis to produce glucose is also an endergonic reaction as it requires energy from sunlight. Therefore, the correct answer is the firecracker exploding in mid-air.

The resting membrane potential of a neuron refers to the electrical charge difference across the cell membrane when the neuron is at rest. A negative value indicates that the inside of the neuron is more negatively charged compared to the outside. In this case, the correct answer of -70 mV suggests that the inside of the neuron is 70 millivolts more negative than the outside. This negative charge is maintained by the activity of ion channels and pumps in the neuron's membrane.

Opening a Na+ channel located within the membrane of a resting neural cell would make the neuron's membrane potential more positive. This is because Na+ ions have a positive charge, and when the channel opens, Na+ ions flow into the cell, increasing the overall positive charge inside the cell. This depolarizes the membrane potential, bringing it closer to the threshold for generating an action potential.

The correct answer is ER, Golgi Apparatus, Membrane. This is because newly formed proteins are synthesized in the endoplasmic reticulum (ER), then they are transported to the Golgi Apparatus for modification and sorting, and finally, they are transported to the cell membrane for secretion or integration into the membrane.

Increasing the number of available enzymes in a chemical reaction increases the production of product from substrate because enzymes act as catalysts, speeding up the reaction rate. By increasing the conductance, the movement of charged particles, such as ions, is facilitated, allowing for more efficient enzyme-substrate interactions. This leads to a higher rate of product formation. Therefore, increasing conductance is the most likely option to increase the production of product from substrate.

The knee-jerk reflex is an involuntary response that occurs when the patellar tendon is tapped, causing the quadriceps muscle to contract and extend the leg. This reflex does not involve the brain in the immediate reaction. Instead, it is a spinal reflex that is mediated by a loop between the afferent neurons, interneurons, and efferent neurons in the spinal cord. The afferent neurons carry the sensory information from the muscle spindle to the spinal cord, where the interneurons relay the signal to the efferent neurons, which then stimulate the quadriceps muscle to contract. The absence of the brain's involvement allows for a quick and automatic response to the stimulus.

In multiple sclerosis (MS), the body's immune system mistakenly attacks and damages the myelin sheath, which is a protective covering around nerve fibers. This damage disrupts the normal flow of electrical impulses along the nerves, leading to a decrease in the rate of action potential conduction. As a result, the nervous system's ability to transmit signals efficiently is compromised, causing the symptoms associated with MS. This answer accurately describes the underlying mechanism of MS.

mRNA binds to the 40s subunit of the ribosome, while tRNA brings amino acids to the 60s subunit. mRNA carries the genetic information from the DNA to the ribosome, where it is used as a template for protein synthesis. tRNA, on the other hand, carries specific amino acids to the ribosome, where they are assembled into a polypeptide chain according to the instructions provided by the mRNA. Therefore, mRNA and tRNA play different roles in the process of protein synthesis.

When ATP is broken down to ADP, only one inorganic phosphate is released from the molecule of ATP. ATP (adenosine triphosphate) is a high-energy molecule that stores energy in its phosphate bonds. When one phosphate group is removed from ATP, it becomes ADP (adenosine diphosphate), and the released phosphate can be used for various cellular processes. Therefore, the correct answer is 1.

Feedback control directly responds to changes in regulated variables, while feed forward control does not. Feedback control continuously monitors the regulated variables and makes adjustments based on the feedback received. It compares the actual output to the desired output and makes changes accordingly. On the other hand, feed forward control does not directly respond to changes in regulated variables. It predicts the changes based on known factors and adjusts the control accordingly, without directly monitoring the regulated variables.

When an action potential reaches the terminal end of an exon, voltage gated Ca2+ channels open triggering neurotransmitter into the synapse. This is because Ca2+ ions play a crucial role in synaptic transmission. The influx of Ca2+ ions into the terminal end of the exon allows for the fusion of neurotransmitter-containing vesicles with the presynaptic membrane, leading to the release of neurotransmitters into the synapse. This triggers the transmission of signals from one neuron to another.

Endergonic reactions typically require the most activation energy because they involve the formation of new bonds and the input of energy to proceed. In an endergonic reaction, the products have higher energy than the reactants, and this energy difference needs to be overcome by providing activation energy. On the other hand, exergonic reactions release energy as they proceed, making them more favorable and requiring less activation energy. The presence of an enzyme can lower the activation energy for both exergonic and endergonic reactions, but endergonic reactions still generally require more activation energy compared to exergonic reactions.

The initiation of an action potential occurs at the axon hillock. This is the region of the neuron where the axon originates from the cell body (soma). The axon hillock contains a high concentration of voltage-gated sodium channels, which are responsible for generating and propagating the electrical signal of the action potential. This region also has a lower threshold for depolarization compared to other parts of the neuron, making it the site where the action potential is first triggered.

Temporal summation refers to the process by which the firing of one excitatory synapse multiple times in quick succession leads to an accumulation of depolarization that exceeds the threshold required to generate an action potential. This occurs because the individual excitatory postsynaptic potentials (EPSPs) generated by each firing of the synapse summate over time, resulting in a larger depolarization. In contrast, spatial summation involves the simultaneous firing of multiple excitatory synapses, while the action potential threshold is the minimum level of depolarization required to trigger an action potential.

Closing voltage-gated calcium channels in the pre-synaptic axon terminal between first and second order sensory neurons would decrease the perception of pain. Calcium channels are responsible for the release of neurotransmitters, and by closing these channels, the release of neurotransmitters across the synapse would be reduced. This would result in a decreased transmission of pain signals from the first to the second order sensory neurons, ultimately leading to a decrease in the perception of pain.

If the pressure of sodium on the outside of the cell decreases while the pressure of sodium on the inside of the cell decreases, it creates a larger concentration gradient. This means that there is a greater difference in the concentration of sodium between the inside and outside of the cell. Since the flow of sodium is driven by this concentration gradient, a larger gradient would result in an increased flow of sodium into the cell. Therefore, the correct answer is that the flow would increase.

Increasing the number of bouncers at the front doors to a bar represents an increase in conductance. Conductance refers to the ease with which a current can flow through a conductor. In this case, the bouncers act as conductors, controlling the flow of people entering the bar. By increasing the number of bouncers, the conductance of people entering the bar increases because more people can be accommodated and allowed in at a faster rate.

Enzymes speed up the rate of a reaction by bringing substrates close to one another so that they are more likely to react. This is known as the enzyme's catalytic function. By binding to the substrates, enzymes create an environment that is conducive to the chemical reaction, allowing it to occur more quickly. Enzymes do not change the thermodynamics of a reaction, so they do not convert exergonic reactions to endergonic ones. Additionally, enzymes do not increase the number of substrates or alter the activation energy of a reaction.

The given statement suggests that the rate of diffusion for substance z increases linearly with increasing concentration gradient. This characteristic is a key feature of simple diffusion, where substances move across a concentration gradient without the need for any external energy or assistance. In simple diffusion, molecules move freely through the cell membrane from an area of higher concentration to an area of lower concentration until equilibrium is reached. Therefore, based on the information provided, the diffusion of substance z is an example of simple diffusion.

Leak channels are the main reason that K+ contributes more to membrane potential than Na+. This is because leak channels are selective for certain ions, and there are more leak channels for K+ than for Na+ in the cell membrane. As a result, K+ ions can diffuse out of the cell more easily through leak channels, leading to a higher concentration of K+ outside the cell and a more negative membrane potential. On the other hand, Na+ ions are less able to diffuse through leak channels, resulting in a lower concentration of Na+ inside the cell and a less negative membrane potential compared to K+.

Both breaking down ATP (ATP hydrolysis) and lighting a match can be defined as exergonic processes. Exergonic reactions release energy as they proceed, and both of these examples involve the release of energy. Breaking down ATP releases energy that can be used by cells for various functions, while lighting a match involves the release of energy in the form of heat and light.

Transcription is the process by which genetic information from DNA is copied into RNA. It occurs in the nucleus of eukaryotic cells, specifically in the nucleoplasm. This is where the DNA is located, and it is where the enzyme RNA polymerase binds to the DNA and synthesizes the RNA molecule. The other options, cytoplasm, endoplasmic reticulum, and Golgi apparatus, are not involved in the transcription process.

The correct answer is A and B. These options both demonstrate negative feedback control. In option A, the release of a hormone is increased in response to high plasma levels of the same hormone, which helps to regulate and maintain hormone levels within a certain range. In option B, the uptake of plasma glucose into skeletal muscle is decreased in response to high muscle glucose content, which helps to prevent excessive glucose uptake and maintain glucose homeostasis. Both examples illustrate feedback mechanisms that work to counteract and regulate changes in the body.

Increasing the number of products would decrease the rate of the reaction because it would cause a shift in the equilibrium towards the reactants, slowing down the forward reaction. Decreasing the number of enzymes would also decrease the rate of the reaction because enzymes act as catalysts, speeding up the reaction by lowering the activation energy. Finally, decreasing the number of substrates would decrease the rate of the reaction because there would be fewer reactant molecules available to participate in the reaction. Therefore, all of these factors would contribute to a decrease in the reaction rate.

The correct answer is "Action potentials from each type of sensor are slightly different due to differences in Na+ channel function." This statement is not one of the "principals of sensory reception" because it refers to the differences in Na+ channel function, which is not a principle of sensory reception. The principles of sensory reception include all receptors eliciting action potentials in afferent nerve fibers, each type of receptor being highly sensitive to one type of stimuli only, and afferent action potentials being interpreted differently based on where they terminate in the CNS.

The muscle stretch reflex is initiated by a group of sensory nerves called the muscle spindle. The muscle spindle is wrapped around intrafusal fibers.

The correct answer is "Endoplasmic reticulum -> golgi apparatus -> vesicle -> membrane" because newly formed proteins are synthesized by ribosomes attached to the endoplasmic reticulum. From there, the proteins are transported to the Golgi apparatus, where they undergo modifications and packaging into vesicles. These vesicles then transport the proteins to the cell membrane for secretion or integration into the membrane.

The Nernst equation calculates the equilibrium potential for a single ion based on its concentration gradient and electrical charge across a membrane. It does not take into account membrane permeability. On the other hand, the Goldman equation considers both concentration gradients and membrane permeability to calculate the membrane potential. It takes into account the permeability of multiple ions, allowing for a more accurate calculation of the membrane potential. The contribution of the Na+/K+ pump is not considered in either equation.

The knee jerk reflex is a clinical test that assesses the function of the Muscle Stretch Reflex. This reflex is also known as the patellar reflex and is triggered when the patellar tendon is tapped, causing the quadriceps muscle to contract and extend the leg. This reflex is important for maintaining posture and balance, as well as protecting the body from potential harm. The withdrawal reflex is a different reflex that involves the removal of a body part from a harmful stimulus, while the Golgi Tendon Reflex is responsible for preventing excessive tension in muscles.

All of the above types of transport, including primary active transport, co-transport, and counter-transport, require the breakdown of ATP. ATP is the main source of energy for cellular processes, including the movement of molecules across cell membranes. In primary active transport, ATP is directly involved in the transport process, providing the energy needed to move molecules against their concentration gradient. In co-transport and counter-transport, ATP is indirectly involved as it powers the ion pumps that establish and maintain the concentration gradients necessary for these transport mechanisms to occur.

The correct answer is "None of the above are true" because increasing substrate concentration typically increases the rate of reaction, while increasing enzyme concentration also increases the rate of reaction. Decreasing substrate concentration and increasing enzyme concentration may not always lead to an increase in the rate of reaction, as the reaction rate is dependent on the availability of both substrate and enzyme. Therefore, none of the statements provided in the options are true regarding enzyme kinetics.

Leak channels allow both Na+ and K+ to diffuse freely across cell membranes. This means that both Na+ and K+ can move in and out of the cell through these channels. Leak channels are the main reason that K+ contributes more to membrane potential than Na+. This is because there are more leak channels for K+ compared to Na+, allowing K+ to move more freely and therefore have a greater impact on the membrane potential. Leak channels are integral membrane proteins, meaning they are embedded within the cell membrane. However, it is not true that leak channels allow 1000 times more Na+ to diffuse than K+.

Opening a K+ channel located within the membrane of a resting neural cell would cause that neuron's membrane potential to become more negative. This is because K+ channels are responsible for allowing the outflow of K+ ions from the cell, leading to hyperpolarization of the membrane potential. As more positive ions leave the cell, the inside of the cell becomes more negative, resulting in a decrease in the membrane potential.

Spatial summation refers to the process by which multiple excitatory synapses on a neuron are activated simultaneously, leading to a cumulative effect on the neuron's membrane potential. This cumulative effect can result in depolarization that exceeds the threshold required to generate an action potential. Therefore, the statement "the firing of more than one excitatory synapse at the same time results in depolarization that is greater than threshold" best defines spatial summation.

The cerebellum is responsible for coordinating voluntary movements and maintaining balance and posture. It receives information from the sensory systems, the spinal cord, and other parts of the brain, and then regulates and fine-tunes motor movements. Adjusting shots in mid-air requires precise control over motor movements, including adjusting the angle, speed, and force of the shot. Therefore, the ability of basketball players to adjust their shots in mid-air is likely a result of the cerebellum's role in motor coordination and control.

Active transport is a process that requires the movement of molecules across a cell membrane against their concentration gradient, which requires the expenditure of energy. This energy is provided by the breakdown of ATP (adenosine triphosphate) into ADP (adenosine diphosphate) and inorganic phosphate. Co-transport and counter-transport are specific types of active transport where the movement of one molecule is coupled with the movement of another molecule or ion. Therefore, all of the given options directly involve the breakdown of ATP to fuel the active transport process.

During depolarization, potassium concentration is higher inside the cell than outside. This is because depolarization refers to the process of the cell becoming less negative and more positive. During depolarization, potassium channels open, allowing potassium ions to flow out of the cell, which increases the concentration of potassium inside the cell compared to outside. This movement of potassium ions helps to repolarize the cell and restore its resting membrane potential.

An afferent action potential occurs at two synapses between the sensory receptor and its termination in the somatosensory area of the brain. This means that the sensory information travels through two synapses before reaching the somatosensory area. The first synapse occurs between the sensory receptor and the primary sensory neuron, while the second synapse occurs between the primary sensory neuron and the somatosensory area of the brain.

The repressor region is not part of a gene. Genes consist of three main regions: the promoter region, which initiates gene expression; the coding region, which contains the instructions for protein production; and the terminator region, which marks the end of the gene. The repressor region, on the other hand, is a DNA sequence that binds to a repressor protein, preventing gene expression by blocking the binding of RNA polymerase to the promoter region. Therefore, it is not considered part of the gene itself.

During the absolute refractory period, the Na+ inactivation gates remain closed. This means that the sodium channels cannot be reopened, preventing the generation of another action potential in the same region. As a result, the action potential can only propagate in one direction, ensuring unidirectional propagation.

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Ligand-gated channels play a direct and essential role in the initiation of an action potential in a post-synaptic neuron. These channels are located on the post-synaptic membrane and are activated by neurotransmitters released from the pre-synaptic neuron. When the neurotransmitter binds to the ligand-gated channels, they open, allowing ions to flow into the post-synaptic neuron. This influx of ions can depolarize the post-synaptic membrane, leading to the initiation of an action potential. Therefore, the correct answer is the initiation of an action potential in a post-synaptic neuron.