1.
_______ neurons gather information from the environment so that _________ neurons can relay the information through the body to the brain, so that a message can come down and tell the ______ neurons to contract muscles.
Correct Answer
C. Sensory; inter; motor
Explanation
Sensory neurons gather information from the environment and transmit it to the interneurons. Interneurons then process and relay this information to the motor neurons. Finally, motor neurons receive the message from the brain and send signals to the muscles, causing them to contract.
2.
_________ is responsible for cutting and splicing messenger RNA to produce a protein.
Correct Answer
C. Non-coding ribonucleic acid (ncRNA)
Explanation
Non-coding ribonucleic acid (ncRNA) is responsible for cutting and splicing messenger RNA to produce a protein. Unlike coding RNA, which directly codes for proteins, ncRNA plays a regulatory role in gene expression. It can bind to messenger RNA and guide the splicing process, ensuring that the correct sections are joined together to form a functional protein. This process is essential for proper protein synthesis and cellular function. DNA carries the genetic information, but it is not directly involved in cutting and splicing mRNA. Phospholipids and carboxyl do not have a role in this process.
3.
The cytoplasm includes _______ and ________.
Correct Answer
A. Cell organelles; cytosol
Explanation
The cytoplasm is the gel-like substance that fills the cell and is responsible for supporting and protecting the cell's organelles. It includes cell organelles, which are specialized structures within the cell that perform specific functions, and cytosol, which is the fluid portion of the cytoplasm. The plasma membrane, also known as the cell membrane, is a separate structure that encloses the cell and controls the movement of substances in and out of the cell. The nucleus, on the other hand, is a separate organelle within the cell that contains the cell's DNA and controls cellular activities. Therefore, the correct answer is "cell organelles; cytosol."
4.
________ are subcellular structures that perform various functions in a cell.
Correct Answer
B. Cell organelles
Explanation
Cell organelles are subcellular structures that perform various functions in a cell. They are specialized compartments within a cell that carry out specific tasks such as energy production, protein synthesis, and waste disposal. Examples of cell organelles include the nucleus, mitochondria, endoplasmic reticulum, and Golgi apparatus. These organelles work together to maintain the overall function and integrity of the cell.
5.
The cell membrane is ___________, meaning it serves as a barrier to passage of some molecules, and it is composed of a double layer of ________.
Correct Answer
D. Selectively permeable; lipid molecules
Explanation
The correct answer is "selectively permeable; lipid molecules". The cell membrane is selectively permeable, which means it allows certain molecules to pass through while preventing others from crossing. It is composed of a double layer of lipid molecules, specifically phospholipids, which have hydrophilic heads and hydrophobic tails. This lipid bilayer structure gives the cell membrane its selective permeability and allows it to regulate the movement of substances in and out of the cell.
6.
____________ are permanently attached to the cell membrane; whereas ________ are only temporarily attached.
Correct Answer
A. Integral membrane proteins; peripHeral membrane proteins
Explanation
Integral membrane proteins are permanently attached to the cell membrane, meaning that they are embedded within the lipid bilayer and cannot be easily removed without disrupting the membrane structure. On the other hand, peripheral membrane proteins are only temporarily attached to the cell membrane, meaning that they can be easily detached and removed from the membrane without disrupting its structure.
7.
Nuclear envelope is to __________ as nucleus is to cell.
Correct Answer
B. Cell membrane
Explanation
The nuclear envelope is a double membrane that surrounds the nucleus, separating it from the rest of the cell. Similarly, the cell membrane is a double layer of phospholipids that surrounds the entire cell, separating it from the external environment. Both the nuclear envelope and the cell membrane serve as barriers that regulate the movement of substances in and out of the cell. Therefore, the relationship between the nuclear envelope and the nucleus is analogous to the relationship between the cell membrane and the entire cell.
8.
Nuclear pores aid in ______________.
Correct Answer
B. Transport of molecules
Explanation
Nuclear pores are involved in the transport of molecules. These tiny channels are present in the nuclear envelope, which surrounds the nucleus of a cell. They allow for the movement of various molecules, such as RNA and proteins, between the nucleus and the cytoplasm. This transport is essential for the proper functioning of the cell, as it allows for the regulation of gene expression, protein synthesis, and other cellular processes.
9.
______________ is/are DNA/protein combinations that are condensed for size and are involved in mitosis/meiosis.
Correct Answer
C. Nucleolus chromatin
Explanation
Nucleolus chromatin refers to the DNA/protein combinations that are condensed for size and are involved in mitosis/meiosis. The nucleolus is a substructure within the nucleus of a cell, and chromatin is the material that makes up chromosomes. During mitosis and meiosis, the nucleolus chromatin undergoes condensation and organization to form chromosomes, which are then distributed to daughter cells. Therefore, nucleolus chromatin is the correct answer in this context.
10.
The endoplasmic reticulum is the __________ of the cell world.
Correct Answer
A. Highway
Explanation
The endoplasmic reticulum is often referred to as the "highway" of the cell because it is responsible for transporting proteins and lipids throughout the cell. Just like a highway facilitates the movement of vehicles, the endoplasmic reticulum allows for the efficient movement of molecules within the cell. It consists of a network of interconnected membranous tubules and sacs, which serve as the routes for transport. Therefore, the comparison to a highway is an appropriate analogy to describe the function of the endoplasmic reticulum.
11.
Anterograde axoplasmic transport refers to substances being pushed toward the ________.
Correct Answer
D. Terminal buttons
Explanation
Anterograde axoplasmic transport refers to the movement of substances in a neuron away from the cell body towards the terminal buttons. This transport mechanism is responsible for delivering various molecules, proteins, and organelles necessary for synaptic communication and neurotransmitter release at the terminal buttons.
12.
Retrograde axoplasmic transport refers to substances being pushed toward the _________.
Correct Answer
C. Soma
Explanation
Retrograde axoplasmic transport refers to the movement of substances from the terminal buttons towards the soma. This process allows for the recycling of cellular components, removal of waste materials, and delivery of signals from the terminal buttons to the soma. The soma, also known as the cell body, contains the nucleus and other essential organelles necessary for the functioning of the neuron. Therefore, it is the correct answer as substances are pushed towards the soma during retrograde axoplasmic transport.
13.
The granular (rough) endoplasmic reticulum produces and packages __________.
Correct Answer
C. Proteins
Explanation
The granular endoplasmic reticulum, also known as rough endoplasmic reticulum, is responsible for producing and packaging proteins. This organelle contains ribosomes on its surface, which are responsible for protein synthesis. As proteins are synthesized, they are transported into the rough endoplasmic reticulum where they undergo further processing and packaging before being transported to their final destination within the cell or outside of it. Therefore, the correct answer is proteins.
14.
The ribosomes, located on the granular endoplasmic reticulum, serve as the ________ of the cell world.
Correct Answer
B. Protein factories
Explanation
Ribosomes are responsible for protein synthesis in cells. They are located on the granular endoplasmic reticulum, which is involved in the production, folding, and transport of proteins. Therefore, the term "protein factories" accurately describes the role of ribosomes in the cell.
15.
Agranular (smooth) endoplasmic reticulum is the __________ of the cell world.
Correct Answer
D. Lipid factory
Explanation
The smooth endoplasmic reticulum (ER) is responsible for lipid synthesis, detoxification, and carbohydrate metabolism. It lacks ribosomes, which gives it a smooth appearance. Lipids, such as phospholipids and steroids, are essential components of cell membranes and play a crucial role in various cellular processes. Therefore, comparing the smooth ER to a "lipid factory" accurately describes its function in the cell world.
16.
The golgi apparatus is the ___________ of the cell world.
Correct Answer
D. Packaging center
Explanation
The golgi apparatus is often referred to as the "packaging center" of the cell world because it is responsible for modifying, sorting, and packaging proteins and lipids into vesicles for transport to their final destinations within the cell or for secretion outside of the cell. It receives these molecules from the endoplasmic reticulum and modifies them by adding sugars or other molecules, and then packages them into vesicles for transport. This process ensures that proteins and lipids are properly sorted and delivered to their intended locations, allowing for proper cell function.
17.
Secretory vesicles in the golgi apparatus contain __________ sent by the granular endoplasmic reticulum, and intend to __________.
Correct Answer
A. Proteins; secrete proteins to outside of cell
Explanation
Secretory vesicles in the golgi apparatus contain proteins sent by the granular endoplasmic reticulum, and intend to secrete proteins to outside of the cell.
18.
The mitochondria serves as the ___________ of the cell world.
Correct Answer
C. Power plant
Explanation
The mitochondria is often referred to as the "power plant" of the cell because it is responsible for producing the majority of the cell's energy in the form of adenosine triphosphate (ATP) through a process called cellular respiration. This energy is essential for the cell to carry out its various functions and processes. Therefore, the term "power plant" accurately describes the role of mitochondria in providing energy to the cell.
19.
The mitochondria produces ATP, which is used as __________.
Correct Answer
D. Energy for functioning in the cell
Explanation
The mitochondria is responsible for producing ATP, which stands for adenosine triphosphate. ATP is considered the energy currency of the cell and is used as a source of energy for various cellular processes and functions. Therefore, the correct answer is "energy for functioning in the cell."
20.
Lysosomes are the ___________ of the cell world.
Correct Answer
B. Digestive system
Explanation
Lysosomes are known as the "digestive system" of the cell world because they contain enzymes that break down waste materials and cellular debris. These enzymes help in the process of digestion within the cell, breaking down larger molecules into smaller ones that can be utilized by the cell for energy or eliminated as waste. Just like the digestive system in our body, lysosomes play a crucial role in maintaining the overall health and functioning of the cell.
21.
Filaments form the ____________ of the cell world.
Correct Answer
C. Skeletal system
Explanation
Filaments form the skeletal system of the cell world. The skeletal system provides structure and support to the cell, similar to how the skeletal system in humans provides support to the body. Just like bones in the human body, filaments in the cell world help maintain the shape and integrity of the cell. They also play a role in cell movement and provide attachment points for various cellular components. Therefore, the correct answer is skeletal system.
22.
__________ is to __________ as input is to output.
Correct Answer
C. Dendrites; axons
Explanation
Dendrites are the branching extensions of neurons that receive electrical signals from other neurons and transmit them towards the cell body (soma). Axons, on the other hand, are the long projections of neurons that transmit electrical signals away from the cell body towards other neurons or muscles. In this analogy, the relationship between dendrites and axons is similar to the relationship between input and output, as dendrites receive signals (input) and axons transmit signals (output). Therefore, the correct answer is Dendrites; axons.
23.
The axon hillock is the place where the ________ and ________ join.
Correct Answer
B. Soma; axon
Explanation
The axon hillock is the place where the soma (cell body) and the axon join. The axon hillock is a specialized region of the neuron where the action potential is initiated. It is located at the base of the soma and acts as a junction between the cell body and the axon. This region contains a high concentration of voltage-gated ion channels, which play a crucial role in generating and propagating the electrical signal along the axon.
24.
_________ are responsible for secreting neurotransmitters.
Correct Answer
A. Terminal buttons
Explanation
Terminal buttons are responsible for secreting neurotransmitters. Terminal buttons, also known as synaptic knobs, are located at the ends of axons and are responsible for transmitting signals to other neurons. When an action potential reaches the terminal buttons, they release neurotransmitters into the synapse, which then bind to receptors on the postsynaptic neuron and transmit the signal. This process allows for communication between neurons and is essential for the functioning of the nervous system.
25.
__________ hold the neurotransmitters in little bubbles, ready to burst at the terminal buttons when an action potential signals it.
Correct Answer
D. Synaptic vesicles
Explanation
Synaptic vesicles are responsible for holding neurotransmitters in little bubbles, ready to be released at the terminal buttons when an action potential signals it. These vesicles store and transport the neurotransmitters, allowing them to be released into the synapse and transmit signals from one neuron to another.
26.
The most common type of axon/dendrite configuration is a ___________ neuron, with _____ axon(s) and _______ dendrite(s).
Correct Answer
D. Multipolar; one; many
Explanation
The correct answer is multipolar; one; many. In a multipolar neuron, there is one axon and many dendrites. This type of neuron is the most common configuration found in the nervous system. The axon carries signals away from the cell body, while the dendrites receive signals from other neurons and transmit them to the cell body.
27.
Astrocytes, oligodendrocyte, and Schwann cells are all examples of ___________
Correct Answer
B. Neuroglia
Explanation
Neuroglia refers to a type of cells found in the nervous system that provide support and protection to neurons. Astrocytes, oligodendrocytes, and Schwann cells are all examples of neuroglia. Astrocytes regulate the chemical environment around neurons, oligodendrocytes produce myelin to insulate axons in the central nervous system, and Schwann cells perform the same function in the peripheral nervous system. Therefore, neuroglia is the correct answer as it encompasses all these types of cells that play crucial roles in supporting and protecting neurons.
28.
The purpose of Astrocytes is to ___________.
Correct Answer
A. Provide nutrition and pHysical support to surrounding cells
Explanation
Astrocytes are a type of glial cell in the central nervous system that play a crucial role in providing nutrition and physical support to surrounding cells. They help maintain the homeostasis of the extracellular environment by regulating the levels of ions, neurotransmitters, and metabolites. They also form a structural framework for neurons, providing them with physical support. Additionally, astrocytes are involved in the formation and maintenance of the blood-brain barrier, which further supports their role in providing nutrition and support to surrounding cells.
29.
The purpose of microglia is to _________.
Correct Answer
C. Serve as pHagocytes eating dead and dying neurons
Explanation
Microglia are a type of immune cells found in the central nervous system. Their main function is to act as phagocytes, which means they engulf and digest dead or dying neurons, as well as other cellular debris. This process helps to remove waste and maintain the overall health of the nervous system. Therefore, microglia serve as phagocytes eating dead and dying neurons.
30.
The purpose of Oligondenrocytes is to __________.
Correct Answer
B. Myelinate segments of several neurons
Explanation
Oligodendrocytes are a type of glial cell in the central nervous system that play a crucial role in the process of myelination. Myelination involves the formation of a protective sheath called myelin around the axons of neurons, which helps to increase the speed and efficiency of electrical signal transmission. Oligodendrocytes are responsible for myelinating multiple segments of several neurons, making them essential for proper neural communication and function.
31.
The purpose of Schwann cells is to _____________.
Correct Answer
D. Myelinate a single segment of a neuron
Explanation
Schwann cells are a type of glial cell in the peripheral nervous system that play a crucial role in myelination. Myelination refers to the process of forming a protective covering around the axons of neurons. Schwann cells wrap around a single segment of a neuron, forming a myelin sheath. This myelin sheath helps to insulate the neuron, allowing for faster and more efficient transmission of electrical signals along the axon. Therefore, the purpose of Schwann cells is to myelinate a single segment of a neuron.
32.
________ potential can be summed up for a cumulative effect.
Correct Answer
C. Gradient
Explanation
Gradient refers to the rate of change or the slope of a function. When potential is summed up for a cumulative effect, it means that the potential is being accumulated or added up over time or distance. The concept of gradient fits well in this context as it represents the change or accumulation of potential.
33.
___________ explains why, after several days, sugar left at the bottom of a glass of water distributes itself even throughout the glass.
Correct Answer
B. Diffusion
Explanation
Diffusion is the process by which particles move from an area of higher concentration to an area of lower concentration. In the case of sugar left at the bottom of a glass of water, the sugar particles will naturally move and spread out throughout the water due to diffusion. This is because the concentration of sugar is higher at the bottom initially, and over time, the sugar particles will randomly move and mix with the water particles, resulting in an even distribution of sugar throughout the glass.
34.
________ are negative, like the inside of the cell, so they want to get out but they can't because the cell membrane is not permeable to it.
Correct Answer
A. Anions
Explanation
Anions are negatively charged ions that are present inside the cell. Since they are negatively charged, they have a tendency to move out of the cell. However, the cell membrane is not permeable to anions, meaning that they cannot freely move across it. Therefore, anions want to get out of the cell, but they are unable to do so due to the impermeability of the cell membrane.
35.
__________ is positive, unlike the inside of the cell, so electrostatic pressure keeps it concentrated inside the cell.
Correct Answer
B. Potassium
Explanation
Potassium is positive, unlike the inside of the cell, so electrostatic pressure keeps it concentrated inside the cell. This means that potassium ions, which have a positive charge, are more likely to be attracted and retained inside the cell due to the electrostatic forces. This concentration gradient of potassium ions across the cell membrane is important for various cellular processes, such as maintaining the cell's resting membrane potential and regulating cell volume.
36.
___________ is negative, unlike the outside of the cell, so electrostatic pressure keeps it concentrated outside the cell.
Correct Answer
C. Chlorine
Explanation
Chlorine is negative, unlike the outside of the cell, so electrostatic pressure keeps it concentrated outside the cell. This means that there is a higher concentration of chlorine ions outside the cell compared to inside. The electrostatic pressure, also known as the electrochemical gradient, helps to maintain this concentration gradient by pushing the negatively charged chlorine ions away from the inside of the cell and keeping them concentrated outside.
37.
_________ is positive, like the outside of the cell, so it wants to move inside the cell but the cell membrane is only somewhat permeable to it and a special pump keeps pushing it back out of the cell.
Correct Answer
D. Sodium
Explanation
Sodium is positively charged, just like the outside of the cell. Due to this positive charge, sodium wants to move inside the cell. However, the cell membrane is only partially permeable to sodium, meaning it allows only some sodium ions to pass through. Additionally, there is a special pump in the cell membrane that actively pushes sodium ions back out of the cell, maintaining a balance and preventing an excessive buildup of sodium inside the cell.
38.
_________ requires a lot of energy to keep working in a cell, up to 40% of the ATP that the cell produces.
Correct Answer
B. Sodium-Potassium pump
Explanation
The correct answer is the Sodium-Potassium pump. The Sodium-Potassium pump is a protein found in the cell membrane that helps maintain the balance of sodium and potassium ions inside and outside the cell. It uses ATP energy to pump three sodium ions out of the cell for every two potassium ions it pumps in. This constant pumping requires a significant amount of energy, accounting for up to 40% of the ATP produced by the cell.
39.
When the membrane potential is resting at -70mV, the cell is considered ___________.
Correct Answer
A. Polarized
Explanation
When the membrane potential is resting at -70mV, the cell is considered polarized. This means that there is a difference in electrical charge between the inside and outside of the cell, with the inside being more negatively charged. This polarization is maintained by the selective permeability of the cell membrane to different ions and the action of ion pumps.
40.
Which of the following is incorrect:
Correct Answer
B. At 0mV, the potassium ion channels open up, the potassium floods out of the cell, the cell stops depolarizing starts repolarizing
Explanation
At 0mV, the potassium ion channels open up, allowing potassium ions to flow out of the cell. This causes the cell to repolarize, not depolarize. Depolarization refers to the process of the cell membrane becoming less negative, while repolarization refers to the process of the cell membrane returning to its resting potential after depolarization. Therefore, the statement that the cell stops depolarizing and starts repolarizing at 0mV is incorrect.
41.
If one were to apply an electrode to a cell but not provide enough electricity to reach the threshold of excitation, what would occur?
Correct Answer
D. Nothing would occur
Explanation
If the applied electricity is not enough to reach the threshold of excitation, the cell would not undergo any changes. This means that neither the potassium ion channel nor the sodium ion channel would open. Without the opening of these ion channels, there would be no movement of ions across the cell membrane, and therefore, no action potential or any other cellular response would occur.
42.
Why is it important for there to be nodes of Ranvier?
Correct Answer
C. Action potential would lose strength along the axon and not be able to signal the terminal buttons to activate
Explanation
Nodes of Ranvier are essential for the proper functioning of the nervous system. These gaps in the myelinated sheath allow for the regeneration of the action potential, preventing it from losing strength as it travels along the axon. Without nodes of Ranvier, the action potential would gradually weaken, making it difficult for the signal to reach the terminal buttons and activate the necessary response. Therefore, the presence of nodes of Ranvier is crucial for maintaining the strength and efficiency of the action potential along the axon.
43.
___________ is/are necessary because otherwise the action potential at the next node of Ranvier would activate an action potential at the current node of Ranvier.
Correct Answer
C. Absolute refractory period
Explanation
The absolute refractory period is necessary because it ensures that the action potential at the next node of Ranvier does not activate an action potential at the current node of Ranvier. During the absolute refractory period, the voltage-gated sodium channels are inactivated and cannot be opened, preventing the generation of another action potential. This allows for the proper propagation of the action potential along the axon, ensuring that it moves in one direction and does not backtrack.
44.
A more intense stimuli may elicit a __________ graded potential and ultimately ________ action potential.
Correct Answer
B. More intense; same intensity
Explanation
When a more intense stimuli is applied, it results in a more intense graded potential. This graded potential, if it reaches the threshold, will trigger an action potential of the same intensity. This means that the strength or magnitude of the action potential does not change, regardless of the intensity of the stimuli.
45.
Excitatory graded potentials ________________
Correct Answer
A. Are depolarizing and bring the cell membrane closer to 0mV
Explanation
Excitatory graded potentials are depolarizing and bring the cell membrane closer to 0mV. This means that they increase the positive charge inside the cell, making it more likely for an action potential to occur.
46.
Rapid depolarization of the cell membrane during an action potential is a result of _________.
Correct Answer
C. Sodium ion channel gates openning
Explanation
During an action potential, the rapid depolarization of the cell membrane is a result of sodium ion channel gates opening. This allows an influx of sodium ions into the cell, leading to a change in the membrane potential and the initiation of the action potential.
47.
______________ contains mitochondria, synaptic vesicles, and cisternae.
Correct Answer
D. Pre-synaptic membrane
Explanation
The pre-synaptic membrane contains mitochondria, synaptic vesicles, and cisternae. This membrane is located at the end of a neuron and is responsible for releasing neurotransmitters into the synaptic cleft, which then bind to receptors on the post-synaptic membrane of the next neuron. The presence of mitochondria suggests that this membrane is involved in energy production and the synthesis of neurotransmitters. The presence of synaptic vesicles indicates that this membrane is responsible for storing and releasing neurotransmitters. The cisternae are likely involved in the regulation and storage of calcium ions, which play a crucial role in neurotransmitter release.
48.
Postsynaptic membrane cannot be a __________.
Correct Answer
D. Nucleus
Explanation
The postsynaptic membrane is the membrane of a neuron that receives signals from the presynaptic neuron. It is responsible for converting these signals into electrical impulses that can be transmitted throughout the neuron. The nucleus, on the other hand, is the central organelle of a cell that contains the genetic material. It is involved in the control of cell activities and the production of proteins. Therefore, the postsynaptic membrane cannot be a nucleus as it is a separate structure involved in different functions.
49.
Which of the following is not an example of postsynaptic potential termination?
Correct Answer
D. Glial cell clean up
Explanation
Glial cell clean up is not an example of postsynaptic potential termination. Postsynaptic potential termination refers to the processes that stop the transmission of signals across the synapse. Reuptake is the process by which neurotransmitters are taken back up into the presynaptic neuron, enzymatic deactivation involves the breakdown of neurotransmitters by enzymes, and the release of AchE (acetylcholinesterase) is responsible for breaking down acetylcholine. However, glial cell clean up refers to the role of glial cells in removing excess neurotransmitters and maintaining the chemical balance in the synapse, but it does not directly terminate postsynaptic potentials.
50.
____________ is the only neurotransmitter that utilizes enzymatic deactivation.
Correct Answer
A. Acetylcholine
Explanation
Acetylcholine is the only neurotransmitter that utilizes enzymatic deactivation. This means that after acetylcholine has fulfilled its role in transmitting signals between nerve cells, it is broken down by enzymes called acetylcholinesterases. This enzymatic deactivation is crucial for maintaining proper neurotransmitter balance and preventing excessive stimulation of the nervous system. GABA, dopamine, and serotonin are neurotransmitters that are deactivated through different mechanisms, such as reuptake or enzymatic breakdown by other enzymes. Therefore, acetylcholine stands out as the only neurotransmitter that relies on enzymatic deactivation.