Transport Across Cell Membrane ( Sodium-Potassium Pump )

Question 1

What is the energy-requiring process of pumping molecules and ions across membranes “uphill” - against a concentration gradient. To move these molecules against their concentration gradient, a carrier protein is needed.

Answer 1

Active transport

Question 2

What can work with a concentration gradient (during passive transport), but some it can move solutes against the concentration gradient (from low concentration to high concentration), with an input of energy.

Answer 2

Carrier proteins

Question 3

In active transport, as carrier proteins are used to move materials against their concentration gradient, these proteins are known as?

Answer 3

pumps

Question 4

As in other types of cellular activities, what supplies the energy for most active transport. One way it powers active transport is by transferring a phosphate group directly to a carrier protein. This may cause the carrier protein to change its shape, which moves the molecule or ion to the other side of the membrane.

Answer 4

ATP

Question 5

What system moves sodium and potassium ions against large concentration gradients?

Answer 5

sodium-potassium pump system

Question 6

the sodium-potassium pump system moves sodium and potassium ions against large concentration gradients. It moves what ions into the cell where potassium levels are high?

Answer 6

two potassium ions

Question 7

the sodium-potassium pump system moves sodium and potassium ions against large concentration gradients. It moves two potassium ions into the cell where potassium levels are high, and pumps what ions out of the cell and into the extracellular fluid.

Answer 7

three sodium ions

Question 8

The sodium-potassium pump is found in the ? of almost every human cell and is common to all cellular life. It helps maintain cell potential and regulates cellular volume.

Answer 8

plasma membrane

Question 9

The active transport of ions across the membrane causes an ? to build up across the plasma membrane.

Answer 9

electrical gradient

Question 10

The number of positively charged ions outside the cell is greater than the number of positively charged ions in the?

Answer 10

cytosol

Question 11

What is electrical potential energy that is caused by a separation of opposite charges, in this case across the membrane.

Answer 11

Voltage

Question 12

voltage across a membrane is called?

Answer 12

membrane potential

Question 13

What favors the movement of positively charged ions (cations) into the cell, and the movement of negative ions (anions) out of the cell.

Answer 13

membrane potential

Question 14

there are two forces that drive the diffusion of ions across the plasma membrane—a chemical force (the ions’ concentration gradient), and an electrical force (the effect of the membrane potential on the ions’ movement). These two forces working together are called an?

Answer 14

electrochemical gradient

Question 15

What is often referred to as a mosaic model because of its semi-permeability and its ability to keep certain substances from entering the cell.

Answer 15

membrane

Question 16

What houses the Na+/K+ pump, ATPase pump, ion transporters, and voltage gated channels, and it is the site of vesicular transport. The structure regulates which ions enter and exit to determine the concentration of specific ions inside of the cell

Answer 16

lipid bilayer

Question 17

Animals and plants require the breakdown of organic substances through ? to generate energy.

Answer 17

cellular respiration

Question 18

Animals and plants require the breakdown of organic substances through cellular respiration to generate energy. This process, which produces ATP, is dependent on the?

Answer 18

electron transport chain

Question 19

Animals and plants require the breakdown of organic substances through cellular respiration to generate energy. This process, which produces ATP, is dependent on the electron transport chain. Electrons travel down this path to be accepted by?

Answer 19

oxygen or other electron acceptors

Question 20

As per membrane potentials, when there a gradient, the molecules flow in the opposite direction. In this case, hydrogen flows back into the cell through a protein known as ? which creates ATP in the process. This action is essential to life because the number of ATP created from each glucose increases drastically.

Answer 20

ATP synthase

Question 21

Represents the difference in electrical charge across the membrane.

Answer 21

Electrical Gradient

Question 22

Represents the difference in the concentration of a specific ion across the membrane.

Answer 22

Chemical Gradient

Question 23

What can help us relate the numerical values of concentration to the electrical gradient?

Answer 23

Nernst equation

Question 24

• Channels that are always open
• Permit unregulated flow of ions down an electrochemical gradient.

Answer 24

Leak Channels

Question 25

- Actively transports Na+ out of the cell and K+ into the cell. - Helps to maintain the concentration gradient and to counteract the leak channels

Answer 25

Na+/K+ ATPase Pump

Question 26

Human nerve cells work mainly on the concept of membrane potentials. They transmit chemicals known as ? through gradients.

Answer 26

serotonin or dopamine

Question 27

Human nerve cells work mainly on the concept of membrane potentials. They transmit chemicals known as serotonin or dopamine through gradients. What receives these neurotransmitters and uses it to perform functions?

Answer 27

brain

Question 28

It has a much higher concentration outside of the cell and the cell membrane is very impermeable to it.

Answer 28

Na+

Question 29

It has a high concentration inside the cell due to the fact that the cell membrane is very permeable to it.

Answer 29

K+

Question 30

What is used to refer to large ions that are found completely inside of the cell and cannot penetrate the cell membrane?

Answer 30

A⁻

Question 31

What are like cables that carry electrical impulses between your brain and the rest of your body?

Answer 31

Nerves

Question 32

What help us feel sensations and move our muscles. They also maintain certain autonomic functions like breathing, sweating or digesting food.

Answer 32

impulses

Question 33

What are present all over your body, especially in your brain and spinal cord?

Answer 33

Neurons

Question 34

Nerves, together with your brain and spinal cord, are the foundation of our?

Answer 34

nervous system

Question 35

Most of the time when doctors use the term “nerve,” they’re referring to the part of your nervous system outside of your brain and spinal cord. This is called your?

Answer 35

peripheral nervous system

Question 36

What nerves carry signals to your brain to help you touch, taste, smell and see?

Answer 36

Sensory nerves

Question 37

What nerves carry signals to your muscles or glands to help you move and function?

Answer 37

Motor nerves

Question 38

These 12 nerve pairs originate in your brain and extend through your face, head and neck. These nerves can have sensory functions, motor functions or both.

Answer 38

Cranial nerves

Question 39

These 31 pairs of nerves branching out from your spinal cord. These nerves can provide sensory function, motor function or both.

Answer 39

Spinal nerves

Question 40

What system is the network of nerves that transmit (carry) signals from all over your body to your spinal cord, which is part of your central nervous system.

Answer 40

peripheral nervous system

Question 41

What system is your brain and spinal cord. It receives and interprets nerve signals from your peripheral nervous system. Your brain integrates these messages (inputs) to inform everything you do, including how you move, feel, behave and think. Some reactions are reflexive, happening below the level of consciousness, like moving your hand away from a hot stove

Answer 41

central nervous system

Question 42

When a nerve sends an electrical impulse: The signal travels down the ?, the “wiring” connection of the nerve.

Answer 42

axon

Question 43

The message converts to a chemical signal at the end of the nerve called the?

Answer 43

axon hillock

Question 44

The message converts to a chemical signal at the end of the nerve called the axon hillock. The chemical releases molecules called ?, into a space that bridges the space between one neuron to another

Answer 44

neurotransmitters

Question 45

The message converts to a chemical signal at the end of the nerve called the axon hillock. The chemical releases molecules called neurotransmitters, into a space that bridges the space between one neuron to another. These bridges are called?

Answer 45

synapses

Question 46

ulnar nerve, median nerve, radial nerve and axillary nerve are be found in?

Answer 46

Arms

Question 47

vagus nerve and phrenic nerve are found in?

Answer 47

Chest and abdomen

Question 48

facial nerve, trigeminal nerve and optic nerve are found in?

Answer 48

face

Question 49

sciatic nerve, femoral nerve, tibial nerve, obturator nerve and sural nerve are found in?

Answer 49

Legs

Question 50

pudendal nerve is found in?

Answer 50

Pelvis

Question 51

cord-like groups of fibers in the center of your nerve.

Answer 51

Axons

Question 52

branches that carry electrical impulses

Answer 52

Dendrites

Question 53

a layer of connective tissue surrounding axons.

Answer 53

Endoneurium

Question 54

a layer of connective tissue that surrounds groups of axons called fascicles.

Answer 54

Perineurium

Question 55

a layer of connective tissue that covers the outer surface of your nerve

Answer 55

Epineurium

Question 56

In your brain, cells called ? surround axons.

Answer 56

oligodendrocytes

Question 57

Outside of your central nervous system (brain and spinal cord), cells called ? surround the axons.

Answer 57

Schwann cells

Question 58

Both oligodendrocytes and Schwann cells contain a fatty tissue called ? It surrounds the axons in a layered sheath (coating).

Answer 58

Myelin

Question 59

What is like the insulation around electrical wiring?

Answer 59

myelin sheath

Question 60

With the development of electrophysiology and the discovery of electrical activity of neurons, it was discovered that the transmission of signals from neurons to their target tissues is mediated by?

Answer 60

action potentials

Question 61

neurons and muscle cells are capable of generating an action potential; that property is called the?

Answer 61

excitability

Question 62

But what causes the action potential? From an electrical aspect, it is caused by a stimulus with certain value expressed in?

Answer 62

millivolts [mV]

Question 63

What stimuli cannot cause an action potential?

Answer 63

Subthreshold stimuli

Question 64

What stimuli are of enough energy or potential to produce an action potential (nerve impulse)?

Answer 64

Threshold stimuli

Question 65

What stimuli also produce an action potential, but their strength is higher than the threshold stimuli?

Answer 65

Suprathreshold stimuli

Question 66

It is important to know that the action potential behaves upon what law? This means that any subthreshold stimulus will cause nothing, while threshold and suprathreshold stimuli produce a full response of the excitable cell.

Answer 66

all-or-none law

Question 67

From the aspect of ions, an action potential is caused by temporary changes in membrane permeability for diffusible ions. These changes cause ? to open and the ions to decrease their concentration gradients.

Answer 67

ion channels

Question 68

What state of the membrane potential related to the action potential which precedes the depolarization?

Answer 68

hypopolarization

Question 69

What state of the membrane potential related to the action potential which follows the repolarization?

Answer 69

hyperpolarization

Question 70

What is the initial increase of the membrane potential to the value of the threshold potential?

Answer 70

Hypopolarization

Question 71

The threshold potential opens voltage-gated sodium channels and causes a large influx of sodium ions. This phase is called the? During this phase, the inside of the cell becomes more and more electropositive.

Answer 71

depolarization

Question 72

The threshold potential opens voltage-gated sodium channels and causes a large influx of sodium ions. This phase is called the depolarization. During depolarization, the inside of the cell becomes more and more electropositive, until the potential gets closer the electrochemical equilibrium for sodium of +61 mV. This phase of extreme positivity is called what phase?

Answer 72

overshoot phase

Question 73

The overshoot value of the cell potential opens voltage-gated potassium channels, which causes a large potassium efflux, decreasing the cell’s electropositivity. This phase is called ?, whose purpose is to restore the resting membrane potential.

Answer 73

repolarization phase

Question 74

Repolarization always leads first to ?, a state in which the membrane potential is more negative than the default membrane potential. But soon after that, the membrane establishes again the values of membrane potential.

Answer 74

hyperpolarization

Question 75

What is the time after an action potential is generated, during which the excitable cell cannot produce another action potential.

Answer 75

refractory period

Question 76

What refractoriness overlaps the depolarization and around 2/3 of repolarization phase. A new action potential cannot be generated during depolarization because all the voltage-gated sodium channels are already opened or being opened at their maximum speed. During early repolarization, a new action potential is impossible since the sodium channels are inactive and need the resting potential to be in a closed state, from which they can be in an open state once again. Absolute refractoriness ends when enough sodium channels recover from their inactive state

Answer 76

Absolute refractoriness

Question 77

What refractoriness is the period when the generation of a new action potential is possible, but only upon a suprathreshold stimulus. This period overlaps the final 1/3 of repolarization

Answer 77

Relative refractoriness

Question 78

An action potential is generated in the body of the neuron and propagated through its ? Propagation doesn’t decrease or affect the quality of the action potential in any way, so that the target tissue gets the same impulse no matter how far they are from neuronal body.

Answer 78

axon

Question 79

The action potential generates at one spot of the cell membrane. It propagates along the membrane with every next part of the membrane being sequentially depolarized. This means that the action potential doesn’t move but rather causes a new action potential of the adjacent segment of the?

Answer 79

neuronal membrane

Question 80

We need to emphasize that the action potential always propagates ?, never backwards. This is due to the refractoriness of the parts of the membrane that were already depolarized, so that the only possible direction of propagation is?

Answer 80

forward

Question 81

What increases the propagation speed because it increases the thickness of the fiber.

Answer 81

Myelin

Question 82

In unmyelinated fibers, every part of the axonal membrane needs to undergo ?, making the propagation significantly slower.

Answer 82

depolarization

Question 83

What is a junction between the nerve cell and its target tissue?

Answer 83

synapse

Question 84

In humans, synapses are chemical, meaning that the nerve impulse is transmitted from the axon ending to the target tissue by the chemical substances called?

Answer 84

neurotransmitters (ligands)

Question 85

If a neurotransmitter stimulates the target cell to an action, then it is an?

Answer 85

excitatory neurotransmitter

Question 86

If a neurotransmitter inhibits the target cell, it is an

Answer 86

inhibitory neurotransmitter

Question 87

What are between two neurons in the central nervous system?

Answer 87

Central synapses

Question 88

What occur between a neuron and muscle fiber, peripheral nerve, or gland?

Answer 88

peripheral synapses

Question 89

What membrane of the terminal button of the nerve fiber?

Answer 89

Presynaptic membrane

Question 90

What membrane of the target cell?

Answer 90

Postsynaptic membrane

Question 91

a gap between the presynaptic and postsynaptic membranes.

Answer 91

Synaptic cleft

Question 92

When the presynaptic membrane is depolarized by an action potential, the calcium voltage-gated channels open. This leads to an influx of calcium, which changes the state of certain membrane proteins in the presynaptic membrane, and results with ? of the neurotransmitter in the synaptic cleft.

Answer 92

exocitosis

Question 93

When the presynaptic membrane is depolarized by an action potential, what channels open? This leads to an influx of calcium, which changes the state of certain membrane proteins in the presynaptic membrane, and results with exocitosis of the neurotransmitter in the synaptic cleft

Answer 93

calcium voltage-gated channels

Question 94

The postsynaptic membrane contains receptors for the neurotransmitters. Once the neurotransmitter binds to the receptor, what channels of the postsynaptic membrane either open or close? These channels are the ion channels, and their opening or closing will cause a redistribution of ions in the postsynaptic cell.

Answer 94

ligand-gated channels

Question 95

What is caused by either threshold or suprathreshold stimuli upon a neuron. It consists of three phases: depolarization, overshoot, and repolarization.

Answer 95

action potential