1 cell

Question 1

glycoprotein is a protein covalently attached to

Answer 1

a carbohydrate

Question 2

the disffusion of H2O across a semi permeable or selectively permeable membrane is termed

Answer 2

Osmosis

Question 3

Oxygen enter a cell via

Answer 3

Diffusion

Question 4

The rate of diffusion of a particle across a membrane will increase if

Answer 4

The lipid solubility of the particle increases

Question 5

In which one of the following transport processes is the substance moving down its electrochemical gradient

Answer 5

Glucose into adipose tissue

Question 6

Which of the following requires energy

Answer 6

Active transport

Question 7

Which of the following characteristics is shared by simple diffusion of alcohol and facilitated diffusion of glucose

Answer 7

Occurs down an electrochemical gradient

Question 8

The Na/K pump is important in axons because it

Answer 8

Maintain concentration gradient of Na and K across the axon membrane

Question 9

Which of the following would occur as a result of the inhibition of Na K ATPase

Answer 9

Increased intercellular Ca concentration

Question 10

Solutions A and B are separated by a semipermeable membrane that is permeable to K,but not to Cl.solution A is 100 mM KCl,and solution B is 1mM KCl.which of the following statements about solution A and solution B is true.

Answer 10

K+ will diffuse from solution A to solution B until a membrane potential develops with solution A negative with respect to solution B

Question 11

The term used to describe,”cell eating “is

Answer 11

Phagocytosis

Question 12

Which of the following processes results in the formation of a food vacuole within the cell that will subsequently be digested by enzymes from the lysosome

Answer 12

Pinocytosis

Question 13

Signaling between cells usually results in the activation of protein

Answer 13

Kinases

Question 14

Which of the following is NOT a typical event associated with cell signaling

Answer 14

Stimulation of apoptosis

Question 15

Sending a signal through the cell membrane can lead to the production of second messagers inside the cell.which of the following can serve as second messagers

Answer 15

cAMP IP3 Ca DG NO

Question 16

Some receptors for growth factors activate a protein kinases cascade with the participation of multiple enzymes to effect a change in expression. Which of the following statements about a protein kinases cascade are true

Answer 16

1 Multiple steps allow the amplification of the signal
2 External signals can lead to changes in gene expression
3 Multiple steps leading to kinase activations can result in cells having different responses,depending on the presence or absence of target proteins
4 multiple steps in activation mean that abnormal stimulation of a cell response such as growth can occur with mutations in more than one gene

Question 17

Estrogen and testosterone are steroid hormones,and are most likely to bind to

Answer 17

Cytoplasmic receptors

Question 18

The endogenous GTPase activity of G-protein serves to

Answer 18

Hydrolyze GTP returning the G protein to a pre-stimulated level of activity

Question 19

The sodium gradient across the nerve cell membrane is

Answer 19

Used as a source of energy for the transport of other ions

Question 20

Membrane excitability will be increased by the greatest amount by

Answer 20

Increasing extra cellular K+

Question 21

Resting potential is

Answer 21

Excess negative ions accumulate inside the plasma membrane

Excess positive ions accumulate outside the plasma membrane

Question 22

The membrane potential will depolarize by the greatest amount if the membrane permeability increases for

Answer 22

Sodium

Question 23

The resting potential of a nerve membrane is primarily dependent on the concentration gradient of

Answer 23

Potassium

Question 24

The action potential of a neuron

Answer 24

Is terminated by efflux of K+

Question 25

Regarding an action potential,what happens immediately after threshold is reached

Answer 25

Increased sodium influx

Question 26

The diffusion of K+out of the cell makes the inside of the cell less positive,or more negative,and acts to restore the original resting membrane potential a process called

Answer 26

Repolarization

Question 27

Both the depolarization and repolarization changes that occur during the action potential are produced by

Answer 27

Diffusion of ions down their concentration gradients

Question 28

During the absolute refractory period along an axon membrane of a neuron,

Answer 28

The neuron is unable to respond to a stimulus of any intensity

Question 29

Depolarization occurs when the membrane charge becomes _______ Positive than resting membrane potential and hyper polarization occurs when the membrane potential charge becomes ________negative than resting membrane potential

Answer 29

More | More

Question 30

In a nerve, the magnitude of the action potential overshoot is normally a function of the

Answer 30

Extra cellular sodium concentration

Question 31

Which of the following words or phrases is most closely associated with an end-plate potential at the neuromuscular junction

Answer 31

Depolarization

Question 32

Which one of the following muscle proteins plays an important role in contraction of both smooth and striated muscle

Answer 32

Actin | Myosin

Question 33

During the process of excitation-contraction in skeletal muscle,calcium is released from the sarcoplasmic reticulum by

Answer 33

Membrane depolarization

Question 34

A drug completely blocks Na channels in nerves. Which of the following effects on the action potential would be expected to produce

Answer 34

Block the occurrence of action potential

Question 35

An increase in sodium conductance is associated with

Answer 35

The upstroke of the smooth muscle action potential

Question 36

Which of the following is not a property of chemically regulated gates

Answer 36

They respond best to membrane potential changes,such as depolarization

Question 37

Which of the following best describes the process of exocytosis

Answer 37

Secretory vesicle fusion and content release

Question 38

The amount of force produced by a skeletal muscle can be increased by

Answer 38

Decreasing the interval between contractions

Question 39

The rate of conduction of action potential along a nerve will be increased by

Answer 39

Myelinating the nerve

Question 40

Increasing the extra cellular potassium concentration will

Answer 40

Decrease potassium permeability

Question 41

Excitation-contraction coupling in smooth muscle is initiated when calcium binds to

Answer 41

Calmodulin

Question 42

The flow of calcium into the cell is an important component of the upstroke phase of action potential in

Answer 42

intestinal smooth muscle

Question 43

_________blocks Acetylcholine receptor sites causing skeletal muscle relaxation

Answer 43

Curare

Question 44

When skeletal muscle is in its resting state,myosin cross bridges are prevented from binding to actin molecules by

Answer 44

Tropomyosin

Question 45

The action potential of skeletal muscle

Answer 45

Spread inward to all parts of the muscle via the T tubule

Question 46

The function of tropomyosin in skeletal muscle include

Answer 46

Acting as a "relaxing protein "at rest by covering up the site where myosin binds to actin

Question 47

The cross-bridges of the sarcomere in skeletal muscle are made up of

Answer 47

myosin

Question 48

The correct temporal sequence for events at the neuromuscular junction is

Answer 48

Uptake of Ca2+ into the presynaptic terminal,release of acetylcholine;depolarization of the muscle end plate

Question 49

Which characteristics or components are shared by skeletal muscle and smooth muscle

Answer 49

Elevation of intracellular Ca2+for excitation-contraction coupling

Question 50

Repeated stimulation of a skeletal muscle fiber causes tetanic contraction because the intracellular concentration of which solute increases and remains at high levels

Answer 50

Ca2+

Question 51

A person with myasthenia gravis notes increased muscle strength when he is treated with an acetylcholine esterase inhibitors.The basis for his improvement is increased

Answer 51

Levels of Ach at the muscle and plates

Question 52

The contractile response in skeletal muscle

Answer 52

Produces more tension when the muscle contracts isometrically than when the muscle contracts isotonically

Question 53

At the muscle end plate,acetylcholine causes the opening of

Answer 53

Na + and K + channels and depolarization

Question 54

Initiation of an action potential in skeletal muscle by stimulating its motor nerve

Answer 54

Requires the release of acetylcholine

Question 55

Which of the following events occurs before depolarization of the T tubules in skeletal muscle in the cell mechanism of excitation-contraction coupling

Answer 55

Depolarization of the sarcolemmal membrane

Question 56

Myasthenia gravis is an autoimmune disorder resulting in reduced numbers of ACh receptors at skeletal-muscle endplates.Which of the following drugs (applied at a pharmacological dose)would be effective in improving neuromuscular transmission in myasthenia gravis patients

Answer 56

Neostigmine (cholinesterase inhibitor)