Composition of Cells

Question 1

_________ are composed of lipids.

Answer 1

Membranes

Question 2

The two major fluid compartments are the _____ and _____.

Answer 2

intracellular; extracellular

Question 3

Where is the concentration of Na+ higher?

Answer 3

in the ECF

Question 3

Where is the concentration of water higher?

Answer 3

it’s the same in the ICF and ECF

Question 4

Membranes are composed of _____.

Answer 4

lipids

Question 5

What are the principal inorganic ions in the cell?

Answer 5

Na+, K+, and Cl-

Question 6

Name the 5 components of ICF or ECF.

Answer 6

1) Na+ 2) K+ 3) Cl- 4) proteins 5) water

Question 7

The excess anions create an _______ potential difference between the inside and the outside of the cell, called the ______.

Answer 7

electrical; membrane potential

Question 7

Stimuli for gated channels include _____, ______, ______, or _______,

Answer 7

1) electricity (voltage gated) 2) mechanical 3) chemicals 4) temperature

Question 8

What components can pass through the membrane?

Answer 8

K+, Cl-, H2O

Question 9

It is estimated that 50% of the energy we expend at rest is used to _____.

Answer 9

pump ions across membranes

Question 10

What is an example of a primary active transporter?

Answer 10

the Na+/Cl- pump

Question 11

The ability of the membrane to withstand the imposed electric force with a strength of about 100,000 volts/cm is due to its __________.

Answer 11

lipid composition

Question 12

Channels behave as _____ or _____ in the membrane.

Answer 12

passive pores; tunnels

Question 13

What is the intracellular fluid comprised of?

Answer 13

mitochondrial, vesicular, nuclear, and other subcompartments

Question 14

The patch clamp technique allows one to see ______.

Answer 14

individual ion channels at work

Question 14

If the energy for transport comes directly from metabolism (usually splitting ATP), the transport is called _________. transport.

Answer 14

primary active

Question 15

Some channels contain molecular ______.

Answer 15

gates

Question 16

Where is the concentration of K+ higher?

Answer 16

in the ICF

Question 16

______ work thousands of times slower than channels.

Answer 16

Transporters

Question 17

Some charged/polar substances cross membranes by passing through _____, which behave as passive pores, or tunnels, in the membrane.

Answer 17

channels

Question 18

Some substances cross membranes by binding to _____ and being escorted (‘carried’) across.

Answer 18

proteins

Question 19

Transporters are also needed in order to _____ to concentrate them on one side against ______.

Answer 19

pump molecules across a membrane; their energy gradient

Question 20

If the transport energy comes from other sources and not ATP, it is called ______.

Answer 20

secondary active transport

Question 21

If 2% of K+ leaks out of the cells, _______.

Answer 21

the pt can die

Question 22

How is the patch clamp technique performed?

Answer 22

A glass pipette touches a cell - gentle suction draws membrane into the mouth of the pipette to form a seal- channel gate opens- record the electric current through the channel

Question 23

What is the extracellular fluid comprised of?

Answer 23

1) plasma 2) lymph 3) interstitial fluid

Question 24

The ability of the membrane to withstand the imposed electric force with a strength of about ________ is due to its lipid composition.

Answer 24

100,000 volts/cm

Question 25

What is the total volume of the extracellular fluid?

Answer 25

13 liters

Question 27

What is the boundary btw the intra- and extracellular fluids?

Answer 27

the plasma membrane

Question 28

The excess ____ create an electrical potential difference between the inside and the outside of the cell, called the membrane potential.

Answer 28

anions

Question 30

Where is the concentration of Cl- higher?

Answer 30

in the ECF

Question 31

The cytoplasm of nearly all cells is electrically _____compared to the ECF.

Answer 31

negative

Question 33

Cells contain a few more _____ ions than _____ ions.

Answer 33

negative; positive

Question 34

Most channels are _______ for particular ions.

Answer 34

selective

Question 35

What is the total volume of the intracellular fluid?

Answer 35

27 liters

Question 36

It is estimated that ____ of the energy we expend at rest is used to pump ions across membranes.

Answer 36

50%

Question 37

Name 2 general kinds of proteins that mediate transmembrane movement of charged substances.

Answer 37

1) channels 2) transporters

Question 39

Secondary active transport also depends on ______.

Answer 39

metabolism

Question 40

Where is the concentration of protein higher?

Answer 40

in the ICF