Week 4 Quiz

Question 1

The boundary that separates the internal cellular environment from the external environment.

Answer 1

Plasma Membrane

Question 2

Subcellular compartments

Answer 2

Organells

Question 3

The plasma membrane is often described as a fluid mosaic consisting of _______ and _______.

Answer 3

Phospholipids and proteins

Question 4

A phospholipid consists of a _______-_______ backbone derived from glycerol with fatty acids attached to two of the ________ and a _______ group attached to the third carbon.

Answer 4

three-carbon; carbons; phosphate

Question 5

When placed into water, phospholipids with spontaneously form _______ or ______, depending on the length of the hydrocarbon chains in the fatty acids.

Answer 5

micelles or bilayers

Question 6

The plasma membrane is a _________ _________ in which the hydrophobic tails of the fatty acids are oriented on the inside of the bilayer and the hydrophilic, polar heads, consisting of the phosphate group and any attached organic molecule, are on the outside of the bilayer, facing either the extracellular fluid or the cytoplasm.

Answer 6

phospholipid bilayer

Question 7

Molecules that are _______ and ________ can cross the membrane more easily than _______ or _______ molecules, which are repelled by the hydrophobic interior of the phospholipids bilayer.

Answer 7

nonpolar and hydrophobic; charged or polar

Question 8

The plasma membrane tends to be permeable to ______, ______ molecules and impermeable to molecules that either carry a charge or are very large.

Answer 8

small, nonpolar

Question 9

Solutes that are able to cross the plasma membrane by diffusion

Answer 9

penetrating solutes

Question 10

Solutes that cannot cross the plasma membrane by diffusion

Answer 10

nonpenetrating solutes

Question 11

Diffusion of water across the plasma membrane

Answer 11

Osmosis

Question 12

Transport proteins that provide a hydrophilic channel that spans the membrane

Answer 12

aquaporins

Question 13

These can achieve equal on both sides of the membrane because they can cross the membrane by diffusion

Answer 13

Penetrating solutes

Question 14

These cannot cross the membrane by diffusion

Answer 14

Nonpenetrating solutes

Question 15

The total number of particles it contains and is expressed in milliosmoles per L (mOsM).

Answer 15

Osmolarity

Question 16

Mammalian cells usually have a total solute concentration of approximately __ mOsM.

Answer 16

300

Question 17

A solution that has the same osmolarity as the cytoplasm.

Answer 17

Isosmotic

Question 18

Describes how the solution affects cellular volume, whether the solution causes a cell to shrink, swell, or maintain its volume.

Answer 18

Tonicity

Question 19

A solution that will not cause a change in cellular volume.

Answer 19

Isotonic solution

Question 20

A solution that causes net movement of water into the cell, causing it to eventually swell

Answer 20

Hypotonic

Question 21

A solution that will cause the cell to shrink

Answer 21

Hypertonic

Question 22

Are red blood cells permeable to water?

Answer 22

Somewhat

Question 23

Red blood cells appear red because they contain an iron-binding protein called

Answer 23

hemoglobin

Question 24

The lysis of a red blood cell

Answer 24

hemolysis

Question 25

In red blood cells, when does hemolysis occur?

Answer 25

when placed into a hypotonic solution, or if it is placed in a hypertonic or isotonic solution containing a solute that can easily cross the plasma membrane

Question 26

A solution containing red blood cells is

Answer 26

opaque

Question 27

If hemolysis occurs, the solution becomes more _____ and absorbs less light.

Answer 27

transparent