Membranes and Transporters (22, 23)

Question 1

Simple diffusion vs Facilitated diffusion

Answer 1

Simple: moves directly through bilayer
Facilitated: moves through transporter protein (channel)

Question 2

Passive transport

Answer 2

Diffusion across concentration gradient (high to low). Includes simple and facilitated diffusion.

Question 3

These molecules move through passive transport directly through the membrane

Answer 3

O2, CO2

Question 4

Phospholipid components

Answer 4

Glycerol backbone, phosphate group, 2 fatty acid chains

Question 5

2 features that affect lipid fluidity

Answer 5

1. Length. Longer the tail, more van der waals forces experienced, less fluidity.
2. Saturation. The more double bonds, the more kinks, the less fluidity.

Question 6

The IMF that results in dynamic nature of the membrane:

Answer 6

Van der Waals: easily formed, easily broken.

Question 7

4 Types of Membrane Proteins

Answer 7

1. Transporter
2. Receptor
3. Enzyme
4. Anchor

Question 8

Can lipids flip in the bilayer?

Answer 8

Not without an enzyme - lateral movement is much more common.

Question 9

What kinds of molecules can easily permeate the bilayer?

Answer 9

Small, nonpolar molecules travelling fast. Ex: O2, CO2, N2

Question 10

What kinds of molecules need transport proteins to move across the bilayer?

Answer 10

Large, uncharged, polar molecules (ex: glucose) as well as small ions.

Question 11

Saturated vs Unsaturated

Answer 11

Saturated with hydrogens. Unsaturated has 1 or more double bonds.

Question 12

Do saturated or unsaturated fatty acids experience tighter packing?

Answer 12

Saturated - no kinkds = tighter packing.

Question 13

3 Functions of the Membrane

Answer 13

1. Separate cellular spaces
2. Selectively permeable
3. Barrier to outside the cell

Question 14

2 Membrane Properties

Answer 14

1. Fluid/dynamic
2. Mosaic - made of phospholipids and proteins

Question 15

Amphipathic

Answer 15

Both hydrophilic and hydrophobic

Question 16

Triglyceride

Answer 16

Glycerol backbone and 3 fatty acid chains. They act as large, uncharged, and hydrophobic energy storage.

Question 17

2 Classifications of Membrane Proteins

Answer 17

1. Integral - extend across
2. Peripheral - bind to either outside or inside

Question 18

Does H2O easily permeate the membrane?

Answer 18

It polar, and uncharged, and small enough to pass through the membrane to a limited extent.

Question 19

Aquaporins

Answer 19

Embedded channel protein specific for water.

Question 20

Primary active transport

Answer 20

Uses ATP directly to move substances against concentration gradient.

Question 21

Secondary active transport

Answer 21

Driven by an electrochemical gradient (potential energy). Often: proton gradient movement can drive the movement of other molecules against concentration gradient.

Question 22

Vacuole

Answer 22

Membrane-bound organelle that absorbs water and contributes to turgor pressure

Question 23

What 2 cellular structures does cell shape depend on?

Answer 23

1. Cell wall
2. Cytoskeleton

Question 24

Function of the endomembrane system

Answer 24

Compartmentalizes the cell.

Question 25

The entire contents of a cell other than the nucleus make up the…

Answer 25

Cytoplasm

Question 26

The jelly-like internal environment of a cell is called…

Answer 26

Cytosol

Question 27

Vesicles

Answer 27

Small, membrane bound sacs that transport substances

Question 28

What organelles does the endomembrane system include?

Answer 28

1. Nuclear envelope
2. Endoplasmic reticulum (rough and smooth)
3. Golgi apparatus
4. Lysosomes
5. Cell membrane
6. Vesicles

Question 29

Function of the rough ER

Answer 29

Synthesis of transmembrane proteins and organelle proteins

Question 30

Function of the smooth ER

Answer 30

Site of fatty acid and phospholipid biosynthesis. Production of lipids!

Question 31

Golgi apparatus function

Answer 31

Modifies and sorts lipids and proteins. Not physically continuous with nucleus or ER

Question 32

Function of lysosomes

Answer 32

Degrade macromolecules. Digestive, come from golgi

Question 33

Hyponatremia

Answer 33

Low concentration of sodium in blood.

Question 34

Proteins that move two molecules across the membrane (2 types):

Answer 34

1. Molecules move in same direction: Symport
2. Molecules move in opposite directions: Antiport

Question 35

ATPase

Answer 35

H+ pump. Embedded pump!

Active proton transport using ATP.

Binds H+, energy from ATP drives bound proton to outside of cell. Repeats.

Question 36

RER protein synthesis for pushed in and embedded proteins