Biol 107 - Biological Membranes

Front 1

Modern membranes are made mostly of _______, but are embedded with or attached to molecules like ______ and ________.

Back 1

Lipids
Carbohydrates
Proteins

Front 2

In most biological membranes, what is the most abundant lipid?

Back 2

Phospholipids

Front 3

What does amphiphilic or amphipathic mean?

Back 3

Molecules that have distinct hydrophobic and hydrophilic regions

Front 4

Phosphatidylcholine is a common ________ in membranes.

Back 4

Phospholipid

Front 5

Describe: Micelle

Back 5

Hydrophobic tails in centre, hydrophilic heads on outside, forms a sphere.

Front 6

Describe: Bilayer Sheet

Back 6

2 molecules thick with hydrophilic heads on the outside, forms a layer or sheet.

Front 7

Describe: Liposome

Back 7

2 molecules thick with hydrophilic heads on the outside, like a bilayer sheet but circularized.

Front 8

Definition: Integral (or intrinsic) protein

Back 8

Protein embedded in the bilayer, due to part of it being hydrophobic

Front 9

Definition: Peripheral (or extrinsic) protein

Back 9

Protein attached loosely to the membrane, usually interaction with an integral protein.

Front 10

Definition: Glycoprotein

Back 10

When carbohydrates are attached to membrane proteins

Front 11

Definition: Glycolipid

Back 11

When carbohydrates are attached to certain membrane lipids.

Front 12

What explains the differences between blood cell types?

Back 12

The different carbohydrates on their cell surfaces.

Front 13

What is responsible for transplant rejection and immunity?

Back 13

Different carbohydrates attached to membranes.

Front 14

What is responsible for the sorting of cells to correct organs in developing embryo?

Back 14

Different carbohydrates attached to membranes.

Front 15

What are three examples of roles that different carbohydrates attached to cell membranes.

Back 15

Recognition of self
Blood Cell types
Sorting of cells in embryo

Front 16

What is an example of another small molecule that is not protein or carbohydrate that can insert itself into cell membrane?

Back 16

Cholesterol

Front 17

What can cholesterol do when part of a cell membrane (3 things)

Back 17

Inserts between phospholipid molecules.
Influence membrane fluidity
Essential for proper function of some membranes

Front 18

What is phase transition?

Back 18

When cell membrane solidifies

Front 19

Two major factors that affects at which temperature phase transition of cell membrane occurs

Back 19

Size of Fatty Acids in Phospholipid
Shape of Fatty Acids in Phospholipid

Front 20

The shorter the chain of a fatty acid, the _________ the temperature required to keep it solid. Why?

Back 20

lower
Less stable interactions

Front 21

The more double bonds in a fatty acid, the ______ the temperature required to keep it solid.

Back 21

Lower

Front 22

Three types of moving molecules across membranes:

Back 22

Diffusion (or passive transport)
Facilitated Diffusion
Active Transport

Front 23

Name the type of molecule best suited for diffusion, and give an example.

Back 23

Small hydrophobic molecule (O2)

Front 24

Name the second best type of molecule suited for diffusion, and give an example.

Back 24

Small uncharged polar molecules (H2O)

Front 25

Why cant larger polar molecules and charged molecules pass through membranes by diffusion?

Back 25

They can't pass through the non-polar phase of the bilayer.

Front 26

The diffusion of H20 is also known as what?

Back 26

Osmosis

Front 27

Two types of transport proteins

Back 27

Channel proteins and carrier proteins

Front 28

Describe function of channel protein (2 points)

Back 28

Form a pore or channel through the membrane. Specific for allowing one type of molecule to pass through.

Front 29

What is aquaporin?

Back 29

A channel protein that allows facilitated diffusion of H2O

Front 30

What are ion channels?

Back 30

Channel proteins that allow facilitated diffusion of certain ions.

Front 31

What is the function of carrier proteins?

Back 31

Change their shape to help molecules move through facilitated diffusion.

Front 32

What does ATP stand for

Back 32

adenosine triphosphate

Front 33

What does ATP break down to

Back 33

ADP (adenosine diphosphate) and Pi (phosphate)

Front 34

What is a sodium-potassium pump?

Back 34

A specific enzyme that is an integral membrane protein involved with active transport.

Front 35

What is the membrane potential?

Back 35

Difference in charges/voltage across a membrane.

Front 36

Movement of charged molecules influenced by two factors:

Back 36

Concentration Gradient
Membrane Potential

Front 37

Charged molecules flow don't flow down simply their concentration gradient, but their ________ gradient.

Back 37

Electro-chemical

Front 38

Definition: Electrogenic pumps

Back 38

Proteins that can "pump" and generate membrane potential.

Front 39

Name an electrogenic pump common in plant, fungal and bacterial cells.

Back 39

H+ pumps

Front 40

Name an electrogenic pump common in animal cells.

Back 40

K+/Na+ pump

Front 41

What is co-transport (or coupled transport). 3 points.

Back 41

A type of active transport.
Creates energy by creating electrochemical gradient.
Couples with other molecules to actively transport.

Front 42

What kind of systems mediate "secondary active transport"?

Back 42

Systems that use carrier proteins driven by ion gradients.

Front 43

What kind of systems mediate "primary active transport"?

Back 43

Systems that use ATP directly (electrogenic pumps like Na+/K+)

Front 44

Definition: Uniporter

Back 44

Carrier/transport proteins that transports only one type of molecule

Front 45

Definition: Symporter

Back 45

Carrier/transport protein that transports two different molecules in the same direction.

Front 46

Definition: Antiporter

Back 46

Carrier/transport protein that transports two different molecules in the opposite directions.