Membranes

Question 1

Are phospholipids amphipathic

Answer 1

Yes, the polar heads interact with water, the hydrophobic tails interact with each other to form the lipid bilayer

Question 2

What are things that affect membrane fluidity

Answer 2

Temperature, Saturated and Unsaturated hydrophobic tails, and Cholesterol

Question 3

how does unsaturated tails affect the membrane

Answer 3

They are kinked, so they prevent close packing of membrane causing fluidity

Question 4

how does saturated tails affect the membrane

Answer 4

saturated hydrocarbon tails pack together causing viscosity

Question 5

how does cholesterol affect the membrane

Answer 5

Happens within animal cells.
At moderate temperature, it reduces phospholipid movement
At low/cold temperatures, it hinders solidification by hindering regular packing of phospholipids

Question 6

Integral Protein

Answer 6

proteins that penetrate into the membrane

Question 7

Transmembrane Protein

Answer 7

Transmembrane Protein are integral proteins that go right through the membrane

Question 8

Peripheral Proteins

Answer 8

Proteins associated with one side of the membrane

Question 9

Gylcoprotein

Answer 9

Protein with chains of sugars attached in very specific configurations. Found in eukaryotic cellular membranes

Question 10

Glycolipids

Answer 10

lipids with a carbohydrate (chains of sugars) attached in very specific configurations. Found in eukaryotic cellular membranes

Question 11

Aquaporin

Answer 11

Channel proteins that allows water through

Question 12

Passive Transport

Answer 12

The diffusion of a substance across a membrane with no energy investment. Does not use ATP

Question 13

Diffusion

Answer 13

Movement of particles of any substance

Question 14

Osmosis

Answer 14

Water moving down its concentration gradient

Question 15

What it means when a substance diffuses down its concentration gradient?

Answer 15

This means it goes from an area of high concentration to low concentration

Question 16

Osmolarity

Answer 16

Total concentration of a solution of all solutes in a solution. Expressed in Osm/L

Question 17

Tonicity

Answer 17

Ability of a surrounding solution to cause a cell to gain or loose water

Question 18

Hypotonic Solution

Answer 18

The solution has low concentration of solute and high concentration of free water. The cell is lysed

Question 19

Isotonic Solution

Answer 19

The solution has equal solutes and free water

Question 20

Hypertonic Solution

Answer 20

The solution has high concentration of solutes and low concentration of free water. Water will leave the cell and the cell will shrink (shrivel)

Question 21

What is the normal solution for a plant

Answer 21

The normal solution is hypotonic. Cell walls allows the cells to survive without exploding

Question 22

Four mechanisms by which molecules move across a membrane

Answer 22

Simple Diffusion, Simple Diffusion through a channel, Facilitated Diffusion and Active transport

Question 23

Simple Diffusion

Answer 23

Movement from higher to lower concentrations straight through the lipid bilayer

Question 24

Simple diffusion through a channel

Answer 24

Movement from higher to lower concentrations through the pore of an membrane channel protein

Question 25

Facilitated Diffusion

Answer 25

Movement from higher to low concentrations via a membrane carrier protein

Question 26

Active Transport

Answer 26

Movement from low to high concentration via a protein transporter. Requires Energy

Question 27

What are the two types of protein that do facilitated diffusion

Answer 27

Carrier Proteins and Channel Protein

Question 28

Channel Proteins

Answer 28

Form pores through which specific molecules pass through. Ex. Ion Channels, Aquaporins

Question 29

Carrier Proteins

Answer 29

First bind,
then the protein changes shape allowing the transported molecule to pass through the membrane. Example. glucose transporter

Question 30

Protein Pumps

Answer 30

proteins that use the energy stored in ATP to move molecules form a low to high concentration. Ex. Sodium-potassium pump

Question 31

Electrochemical Gradient

Answer 31

difference in charge across a membrane

Question 32

Co-transport

Answer 32

Coupled transport of chemical substances (two distinct molecules) across a cell membrane