Ch5 Membrane Structure & Function

Question 0

Plasma membrane

Answer 0

Separate cell from surrounding, contains an abundance of phospholipid

Question 1

Cellular membranes

Answer 1

Fluid mosaics of lipids and proteins

Question 2

Selective permeability

Answer 2

Allow some substances to cross it more easily than others

Question 3

Amphipathic molecules

Answer 3

Phospholipids, containing hydrophobic and hydrophilic regions

Question 4

Fluid Mosaic model

Answer 4

States that a membrane is a fluid structure with a “mosaic” of various proteins embedded in it

Question 5

Phospholipid structure consists of?

Answer 5

Glycerol, a 3-carbon poly alcohol & 2 fatty acid is attached to the glycerol (Nonpolar and hydrophobic a.k.a. water fearing)

spontaneously forms a bilayer, fatty acids are on the inside but phosphate groups are on both servers surfaces

Question 6

Phospholipids arrange and a?

Answer 6

Bilayer

Question 7

Bilayers are…?

Answer 7

Fluid

Question 8

What two things can move through the membrane?

Answer 8

Individual phospholipids and proteins

Question 9

Membrane switch from a fluid state a solid state…?

Answer 9

When temperature cools

Question 10

Cholesterol

Answer 10

Steroid that has different effects on membrane fluidity at different temperatures a.k.a. “fluidity buffer “

• In warm temperatures such as 37°C cholesterol restrains movement of phospholipids
• cool temperatures it maintains fluidity by preventing tight packing

Question 11

Membrane

Answer 11

A collage of different proteins, often group together, embedded in the fluid matrix of the lipid bilayer that determines most of the membrane’s specific function

Question 12

Peripheral proteins

Answer 12

Bound to the surface of the membrane

Question 13

Integral proteins

Answer 13

Penetrates the hydrophobic core

Question 14

Transmembrane proteins

Answer 14

Hydrophobic regions of an integral protein consists of one or more stretches of nonpolar amino acids

Question 15

Six major functions of membrane proteins

Answer 15

1. Transporter
2. Enzyme
3. Cell surface receptor
4. Cell surface identity marker
5. Cell to cell adhesion
6. Attachment to the cytoskeleton

Question 16

Glycolipids

Answer 16

Forms when membrane carbohydrates covalently bond to lipids

Question 17

Glycoproteins

Answer 17

(More common) forms when membrane carbohydrates covalently bond to protein

Question 18

A process control by the plasma membrane…?

Answer 18

When a cell must exchange interior materials with its surroundings, selectively permeable regulates the cell molecular traffic

Question 19

Transport proteins

Answer 19

Allow passage of hydrophilic substances across the membrane

Question 20

Channel proteins

Answer 20

A type of transport proteins that has a hydrophilic channel that certain molecules or ions can use as a tunnel

Question 21

Aqua Porins

Answer 21

Channel proteins that facilitate the passage of water

Question 22

Carrier proteins

Answer 22

Type of transport protein that bind to molecules and change shape to shuttle them across the membrane

Question 23

Passive transport

Answer 23

Diffusion of a substance across a biological membrane in which no energy is required and the molecules move in response to a concentration gradient… Spontaneous process

Question 24

Diffusion

Answer 24

Movement of molecules from high concentration to low concentration (will continue until the concentration is the same in all regions EQUILIBRIUM )

Question 25

Concentration gradient

Answer 25

The region which the density of a chemical substance increases or decreases… Substances diffuse down with no work involved

Question 26

Osmosis

Answer 26

Diffusion of water across a selectively permeable membrane… Low to high solute concentration

Question 27

Cytoplasm of the cell is a solution aqueous solution

Answer 27

• water is the solvent

- dissolved substances are solutes

Question 28

Tonicity

Answer 28

The ability of the surrounding solution to cause a cell to gain or lose water

Question 29

Isotonic solution

Answer 29

Solute concentration is the same as it is inside the cell ; no net water movement across the plasma membrane

Question 30

Hypertonic solution

Answer 30

Solute concentration is greater than that inside of cell; cell loses water

Question 31

Hypotonic solution

Answer 31

Solute concentration is less than that inside the sale, cell gains water

Question 32

Osmoregulation

Answer 32

Control of solute concentration and water balance, is a necessary adaption for life in such environment