Membranes and Channels

Question 1

Importance of cell membrane

Answer 1

• proper nutrition
• maintenance of irritability
• homeostasis

Question 2

cell membrane is a ___ ___ permeable barrier that surrounds all living cells

Answer 2

highly selective

Question 3

properties of cell membrane

Answer 3

• define boundaries
• compartmentalization
• signal detection
• cell-to-cell communication
• surround all animal cells
• extraordinary thin
• lipid-based structure

Question 4

Describes the organization of cell membranes. phospholipid drift and move like a fluid

Answer 4

fluid mosaic model

Question 5

Composition of membrane

Answer 5

Phospholipids, proteins, and carbohydrates

Question 6

Lipid and protein molecules kept together by ______

Answer 6

non-covalent interactions

Question 7

impermeable to the passage of most water-soluble molecules

Answer 7

lipid bilayer

Question 8

fundamental structure of the membrane

Answer 8

lipid molecules

Question 9

Proteins embedded in the bilayer provide a mechanism for trans-membrane transport

Answer 9

integral proteins

Question 10

Protein associated with the surface of the membrane via electrostatic interaction

Answer 10

peripheral proteins

Question 11

Catalyzing reactions in the cytoplasm

Answer 11

enzymes

Question 12

acts as ___ (specific binding site hormones or other chemicals can bind; used for ___ and ___)

Answer 12

receptors; cell signaling and cell recognition

Question 13

Special functions of proteins

Answer 13

ARRET
- Adhesion
- Recognition
- Receptor
- Enzymes
- Transport

Question 14

clumping of RBCs caused by the reaction between antibodies on the blood plasma and the antigen on the RBCs

Answer 14

agglutination

Question 15

A condition where a pregnant women who is Rh positive becomes exposed to Rh negative blood from her baby

Answer 15

Rh sensitization

Question 16

Found on the outer surface and attached to the proteins or sometimes to the phospholipids

Answer 16

carbohydrates

Question 17

Carbohydrates on membranes

Answer 17

glycoproteins and glycolipids

Question 18

Cell coat outside the cell membrane

Answer 18

glycocalyx

Question 19

Glycoprotein bears oligosaccharide side chains and vital for ___ ___ and ___

Answer 19

cell recognition and communication

Question 20

Primary types of lipids

Answer 20

1. Phosphoglycerides
2. Sphingolipids
3. Sterols

Question 21

Glycerol backbone

Answer 21

phosphoglycerides

Question 22

Backbone made of sphingosine bases

Answer 22

Sphingolipids

Question 23

Cholesterol, nonpolar and only slightly soluble in water

Answer 23

sterols

Question 24

Lateral movement of lipids and proteins within a surface of the bilayer is very common

Answer 24

membrane fluidity

Question 25

Splits a membrane along the middle of the phospholipid bilayer prior to electron microsope

Answer 25

freeze fracture

Question 26

What is revealed in freeze fracture

Answer 26

protein particles insterspersed with a smooth matrix supporting the fluid mosaic model

Question 27

It makes membranes highly impermeable to most polar molecules

Answer 27

hydrophobic interior

Question 28

Regulates the passage of materials in and out of the cell

Answer 28

Selective permeability

Question 29

The rate at which a substance can passively penetrate a cell membrane

Answer 29

membrane permeability

Question 30

Transport systems

Answer 30

- Passive processes - Active transport

Question 31

Passive processes

Answer 31

- no energy expenditure and move down their normal gradient - simple diffusion/ lipid diffusion

Question 32

Active transport

Answer 32

requires metabolic energy and moves substance against their gradient

Question 33

Depends on concentration and electrical gradients

Answer 33

passive transport

Question 34

Three Basic Routes

Answer 34

1. Dissolving in the lipid phase 2. Diffusion through labile or fixed aqueous channels 3. Carrier-mediated transport

Question 35

Random thermal motion of suspended or dissolves molecules causes their dispersion from regions of higher concentration to regions of lower concentrations

Answer 35

diffusion

Question 36

Fick's Law

Answer 36

1. proportional to the difference in partial pressure 2. proportional to the area of the membrane 3. inversely proportional to the thickness of the membrane

Question 37

Rate at which substance passively penetrates the membrane under a specified set of conditions

Answer 37

Permeability

Question 38

Intrinsic factors governing diffusion across membranes

Answer 38

- Size rule - Polarity rule - Ionic rule

Question 39

Factors of rate of diffusion

Answer 39

- Size - Temperature - Steepness of the concentration gradient - Charge - Pressure

Question 40

Factors that influence mobility of solute molecule

Answer 40

1. Lipid solubility 2. Hydrogen Bond with water 3. Molecular weight 4. Molecular shape 5. Partition coefficient

Question 41

ratio of distribution of a substance between two different liquid phases

Answer 41

partition coefficient