Chapter 7

Question 1

Lipids; Phospholipid

Answer 1

Major component of the plasma membrane is this

Question 2

Hydrophohilic Heads Location

Answer 2

At phospholipids, are located at the internal and external surfaces, separating two aqueous regions

Question 3

Hydrophobic tails Location

Answer 3

Located in the interior of the membrane

Question 4

Who do the Phospholipids move?

Answer 4

They move laterally, contributing to the fluidity of membrane

Question 5

Unsaturated hydrocarbon tails have…

Answer 5

kinks in them preventing over packing between adjacent molecules

Question 6

Membrane; Lipids; Cholesterol

Answer 6

Reduces fluidity but prevents membrane solidification at cold temperature

Question 7

What is embedded in the lipid layer?

Answer 7

Glycoproteins and Glycolipids

Question 8

What passes through phospholipid membrane?

Answer 8

Small and hydrophobic

Question 9

Are unsaturated fatty acids or saturated faty acids more fluid?

Answer 9

Unsaturated fatty acids

Question 10

Hydrophobic (non-polar) molecules

Answer 10

Can dissolve in the lipid layer and pass through the membrane rapidly

Question 11

Hydrophilic molecules

Answer 11

includes ion and polar molecules and do not cross the membrane easily

Question 12

Membrane Protein Function

Answer 12

Determines most of the membranes specific functions

Question 13

Asymmetrical Distribution of Protein

Answer 13

Membranes have distinct inside and outside faces. Determined by whether membrane is built by ER or Golgi.

Question 14

Peripheral Proteins

Answer 14

Bound to the surface of the membrane

Question 15

Integral Proteins

Answer 15

Penetrate the hydrophobic core

Question 16

Transmembrane Proteins

Answer 16

Integral proteins span entirety of membrane
Hydrophobic regions of an integral protein consist of one or more stretches of non-polar amino acids, coiled into alpha helixes

Question 17

Six Major Functions of Membrane Protein

Answer 17

Transport
Enzymatic Activity
Signal Transduction
Cell-Cell Recognition
Intercellular Joining
Attachment to the cytoskeleton and extracellular matrix

Question 18

Transport

Answer 18

Moves against gradient

Question 19

Enzymatic Activity

Answer 19

Follows a specific sequence

Question 20

Signal Transduction

Answer 20

Signaling Pathway. Signal binds to whole series of reactions

Question 21

Cell-Cell Recognition

Answer 21

To bind they need to have complementary proteins. Sponge example

Question 22

Intercellular Joining

Answer 22

Liver cells don’t mix with kidney cells

Question 23

Transport Proteiins

Answer 23

allows passage of hydrophilic substances across the membrane. Specific for substance it moves

Question 24

Channel Proteins have..

Answer 24

a hydrophilic channel that certain molecules or ions use as a tunnel

Question 25

Channel Proteins Example

Answer 25

Aquaporins - Facilitate the passage of water

Question 26

Carrier Proteins..

Answer 26

binds to molecules to change shape to shuttle them across membrane

Question 27

Ion Channels..

Answer 27

facilitate the diffusion of ions. Gated channels open or close in response to a stimulus

Question 28

Active Transport..

Answer 28

moves substances against their concentration gradients

Question 29

Active Transport; Sodium-Potassium Pump

Answer 29

Maintains large excess of Na+ ions outside and less inside. Transport 3 Na outside and 2K inside.

Question 30

What is the main pump in plants, fungi, and bacteria?

Answer 30

Proton Pump

Question 31

Co-Transport

Answer 31

Occurs when active transport of a solute indirectly drives transport of other substances

Question 32

Uniporter

Answer 32

Integral membrane protein binds to one molecule at a time and transports it with its concentration gradient

Question 33

Symport

Answer 33

Integral membrane protein that transports many different molecules across membrane in the same direction

Question 34

Antiport

Answer 34

Integral membrane protein that transports many different molecules of proteins across membrane in opposite direction

Question 35

What do small molecules and water enter or leave the cell through?

Answer 35

Lipid bilayer or via transport proteins

Question 36

How do large molecules such as polysaccharides and proteins cross the membrane?

Answer 36

Vesicles

Question 37

Does bulk transport require energy?

Answer 37

Yes

Question 38

Exocytosis

Answer 38

Transport vesicles migrate to the membrane, fuse with it, and release their contents outside the cell.

Question 39

Endocytosis

Answer 39

Cell takes in macromolecules by forming vessicles from the plasma membrane

Question 40

Three types of endocytosis?

Answer 40

Phagocytosis Pinocytosis Receptor- Mediated Endocytosis

Question 41

Phagocytosis

Answer 41

A cell engulfs a particle in a vacuole. Vacuole fuses with a lysosome to digest in the particle

Question 42

Pinocytosis (Cell Drinking)

Answer 42

Uptake of liquid material enclosed in vesicles form by invagination of membrane

Question 43

Receptor-Mediated Endocytosis

Answer 43

Cells absorb metabolities/hormones/viruses by inward budding of membrane vesicles containing proteins with receptor sites specific to the molecule being absorbed

Question 44

How does HIV recognize & infect

Answer 44

HIV must bind to the immune cell surface protein CD4 and "co-receptor" CCR5. HIV cannot enter cells individuals that lack CCR5