Membrane Structure And Function 1

Question 1

Phospholipids

Answer 1

Amphipatic molecule - hydrophobic and hydrophilic part
Form a bilateral w hydrophilic heads facing towards water surface and hydrophobic tails facing inwards towards the bilayer

Question 2

Main components of membranes

Answer 2

Lipids and proteins, but also carbohydrates

Question 3

Fluid mosaic model

Answer 3

Phosopholipid bilayer (fluid state w fatty acids - moving thing) and proteins - mosaic combo
Phsoplipid is fluid. Proteins, lipids, carbohydrates imbedd3d on it

Question 4

Glycoproteins

Answer 4

Any protein attached to carbohydrates

Question 5

Weak hydrophobic interactions generally hold membranes together

Answer 5

Lots of hydrophobic tails - interactions
Lipids and proteins can move sideways
Rarely flip-flop from one phospholipid layer to the other
Some proteins drift across bilayer
Some proteins (especially attached to the cytoskeleton) Move around as tho guided - directly

Question 6

Membrane fluidity is influenced by temperature

Answer 6

Bad for the cell to be too liquid or too solid
Why our body maintains our temperature inside the body

Question 7

U saturated fatty acids more fluid
More saturated more solid
Need right amount of both

Answer 7

And components of the membrane

Question 8

Steroid cholesterol - wedged between phospholipid layers
Fluidity buffer
Helps maintain fluidity of membrane
Prevents tight packing in cold, and restrains phospholipids in warmth

Question 9

Transmembrane proteins

Answer 9

Span the entire membrane
Integral membranes
Hydrophobic and hydrophilic part

Question 10

Integral proteins

Answer 10

extend part way into the hydrophobic interior
Help hydrophilic molecules pass from one side of the membrane to the other hydrophilic channel
Consist of nonpolar amino acids usually coiled into a helical
Hydrophilic in contact w aqueous environment

Question 11

Peripheral proteins

Answer 11

Not embedded in the lipid bilayer
Loosely bound to the surface of the membrane - often to integral proteins

Question 12

Transport function of plasma membrane

Answer 12

Transportation of specific salutes into or out of the cell

Question 13

Enzymatic activity - function of plasma membrane

Answer 13

Catalyzing 1 of a number of steps of a metabolic pathway

Question 14

Signal transduction - function of plasma membrane

Answer 14

Relaying hormonal messages to the cell

Question 15

Some transmembrane proteins attach where on the cytoplasm side

Answer 15

Cytoskeleton

Question 16

On extracellular side of membranes

Answer 16

Some membrane proteins (integrins) attach to the fibers of the extracellular matrix - gives animal cells a stronger framework than the plasma membrane alone can provide

Question 17

Cell to cell recognition - protein function

Answer 17

Allowing other proteins to attach two adjacent cells together

Question 18

Intercellular joining - function of proteins

Answer 18

Joining adjacent cells with gaps or tight junctions

Question 19

Protein function - attachment to the cytoskeleton and extracellular matrix

Answer 19

Maintaining cell chape and stabilizing the location or certain membrane proteins

Question 20

How do cells recognize each other

Answer 20

By binding to molecules on the surface of the membrane
Many molecules are bonded to short, branched chains of carbohydrates

Question 21

Glycolipids

Answer 21

Carbohydrates bonded w lipids

Question 22

Glycoproteins

Answer 22

Carbohydrates bonded w proteins

Question 23

Carbohydrates on the extracellular side of the plasma membrane vary from—

Answer 23

Species to species
Individual to individual
And cell type to cell type

Question 24

The four human blood groups differ in

Answer 24

The carbohydrates part of gpycoproteins on the surface of red blood cells