Membranes structure and function

Question 1

cytoplasm meaning

Answer 1

what is inside the cell, surround by membranes

Question 2

membranes are _ and _ structures.

Answer 2

dynamic and fluid

Question 3

three important functions of plasma membrane

Answer 3

1. cell signaling
2. import and export
3. movement and expansion

Question 4

membrane lipids are _ , having a hydrophilic (water-loving) end and a hydrophobic (water-fearing) end

Answer 4

amphipathic

Question 5

5 types of phosphilipids

Answer 5

Phosphatidylcholine (PC)
sphingomyelin (SM)
phosphatidylethanolamine (PE)
phosphatidylserine (PS)
phosphatidylinositol (PI)

Question 6

3 types of energy dependent lipid transporters that translocate the different phospholipids from one membrane leaflet to the other

Answer 6

Flippases are responsible for translocating aminophospholipids (PS or PE) from the outer to inner leaflet (FLIP IN)

Floppases transport cholinephospholipids (PC and SM) from the inner to outer leaflet. (FLOP OUT)

Bidirectional phospholipid transport is catalyzed by a scramblase, which may be activated by Ca2+ influx into the cell or by apoptosis (programmed cell death) pathways. Scramblase activation breaks down phospholipid asymmetry, and allows PS to appear at the cell surface.

Question 7

Kennedy pathway (ER phospholipid biosynthetic pathway)

Answer 7

Question 8

Cardiolipin

Answer 8

found in inner mitochondrial membrane, but can be relocated to outer membrane for degradation of old and disfunctional mitochindria. Overexpression lead to mitochondria death

Question 9

what allows animal cells to not need cell wall

Answer 9

cholesterol (hydroxyl group attached to four ring structure provides rigidity of membrane)

Question 10

integral vs peripheral membrane protein

Answer 10

Integral proteins are tightly embedded in the membrane and include transmembrane and lipid-anchored proteins.
Peripheral proteins are attached to the membrane only through non-covalent interactions with other proteins (can be released by extremes of ionic strength or pH.)

Question 11

protein structure (picture)

Answer 11

Question 12

Lipid Rafts are microdomains in the membrane with an increased abundance of sphingolipids, cholesterol and specific lipid raft

Answer 12

Highly hydrophobic, thicker,

Question 13

cytoskeletal filaments

Answer 13

increasing membrane stability and reducing fluidity, reinforces the integrity of the plasma membrane

Question 14

Caveolae

Answer 14

have a high concentration of the cholesterol-binding protein caveolin. They are important in endocytosis and signal transduction, among other functions.

Question 15

aminophospholipid VS cholinephospholipids

Answer 15

aminophospholipids (PS or PE)
cholinephospholipids (PC and SM)

Question 16

scramblase function

Answer 16

scramblase allow PS to surface on the cell, allowing blood clot formation

Question 17

The simplest form of sphingolipid

Answer 17

ceramide

Question 18

glycoprotei