Lecture 14 - Membrane Structure (Ch 11)

Question 1

Describe the tail part of a lipid

Answer 1

uncharged, nonpolar, hydrophobic

Question 2

In osmosis, how does water move through concentration gradients?

Answer 2

Water moves from areas of low to high solute concentrations

Question 3

Cholesterol is ideal for what situation?

Answer 3

When temperatures drop, cholesterol helps phospholipids to be properly spaced; they also prevent being too fluid in room temps

Question 4

Peripheral proteins are found on either layer of the membrane , T/F?

Answer 4

True- but one, not both for each one

Question 5

Integral proteins typically hold what job

Answer 5

They can be transporters or channels

Question 6

Glucose molecules are too big and polar to cross the cell membrane by themselves, true or false?

Answer 6

True; they rely on integral proteins

Question 7

Glycoproteins and glycolipids allow you to

Answer 7

recognize and signal other cells!

Question 8

Which glycoprotein is found by HIV to infect cells? but usally this glycoprotein is for..

Answer 8

CD4; cell immunity

Question 9

The most abundant phospholipid in the membrane is

Answer 9

phosphatidylcholine

Question 10

Galactocerebroside is a typie of ___

Answer 10

glycolipid

Question 11

What is an example of hydrophilic molecules attracting water molecules

Answer 11

acetone

Question 12

What is an example of hydrophobic molecules avoiding water? Describe the process

Answer 12

2 methylpropane; water makes a cage around 2 methylpropane to max out h bonding duudeee

Question 13

How do phospholipids repair themselves?

Answer 13

By spontaneous rearrangment of phospholipids, you can heal the membrane if it tears or holes

Question 14

Which conformation of the membrane is energetically favorable?

Answer 14

the ball shape (enclosed) comes out on TOP compared to the flat one

Question 15

What has the highest influence of membrane curvature?

Answer 15

The lipid hydrophilic head

Question 16

What type of movement barely happens in the bilayer?

Answer 16

Flipflopping lipdis

Question 17

What movements happen usually in bilayers?

Answer 17

Flexion, rotation, and lateral diffusion

Question 18

How do lower temperatures affect phospholipid compositions in MICROBES?

Answer 18

Low temp makes the phospholipids have more double bonds and shorter tails (more fluid)

Question 19

How do higher temperatures affect phospholipid compositions in MICROBES?

Answer 19

High temp makes phospholipids have single bonds and longer tails (less fluid)

Question 20

-% of membrane lipid content is cholesterol; where does it fit in?

Answer 20

20%; in spaces left by unsaturated fats’ kinks

Question 21

Why is important to have a fluid membrane mosiic modelas dadalsdkjalsd?

Answer 21

For cell signaling, cell division, fusing membranes, and distributing proteins after they are made

Question 22

Where does membrane synthesis begin? On which surface?

Answer 22

the ER; on the cytosolic side

Question 23

Which ones random: flippase or scramblase?

Answer 23

scramblase

Question 24

What are the steps to making a membrane?

Answer 24

Phospholipds areDEPOSITED into cytosolic side of ER, then FLIPPED to noncytosol side using enzymes

Question 25

Which lipids do flippases move and where are they going? where are these enzymes working?

Answer 25

P.ethylalanine and p.serine move from inner to outer lelaflet; they work with incoming lipids from the ER in the golgi app

Question 26

Plasma membranes range from__ to __ nm in thickness.

Answer 26

5-10 nm

Question 27

What plasmamembrane movement is NOT spontaneous; what does it mean to be spontensous vs random?

Answer 27

moving between the bilayers; spont = no help (energy assistance) and random -= no order

Question 28

Which lipids can I find in the cytosolic side (inner leaflet)

Answer 28

Phos insitol (PI) , phosphotidylserine (PS) and phos ethanolamine (PE) get moved here

Question 29

What lipids can I find on the extracellular (outer leaflet) side of the membrane?

Answer 29

Phos choline (PC), glycolipids (GL), and sphingomyelin (SM)