Biochem Block 1: Membrane Lipids (Sadik)

Front 1

Lipid membrane is a fluid mosaic composed of:

Back 1

50% proteins
40% lipids
10% carbohydrates

Front 2

On the cell membrane, recognition markers include (2 markers)

Back 2

1. glycolipids
2. glycoproteins

Front 3

Lipids in plasma membrane have 5 functions:

Back 3

1. structural
2. substrates for energy
3. reservoirs for signaling molecules
4. hormones
5. antioxidants

Front 4

Amphiphatic molecules found in the plasma membrane include:

Back 4

1. phospholipids (duh)
2. sphingolipids
3. cholesterol (for fluidity)

Front 5

the most abundant secondary protein structure found in membrane proteins?

Back 5

alpha helix

Front 6

What part of cholesterol is polar and makes it a weak amphiphilc compound?

Back 6

the OH group

Front 7

What are phospholipids composed of?

Back 7

1. glycerol
2. fatty acids. Not free, but activated fatty acid...activated by acylation. think of the A in acetyl CoA - acylates something to activate it. once activated it can form phospholipids.
3. phosphoric acid (H3PO4)

Front 8

what is the most abundant protein that helps transport hydrophobic stuff in the blood?

Back 8

albumin

Front 9

3 common polar heads in phospholipids include:
what they all have in common is ______

Back 9

1. choline
2. ethanolamine
3. serine


all these compounds have an OH group. this group allows esterification

(CES...think "the seas (CES) are polar")

Front 10

Phosphatidic acid can be esterified with choline to make

Back 10

phosphatidyl choline (lectithins)

Front 11

importance of lecithins

Back 11

lecithin : sphingomyelin ratio tells us the optimum time for elective termination of pregnancy

Front 12

phosphoric acid can be esterified with ethanolamine to produce

Back 12

phosphatidyl ethanolamine

Front 13

50% of the heart's phospholipids are

Back 13

plasmalogens (phosphatidyl ethanolamine)

Front 14

phosphatidic acid can be esterified with serine to make ________, which is found mainly in ________

Back 14

phosphatidyl serine, the inner leaflet of cell membrane

Front 15

if a cell is dying through apoptosis, a signal to tell the extracellular environment that this is happening is:

Back 15

the appearance of serine on the outer membrane

Front 16

phosphatidic acid can be esterified with inositol to create _________. this is part of the _______________.

Back 16

phosphatidyl inosITol, part of the vITamin B complex

Front 17

cardiolipin, important in contraction of myocardium, is made up of

Back 17

phosphatidyl glycerol

Front 18

When you have a double bond, you have a ___________ in the long chain of fatty acids, making the lipid membrane more ___________

Back 18

bend, fluid

Front 19

Triglycerides are hydrophobic or hydrophilic?

Back 19

totally hydrophobic

Front 20

DPPC is a ________________ and is a major constituent of _____________.

Back 20

phosphatidyl Choline, lung surfaCtant

Front 21

The absence of surfactant, a major constituent of which is DPPC, causes ______________.

Back 21

acute respiratory distress syndrome (ARDS)

Front 22

Most phospholipids contain fatty acids with __ carbons.

Back 22

16 and18

Front 23

unsaturated fatty acids comprise ___% of the lipids in the cell membrane

Back 23

50

Front 24

unsaturated fatty acids are have one or several ________________.

Back 24

unconjugated double bonds

Front 25

Double bonds are usually in the ___ configuration because

Back 25

cis, cis prevents side by side associations

Front 26

unsaturation and cis configuration result in

Back 26

1. membrane fluidity
2. facilitation of transport
3. lowering of melting point

Front 27

For phospholipids, melting point is dependent on what 2 things

Back 27

1. degree of side-by-side associations (more side by side, higher melting pt)
2. the length of the chain (higher chain, higher melting pt)

Front 28

Organisms living in cold environments have ___________ fatty acids in their membrane

Back 28

unsaturated, because this gives the membrane a much lower freezing point

Front 29

When naming fatty acids, omega-3 means

Back 29

the double bond is found 3 carbons away from the methyl group (oMega = Methyl)

Front 30

when naming fatty acids, delta 3 means

Back 30

the double bond is 3 carbons away from the carboxylic acid

Front 31

Arachidonic acid is considered an ____________ fatty acid. Why?

Back 31

essential. animals do not make fatty acids with a double bond beyond carbon 9

Front 32

Arachidonic acid is a precursor for

Back 32

1 prostaglandins (by cyclooxygenase Cox1 and Cox2)
2. leukotrienes (by lipooxygenase)

Front 33

Saturated fat intake is correlated with ___________

Back 33

coronary heart disease

Front 34

Cholesterol is composed of how many rings?

Back 34

4

Front 35

Cholesterol increases fluidity of the cell membrane if it comprises less than ___% of the membrane

Back 35

30. Any more and it would make the membrane more rigid

Front 36

If a membrane is very fluid, cholesterol acts to

Back 36

stabilize the membrane

Front 37

What group on cholesterol can be esterified with a fatty acid?

Back 37

hydroxyl group

Front 38

what is a cholesteryl ester? is it hydrophobic or hydrophilic?

Back 38

cholesterol + fatty acid = cholesteryl ester

hydrophobic

Front 39

In sphingosine phospholipids, the fatty acid forms a ______ bond with the amino group on carbon # __?

Back 39

amid

2

Front 40

Sphingomyelin happens when _________ is esterfied to phosphoric acid of a sphingolipid. What is rich in sphingomyelin?

Back 40

choline

myelin sheaths

Front 41

Sphingolipids + attached carbohydrates = ?

Back 41

glycolipids

Front 42

Major blood groups are determined by

Back 42

glycolipids on blood cell membranes

Front 43

Example of lipid anchored proteins

Back 43

prions

Front 44

Organisms that live in cold environments, like e.coli, tend of have...

Back 44

highly unsaturated fatty acids in their lipid membranes

Front 45

Phospholipids in the cell membrane (are, are not) strongly hydrophobic.

Back 45

NOT

Front 46

T or F. Cholesterol can move freely in and out of the membrane.

Back 46

TRUE

Front 47

T or F. The plasma membranes of the cells of vertebrate animals contain less proteins than the mitochondrial membranes

Back 47

TRUE

Front 48

T or F. The carbohydrate found in membranes is virtually all part of either glycolipids or glycoproteins.

Back 48

TRUE