Lipid and biological membrane

Question 1

some general features of biological membrane

Answer 1

• made up lipid bilayers
• fluidity, semipermeable
  -asymmetry
• noncovalent

Question 2

what does lipid made of?

Answer 2

fatty acid

Question 3

what other factors can be found on lipid bilayer?

Answer 3

membrane protein (pumps, channels, receptors)

Question 4

how to name saturated fatty acid?

Answer 4

add - anoic acid/ -anate

Question 5

how to name unsaturated fatty acid with one double bond?

Answer 5

add -enoic acid/ -enate

Question 6

how to name unsaturated fatty acid with two double bond?

Answer 6

add -dienoic/ -dienate

Question 7

delta number show the position of the double bond from ?

Answer 7

head to tail (from COOH)

Question 8

omega number show the position of the double bond from ?

Answer 8

tail to head (from CH3)

Question 9

some general feature of fatty acids

Answer 9

• long carbon chain (16-18 C)
• unbranched
• can be saturated/ unsaturated
• water insoluble

Question 10

why does lipid is used to form membrane?

Answer 10

because of hydrophobic property

Question 11

3 common types of membrane lipid

Answer 11

• phospholipid
• glycolipid
• cholesterol

Question 12

2 types of phospholipid

Answer 12

• phosphoglyceride
• sphingolipid

Question 13

general structure of phosphoglyceride

Answer 13

2 fatty acid + glycerol + phosphate + alcohol

Question 14

what is the simplest phosphoglyceride?

Answer 14

phosphotidate

Question 15

why does phosphotidate is the simplest form of phosphoglceride?

Answer 15

phosphate is not further modified

Question 16

structure of phosphotidate

Answer 16

2 fatty acid + glycerol + phosphate

Question 17

structure of sphingolipid

Answer 17

sphingosine-base + amino alcohol

Question 18

structure of glycolipid

Answer 18

cerebroside + glucose/ galactose

Question 19

structure of cholesterol

Answer 19

• 4 hydrocarbon rings
• Oriented parallel to fatty acid chains of
  phospholipids in membranes

Question 20

structure of Archaea’s lipid

Answer 20

ether lipid with branched chains

Question 21

which part (head/ tail) is hydrophobic?

Answer 21

tail

Question 22

which structure can fatty acid form?

Answer 22

micelles

Question 23

which structure can lipids form?

Answer 23

liposomes

Question 24

what are some interactions stabilize the bilayer?

Answer 24

hydrophobic, van der Waals, electrostatic, H-bonds

Question 25

technique to insert ion/molecule into liposomes

Answer 25

sonicating (using soundwave)

Question 26

how do liposomes self-reproducing?

Answer 26

at pH= 8.5, oleate anhydride is hydrolyze into oleate

Question 27

which fatty acid can form vesicles?

Answer 27

oleate

Question 28

why water is the exception for membrane permeability?

Answer 28

- low molecular weight - high concentration - lack of complete charge

Question 29

3 groups of membrane proteins

Answer 29

- integral protein - peripheral protein - lipid-linked protein

Question 30

what interaction does integral membrane protein have?

Answer 30

nonpolar interactions

Question 31

what interaction does peripheral membrane protein have?

Answer 31

electrostatic and hydrogen bond interaction with head of lipid

Question 32

when do soluble proteins can associate with membrane?

Answer 32

when hydrophobic groups are attached to the proteins (covalently)

Question 33

3 hydrophobic groups

Answer 33

- palmitoyl group - farnesyl group - glycosylphosphatidylinositol (GPI) anchor

Question 34

where does palmitoyl group bind?

Answer 34

attached to Cys by a thioester bond

Question 35

where does farnesyl group bind?

Answer 35

attached to Cys at carboxyl terminus

Question 36

where does glycosylphosphatidylinositol (GPI) anchor bind?

Answer 36

attached to carboxyl terminus

Question 37

which structure would likely to have lower Tm?

Answer 37

short, unsaturated chain

Question 38

You are trying to fractionate the proteins of a membrane. In general, in which order (from easiest to hardest) will proteins be release from the membrane?

Answer 38

peripheral < lipid-linked < integral protein

Question 39

A beta barrel has a hydrophilic interior and a hydrophobic exterior. What pattern do you expect to see in the proteins primary structure? A. A long stretch of hydrophobic amino acids B. Approximate 20 hydrophobic amino acids followed by 20 hydrophilic amino acids C. A long stretch of hydrophilic amino acids D. Alternating hydrophilic/hydrophobic amino acids E. Will depend on the function of the beta barrel

Answer 39

D. Alternating hydrophilic/hydrophobic amino acids

Question 40

which type of membrane that serves as an electrical insulator around certain nerve fibers and have low content of protein?

Answer 40

myelin

Question 41

which type of membrane protein that required detergent to release protein?

Answer 41

homodimeric integral membrane protein

Question 42

what is the structure of the homodimeric integral membrane protein?

Answer 42

bound by a set of α helices that extend from the bottom of the protein into the membrane

Question 43

where is integral protein located?

Answer 43

lies on the along the outer surface of the membrane

Question 44

Tm decreases with ____________ concentration of cholesterol

Answer 44

increased

Question 45

what does lipid raft contains?

Answer 45

Made by sphingosine-containing glycolipids, proteins, and cholesterol

Question 46

what is the function of rigidity of lipid raft?

Answer 46

- prevent receptors from diffusing away - Serves as scaffold to bring receptors together and preclude other proteins

Question 47

explain how does membranes are asymmetric

Answer 47

All biological membranes have different lipid components and enzymatic activity on each layer

Question 48

which type of diffusion move thru membrane laterally, rapid, and spontaneous?

Answer 48

lateral diffusion

Question 49

which type of diffusion transition from one side of the membrane to another, usually slow?

Answer 49

transverse diffusion (flip-flop)

Question 50

which type of membrane does not have cell wall, but have plasma membrane?

Answer 50

eukaryotic membrane

Question 51

which type of membrane has 1 lipid bilayer?

Answer 51

prokaryotic membrane (gram +)

Question 52

which type of membrane has 2 seperate lipid bilayers?

Answer 52

prokaryotic membrane (gram -)

Question 53

what is the similarity between sphingolipid and glycolipids?

Answer 53

both made from sphinogosine