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Flashcards in Cell Membranes Deck (114)
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1

What does the world amphipathic mean

It means that the membrane lipid has both hydrophilic and hydrophobic parts

2

Why do membrane lipids act as a permeability barrier

It is difficult for most solutes to simply diffuse through

3

How would you describe the general structure of membrane lipids

water hating fatty acyl chains associate with each other and water loving polar head groups interface with the water

4

What enzyme is involved in the synthesis of fatty acyl chains

Fatty acid synthase

5

Describe roughly how a fatty acid chain is synthesised

a two carbon unit joins with a three carbon unit, the loss of carbon occurs, you get a 4c unit and this is repeated until you obtain a long fatty acid chain

6

what is the two carbon molecule involved in fatty acyl synthesis

acetyl coA

7

what is the three carbon molecule involved in fatty acyl synthesis

malonyl coa

8

how many carbons does palmitic acid have and how many double bonds

it is fully saturated because it has no double bonds and it has 16 carbons

9

what is a fatty acid desaturase

A fatty acid desaturase is an enzyme that removes two hydrogen atoms from a fatty acid, creating a carbon/carbon double bond.

10

what is the carboxyl end of a fatty acid referred to as

carboxyl end

11

what is the methyl end of a fatty acid referred to as

the omega end

12

when delta is used to describe a fatty acid chain what does it mean

delta - indicating that the double bond is created at a fixed position from the carboxyl group of a fatty acid (for example, Δ9desaturase creates a double bond at the 9th position from the carboxyl end).

13

when omega is used to describe a fatty acid chain what does it mean

omega (e.g. ω3desaturase) - indicating the double bond is created between the third and fourth carbon from the methyl end of the fatty acid.

14

is cis or trans commonly found in nature

cis

15

if two hydrogen atoms are removed from the same side in a fatty acid how would you describe the fatty acid

it would be cis

16

if two hydrogen atoms are removed from opposite sides in a fatty acid, it would be referred to as

trans

17

trans fatty acids have what kind of shape

they are straight

18

what does polyunsaturated mean

Polyunsaturated fats are lipids in which the constituent hydrocarbon chain possesses two or more carbon–carbon double bonds.

19

what are the two essential fatty acids

Only two fatty acids are known to be essential for humans: alpha-linolenic acid (an omega-3 fatty acid) and linoleic acid (an omega-6 fatty acid).

20

why must we obtain the two essential fatty acids from our diet

this is because we do not have the desaturase enzymes to remove the hydrogens from omega3 or omega6 carbons

21

why are essential fatty acids referred to as essential

because we must get them from our diet

22

what is the actual name for omega-6 fatty acid

linoleic acid

23

what is the actual name for omega-3 fatty acid

alpha-linolenic acid

24

what are the essential fatty acids omega3 and omega6 required for

they are important precursors in a pathway to arachidonic acid and eicosapentaenoic acid

25

what is the function of arachidonic and eicosapentaenoic acid

they are used in paracrines so cell-cell communication

26

what is the enzyme used to convert arachidoni and eicosapentaenoic acid into paracrines

cyclo-oxygenase 2 (cox-2)

27

list three paracrines

leukotrienes, prostaglandins and thromboxanes

28

what is the function of leukotrienes, prostaglandins and thromboxanes

they are mediators of inflammation, pain, fever, immunosuppresion, clotting, blood vessel constriction, airway constriction

29

which three drugs inhibit cox-2 and therefore do not allow the production of paracrines and therefore don't allow pain to be felt

aspirin, ibuprofen and indomethicin

30

what is the enzyme that converts linoleic acid and alpha linolenic acid into the arachidonic acid and the eicosapentraenoic acid

elongases desaturases