L17-18

Question 1

what are lipids?

Answer 1

heterogeneous group of compounds relatively insoluble in water but soluble in organic material

includes fats , oils , steroids

Question 2

what are the important functions of lipids ?

Answer 2

efficient source of energy ( triacylglycerol )

component of bio-membranes

provide fat soluble vitamins

precursor of hormones , vitamins , bile acids/ salts

thermal insulated

electrical insulator

Question 3

what are simple lipids composed of ?

Answer 3

Fatty acid + alcohol

ex: fats and waxes

Question 4

what are complex lipids composed of ?

Answer 4

fatty acid + alcohol + other group

phospholipids
glycolipids
sulpholipids
lipoproteins

Question 5

what are some examples of derived lipids ?

Answer 5

steroids

eicosanoids

Question 6

what type of acids are fatty acids ?

Answer 6

aliphatic carboxylic acids

Question 7

most naturally occurring fatty acids have an___ number of carbon molecules .

Answer 7

even

Question 8

odd chain fatty acids are seen in ____

Answer 8

microbial cell wall and milk

Question 9

where are the categories of chains according to chain length ?

Answer 9

short chain : 2-6

medium chain: 8-14

long chain:16-18

very long chain:20 onwards

Question 10

what are saturated fatty acids ?

Answer 10

fatty acids that do not contain double bonds (presence of long chain saturated FA makes)

Question 11

what are the most abundant fatty acids in the body ?

Answer 11

Palmitic acid

stearic acid

Question 12

what are unsaturated fatty acids ?

Answer 12

fatty acids that contain double bonds

Question 13

what configuration does the double bond of naturally occurring unsaturated fatty acids exist in ?

Answer 13

CIS configuration

Question 14

whaat are mono-unsaturated fatty acids ?

Answer 14

Unsaturated fatty acids that contain only 1 double bond

Question 15

what are polyunsaturated fatty acids ?

Answer 15

unsaturated fatty acids with more that one double bond

present in fish oil and many plant oils

Question 16

what are some essential fatty acids ?

Answer 16

polyunsaturated satty acids namely linoleic acids and linolenic acid

arachidonic acid becomes essential if its precursor linoleic acid is not provided in sufficient amounts

Question 17

why are essential fatty acids not synthesized by the body naturally ?

Answer 17

because humans lack the enzymes that can introduce double bonds beyond carbon 9-10

Question 18

what are the functions of Functions of essential fatty acids

Answer 18

Required for the membrane structure and function.

Precursors of prostaglandins and leukotrienes.

They decrease blood cholesterol and prevent atherosclerosis.

Required for the prevention of fatty liver.

Deficiency causes scaly dermatitis, hair loss and poor wound healing.

Question 19

melting point of fatty acids increases with ___

Answer 19

chain length

Question 20

as the number of double bonds increases the melting point ___

Answer 20

decreases

Question 21

what are triacylglycerols composed of?

Answer 21

they are composed of a glycerol backbone to which 3 fatty acids are esterifies

Question 22

what is the storage of lipids in adipose tissue /?

Answer 22

triacylglycerols

Question 23

TAG’s are hydrophobic, nonpolar and neutral.

TAG’s are not present in membranes.

Answer 23

–

Question 24

TAGs containing mainly saturated fatty acids are ___

Answer 24

are solid at ordinary temperature. They are called as fats. Fats are mainly of animal origin.

Question 25

TAGs containing mainly unsaturated fatty acids are ____

Answer 25

are liquid at 200C. They are called as oils and are present in vegetables.

Question 26

what hydrolyzes triacylclylcerols in the body ?

Answer 26

lipases

Question 27

when does hydrolysis of triacylyglycerols occur in the body ?

Answer 27

during digestion of deitrey fat and mobilization of TAG from adipose tissue

Question 28

what typer of fat is more sucsptiable to rancidity ?

Answer 28

fats containing more unsaturated fatt acids

Question 29

how are trans fatty acids formed ?

Answer 29

when liquid vegetable oils are partially hydrogenated to make oils more solid and separable . as a side effect , reconfiguration at some double bond occurs

Question 30

Trans-Fatty acids increase total & LDL cholesterol and reduce HDL cholesterol.
Both saturated FA as well as trans - unsaturated FA are detrimental (bad) to cardiac health.

Answer 30

–