lipids

Question 1

are lipids water soluble?

why are they not considered polymers?

Answer 1

no

Lipids are not considered polymers because they do not consist of repeated monomer units linked together through covalent bonds, which is a defining characteristic of polymers. Instead, lipids are a diverse group of organic molecules that have unique and variable structures.

Question 2

polymers

Answer 2

a uniform repetition of monomeric units.

Question 3

what are the main biological functions of lipids?

Answer 3

Energy storage
Heat/Insulation
Structural components of cell membrane communication

Question 4

name the types of lipids

Answer 4

Fatty acids
Triacylglycerols
Phospholipids
Sphingolipids
Steroids

Question 5

what is the general formula for fatty acids?

what do we mean when we say fatty acids are amphipathic?

Answer 5

H(CH2)nCOOH

means they have both hydrophilic and hydrophobic regions

Question 6

what is the typical range for the number of carbons in fatty acid chains that are found in plants and animals?

Answer 6

between 16 and 18

Question 7

by what means are lipids mostly circulated around the body

Answer 7

by being bound to albumin

Question 8

what are fatty acids found at high levels in the plasma during fasting?

Answer 8

The increase in fatty acids in the plasma during fasting is directly connected to the process of lipolysis. Lipolysis is the biochemical process by which stored triglycerides (fat) in adipose tissue are broken down into their constituent fatty acids and glycerol. These released fatty acids are then released into the bloodstream, leading to higher plasma levels of free fatty acids (FFAs) during fasting. this helps to produce energy

Question 9

features of saturated fatty acids

Answer 9

they have only single bonds between their carbons
they have a linear appearance
they are solid at room temperature

Question 10

features of unsaturated fatty acids

Answer 10

One or more C=C bonds
They have C=C double bonds that give distinct bend
Reduces Tm(melting point), therefore, they are liquid at room temp

Question 11

what effect does a low saturation have on the melting point of fatty acids

Answer 11

it results to a low melting point

Question 12

Describe the composition of triglycerides(triacylglycerols) (TAGs)

Answer 12

Glycerol head group attached to 3 fatty acid chains

Question 13

how are TAGs stored?

Answer 13

they are stored as cytoplasmic lipid droplets

Question 14

enzyme that hydrolyses lipids into glycerol and 3 fatty acids

Answer 14

lipase

Question 15

homogenic fatty acids

heterogenic fatty acids

Answer 15

fatty acids of the same structure

fatty acids of different structures

Question 16

saturated fats

example

Answer 16

fats composed of saturated fatty acids

most animal fats

Question 17

examples of unsaturated fats

Answer 17

plant and fish fats (aka oils)

Question 18

where in mammals are fats stored?

Answer 18

in the adipose tissue

Question 19

which stores more energy, carbohydrates or fats

Answer 19

fats store double the amount of energy that carbohydrates store

Question 20

composition of phospholipids

Answer 20

glycerol, two fatty acids and a phosphate group

Question 21

sphingolipid composition

Answer 21

sphingosine, one fatty acid, and an R-group

Question 22

functions of sphingolipids

Answer 22

Cell recognition
Cell Signaling
Lipid rafts

Question 23

steroids

Answer 23

Steroids are lipids with a common carbon skeleton consisting of four fused carbon rings

Question 24

what results to there being different steroids

Answer 24

different functional groups being attached to the rings

Question 25

what is the base for all steroid hormones and bile acids

Answer 25

cholesterol

Question 26

name some steroid hormones

Answer 26

cholesterol
Oestrogen
testosterone
progesterone
Glucocortecoids

Question 27

where in the mammalian system is cholesterol synthesized

Answer 27

the liver

Question 28

what is the total average body composition of cholesterol?

what percentage of this is part of the cell membrane structure

Answer 28

150g

90 percent

Question 29

lipid transport is undertaken by

Answer 29

apolipoproteins

Question 30

briefly describe lipid transport

Answer 30

Dietary lipids are transported from the intestine to the liver (exogenous)

Lipids are then transported from the liver to peripheral tissues (endogenous)

Question 31

what are the classes of lipoproteins?

Answer 31

Chylomicron
VLDL(Very Low-Density Lipoproteins)
LDL(Low-Density Lipoproteins)
HDL(High-Density Lipoproteins)

Question 32

which one of the classes of lipoproteins has the lowest density(i.e low protein: lipid ratio)

Answer 32

chylomicrons

Question 33

which one of the classes of lipoproteins has the highest weight of triacylglycerols

Answer 33

chylomicrons

Question 34

which one of the classes of lipoproteins has the second highest triacylglycerols as % of weight

Answer 34

VLDL

Question 35

glyceride

Answer 35

type of lipid composed of glycerol and fatty acids