TOPIC 1 BIO MOLECULES- Lipids

Question 1

What are the two main types of lipids?

Answer 1

-Phospholipids
-Triglyceride

Question 2

What is a lipid?

Answer 2

Biological molecules made of carbon, hydrogen and oxygen which are only soluble in organic solvents such as alcohols

Question 3

What are triglycerides

Answer 3

lipids made up of one molecule of glycerol and 3 molecules of fatty acids joined by ester bonds formed in condensation reactions

Question 4

How is the residual group normally formed for triglycerides?

Answer 4

from a hydrocarbon chain

Question 5

Do fatty acids have a carboxyl group?

Answer 5

yes (COOH)

Question 6

What are saturated lipids?

Answer 6

contain only single bonds between carbon atoms

Question 7

What are unsaturated lipids?

Answer 7

Contain double and single bonds between carbon atoms

Question 8

Where are saturated fats found?

Answer 8

animal fats

Question 9

where are unsaturated fats found?

Answer 9

plant oils

Question 10

how is triglycerides structure related to its properties

Answer 10

low mass: energy ratio- good storage molecule with a lot of energy(high calorific value)from oxidation

non polar lipids- insoluble, water potential is not affected

insoluble hydrocarbon chain- no effect on water potential and can be used for waterproofing

slow conductor of heat- thermal insulation

less dense than water- buoyancy of aquatic animals

Question 11

Can the R group of a fatty acid be saturated or unsaturated

Answer 11

yes

Question 12

Is it true that in phospholipids one of the fatty acids of a triglyceride is substituted by a phosphate-containing group

Answer 12

yes

Question 13

are phosphate heads hydrophilic or hydrophobic ?

Answer 13

hydrophilic (attracts water)

Question 14

a phosphate tails hydrophilic or hydrophobic?

Answer 14

hydrophobic (repels water)

Question 15

how are phospholipids structure related to their properties

Answer 15

polar bilayer can be formed in aqueous environments
hydrophilic head can hold at the at the surface of the cell
surface membrane
can form glycolipids with carbohydrates which are important on the cell surface membrane for cell recognition

Question 16

What do phospholipids form as result of being in contact with water?

Answer 16

micelles

Question 17

What is the emulsion test used for?

Answer 17

to test for the presence of lipids

Question 18

describe the structure of phospholipids

Answer 18

amphipathic molecule -glycerol backbone attached to 2 hydrophobic fatty acid tails and 1 hydrophilic polar phosphate head

forms a phospholipid bilayer in water which is a component of membranes

tails can splay outwards which allow for waterproofing

Question 19

what are the similarities of phospholipids and triglycerides

Answer 19

both have a glycerol backbone

both may be attached to a mixture of saturate, monosaturated and polyunsaturated fatty acids

both contain carbon, hydrogen and oxygen

both are formed from condensation reactions

Question 20

what are the differences between phospholipids and triglycerides

Answer 20

phospholipids:
-2 fatty acids and 1 phosphate group attached
-hydrophilic head and hydrophobic tail
-used primarily in membrane formation

triglycerides:
-3 fatty acids attached
-entire molecule is hydrophobic
-used prinmarly as a storage molecule( oxidation releases energy)

Question 21

are phospholipids and triglycerides polymers?

Answer 21

no they are not made from small repeating units, they are macromolecules

Question 22

what is LDL

Answer 22

low density lipoprotein cholesterol ( bad)

Question 23

What is HDL

Answer 23

high density lipoprotein cholesterol (good)

Question 24

Which lipid produces more LDl and which one produces more HDl

Answer 24

staurated= more LDL
unsaturated= more HDl