lipids 1 : triglycerides

Question 1

define lipids

Answer 1

a group of substance that are soluble in alcohol rather than water.
- they include triglyceride , phospholipids,glycolipids and cholesterol

Question 2

what does lipids contain ?

Answer 2

large amounts of carbon and hydrogen + smaller amount of oxygen

Question 3

why are lipids not soluble in water ?

Answer 3

as they aren’t polar
–> therefore they don’t attract water molecules but do dissolve in alcohol

Question 4

what are the 3 most important lipids in living things ?

Answer 4

triglycerides , phospholipids and steroids

Question 5

what aren’t these lipids and why ?

Answer 5

they aren’t polymers because they have different components bonded

Question 6

what are lipids ?

Answer 6

macromolecules

Question 7

define macromolecule

Answer 7

a very large , organic molecule

Question 8

what are triglycerides made up of ?

Answer 8

made up of glycerol and fatty acids

Question 9

what are there many types of ?

Answer 9

fatty acids

Question 10

what must happen for essential fatty acids to be complete ?

Answer 10

• must be ingested within our body in order to make them

Question 11

draw the structure of glycerol

Answer 11

find in text book :)

Question 12

how many carbon atoms does glycerol have ?

Answer 12

3 carbon atoms

Question 13

what is glycerol and what does that mean ?

Answer 13

an alcohol
- has free -OH groups (3)
- which is important to the structure of triglycerides

Question 14

what does fatty acids have structure-wise ?

Answer 14

a carboxyl group (-COOH) on one end
- attached to a hydrocarbon tail - (made of only carbon and hydrogen atoms

Question 15

how long could the fatty acid tails be ?

Answer 15

anything from 2 to 20 carbons long

Question 16

how does the ionisation work within the structure ?

Answer 16

• the carboxyl group ionises into H+ and a -COO- group
• this structure is therefore and acid because it can produces free H+ ions

Question 17

what does it mean if a fatty acid is saturated ?

Answer 17

this means that there are no C=C bonds in the molecules

Question 18

draw the structure of fatty acids

Answer 18

find in the text book :)

Question 19

what does it mean if a fatty acid is unsaturated ?

Answer 19

there is a double bond between 2 of the carbon atoms instead
–> which means that fewer hydrogen atoms can be bonded to the molecule

Question 20

what does it mean if a fatty acid is monosaturated and example ?

Answer 20

a single C=C bond makes a fatty acid + oleic acid

Question 21

what does it mean if a fatty acid is polysaturated and example ?

Answer 21

more than one C=C bond makes a fatty acid + linoleic acid

Question 22

what does having on or more C=C bond change and why ?

Answer 22

the shape of the hydrocarbon chain , giving it a kink where the double bond is
–> as these kinks push the molecules apart slightly

Question 23

what does animal lipids contain lots of and they are ?

Answer 23

• lots of saturated fatty acids
  –> are often solid at 20 degree celsius

Question 24

what does it mean if there is more unsaturated fatty acids ?

Answer 24

the melting point is lower

Question 25

what does a triglyceride consist of ?

Answer 25

one glycerol molecule bonded to 3 fatty acids

Question 26

what reaction happens for a triglyceride to form ?

Answer 26

a condensation reaction

Question 27

what bond forms when a reaction occurs ?

Answer 27

ester bond

Question 28

what happens during the reaction ?

Answer 28

3 -OH groups and 3 - fatty acids will bond

Question 29

what is produced during this reaction ?

Answer 29

a water molecule

Question 30

what may the fatty acids be ?

Answer 30

different

Question 31

what reaction occurs for a triglyceride to be broke ?

Answer 31

a hydrolysis reaction

Question 32

what bond is broken in this reaction ?

Answer 32

an ester bond

Question 33

what is used up during this reaction ?

Answer 33

a water molecule

Question 34

what is type of bond is an ester bond ?

Answer 34

a covalent bond

Question 35

what are the 5 types of functions of a triglyceride ?

Answer 35

- energy store - insulation - buoyancy - protection

Question 36

when can triglycerides be broken down and what into ?

Answer 36

in respiration - release energy and generate ATP

Question 37

what is the steps for this to occur ?

Answer 37

- hydrolyses the ester bonds - then both glycerol and fatty acids broken down into carbon dioxide and water - respiration of a lipid produces ore water than respiration of a sugar

Question 38

what is the benefit of triglycerides not being soluble in water ?

Answer 38

they can be stored without affecting the water potential of the cell

Question 39

where do mammals store fat ?

Answer 39

in adipose cells under the skin

Question 40

what does 1g of fat release and why ?

Answer 40

- twice as much energy as 1g of glucose - as lipids have a higher proportion of hydrogen atoms than carbohydrates and almost no oxygen atoms

Question 41

what is adipose tissue a storage location for and why ?

Answer 41

lipid in whales acting as a heat insulator

Question 42

what does lipids in a nerve cell act as ?

Answer 42

an electrical insulator

Question 43

what do animals preparing for hibernation do ?

Answer 43

store extra fat

Question 44

what is fat in comparison to water and how is this a benefit ?

Answer 44

- fat is less dense than water --> it is used by aquatic mammals to help them stay afloat

Question 45

what do humans have around delicate organs and why ?

Answer 45

- fat such as kidneys to act as a shock absorber

Question 46

what is the peptidoglycan cell wall covered in ?

Answer 46

lipid-rich outer coat