Lipids exam paper

Question 1

describe the difference between the structure of a triglyceride molecule and the structure of a phospholipid molecule

Answer 1

A phospholipid replaces one of the fatty acids with a phosphate molecule

Question 2

what are reasons a molecule cannot cross a cell surface membrane

Answer 2

The molecule can be too large

The molecule could be polar

Question 3

what is an advantage of using a pH meter rather than a pH indicator

Answer 3

it gives numerical readings
Data is quantitative not qualitative
greater accuracy and precision

Question 4

how does E. coli maintain its shape even though it has no cholesterol

Answer 4

it has a cell wall that is rigid, so it keeps the structures shape

Question 5

why does monitoring of a mixtures pH show whether it contains lipase

Answer 5

The hydrolysis of lipids produces fatty acids this lowers the pH of mixtures and also means that lipids are present

Question 6

 what kind of bond forms between glucose and fructose molecule

Answer 6

glycosidic bond 

Question 7

give one way the structure of triglycerides is different to olestra

Answer 7

three fatty acids

Question 8

how many molecules of water would be produced when one molecule of Olestra is formed

Answer 8

9

Question 9

explain two ways fatty acids are important in the formation of new cells

Answer 9

1) when fatty acids respire they release energy  that can be used for cell production
2) fatty acids are used to make phospholipids, The more phospholipids the more membranes are made

Question 10

what substance do muscles use as their immediate energy source

Answer 10

ATP