Biological Molecules Q/A

Question 1

What is meant by a polymer?

Answer 1

A macromolecule made up of repeated sub units. Or molecules made from a large number of monomers joined together.

Question 2

Give one example of a biologically important polymer other than starch or DNA

Answer 2

Cellulose

Question 3

b) i) In an investigation the enzyme amylase was mixed in a test tube with a buffer solution and a suspension of starch. The amylase broke down the starch to maltose. When all the starch has been broken down a sample was removed from the test tube and tested with biuret reagent. Explain why a buffer solution was added to the amylase starch mixture.

Answer 3

The buffer solution keeper the pH the same throughout so as amylase is an enzyme it doesn’t denature or change in the reaction

Question 4

bii) What colour reagent would you expect the sample to go when tested with biuret reagent?

Answer 4

Lilac

Question 5

Starch, Cellulose and Glycogen . Which are found in plant cells? Which contains glycosidic bonds? Which contains Beta Glucose?

Answer 5

Starch and Cellulose are found in plant cells . Starch and Cellulose and Glycogen contains glycosidic bonds. Cellulose contains Beta Glucose.

Question 6

Name the type of reaction that would break down these carbohydrate into their monomers.

Answer 6

Hydrolysis

Question 7

Give one feature of starch and explain how this feature enables it to act as a storage substance

Answer 7

Feature: Coiled Explanation: Therefore it is compact molecule with a lots of glucose in a small space

Question 8

Name the monomers that form a cellulose molecule

Answer 8

Beta Glucoses

Question 9

Write two ways in which the structure of cellulose is different from the structure of starch.

Answer 9

Starch has a coiled chain and contains alpha glucose bonds. Cellulose has a linear chain and contains Beta glucoses.

Question 10

the structure of cellulose is related to its role in plant cells walls. Explain how.

Answer 10

Long straight chains made from hydrogen bonds. Forming a microfibril. Providing strength

Question 11

how do you work out magnification?

Answer 11

image ÷ actual REMEMBER I AM AS THE TRIANGLE

Question 12

Describe the difference between the structure of a triglyceride molecule and the structure of a phospholipid molecule.

Answer 12

Triglyceride has 3 fatty acid chains and a glycerol molecule whereas a phospholipid has 2 fatty acid chains and a phosphate group is added.

Question 13

Explain how sulphur containing amino acids help to give keratin molecules their characteristic strength

Answer 13

keratin contains di sulphide bridges which hold the molecules together giving it strength

Question 14

A protein contains 151 amino acids. What is the total number of peptide bonds in this molecule?

Answer 14

150 ( it’s always one less)

Question 15

What would be the DH value of a protein if it were completely hydrolysed to amino acids? Explain how you arrived at your answer.

Answer 15

DH value is 100 becuase 100 times the number of peptide bonds hydrolysed will always be 100× more than the total number of peptide present when a number is divided by a number a 100× times less than its value the answer will always be 100

Question 16

What must you not assume if there is a correlation

Answer 16

Just becuase there is a correlation doesn’t mean that it is the direct causation to the topic it may just contribute towards it but they may be other factors involved

Question 17

Describe how you could use the emulsion test to show the presence of oil in a same of fish.

Answer 17

Add ethanol to the fish and crush the sample of needed if there are bits in it. Shake the sample to see if the lipid dissolves in it and filter it then add water. if the substance turns into a cloudy white emulsion then oil is present.

Question 18

Omega 3 fatty acids are unsaturated. What is an unsaturated fatty acid?

Answer 18

Unsaturated fatty acids have double carbon to carbon bonds and it’s less dense as less bonds are packed togther. It contains double chains making it bend.

Question 19

Starting with separate molecules of glucose, fructose, and fatty acids, how many molecules of water would be produced when one molecule of olestra is formed?

Answer 19

9