Section 1: Biological Molecules

Question 1

What are the types of bonds seen in molecules?

Answer 1

-Covalent bonding
-Ionic Bonding
-Hydrogen Bonding
-Disulphide bridges
-hydrophobic-hydrophilic interactions

Question 2

What are monomers?

Answer 2

Small molecular subunits that can create larger molecules/polymers

Question 3

What are polymers?

Answer 3

Long chains of repeating subunits/monomers

Question 4

What is a condensation reaction?

Answer 4

The joining of two molecules by releasing a H2O molecule

Question 5

What is a hydrolysis reaction?

Answer 5

The breaking down of a bond between two molecules by adding a H2O molecule

Question 6

What are some examples of monomers?

Answer 6

-Monosaccharides
-Amino Acids
-Monoglycerides
-Mononucleotides

Question 7

What are some examples of polymers?

Answer 7

-Polysaccharides
-Polypeptides
-Polynucleotides (like DNA)

Question 8

What bond is between molecules in di/polysaccharides?

Answer 8

Glyosidic bonds

Question 9

What disaccharide is formed by the condensation of two glucose molecules?

Answer 9

Maltose

Question 10

What disaccharide is formed by the condensation of glucose and fructose?

Answer 10

Sucrose

Question 11

What disaccharide is formed by the condensation of glucose and galactose?

Answer 11

Lactose

Question 12

What are the two isomers of glucose?

Answer 12

Alpha glucose and Beta glucose

Question 13

How do you test for reducing sugars?

Answer 13

-Add a sample of food in liquid form and an equal amount of Benedict’s reagent
-Gently heat the mixture in a water bath

Question 14

How do you test for non-reducing sugars?

Answer 14

1.) Add hydrochloric acid to a sample of liquid food and leave the sample in a gently boiling water bath for five minutes

2.) Neutralise the solution with sodium hydro-carbonate and check with litmus paper that the solution is neutral or alkali

3.) Add Benedict’s reagent and gently heat the mixture

Question 15

What colour will Benedict’s reagent be if a reducing sugar is present?

Answer 15

Brick red

Question 16

How do you test for starch?

Answer 16

Add a few drops of iodine to a food sample

Question 17

What colour change can be observed if the iodine test is positive?

Answer 17

Orange/yellow to blue-black

Question 18

What isomer of glucose is starch made of?

Answer 18

Alpha-glucose

Question 19

What is the role of starch?

Answer 19

Energy storage

Question 20

Why is starch suitable for its function?

Answer 20

-Insoluble (Can’t be drawn in cells via osmosis)
-Compact (To fit in tight spaces)
-Upon hydrolyzation forms glucose (for ready use in respiration)
-The branched form has many ends which enzymes can work on (glucose is released very rapidly)

Question 21

Is starch found in animal cells?

Answer 21

No

Question 22

What carbon linkages does glycogen have?

Answer 22

C1-4 and plenty C1-6

Question 23

What two forms of starch are ther?

Answer 23

Amylose and Amylopectin

Question 24

What isomer of glucose is glycogen made of?

Answer 24

Alpha-glucose

Question 25

What is the main difference between starch and glycogen?

Answer 25

-Starch has less branches while glycogen is more highly branched

Question 26

Glycogen is a storage molecule. Why is it suitable for its function?

Answer 26

-Insoluble (Can't be drawn in cells via osmosis) -Compact (To fit in tight spaces) -Upon hydrolyzation forms glucose (for ready use in respiration) -The branched form has many ends which enzymes can work on (glucose is released very rapidly)

Question 27

Why is glycogen a better storage molecule than starch?

Answer 27

More branches allow for more glucose to be released and used for respiration. As animals have a higher metabolic rate than plants this is ideal.

Question 29

What carbon linkages does starch have?

Answer 29

-C1-4 linkages in amylose -C1-4 & C1-6 linkages in amylopectin

Question 30

Is cellulose branched or straight chained?

Answer 30

Straight chained

Question 31

What glucose isomer is cellulose made of?

Answer 31

Beta-glucose

Question 32

What is a microfibril?

Answer 32

Groups of parallel molecular chains which are cross linked via hydrogen bonds