Biology, Carbs And Lipids

Question 1

What is a monomer?

Answer 1

Monomer’s are small identical or similar molecules which can be condensed to make larger molecules.

Question 2

What is a polymer

Answer 2

Polymers are large molecules made from condensing 3 or more identical or similar monomers together.

Question 3

State and describe the type of reaction involved in breaking a chemical bond.

Answer 3

Hydrolysis- the addition of water to break a named chemical bond.

Question 4

State and describe the type of reaction involved in forming a chemical bond.

Answer 4

Condensation- the removal of water to form a named chemical bond.

Question 5

Name the bond between carbohydrate monomers.

Answer 5

Glycosidic bond

Question 6

How is sucrose, lactose and maltose formed?

Answer 6

Sucrose- glucose and fructose
Lactose- glucose and galactose
Maltose- glucose and glucose

Question 7

How do you remember monosaccharides?

Answer 7

A-glucose- Penguin
B-glucose- Egyptian hands
Fructose- House
Galactose- Raver

Question 8

Describe the biochemical test for reducing sugars.

Answer 8

1- Add Benedict’s solution and heat to 95C
2-Red precipitate shows presence of reducing sugar

Question 9

Describe alternate ways to measure the concentration of a reducing sugar.

Answer 9

1- Calibration curve
2- Filter and dry. Then find the mass

Question 10

Explain how the structure of a cellulose relates to its function.

Answer 10

1- long, straight, unbranched chains of beta glucose
2- joined by many weak hydrogen bonds
3- to form microfibrils
4- because many weak hydrogen bonds are strong in large numbers
5- providing strength and rigidity to the cells walls

Question 11

Explain three ways in which starch molecules are adapted for their function in plant cells.

Answer 11

Insoluble SO doesn’t affect water potential
Helical/ coiled SO compact
Large SO doesn’t leave the cell

Question 12

Describe the biochemical test for a non-reducing sugar, (sucrose).

Answer 12

1- Benedict’s test gives negative result
2- add HCl and heat to 95C
3- add an alkali to neutralise
4- add Benedict’s solution and heat to 95C
5- red precipitate shoes presence of non-reducing sugar

Question 13

Describe the potassium iodide test for starch.

Answer 13

Add potassium iodide solution
Black shows presence of starch

Question 14

Describe how a triglyceride is formed.

Answer 14

ONE glycerol, THREE fatty acids
THREE condensation reactions
THREE ester bonds

Question 15

What is a saturated fatty acid?

Answer 15

Maximum number of hydrogens

Question 16

What is an unsaturated fatty acid?

Answer 16

Double bond between carbon atoms

Question 17

Describe the emulsion test.

Answer 17

1- Grind sample to release lipids
2- mix with ethanol and shake
3- add water and shake
4- positive result is a cloudy, white emulsion

Question 18

What does an emulsion test detect?

Answer 18

Lipids

Question 19

Describe the buriet test.

Answer 19

1- add buriet reagent to sample
2- positive result is purple

Question 20

What does the buriet test detect?

Answer 20

Proteins

Question 21

Compare and contrast the structure and properties of triglycerides and phospholipids.

Answer 21

BOTH contain water bonds,
BOTH contain glycerol,
BOTH insoluble in water,
BOTH contain C,H and O WHEREAS phospholipids also contain P,
Triglycerides have 3 fatty acids WHEREAS phospholipids have 2 fatty acids,
Triglycerides are hydrophobic WHEREAS phospholipids are hydrophilic,
Phospholipids form monolayer/bilayer/ micelle WHEREAS triglycerides do not

Question 22

Describe how the structure of glycogen is related to its function

Answer 22

Helix SO compact
Polymer of glucose SO easily hydrolysed
Branched SO more ends for hydrolysis
Insoluble SO doesn’t affect water potential
Glucose SO provides respiratory substrate for energy