Biology summer task

Question 1

What is a monomer?

Answer 1

A monomer is a smaller molecule or single unit which can bond together to form polymers.

Question 2

What is a polymer?

Answer 2

A macromolecule which consists of small chains of identical monomers bonded together via condensation reactions where a water molecule is lost.

Question 3

Name 3 monosaccharides:

Answer 3

Glucose, Fructose and Galactose

Question 4

Name 3 disaccharides:

Answer 4

Sucrose, Lactose and Maltose

Question 5

Name 3 polysaccharides and state where they are found (human or animal):

Answer 5

• Starch: found in plants (source of energy)
• Glycogen: in humans (in the liver)
• Cellulose: in plant cell walls

Question 6

Draw the structure of Alpha glucose:

Answer 6

Answer Drawn.

Question 7

Draw the structure of beta glucose:

Answer 7

Answer Drawn.

Question 8

State and explain the difference between the structure of Alpha and Beta glucose:

Answer 8

In the Alpha glucose structure the OH, carbon 1 group is below the ring whereas in Beta the OH group is above the ring.

Question 9

What is the monomer of protein? Draw the structure of this monomer:

Answer 9

The monomer of protein are Amino acids.

Question 10

What do nucleotides consist of- be specific with the structure and names of these components.

Answer 10

Phosphate group- the circle
Pentose sugar- deoxyribose
Nitrogenous base- Adenine, Cytosine, Guanine and Thymine.

Question 11

How is the structure of a phosphilid different to a triglyceride molecule?

Answer 11

A phosphilid only has two fatty acid molecules bonded to the glycerol as the third fatty acid molecule was replaced by a phosphate molecule.

Question 12

What is the difference between unsaturated and saturated fatty acids?

Answer 12

Unsaturated fatty acids have a double carbon to carbon bond c=c, whereas saturated only has a single bond between the carbon atoms c-c.

Question 13

What is the food test for starch, how is it carried out and what is a positive result?

Answer 13

The food test for starch is adding iodine to the food, a positive result would be a colour change from orange/brown to blue/black.

Question 14

What is the food test for protein, how is it carried out and what would a positive result look like?

Answer 14

The test for protein is to add biuret solution and it turns from a blue to a purple colour is protein is present.

Question 15

What is the food test for reducing sugars? How is it carried out and what is a positive result?

Answer 15

The food test for reducing sugars is the benedict’s reagent test, add benedict’s to the food sample and heat in a water bath for approx. 2 minutes, the solution should turn from a blue to a brick red is positive.

Question 16

Test for lipids, how is it carried out and what is the result?

Answer 16

The test for lipids is the emulsification test, add ethanol to your food sample and shake the solution, if the result is positive then a red oil will float on the surface.

Question 17

What is the non-reducing sugar test testing for, and how is it carried out?

Answer 17

The test is testing for all monosaccharides and maltose and lactose. Do the benedict’s test and get a negative result, then boil with dilute acid and neutralise this with a dilute base. Then add benedict’s solution again and heat. Then look for the colour change blue to brick red precipitate.