Biology summer task Flashcards
What is a monomer?
A monomer is a smaller molecule or single unit which can bond together to form polymers.
What is a polymer?
A macromolecule which consists of small chains of identical monomers bonded together via condensation reactions where a water molecule is lost.
Name 3 monosaccharides:
Glucose, Fructose and Galactose
Name 3 disaccharides:
Sucrose, Lactose and Maltose
Name 3 polysaccharides and state where they are found (human or animal):
- Starch: found in plants (source of energy)
- Glycogen: in humans (in the liver)
- Cellulose: in plant cell walls
Draw the structure of Alpha glucose:
Answer Drawn.
Draw the structure of beta glucose:
Answer Drawn.
State and explain the difference between the structure of Alpha and Beta glucose:
In the Alpha glucose structure the OH, carbon 1 group is below the ring whereas in Beta the OH group is above the ring.
What is the monomer of protein? Draw the structure of this monomer:
The monomer of protein are Amino acids.
What do nucleotides consist of- be specific with the structure and names of these components.
Phosphate group- the circle
Pentose sugar- deoxyribose
Nitrogenous base- Adenine, Cytosine, Guanine and Thymine.
How is the structure of a phosphilid different to a triglyceride molecule?
A phosphilid only has two fatty acid molecules bonded to the glycerol as the third fatty acid molecule was replaced by a phosphate molecule.
What is the difference between unsaturated and saturated fatty acids?
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.
What is the food test for starch, how is it carried out and what is a positive result?
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.
What is the food test for protein, how is it carried out and what would a positive result look like?
The test for protein is to add biuret solution and it turns from a blue to a purple colour is protein is present.
What is the food test for reducing sugars? How is it carried out and what is a positive result?
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.
Test for lipids, how is it carried out and what is the result?
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.
What is the non-reducing sugar test testing for, and how is it carried out?
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.
