recall test

Question 1

explain how the structure of starch relates to its function?

Answer 1

-starch has a main role of energy storage
-insoluble in water, therefore isnt affected by osmosis or affects water potential
-compact meaning lots can be stored
-large therefore doesn’t diffuse out of cells

Question 2

describe the test for reducing sugars

Answer 2

-add benedict’s reagent to a reducing sugar (glucose)
-heat in water bath for 5 minutes
-a positive result would end in a brick red colour, suggesting a large amount of reducing sugar
-the colour change can also vary from orange, yellow, green dependant on amount of reducing sugar
-a negative result would remain blue

Question 3

what kind of bonds would you find between glucose?

Answer 3

-when glucose molecules link together in a long chain, polysaccharides are formed
-the link formed between each molecule is known as a glycosidic bond
-these glycosidic bonds are formed by condensation reactions

Question 4

what kind of bonds would you find between glycerol and fatty acids?

Answer 4

-triglycerides contain three ester bonds between the fatty acids and the glycerol molecule formed by condensation reactions
-an ester bond forms when a hydroxyl group from the glycerol (OH) and carboxyl group from the fatty acid join (COOH)
-the H from the glycerol combines with the OH from the fatty acid to make water

Question 5

what kind of bonds would you find between amino acids?

Answer 5

-each amino acid is attached to another amino acid by a covalent bond, known as a peptide bond
-in order to from a peptide bond a hydroxyl group (OH) is lost from the carboxyl group of one amino acid and a hydrogen atom is lost from an amine group of another amino acid

Question 6

explain why cells need to be placed in a cold, buffered solution that is the same water potential as the tissue before cell fractionation

Answer 6

-the solution needs to be cold to reduce activity of enzymes that break down organelles
-it needs to be buffered to maintain a constant pH as could affect organelle structure
-it also needs to have the same water potential to prevent water from moving into the organelles via osmosis, causing them to expand/burst

Question 7

describe the function of ribosomes

Answer 7

-produce proteins by translating genetic information from DNA

Question 8

describe the function of the rough endoplasmic recticulum

Answer 8

-synthesises proteins

Question 9

describe the function of mitochondria

Answer 9

-produce energy through cellular respiration

Question 10

describe the events of prophase

Answer 10

-chromosomes condense becoming shorter and thicker
-nucleolus and nuclear envelope start to break down
-centrioles move to the opposite poles of the cell
-spindle fibres start to develop

Question 11

name the 3 stages of the cell cycle

Answer 11

-interphase
-nuclear division
-cytokinesis