Unit 1 Biology

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  • Created by: shriya
  • Created on: 20-05-13 19:40

Describe the 3 dimensional structure of a Enzyme protein

·         Globular

·         State they have an active site

·         Reference to named bonds and interactions between the R groups

·         Hydrophobic interactions between R groups di-sulphide bridges hydrogen bonds and ionic bonds alongside with Vander Waals forces. (Total 3 marks)


How does the primary structure determine the final structure?


·         Position/ sequence/order of the amino acids

·         This determines the types of bonds and folding that will take place

·         It determines the shape and properties of the active site

·         Causes enzyme substrate complex to be formed

·         The enzyme is then hydrophilic on the outside and hydrophobic on the inside

·         Hence it also creates solubility in water




·         It occurs through the cell membrane

·         The membrane is quite thin

·         Oxygen enters from water

·         Carbon dioxide leaves cell into water

·         O2 and CO2 are both non polar molecules and so diffuse in

·         Down a concentrate gradient

·         And an amoeba has a large surface area to volume ratio


If two beetroot experiments were being carried out what factors have to be kept constant for both experiments?


·         The pre-treatment methods should be the same

·         The size of the beetroot cut should be the same

·         Beetroot storage conditions should be the same

·         Incubation time should be the same

·         Volume concentration

·         PH water


Comment on how the results could be more reliable ?


·         If not before then in the second experiment use a colorimeter as it is more precise

·         The experiment was repeated



Describe the structure of glycogen and explain why it insoluble?


·         Glycogen consist of Alpha glucose

·         That are joined together by (1-4) and (1-6) glycosidic bonds

·         Branched structure

·         And it has a compact structure

·         It hydrolysed rapidly

·         Leading to more glucose in less space

·         So it has low solubility

·         Does not diffuse outside the cell

·         And hence has no osmotic effect




(This answer in the exam got all 3 marks)










The ethical and social issues with parental testing


·         If the disease is identified the child still has a right to live and abortion is murder if a miscarriage takes place

·         False positive/negative and the consequences behind it for example if the results for a genetic order prove positive and yet are wrong then a perfectly healthy foetus could be aborted

·         Who has the right to decide whether the tests should be performed or not?   It can cost quite a lot there may not be agreement


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