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21 Cards in this Set
- Front
- Back
What does the nucleotide consist of? |
A pentose sugar A phosphate group An organic group:C,A,G,T,U |
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A phosphodiester bond |
The bond between the pentose sugar of one mononucleotide and the phosphate group of another |
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Ribonucleic acid |
It is made of the pentose sugar which is usually ribose. It is also made up of four organic bases which are Uracil,Adenine ,Guanine and Cytosine One type transfers genetic information from the DNA to the ribosomes |
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The types of RNA are: |
messenger RNA transport RNA Ribosomal RNA |
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DNA structure |
It is also made of a deoxyribose sugar and organic bases which are Adenine,Guanine , Cytosine and Thymine It is made of two strands which are joined together by hydrogen bonds |
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Double helix |
The uprights of phosphate and deoxyribose wind around one another to form a double helix |
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The DNA molecule is stable because? |
(i)The phosphodiester bond protects the more chemically reactive organic bases inside the double helix |
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What are the functions of DNA |
It is very stable can therefore be passed from generation to generation without change It's two separate strands are joined by hydrogen bonds which are easily separated during replication It is immensely large therefore carries a large amount of information |
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process of semi conservative replication |
The hydrogen bonds joining the base pairs are broken down by DNA helicase The two strands of DNA unwind and act as templates for activated polynucleotides to join in The nucleotides are joined together by DNA polymerase Each of the new DNA contains one original and new strand |
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The conservative model |
It suggested that the original molecule remained intact and a separate daughter DNA is built from new molecules Of the two molecules produced,one would be entirely new and one would be entirely original |
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The structure of ATP |
a ribose sugar adenine phosphates |
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How ATP stores energy |
The bonds between phosphate molecules are unstable so have a low activation energy. When broken they therefore release a considerable amount of energy only the terminal phosphate is released ATP +H2O to produce ADP a phosphate molecule and energy This happens by hydrolysis and ATP hydrolase is also involved |
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synthesis of ATP |
It involves the addition of a phosphate molecule to ADP |
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Roles of ATP |
It is an immediate source of energy source why ATP is a better energy source compared to glucose Each ATP molecule releases less energy than glucose molecules. The energy for reactions released is therefore much smaller and manageable quantities The hydrolysis of ATP to ADP is a single process which only requires one step to produce energy. Whilst energy from glucose is a long series of reactions and therefore energy takes longer to be released |
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Uses of ATP |
Metabolic processes secretion active transport movement activation of molecules |
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Functions of water |
Specific heat capacity:Since water molecules stick together,it takes more energy to separate them. It takes more energy to heat a given mass of water,that is water has specific water capacity Latent heat of vaporisation:H bonding between water molecules means that it requires a lot of energy to evaporate 1 gram of water Cohesion and surface tension in water:Water has large cohesive forces which allow it to be pulled through a tube |
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Importance of water to living organisms |
In metabolism is used to break down many complex molecules by hydrolysis Water is a major raw material in photosynthesis It also acts as a solvent Its evaporation in living organisms allow them to cool off |
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why can base pairing not take place between adenine and cytosine and guanine with thymine |
Hydrogen bonds link the base pairs. The molecular structure are such that the hydrogen bonds cannot form between adenine and cytosine and guanine and thymine |
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A hypotheisis |
An explanation of something based on scientific logic and reasoning |
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why ATP an immediate source of energy? |
Energy is released very rapidly. ATP requires only one step to produce energy and the energy is directly transferred to the reaction requiring it |
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explain how ATP can make an enzyme catalysed reaction take place more readily |
It transfers one of its phosphate to the molecule and this lowers the activation energy,enzymes work by lowering the activation,they therefore have less work to do so function more readily. |