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Biological molecules - Coggle Diagram
Biological molecules
4.2 - Structure of DNA
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DNA is the material that makes up our genes and chromosomes. It carries a code which instructs the cell which amino acids to link together, in which sequence, to make proteins.
DNA is made of smaller molecules called nucleotides. Nucleotides are molecules that are linked togher into long chains, to make up a DNA molecules.
Each nucleotide contains a base. A base is one of the components of DNA. 4 bases A,C,G,T and their sequences that determines the proteins that are made in a cell.
A always forms bonds with T, C always forms bond with G. This is called complementary base pairing.
4.1 - Carbohydrates, fats and proteins
Carbohydrates
Carbohydrates are substances that include sugars, starch and cellulose; they contain carbon, hydrogen and oxygen(CHO).
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Sugars
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Glucose is arranged in an hexagon form and is the way that carbs are transported around the human body..
When glucose molecules can link together to form large molecules called glycogen. This happens in animals and humans
in plants when glucose molecules are linked together they form starch and can be stored as starch is insoluble in water and starch can be broken down to be used as glucose again.
The presence of strach can be detected by using iodine solution.
The colour of iodine solution is brown and if starch is present the coulour change will take place from brown to blue-black
Benedicts solution can be used to detect reducing sugars.
the colour of benedicts solution is blue and if reducing sugars are present then the colour change will happen from blue to green and gradually from green to brick-red.
Fats and oils
Fats are lipids that are solid at room temperature.
Oils are lipids that are liquid at room temperature.
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They contain the same three elements as carbohydrates.Carbon, hydrogen and oxygen.
The test to check if fats are present in the food is ethanol emulsion test. Fats are oils are only soluble in ethanol. Firstly, the food is shaken with ethanol added to it to make sure all the fats in it are dissolved in the ethanol. They poured into a clean tube containing water. if fats is present in the food, there will be cloudy white droplets been seen.
Proteins
Proteins are a substance whose molecules are made of many amino acids linked together; each different protein has a different sequence of amino acids.
Made of four elements - carbon, hydrogen, oxygen and nitrogen(CHON)
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The test to check if proteins are biuret reagents. Colour changes from blue to violet in contact of proteins.
Proteins can be used as antibodies, pathogens and keratin and enzymes.
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