AQA GCSE Biology - 9.4 Metabolism and
The Liver Exam With Complete Solutions
metabolism - Answer sum of all reactions in cell or body
Give 6 metabolic reactions - Answer -conversion of glucose to starch, glycogen and cellulose
-formation of lipids
-forming amino acids which are used to make proteins
-respiration
-photosynthesis
-breakdown of extra proteins in the liver to form urea for excretion
what 2 things are needed to make up lipids? - Answer 1 molecule of glycerol
3 molecules of fatty acids
what 2 things are needed to make up amino acids? - Answer nitrate ions and glucose
3 functions of liver - Answer -detoxifying poisonous substances e.g. ethanol from alcohol
-passing breakdown products, such as amino acids, into blood so that they can be excreted by the
kidneys
-breaking down of old blood cells and storing the iron until it is needed to make new blood cells
where is lactic acid broken down - Answer in the liver
Give the 4 steps of the breakdown of lactic acid - Answer -blood transports lactic acid to liver
-lactic acid converted back to glucose using oxygen
-normally glucose broken down forming water and CO2
-if glucose isn't needed in the liver it's converted to glycogen and is stored in liver until needed
The Liver Exam With Complete Solutions
metabolism - Answer sum of all reactions in cell or body
Give 6 metabolic reactions - Answer -conversion of glucose to starch, glycogen and cellulose
-formation of lipids
-forming amino acids which are used to make proteins
-respiration
-photosynthesis
-breakdown of extra proteins in the liver to form urea for excretion
what 2 things are needed to make up lipids? - Answer 1 molecule of glycerol
3 molecules of fatty acids
what 2 things are needed to make up amino acids? - Answer nitrate ions and glucose
3 functions of liver - Answer -detoxifying poisonous substances e.g. ethanol from alcohol
-passing breakdown products, such as amino acids, into blood so that they can be excreted by the
kidneys
-breaking down of old blood cells and storing the iron until it is needed to make new blood cells
where is lactic acid broken down - Answer in the liver
Give the 4 steps of the breakdown of lactic acid - Answer -blood transports lactic acid to liver
-lactic acid converted back to glucose using oxygen
-normally glucose broken down forming water and CO2
-if glucose isn't needed in the liver it's converted to glycogen and is stored in liver until needed
