Biochemistry D1. : Analyse how the structure and functions of these biological compounds relate to their roles in cells in terms of: Energy storage, Enzyme function and mechanisms of enzyme action, Cell membrane structure

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Just leaving this here.

The structure and functions of these biological compounds relate to the roles of energy storage, enzyme function and cell membrane within these cells. These roles are vital within animal cells energy storage.

The main energy storage compounds are starch in plants and glycogen in animals. Energy storage is essential for animals as they need energy as a reserve. There are two hormones within the body that are responsible for the maintenance of glucose concentration levels. These are insulin and glucagon. Insulin is released when the blood sugar levels are too high, in response to this the transport of glucose across the cell membrane is increased in order for it to enter the cells. It then becomes metabolised. Glucagon happens when blood sugar levels drops too low. Within glucose are atoms, the structure of these atoms are in a covalent bond (therefore has a strong structure). When these covalent bonds are broken, this results in a huge amount of energy being released. This explains why it is a good source of energy as these bonds are strong. The structure of glycogen is known for being broken down easily and converted to glucose. This is a good source of energy.
Starch is useful as an energy storage compound within plants because of many factors such as they do not affect the water concentration inside cells and they do not move away from the storage areas in the plant. starch can be converted into other substances in plants. For example, cellulose for cell walls and proteins for growth and repair. Starch also enables a large amount of energy to be stored in a small space. Being not very soluble in water is useful for a storage compound.

Each protein has a unique tertiary structure, this allows for its own functions and properties. Below is a diagram showing this tertiary protein structure.  (insert image of tertiary protein structure). 

These are held together by bonds which are known as hydrogen and ionic between the ‘R’ groups on adjacent chains. Enzymes are only able to function a narrow range of temperatures and pH levels due to the hydrogen bonds. This is because the hydrogen bonds are holding the structure together. The amino acids consist of proteins; this would mean they have a basic structure. These have amino groups, carboxyl acid group and a hydrogen atom. The 4th bond to the ‘alpha’ carbon links the amino acid side of the chain. This is marked as ‘R’. The 3D shape these bonds maintain is high in numbers, however it is weak. The 3D structure of enzymes form pockets and protrusion that can hold and fit into their substrate molecules. The shape of these structures is important being a factor in the specificity of the enzyme. The binding of the substrate to the enzyme also changes the shape of the enzyme is many cases. This change in shape is essential for catalysing the product formation. This means these bonds are easily broken down resulting in the enzyme to lose its shape. This process is known as ‘enzyme denaturation’. This explains why enzymes are only active over certain range in temperature and pH.

Below shows the enzyme substrate complex process: (insert image).

Lock and Key theory:
⦁ Enzymes Are Locks
Enzymes work like a lock in the chemical reaction process that's necessary to maintain life. Each enzyme can attract its specific substrate and accelerate the chemical reaction that must occur in the appropriate time span.
⦁ Enzymes Sites Are Keyholes
The enzyme sites work like the keyhole in a lock. Like the lock on a door, only certain keys will fit in the keyholes, and perhaps only one key will open the lock. Put the wrong key into the keyhole, and you can prevent the correct key from unlocking the door.
⦁ Substrates Are Keys
Each enzyme will only respond to one or two substrates, which work like keys for the enzyme lock. The molecular structure of the substrate must correspond in size and shape to the receptor site on the enzyme to produce the desired chemical response. When the enzyme locates its appropriate substrate, the substrate enters the receptor site and both the enzyme and substrate transform to create a complete union so the chemical reaction can occur.



Below shows the structure of enzymes in relation to the enzyme denaturation process. (insert image).

The cell membranes structure is influenced by phospholipids and proteins. Phospholipids are produced from triglycerides, however within the structure one of the fatty acid chains is replaced with a phosphate group. There are other atoms which are attached to the phosphate. As the phosphate group is negativity charged, it attracts water. The phospholipids create a layer within the cell in order to control the entrance and exits of molecules. This phospholipid layer gives a fluid like structure. the partially permeable membrane of the bilayer determines by the distribution of proteins and phospholipids.

The interior of the cell is primarily made of water. Likewise, the exterior of the cell is usually surrounded by watery fluid. This means that the plasma membrane could not possibly consist of just one layer of phospholipids. This is because the hydrophobic (or water fearing) tail region would have to interact with one of the watery regions inside or outside of the cell. So instead, the cells have evolved to have two layers of phospholipids.



Reference list
. 2016. . [ONLINE] Available at: http://www.3dmoleculardesigns.com/Teacher-Resources/Enzymes-in-Action-Kit.htm.
BBC - GCSE Bitesize: Denaturing of enzymes. 2016. BBC - GCSE Bitesize: Denaturing of enzymes. [ONLINE] Available at: http://www.bbc.co.uk/schools/gcsebitesize/science/add_edexcel/cells/enzymesrev3.shtml.

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Xo.

             

Biochemistry M3. Use your experimental results to explain why enzymes are active over a relatively narrow range of temperature and pH. Explain why the rate of enzyme activity eventually reaches a limit as the substrate concentration increases.

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Just another essay for you all.

Enzymes perform as catalysts which are in charge of the rate of biochemical reactions. Each enzyme has an active site. This is when the enzyme and the substrate combine for a short period of time to create an enzyme substrate complex. The lock and key theory is in place to describe that the shape of the active site shares similarities to the substrate, which means when they meet they connect perfectly together. Enzymes have a narrow range of pH and temperature and this is due to the fact that they can be destroyed at extreme levels.

Within the experiment that I carried out, observing the effect of temperature on the enzyme amylase it was clear there was a connection between temperature and the time that it took for the enzyme to finish breaking down the starch. Between the temperatures 22°C and 50°C, the time changes decreased from 9 seconds to 2 seconds. Due to the temperature increases, this means that kinetic energy also increases which then increases the chances of enzyme and substrate colliding which also means that the rate of the reaction is quite fast. This is shown within the graph which represents the time taken for the starch to be broken down at 55°C was 7 seconds. This was because of the enzyme in this reaction becoming denatured due to the temperature being so high. This is because the hydrogen bonds holding the enzyme together are broken, therefore takes longer for the enzyme to function.

pH levels can also impact enzyme activity. When the pH is increased, the amount of enzyme substrate complex will also be increased until the peak pH is discovered. The peak pH level of an enzyme is 7. The bonds that hold the enzyme can be denatured. This is due to the breaking which decreases the rate of reaction as the enzyme no longer functions.

The second experiment I carried out shows the rate of enzyme activity reaches a limit while the substrate concentration rises. The percentage of hydrogen peroxide is increased; this had an effect on the way that the substrate concentration affected the capability of the enzyme catalase and increased the rate of the reaction. This is shown within the results of the graph as the increased rate of the reactions is steady. When the rare if the reactions increase, this is caused by the increase of substrates within the solution, the chances of the enzyme and the substrate colliding in the active site are high. The rate of the reaction will eventually get to a stage where it will decrease due to the tolerance levels. The enzymes are no longer able to react any faster.

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Biochemistry P6. Describe the suspected causes, diagnosis, effects (signs and symptoms) and usual treatments of either diabetes mellitus or under/overactive thyroid. Of any of the inborn errors of metabolism listed. For D2 provide the information above for both diabetes mellitus and under/overactive thyroid and all of the 4 inborn errors of metabolism listed. Provide details of the role of the relevant enzymes for all 4 of these errors.

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Another day another essay. Let me know your thoughts!

Our metabolism is in charge of the breakdown of foods which contain proteins, carbohydrates and fats in our bodies changing them into sugar and acid in order to create energy. Some people may experience problems which are known as metabolic disorders which disrupts this process and causing the body to lack or to produce too much of a particular substance.

Metabolic disorders can be developed when the liver or pancreases fails to function properly due to a disease. Examples of these disorders are diabetes, hypothyroidism and hyperthyroidism.

Diabetes is a lifelong condition which causes an individual’s blood glucose levels to become so high that they are unable to be controlled the homeostatic mechanisms within our body. There are two types of diabetes, ‘type 1 diabetes’ and ‘type 2 diabetes’. Type 1 diabetes is caused by the immune system destroying the cells in the pancreas that make insulin. This causes diabetes by leaving the body without enough insulin to function normally (autoimmune reaction). There is no specific cause of this but some triggers could be viral/bacterial infection, chemical toxins in food or an unidentified component causing the autoimmune reaction. Type 2 diabetes is caused by different factors such as family history, diet and obesity. Symptoms of both types of diabetes are the same however type 1 diabetes may take only weeks to develop whereas type 2 diabetes may take years to develop and diagnosis. The main symptoms are fatigue, blurred vision, cuts/wounds healing slow, weight loss, urinating more than usual etc. Type 1 diabetes and type 2 diabetes is diagnosed by a range of tests for instance, urine/blood tests, glycated haemoglobin (HbA1c) test. Type 1 diabetes can also be tested by antibody tests and type 2 diabetes can be tested by glucose tolerance test (GTT). There is no cure for diabetes but there is treatment and medication to maintain the health of those who suffer from the condition. Treatment for diabetes includes diet control, exercise, home blood glucose testing, and in some cases, oral medication and/or insulin. Approximately 40% of people with type 2 diabetes require insulin injections. Diabetes does not only cause impairment in the metabolism of sugars but is also associated with abnormal metabolism of fats and proteins. Therefore, all three key enzymes lipase, protease and amylase are vital in managing diabetes because they will help digest all three groups of nutrients: proteins, fats and sugars.
Hypothyroidism or also known as an underactive thyroid is where there isn’t enough of the hormones being produced. The main reason for an underactive thyroid is due to the immune system attacking the thyroid gland and damaging it or damage as a result of thyroids cancer or an overactive thyroid. Symptoms for an underactive thyroid may take time and the condition may not be diagnosed for many years. Some of these symptoms include fatigue, constipation, depression etc. In order to diagnose this condition, tests would be run for instance thyroid function tests. An underactive thyroid is usually treated by taking daily hormone replacement tablets called levothyroxine.
Hyperthyroidism or also known as an overactive thyroid is when there is too much of the hormones being produced in the body. There are several possible underlying causes, the most common being ‘Graves’ disease’, in which the body's immune system targets the thyroid gland and causes it to produce too much of the thyroid hormones. there are many symptoms resulting from this condition such as nervousness/anxiety, unexplained weight loss, swelling of thyroid gland (found in throat). In order to diagnose this condition, tests would be run for instance thyroid function tests. The treatment given for an overactive thyroid is called thionamides which stops the thyroid gland producing so much.

Metabolic disorders are caused by a genetic abnormality in which a specific enzyme is missing. This missing enzyme can result in serious harm and can also be harmless at the same time. This depends on the disorder however.
Galactosemia is an inherited disorder which causes babies within their first few weeks to lose their appetite. It’s possible they would suffer from vomiting, become jaundiced and have growth abnormalities. This is caused due to the high level if the monosaccharide galactose within the blood. The galactose 1-phosphate uridyl transferase is the enzyme in which are necessary for metabolising galactose and the lack of this caused the disorder to occur. The liver would also enlarge and within the urine, amino acids and proteins are now present. If a child with this condition doesn’t receive medical attention/treatment on time, this could lead to further develops such as within the cataracts galactose plays a role in the clear lens proteins. Other complications of this disease include brain damage, kidney damage and spleen damage. The diagnosis of Galactosemia is concluded when galactose and galactose 1-phosphate are identified within the urine. This is then further analysed and confirmed when the relevant enzyme is not present within the blood and the liver cells. It is vital that if there is a history of this condition within an individual’s family, that they and their family members be tested as soon as they are born. If a person does suffer from this condition, it’s important they don’t consume dairy products such as milk. This is due to galactose present within lactose which is found is dairy products. If a woman is pregnant and is aware that this condition runs in the family and as the baby could possibly have the condition, the pregnant woman cannot eat dairy products throughout the duration of her pregnancy.

Phenylketonuria (PKU) is an amino metabolism disorder and is a rare genetic condition. The body is unable to break down a substance called phenylalanine. This results in building up in the blood and brain. High levels of phenylalanine can damage the brain and could lead to brain damage. The symptoms of this condition are learning disabilities, behaviour problems and epilepsy.  There are different methods of diagnosing this condition. One is done by the heel prick test which is carried out during the first few weeks of a baby’s life. This test checks for range of conditions. If the illness is confirmed by the heel prick test, another test would be carried out which would determine the high phenylalanine levels then the individual would be referred to health professionals to specialise in treating for the disease.  To treat this disease, most people will suffer severe learning difficulties and would need care for the rest of their lives. The main treatment is to eat a low-protein diet such as potatoes and avoid high protein foods such as dairy products, meat etc. As these individuals wouldn’t be getting the nutrients from these foods, they would have to take amino acid supplements to ensure normal growth. Phenylalanine is usually broken down by the body by an enzyme known as phenylalanine hydroxylase however people who suffer from PKU are not able to do so because of an alternation in their DNA. This then causes phenylalanine levels in the blood to rise.
Glycogen storage disorders are a group of inherited diseases that result from the lack of one of the enzymes that are involved when changing glucose to glycogen or the breakdown of glycogen to glucose. There is over 12 different types of these disorders due to the number of different enzymes involved within the production of glycogen. Each of these disorders has different malfunctions which are low muscle tone, hypoglycemia (low blood sugar), heat intolerance etc.  The condition is diagnosed through a range of tests and if this condition runs through an individual’s family, they would be tested after they are born.  There would be blood tests carried out to test sugar levels and liver/kidney function and there would be scans such as an abdominal ultrasound scans. The treatment for these disorders all depends on as different types requires different treatment. With the majority of them, the treatments goal is to stablise blood sugar/energy levels. Individuals with these disorders would be put on a high protein diet. People who suffer from these diseases would be prone to having a low immune system and therefore would regularly take antibiotic medication to protect themselves from infections. If there is an enzyme lack in the production of glycogen, this can decrease the amount of normal glycogen produce. Low levels of glucose in the body (hypoglycemia) and a buildup of glycogen within the muscles and liver can be a result of problems in regards to the enzymes involved with the breakdown of glycogen into glucose.
Fructose intolerance is a disorder which is the result of the lack of protein needed for the breakdown of fructose, fructose is a sugar which is produced normally within the body. This disease can be inherited. The cause as well as inherited It may be somewhat self-imposed by our modern sugar-heavy diets. Humans have not yet evolved systems to cope with such high sugar consumption that is present within our society such as within in soft drinks, confectionery, desserts etc.  The symptoms for this condition includes fatigue, malabsorption issues (anemia), gastro-intestinal distress (bloating) etc. The diagnosis for this condition is carried out by either a H2 breath test, however this method is seen nowadays as non-reliable so a new alternative method of testing for the condition is done by using stool analysis. A Fructose-free or low-sugar diet is the best treatment. This is easy if you know which foods contain fructose - but many processed foods include fructose so foods such as this should be avoided. The enzyme responsible for this produce is known as aldolase B which is produced in the liver. This condition occurs when this enzyme is missing. Aldolase B is responsible for the second step in the metabolism of fructose, which breaks down the molecule fructose-1-phosphate into glyceraldehyde and dihydroxyacetone phosphate. To a lesser degree, aldolase B is also involved in the breakdown of the simple sugar glucose.

Reference list

NHSChoices Home Page. 2016. NHSChoices Home Page. [ONLINE] Available at: http://www.nhs.uk/pages/home.aspx.

Patient. 2016. Glycogen Storage Disorders. Inborn errors of metabolism | Patient. [ONLINE] Available at: http://patient.info/health/glycogen-storage-disorders-leaflet.

WebMD. 2016. Diagnosis of Diabetes. [ONLINE] Available at: http://www.webmd.com/diabetes/guide/diagnosis-diabetes.

Your Study pal,
Xo.

P5 Biochemistry For any 2 of the 3 enzyme experiments that you performed: Describe how the experimental results were obtained (method), Provide a suitable table and graph for your results, ⦁ Explain what each graph shows regarding enzyme activity.

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Heres another to enjoy,

The first experiment was to show how the temperature affects the activity of the amylase. The method in which we used to gain these results is:

• Measure the room temperature with a new thermometer and use a pen to name the beakers 1 and 2. Divide 10 test tubes into 2 groups and name then 1-5 in each group. Stopwatches are required to record the time in which the blue/black colour disappears.

•  Crushed ice is then added to beaker 1 and I must be filled with tape water. Beaker 2 is filled up with tap water. A thermometer is placed in each beaker and we left it for a few minutes. Once the temperatures reached the reaction temperature the experiment begins. 3cm³ of amylase must be added into a 10cm³ measuring cylinder, add more drops or pour away drops until it reaches the 3cm³ marks and then pour the solution into beakers 1-5. Repeat the step to the starch solutions and pour then into beakers 1-5 in the second group. 
•  Test tubes 1 from each group must be put into beaker 1. Test tubes 2 from both groups must be put into a water bath of 40°C. 
• The temperature of each of the solutions must be checked every 30 seconds using thermometers to determine the current temperatures of the solution. 
•  If the two types of solution in one container have already reached the reaction temperature, then up and start the corresponding stopwatch as fast as you can. Add a drop of iodine solution immediately into the mixture of amylase solution and starch solution. 
•  The colour then must be checked. When the blue/black colour disappears then the time must be recorded.

At this point add a table to show the results of the experiment on how temperature effects the activity of amylase.

For e.g. 

c         Time in minutes

20°C 9

30°C 6

40°C 5

45°C 4

50°C 2

55°C 7

The technique to test how the concentration of hydrogen peroxide affects the rate of the reaction is as follows:

⦁ Add 2cm³ of yeast into one test tube and in another test tube, add 4cm³ of hydrogen peroxide solution at a concentration of 20% into the other tube. A pipette is used in order to measure the volumes. It’s important to note that the measurements are accurate to ensure a fair test. 

⦁ The hydrogen peroxide solution is then poured into the test tube which contains the yeast. Then the gas syringe stopper is put at the end of the test tube and the stopwatch is then started. 

⦁ The experiment bubbles at this point will then rise up the tube and the gas syringe will move outwards. When this passes the 30cm³ marks, the stopwatch must be stopped and the time must be recorded. 

⦁ The test must be recorded at least three times so an average is obtained. Once the time is taken is found, the rate can be worked out by using this formula: rate= 1000/time in secs.

You now might want to add a table to show the effect of substrate concentration on enzyme activity (catalase)

% Hydrogen Peroxide Time in secs Rate

10%                          286                  3.5

20%                                 182                  5.5

30%                                 160                  6.3

40%                                 139                  7.2

50%                                 130                  7.7

60%                                 120                  8.3

70%                                 110                  9.1

80%                                 100                  10

90%                                 104                  9.6

100%                         96                  10.4

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Biochemistry P4 describe the process of anaerobic respiration and use it to describe the type of respiration that occurs during a short sprint and during a marathon

Hi everyone! Back again with a few more essays for you. This is just a short one that covers a pass! Respiration is a series of reactions where glucose releases energy. There are two types of respiration: -Aerobic respiration (needs oxygen) -Anaerobic respiration (doesn’t need oxygen) When we exercise, our body heats up we breathe faster and our heart rate increases. Therefore, during a marathon aerobic respiration would occur. The formula for aerobic respiration is: Glucose + Oxygen Carbon Dioxide + Water (+energy) During exercise, the muscles tend to respire more than what they would when they are resting. The result of this is having the need oxygen and glucose more quickly; therefore the removal of waste carbon dioxide must happen quickly. This action is done by the heart rate and breathing rate increasing. When the heart rate rises, the rate of blood flow likewise increases. This results in the rate of gaseous exchange to increase in the lungs. The muscles support to store the glucose in the form of glycogen to allow it to be used as glucose during the period of exercise. It’s essential within this process that respiration and breathing are not the same. Respiration releases the energy and breathing means to release air in and out of the lungs. During exercise, it is also possible not to obtain oxygen. Anaerobic respiration occurs in this case, such as during a short sprint. Anaerobic respiration is the incomplete breakdown of glucose as it releases about 5% of the energy which is released by aerobic respiration. The waste product in this form of respiration is lactic acid, not carbon dioxide and water. Anaerobic respiration uses this formula: Glucose Lactic Acid (+little energy) When the height of the intense exercising is taking place, the heart cannot provide enough oxygen to the muscles. As lactic acid builds up from the anaerobic respiration, this causes the muscles to tire out due to long periods of exercise which is known as muscle fatigue. This results in the muscles stopping to contract effectively in order to allow the other person to exercise. Due to the breakdown of glucose being incomplete, this means that little energy is released during this form of respiration compare to aerobic. Anaerobic respiration produces oxygen debt. This is the amount of oxygen required to oxidise lactic acid to carbon dioxide and water. Due to oxygen debt, this explains why we breathe heavily after a period of exercise. As we breathe/pant after exercise, this provides the oxygen needed in order to break down the lactic acid. Reference list BBC Bitesize - GCSE Biology - Aerobic and anaerobic respiration - Revision 1. [ONLINE] Available at: http://www.bbc.co.uk/education/guides/zm6rd2p/revision. Look out for more to come ! your study pal Xo