Saturated and Unsaturated fatty acids:

Saturated fatty acids do not contain a double carbon bond between the carbon atoms

Unsaturated fatty acids do contain one or more double carbon bonds between the carbon atoms

Distinguish between essential and non-essential amino acids:

Non-essential amino acids are acids that can be produced by the body

Essential amino acids cannot be produced by the body and must be attained from elsewhere such as food sources

Discuss how the recommended distribution of dietary macronutrients differs from endurance athletes to non-athletes:

1) During endurance aerobic exercise, the muscles depend on glycogen stores as a source of energy

2) Gylocgen stores are dependent on the amount of carbohydrates ingested

3) Therefore an endurance athlete is likely to be recommended a diet which is rich in carbohydrates compared to a non-athlete so that they can replenish their glycogen stores and reduce risk of fatigue

4)An athlete is also likely to have more degraded muscle due to training, so they will also need to have a higher protein intake for growth and repair of muscle fibres

5) Finally, an endurance athlete would also need to have a higher fat intake, as when glycogen stores have run out, the body uses fat stores for excess energy

Anabolism

The reaction, requiring energy, of turning smaller compounds into more complex and larger ones, usually organic matter

Aerobic Catabolism

The breaking down of larger, more complex chemical compounds into smaller, more simple compounds with the net release of energy

Anaerobic catabolism

The breaking down of larger, more complex chemical compounds into smaller, more simple compounds with the net release of energy and in the absence of oxygen

Glucose is diffused into the liver or skeletal muscle to be stores as glycogen after a condensation reaction producing water as a byproduct due to the glycosidic reaction where the two excess oxygen molecules bind to the carbon atoms in the new di/oligo/polysaccharide

After eating a meal containing carbohydrates and fat, blood sugar levels will increase.

Therefore, a regulatory hormone called insulin is released which regulates the levels of blood sugar in the body.

Insulin is secreted by the pancreas after the blood sugar levels are detected by the hypothalamus.

Insulin causes an increase in the diffusion of glucose into the liver and skeletal muscle where it is converted to and stored as glycogen after a process called glycogenesis.

This therefore reduces the amount of glucose and the blood and blood sugar levels begin to drop.

Furthermore, insulin also prevents the breakdown of fat into glycogen

Therefore promoting the accumulation of fat in the body after a meal containing carbohydrates and fats.

Once the blood glucose levels have dropped too low, this is again detected by the hypothalamus which signals the pancreas to release a different regulatory hormone called glucagon.

Glucagon increases the rate of glycogenolysis and the glucose is released into the blood again.

Thereby increasing the blood sugar levels again.

Glucagon is a hormone secreted by the pancreas in response to nerve signals from the hypothalamus to increase the blood glucose levels in the blood.

During fasting, blood glucose levels are very low due to a reduced amount of food intake.

Therefore, glucagon is released by the pancreas to increase the rate of glycogenolysis in the liver and skeletal muscle

This increases the blood glucose levels in the blood as more glucose is released into the blood after being broken down from stored glycogen

During exercise, there is a need for an increased blood glucose level in the blood for muscle contraction at a higher intensity

Therefore, adrenaline is released by the adrenal glands to increase rate of glycogenolysis and increase glucose levels in the blood

This means that there is a higher amount of glucose in the blood to travel around the body and supply the working muscles with sufficient energy during exercise

During exercise, there is an increased intensity and stress on the body due to larger amounts of muscle contraction

This means that a larger amount of glucose needs to be circulating in the blood to provide muscles with sufficient energy.

Therefore, insulin levels in the blood decrease to allow for a reduced rate of diffusion of glucose into the liver where it usually would be stored as glycogen.

Meanwhile, glucagon and adrenaline levels increase to allow for a faster rate of glycogenolysis to further increase the glucose levels in the blood as glycogen is broken down back into glucose and released into the blood from the liver and skeletal muscle.

Therefore, there is an increased amount of glucose in the blood allowing for better utilization of energy by the working muscles so that muscle contraction can be prolonged at a higher intensity during exercise.

Explain how ATP can be replenished from ADP+P:

Phosphocreatine is a high energy molecule released to replenish ATP stores in the first 10 seconds of high intensity exercise.

Phosphocreatine is broken down into creatine and a phosphate, this reaction also creates enough energy for the phosphate to bind to the ADP to replenish it to ATP

This allows the new ATP to be used again to provide more muscle contraction and maintain a short burst of high intensity exercise

However, only one ATP molecule can be replenished for every phosphocreatine molecule

This is a good system because it produces rapid regeneration of ATP as phosphocreatine stores can replenish very quickly

This is a bad system because there is only a limited PC supply and the ratio of PC to ATP replenishment is only 1:1

Describe the re-synthesis of ATP using the lactic acid system:

This system uses anaerobic glycolysis for the regeneration of ATP

Glucose is broken down into pyruvic acid by phosphofructokinase

The pyruvic acid is then converted into lactic acid due to the absence of oxygen

The energy generated from the breakdown of glucose into the pyruvic acid is enough to regenerate 2 ATP molecules

This is because the by-product of lactic acid created limits the amount of ATP that can be resynthesized.

This is a good system as it produces an extra boost of energy
There are also few chemical reactions required compared to the aerobic system

This is a bad system because lactic acid denatures enzymes, thereby decreasing the rate of chemical reactions taking place
Also, there are only 2 ATP molecules produced at a time compared to 38 in the aerobic system

How does the aerobic system re-synthesize ATP from ADP:

Pyruvic acid diffuses into the inner matrix of the mitochondria to form acetyl CoA

Acetyl CoA is the entry enzyme for the Krebs cycle - the process of producing energy in all living organisms via aerobic respiration which produces 2 ATP molecules, carbon dioxide and hydrogen

The carbon dioxide is breathed out and the hydrogen is split into ions and electrons

The hydrogen ions and electrons are carried by hydrogen carriers to the electron transport chain

The hydrogen ions are oxidised to form 2 further water molecules while the electron is used as a form of energy to create 34 more ATP molecules

Fats are also broken down into glycerol and 3 fatty acids - these fatty acids are then broken down in the mitochondria to form acetyl CoA

Acetyl CoA is the entry molecule for the Krebs cycle and the process is repeated, approximately forming a further 2 ATP molecules in a similar time

Therefore a total of 38 ATP molecules are produced by the aerobic system

This is a good system because it produces 38 ATP molecules and it can also be steadily maintained due to large glycogen and triglycerol storage

This is a bad system because it contains many complicated chemical reactions and therefore cannot be performed immediately. It is also slow as fatty acid transportation to muscles is slow

Characteristics of the energy systems and their contributions during exercise:

1) Duration:
PC = <10 seconds Lactic = 10< t >3 minutes
Aerobic = 3+ minutes

2) Amount of ATP produced:
PC = 1
Lactic = 2
Aerobic = 38

3) Fuel:
PC = phosphocreatine
Lactic = phosphofructokinase breaks down glucose into pyruvic acid
Aerobic = glucose and triglycerol

4) By-product:
PC = none
Lactic = lactic acid
Aerobic = water and carbon dioxide