Topic 3: Energy systems

Question 1

List the macronutrients

Answer 1

Carbohydrates, Proteins, Lipids (fats), Water

Question 2

List the micronutrients

Answer 2

Vitamins, minerals

Question 3

Outline the function of macronutrients

Answer 3

Carbohydrates: Fuel, energy storage, cell membrane, DNA, RNA

Lipids (Fats): Fuel, energy storage, cell membrane, hormones, precursor of bile acid

Protein: Structure, transport, communication, enzymes, protection, fuel

Water: Medium for biochemical reactions, transport, excretion

Question 4

Outline the functions of microunits

Answer 4

Vitamins: Energy release from macro units, metabolism, bone health, blood health, eyesight

Minerals and trace elements: Minerlizations of bones and teeth, blood oxygen transport, defense against free radicals, muscle function

Question 5

State the chemical composition of a glucose molecule.

Answer 5

The molecular formula of glucose is C6H12O6 (1:2:1 ratio)

Question 6

Identify a diagram representing the basic structure of a glucose molecule

Answer 6

Question 7

Explain how glucose molecules can combine to form disaccharides and polysaccharides.

Answer 7

Condensation reaction

Condensation reaction: The linking of a monosaccharide to another monosaccharide, disaccharide, or polysaccharide by the removal of a water molecule.

Question 8

State the composition of a molecule of triacylglycerol.

Answer 8

Triglycerides are made up of a glycerol molecule and 3 fatty acid chains.

Question 9

Saturated fats

Answer 9

Saturated fatty acids have no double bonds between the individual carbon atoms of the fatty acid chain.

Saturated fats originate from animal sources, for example meat, poultry, full-fat dairy products and tropical oils, such as palm and coconut oils.

Question 10

unsaturated fats

Answer 10

Unsaturated fatty acids contain one or more double bonds between carbon atoms within the fatty acid chain.

Unsaturated fats originate from plant-based foods for example olive oil, olives, avocado, peanuts, cashew nuts, canola oil and seeds, sunflower oil and rapeseed.

Question 11

State the chemical composition of a protein molecule

Answer 11

Formed by amino acids

Linked in chains through peptide bonds

The body breaks down food into amino acids and then makes its own protein.

Question 12

Distinguish between an essential and a non-essential amino acid.

Answer 12

Essential amino acids cannot be synthesized by the human body and must be obtained from diet.

Non-essential amino acids can be synthesized by the human body.

Question 13

State the approximate energy content per 100 g of carbohydrate, lipid and protein.

Answer 13

Joule = a single unit of energy 1000J = 1kJ

1720kj = 100g protein

1760kj = 100g carbohydrate

4000kj = 100g fat

Question 14

outline metabolism

Answer 14

Metabolism: All the biochemical reactions that occur within an organism, including anabolic and catabolic reactions.

Question 15

outline anabolism

Answer 15

Energy requiring reactions whereby small molecules are built up into larger ones.

Question 16

outline catabolism

Answer 16

Chemical reactions that break down complex organic compounds into simpler ones, with the net release of energy.

Question 17

outline anaerobic catabolism

Answer 17

Anaerobic catabolism: Compounds breaking down in the absence of oxygen

Question 18

State the major sites of triglyceride storage.

Answer 18

Most fats are stored in the body as Triglycerides or Triacylglycerol in the adipose tissue and skeletal muscle

Question 19

Explain the role of insulin in the formation of glycogen and the accumulation of body fat.

Answer 19

Not only does insulin tell the body to store excess glucose as glycogen, but it also stimulates lipogenesis or the formation and storage of Triglycerides. This occurs by;

1) The uptake of fatty acids by fat cells, which are converted to triglycerides. Triglycerides are then stored for future use in the adipose tissue as body fat.
2) The conversion of excess glucose into triglycerides, which are also then stored in the adipose tissue as body fat

Question 20

Outline glycogenolysis

Answer 20

When the body needs more glucose than it has from the diet, it breaks down the glycogen stores in the liver and muscle, back into to glucose.

Question 21

Outline lipolysis.

Answer 21

Triglycerides are released into the bloodstream and broken down into fatty acids and glycerol

Question 22

Outline the functions of glucagon and adrenaline during fasting and exercise.

Answer 22

Exercise or prolonged time with no food, blood glucose drop detected by pancreas, glucagon released by α-cells of pancreas, stimulates glycogenolysis, increased blood glucose levels and use.

Adrenaline: Also increases with low glucose levels and also promotes glycogenolysis and lipolysis

Question 23

Annotate a diagram of the ultrastructure of a generalized animal cell.

Answer 23

golgi bodies = Golgi apparatus (animal cells have no cell wall or chloroplasts)

Question 24

Annotate a diagram of the ultrastructure of a mitochondrion

Answer 24

Question 25

Define the term cell respiration

Answer 25

Cell respiration is the controlled release of energy in the form of ATP from organic compounds in cells.

Question 26

Explain the role of ATP in muscle contraction.

Answer 26

ADP is transformed into ATP by myosin at the myosin head, this allows the pull of the sarcomere. ATP is the energy needed for a muscle contraction to occur.

Question 27

Explain how adenosine can gain and lose a phosphate molecule.

Answer 27

Phosphate groups are very energy-rich

Gain: When a phosphate molecule is added back through energy ADP can be made

Loose: ATP is combined with water it loses a phosphate molecule which results in ADP

Question 28

Describe the re-synthesis of ATP by the ATP–CP system

Answer 28

Creatine phosphate (a high energy molecule) is broken down to provide a phosphate molecule for the re-synthesis of ATP that has been utilized during the initial stages of exercise.

Question 29

Describe the production of ATP by the lactic acid system

Answer 29

Also known as anaerobic glycolysis—the breakdown of glucose to pyruvate without the use of oxygen. Pyruvate is then converted into lactic acid, which limits the amount of ATP produced (2 ATP molecules)

Question 30

Explain the phenomena of oxygen debt

Answer 30

Oxygen debt is now known as excess postexercise oxygen consumption (EPOC).

Oxygen debt is defined as the extra volume of oxygen that is needed to restore all the energetic systems to their normal state after exercise.

Question 31

Explain the phenomena of oxygen deficit

Answer 31

Oxygen deficit is when the need of oxygen and oxygen supply do not match in the first moments of exercise

Question 32

Describe the production of ATP from glucose and fatty acids by the aerobic system

Answer 32

in the presence of oxygen pyruvate is processed by the Krebs cycle which liberates electrons that are passed through the electron transport chain producing energy (ATP).

Fats are also broken down by beta oxidation that liberates a greater number of electrons thus more ATP. In the presence of oxygen and in extreme cases protein is also utilized.

Question 33

Discuss the characteristics of the three energy systems and their relative contributions during exercise

Answer 33

As exercise intensity increases, so too does the requirement for ATP. At higher intensity exercise, ATP requirements immediate and in a large amount. At lower intensity exercise, ATP requirement is more slow and constant

Question 34

Evaluate the relative contributions of the three energy systems during different types of exercise.

Answer 34

Depending on the sport different energy systems will be used e.g. rugby is endurance based (aerobic) however also has quick energy needed for a tackle (creatine phosphate)