Energy Systems (5) & Nervous System (6)

Question 1

What are the 3 key energy nutrients?

Answer 1

Food is broken down into three nutrients during digestion:

1. Protein
2. Fats
3. Carbohydrates

Question 2

Properties of CARBOHYDRATES (3)

Answer 2

1. Yields 4 calories per gram
2. Originates from plants
   → Fruits and vegetables as well as grain in pasta and bread
3. Carbohydrates are broken down into GLUCOSE
   → Stored in the LIVER as GLYCOGEN
   → Glucose can be carried through the body by blood and used as an energy source

Question 3

ATP - Adenosine Triphosphate (4)

Answer 3

1. Before nutrients can be used as energy, they need to be reformed into a universal form of energy that can be used for muscle contraction.
2. This form of energy is called ATP.
3. ATP consists of 3 phosphate molecules attached by a high-energy bonds to a molecule of adenosine.
4. Energy is released when a phosphate is broken from the ATP molecule.
   → Resulting in ADP, a phosphate molecule and energy

Question 4

2 Energy Systems - ANAEROBIC (4)

Answer 4

1. Anaerobic (without oxygen).
2. Occurs quickly in the muscle fibres.
3. Uses chemicals and enzymes that are already present.
4. Short-lived physical action.

Question 5

2 Energy Systems - AEROBIC (3)

Answer 5

1. Occurs in the mitochondria.
2. Leads to complete breakdown of glucose.
3. Fats and proteins are also used.

Question 6

What are the 3 METABOLIC PATHWAYS? (3)

Answer 6

1. ATP-PC (Anaerobic alactic)
2. Glycolysis (Anaerobic lactic)
3. Cellular respiration (Aerobic)

Question 7

Step 1 : ATP-PC (anaerobic alactic) (6)

Answer 7

1. First and simplest pathway
2. Yields enough ATP for about 10-15 seconds.
3. PC = phosphocreatine, a compound that is stored in the muscles and is readily accessible.
   → Phosphate breaks from creatine and is attached to ADP to convert back to ATP.
4. “Alactic” because lactic acid is not produced.
5. Relies solely on readily available phosphocreatine.
6. Does not involve metabolism (breakdown) of glucose.

Question 8

Step 2 : GLYCOLYSIS (anaerobic lactic) (6)

Answer 8

1. First step to complete breakdown of glucose.
2. The amount of ATP produced will allow athlete to perform for an additional 1-3 minutes.
3. Glucose is partially broken down to provide ATP.
4. More complex than ATP-PC because it involved 11 reactions and yields 2x as much ATP.
5. Does not require oxygen.
6. Through a series of reactions, glycolysis transfers energy from glucose and rejoins phosphate to ADP (creates two molecules of ATP)

Question 9

Glycolysis - PYRUVATE & LACTIC ACID (3)

Answer 9

1. Pyruvic acid is the main product of glycolysis.
2. Because there is no oxygen this process stops at the glycolysis stage.
3. Pyruvic acid is then converted into LACTIC ACID
   → Lead to muscle exhaustion
   → With the presence of oxygen, pyruvic acid begins the aerobic system.

Question 10

Step 3 : AEROBIC SYSTEM (cellular respiration) (6)

Answer 10

1. Occurs in the mitochondria therefore referred to as cellular respiration.
2. At this stage, fats and proteins can be used as energy sources
3. Fats are the predominant source of energy in exercise lasting longer than 20 minutes while proteins are used in chronic situations such as starvation.
4. Results in complete breakdown of glucose.
5. Yields highest quantity of ATP (36)
6. Undergoes three subpathways.
   → 1. Glycolysis
   → 2. Krebs cycle
   → 3. Electron transport chain

Question 11

Subpathway : GLYCOLYSIS (3)

Answer 11

1. Same as the anerobic lactic system EXCEPT;
2. In the presence of oxygen, pyruvic acid is converted into ACETYLE COa instead of lactic acid
3. Acetyl Coa then enters krebs cycle

Question 12

Subpathway : KREBS CYCLE (3)

Answer 12

1. After 8 reactions, 2 ATP molecules are produced
2. Also produced are new compounds capable of storing “high energy” electrons.
3. The high energy electrons produced in the krebs cycle are sent to the mitochondria, thus starting the electron transport chain.

Question 13

Subpathway : ELECTRON TRANSPORT CHAIN (3)

Answer 13

1. Final stage of cellular respiration.
2. Large amounts of ATP are produced.
3. Carbon dioxide and water are the only by-product.

Question 14

Introduction to LACTIC ACID (3)

Answer 14

1. Blood lactate threshold = the point where lactate levels in the blood increase suddenly beyond resting values. (aka anaerobic threshold)
2. The intensity of exercise at which lactate begins to accumulate faster than it can be removed.
3. Varies from person to person.
   → Untrained people have a low anaerobic threshold and reach their threshold at 50-60% of their VO2 max.
   → Elite endurance athletes have a high threshold and do not reach their threshold until 70-80% of their VO2 max.

Question 15

HOW and WHY do we need to RAISE OUR LACTIC THRESHOLD? (4)

Answer 15

1. Raising lactic threshold is the main objective in physical training.
2. There are two ways to achieve this:
   → Use ANAEROBIC TRAINING to extend the amount of time before lactate buildup occurs.
   → Use AEROBIC-STYLE (endurance) training to improve cardiorespiratory capacity.
   → This helps increase the concentration of mitochondria + myoglobin in the muscle fibres = improved efficiency of oxygen transfers, .

Question 16

Explain the CORI CYCLE (5)

Answer 16

1. Process where lactic acid is converted to pyruvate
2. Lactate is transported (by blood) to the liver and converted back to glucose.
3. It is then converted into glycogen so that it can be used for energy and stored in the liver.
4. occurs during anaerobic lactic exercises.
5. The opposite of glycolysis.

Question 17

Explain the properties of FATS (3)

Answer 17

1. Contains large quantities of stored energy (more than 2x carbohydrates and proteins)
2. FATTY ACIDS: types of fats found in muscles cells and adipose tissue that can be used for energy (stored in the body as triglycerides)
3. LIPOLYSIS: process where triglycerides are broken down and the resulting fatty acids become available to be used as an energy source.

Question 18

Explain the properties of PROTEINS (8)

Answer 18

1. Unlike carbs and fats, there are no “protein reserves”, it is not readily available.
2. All proteins are part of existing body tissue or actively engaged in the metabolic system.
3. Protein is comprised of ~20 different amino acids which are used to form various body tissues.
4. To be used as an energy source, protein must first be broken down into separate amino acids.
5. The aa alanine is the main contributor
   → It is converted to glycogen in the liver which is then transported as glucose through the bloodstream.
6. As a source of energy, protein plays an important role in endurance-type activities.
7. More generally, it is used in chronic conditions when glycogen stores have been significantly diminished.
8. In the absence of other energy sources, the body breaks down protein as a backup.

Question 19

Properties of SLOW-TWITCH muscle fibers (7)

Answer 19

1. Red/ dark in colour due to the presence of oxygen in the muscle fibers.
2. Generates tension slowly.
3. Relaxes slowly.
4. Able to maintain a lower level of tension for a long duration.
5. Useful in long-distance activities.
6. Low levels of an enzyme called MYOSIN ATPase used to provide instant energy for muscle contraction.
7. Also has low levels of GLYCOLIC ENZYMES which allows the release of glycogen within muscles.

Question 20

What is an ENZYME? (2)

Answer 20

1. An enzyme is a protein that acts as a catalyst for chemical reactions.
2. The enzyme itself is not affected by the chemical reactions.

Question 21

Properties of FAST-TWITCH muscle fibers (6)

Answer 21

1. More pale in colour (lack of oxygen in the muscle fibers).
2. Tense and relaxes quickly.
3. Can generate large amounts of tension for short periods of time.
4. High level of myosin ATPase and glycolytic enzymes.
5. Activate 2-3x faster than slow-twitch fibers.
6. Activities such as short sprints, powerlifting, explosive jumping

Question 22

The importance of MYOGLOBIN (4)

Answer 22

1. The differences between muscle fibre types = the extent to which the muscle relies on oxygen in the production of energy.
2. MYOGLOBIN is a protein that delivers oxygen to working muscles.
3. This allows energy-producing biochemical reactions to be sustained over a long period of time.
4. Using aerobic processes for energy production = ability to sustain activity longer.

Question 23

THREE TYPES of FIBER’S (3), (2), (2)

Answer 23

1 type of slow-twitch
2 types of fast-twitch

Slow-twitch - TYPE 1 or SLOW OXIDATIVE (SO):
→ these muscles generate energy slowly.
→ More fatigue-resistant.
→ Depend on aerobic processes.

Fast-twitch - TYPE IIA or FAST OXIDATIVE GLYCOLYTIC (FOG)
→ Intermediate (in between type I and type IIB).
→ High-speed energy release.

Fast-twitch - TYPE IIB or FAST GLUCOLYTIC (FG)
→ Store a lot of glycogen and high levels of enzymes necessary for quick contractions.
→ Does not require oxygen.

Question 24

The DISTRIBUTION of muscle fiber types (2)

Answer 24

1. A muscle’s fiber makeup determines its functions/ what it does, giving us an indication of what it is made of.
2. Use the term TONIC MUSCLES and PHASIC MUSCLES as a way to describe basic functions.

Question 25

What are TONIC MUSCLES? (2)

Answer 25

1. Assists the body with maintaining posture or stability during walking, standing etc,.
2. High % of type 1 (slow -witch) muscle fibers (i.e soleus)

Question 26

What are PHASIC MUSCLES? (1)

Answer 26

1. Higher % of type IIA and IIB fibers (i.e biceps)

Question 27

How do I find out MY muscle type (2)

Answer 27

1. The only way to find out what percentage of muscle fiber types you have is to have a biopsy performed.
2. Must acquire a tissue sample.
   → Take a small piece of the muscle and place it under a microscope.