Kinesiology: Physiology - Metabolism and Energy

energy

ability to do work

1st law of thermodynamics

energy can’t be created or destroyed only converted from a form to another

• all energy on earth ultimately comes from the sun

macronutrient - carbohydrate

• all carbs come from plant sources

• can be simple or complex

  • simple: sugar and startch

  • complex

    • fibre and whole grain

• 4.3 kcal/g

• sources: legumes, grains, sugars, stems & roots

macronutrient - carbohydrate: sugar

• glucose

• fructose

• sucrose

• maltose

macronutrient - carbohydrate; startch

long chains of glucose formed for storage

macronutrient - carbohydrate; glocogen

animal form of startch

macronutrient - carbohydrate; fibre

undigestible part of plant

macronutrient - lipids

long chains attached to glycerol

• mono, di, and triglycerides

• insulates

• protects

• membrane - controls what enters and exists

• 9.3 kcal/g

• processed in liver

• sources: meat, diary, coconut, nuts, avocado, legumes, fish, olives, seeds

macronutrient - lipids; glycerol

fatty acid chains

macronutrient - protein

key component made up of long chains of amino acids

• 20 diff amino acids

  • 8 are essential

• sources; meat, eggs, legumes

• uses:

  • everything

  • muscle

• 11kcal/g

• amino part of an amino acid is sent to the liver where it’s deaminated (urinated)

ATP

adenosine triphosphate

• generated by cells through various processes most involving the metabolism of macronutrients

• ATP → ADP + Pi + E

ADP

adenosine diphosphate

• comes from ATP and when it turns to ADP, lots of energy is released

Cellular respiration

Biochemical process which cell breaks down GLUCOSE into its components & uses energy released to form ATP

Glycolysis

Occurs in the cytoplasm & is anarobic

• series of biochemical reactions (10) that turn 1 molecule of glucose (6c) into 2 molecules of pyruvic acid

• 1st & 3rd steps involve the consumption of atp where it phosphorylates the glucose molecules

• Following 7 steps, 4 new atp molecules are formed

Process is anaerobic but most times sufficient O2 is present

• pyruvate proceeds to next stage → Kreb’s cycle where pryruvate becomes lactic acid

• In short bursts (1-2mins) with rest between lactic acid is removed from muscle & brought into liver & safely metabolized but if anabolic activity persists, the lactic acid builds up in muscles stopping function

Kreb’s Cycle

Aerobic process that occurs in the mitochondrial matrix

• pyruvate is decarboxylated forming acetyl-CoA (2-C molecule)

• Acetyl-CoA joins with oxaloacetic acid (4C) to make citric acid (6C)

• Oxaloacetic acid is reformed to start cycle again

Cycle happens twice since there is 2 pyruvate

2 NADH + 2ATP (glycolysis)

8NDH + 2 ATP + 2FADH2 (krebs)

---

10 NADH + 4ATP + 2FADH2

Electron Transport Chain

Aerobic process directly involving O2 that occurs in the inner mitochondrial membrane

• embedded in membrane are a series of biomolecules

• NADH & FADH2 are passed along a sequence of membrane molecules & @ certain spots the H+ ions are passed through the membrane and form water

• Protons fuel phosphorylation of ADP

• For every NADH, 3 ATP forms

• Every FADH2, 2 ATP forms

10NADH + 2 FAH2 + 4ATP

X3 atp. X2atp. 4atp

---

38 ATP

Metabolism of lipids - glycerol

Metabolism of lipids - fatty acid

Metabolism of Proteins

Energy systems during exercise - cellular respiration

Full aerobic breakdown of glucose to form max amount of ATP

• main source of energy in endurance activities (3 mins+)

Energy systems during exercise - anaerobic glycolysis

Glycolysis as previously discussed but in a low O2 environment

• causes lactic acid to build up ( 30s - 3 min activity)

Energy systems during exercise - ATP PC system

Anaerobic where phosphocreatin can phosphorylation small amounts of ADP into ATP

• 1-15 seconds

Alactic

No breakdown of glucose so no lactate is produced

Phosphocreatin

Chemical that’s readily available in muscle cells

Muscle fibres types and energy - slow twitch

Contract and relax slowly but can maintain low tension for long periods of time

• dark red - high blood supply

• Contains lower levels of enzymes that break down glycogen into glucose

  • Suited for long distance

Muscle fibre types & energy - fast twitch

Contracts and relaxes quickly & generates high tension for only short periods

• pale - less blood supply

• High enzyme muscles

Myoglobin

Protein that stores & delivers oxygen to working muscles

• slow twitch muscles have a lot of myoglobin

• Fast twitch muscles have less myoglobin