Energy Sources and Pathways

Energy Systems

one pathway (cellular respiration)

- involves many enzymes and several
complex sub-pathways

- leads to the complete breakdown of
glucose

-Requires oxygen

- can occur in two separate metabolic pathways

one not involving the breakdown of glucose (ATP-PC)

one involving partial breakdown of glucose (Glycolysis)

- occurs without the use of oxygen

Myoglobin

- oxygen-binding protein located primarily in muscles

- fast twitch muscle fibres are low in myoglobin

- slow twitch muscles fibres are high in myoglobin

- delivers oxygen to working muscles when they need it

- acts as a storage unit for oxygen

Energy Sources

Creatine Phosphate

used as an energy source for
anaerobic alactic system

provides quick, short
lasting energy

Glucose

used as an energy source for
the anaerobic lactic system

provides energy quickly

broken down into pyruvate, which
is converted to lactate

Carbs, Fats
and Protein

used as an energy system for
the aerobic lactic system

provides energy for long periods
of time

they are broken down to produce
ATP during exercise

Nutrients

3 Key Nutrients

- Protein

- carbohydrates

- most important source of energy

- one of the most abundant natural
substances in nature

- essential for human life

provide materials to build cell membranes

- provide energy use for cells

- fats

- chemical substances obtained from food

- supply energy

- regulate cellular acyivity

- build and repair tissues

Muscle Fibre Types

Slow Twitch Muscle Fibers:

- ideal for long distance activities

- red or dark in colour

- generate and relax tension

- able to maintain a lower level
of tension for long durations

Fast Twitch Muscle Fibres:

Type 2A Fibres:

- muscle fibres are intermediate
type muscle fibres

- allow for high-speed energy release

Type2B Fibres

- stores lots of oxygen and high level of enzymes
necessary for quick contractions

- does not require oxygen

- more pale in colour

- have ability to relax and tense quickly

- can generate large amounts of tension
with relatively low endurance levels

- ideal for short lasting activities