Introduction to metabolism Flashcards
What is the energy currency?
ATP
Where is energy stored?
Phosphoanhydride bonds
What 3 systems regenerate ATP?
- PCr
- Glycolysis
- Oxidative phosphorylation
How much ATP can be regenerated during glycolysis? - both glucose and glycogen source
Glucose - 2 ATP
Glycogen - 3 ATP
Why does glycogen produce more ATP in glycolysis?
Less ATP is needed to be reinvested, therefore gain of 3 ATP
How much ATP is regenerated during oxidative phosphorylation? - both CHO and fat
CHO - 36 ATP
Fat - 130 ATP
What is the trade-off concerning ATP regeneration?
Power-capacity trade-off
Why must ATP be regenerated?
To maintain level of contractile activity
What system is predominant in exercise?
Relative contribution - depending on the exercise intensity and duration
What are the 3 sources of fuel?
- CHO
- fat
- protein - not majorly
What is the preferred fuel source during prolonged, low intensity exercise?
Fat - most abundant, even in lean athletes
What happens to the fuel source as exercise intensity increases?
Become less reliant on fat and turn to circulating glucose and glycogen stores
What happens to the fuel sources and their contribution as duration of exercise increases?
CHO depletes
Muscle TG depletes
But, plasma fat increases
Name 3 functions of nutrients on a whole.
- Energy provision
- Promote growth and development
- Regulate metabolism
Name the macronutrients.
- CHO
- Fat
- Protein
- Water
Name the micronutrients
- Vitamins
- Minerals
- Trace elements
Functions of CHO
- Energy source
- Health benefits - fibre
Approximately what % does CHO contribute to energy intake?
60%
Is CHO considered an essential or non-essential nutrient? And why?
Non-essential - glucose can be produced via gluconeogenesis
Name 3 sources of CHO
- Sugars
- Starches
- Fibre
Name the 3 types of CHO
- Monosaccharides
- Disaccharides
- Polysaccharides
What are the functions of fat? (5)
- Energy source
- Protection of vital organs
- Cell membrane formation
- Precursor of bile, hormones and steroids
- Fat soluble vitamin intake
Approximately what % does fat contribute to energy intake?
30%
What is the most abundant fat? And what is the difference between saturated and unsaturated fat?
Triglycerides (TG)
Saturated - no double bond
Unsaturated - double bond
Functions of protein
- Provide cell structure
- AA have metabolic roles
- AA are precursors for protein synthesis, neurotransmitters, DNA and RNA
Approximately what % does protein contribute to energy intake?
10%
What is the difference between essential and non-essential AA?
Essential - must be consumed within diet
Non-essential - ability to be produced by the body
What makes a complete protein?
Containing all 9 AA
Name a method that assesses protein quality? And how?
PDCAA - rating out of 1
Approximately how much water makes up the adult body?
60%
2/3 intracellular
1/3 extracellular
Name the functions of water
- Nutrient transport
- Protection
- Temp regulation
- Biochemical reactions
- Medium for reactions
Name 3 types of ways to assess dietary intake
- Diet record
- 24hr recall
- Food frequency questionnaire
What are the main problems with dietary self-assessment?
- Compliance
- Bias in memory/reporting
- Altered behaviour
- Underestimating
What is the preferred method to assess dietary intake?
Regular monitoring of weight and body composition
