energy
food is energy currency of our biological system - CHO
Energy is required for (3)
1.** basal metabolism** (normal processes of growth and maintenance; most of heat production)
2. thermic effect of food (use of dietary fuels)
3. physical activity (EEPA)
how is energy from energy-yielding nutrients “captured”
by ATP and other carriers
What is the main byproduct of energy production? Why? Which specific processes? Explain teh specific process?
HEAT
1. Obligatory essential: from catabolic and anabolic reactions (use/make ATP)
ex: muscle contraction, protein synthesis, RNA synthesis, secretion
2. Regulatory: homeostasis of body temp + maintenance
ex: shivering, uncoupling
- thermogenesis TEF and EEPA
External influences on heat production
- endocrine: T3, T4, insulin, glucagon, catecholamines, growth hormone
- neural: ANS - epinephrine , acetylcholine, norepinephrine
- circulatory: energy supply, waste removal
What is the overall reaction of glycolysis?
Glucose + 6O₂ + 38 ADP + 38 Pᵢ
→ 6 CO₂ + 6H₂O + 38 ATP
What are the products of one cycle of OP for 1 mole of glucose?
12 H₂O + 10 NAD⁺ + 2 FAD + 34 ATP
What are the products of the CAC for 1 mole of glucose
6 CO₂ + 8 NADH + 8 H⁺ + FADH₂ + 2 ATP
Oxidative phosphorylation, rate limiting step
chain of reactions located in inner mitochondrial membrane:
ADP + Pi = ATP
- Rate limiting step: availability of ADP
Concept of uncoupling
- normal ETC → max efficiency of E transfer
- disruption of ETC mid-way can ↓ATP production
- more loss to HEAT… causes ↑O₂ consumption & oxidation of NADH & FADH without ↑ATP synthesis,
ex: caffeine/nicotine/ amphetamines disrupt ATP synthesis ‘uncoupling’
how much energy do you lose in the form of heat?
~80%
(~60% due to biochemical inefficiency of converting duel energy into ATP + ~24% heat loss due to biochemical inefficiency of coupling ATP to work)
energy yields of glucose/palmitic acid/alanine
- glucose = 3.8kcal / g
- palmitic acid = 9.3kcal / g
- alanine = 3.5kcal / g
what are the major functions of the GI tract (3)
- digest complex molecules
- absorb nutrients
- barrier to entry of bacteria
what are the anti bacterial and digestive components of saliva? (4)
anti-bacterial: thiocyanate, lactoferrin, lysozyme
digestive: amylase
glands in stomach secrete gastric juice containing… why is it so acidic?
- water, electrolytes, enzymes
- activates zymogens, denatures proteins (exposes areas on macronutrients), kills bacteria
role of small intestine
- bulk absorption; movement of solutes, water, nutrients
maximized surface area for greater absorption
