Digestion

Question 1

energy

Answer 1

food is energy currency of our biological system - CHO

Question 2

Energy is required for (3)

Answer 2

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)

Question 3

how is energy from energy-yielding nutrients “captured”

Answer 3

by ATP and other carriers

Question 4

What is the main byproduct of energy production? Why? Which specific processes? Explain teh specific process?

Answer 4

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

Question 5

External influences on heat production

Answer 5

• endocrine: T3, T4, insulin, glucagon, catecholamines, growth hormone
• neural: ANS - epinephrine , acetylcholine, norepinephrine
• circulatory: energy supply, waste removal

Question 6

What is the overall reaction of glycolysis?

Answer 6

Glucose + 6O₂ + 38 ADP + 38 Pᵢ
→ 6 CO₂ + 6H₂O + 38 ATP

Question 7

What are the products of one cycle of OP for 1 mole of glucose?

Answer 7

12 H₂O + 10 NAD⁺ + 2 FAD + 34 ATP

Question 8

What are the products of the CAC for 1 mole of glucose

Answer 8

6 CO₂ + 8 NADH + 8 H⁺ + FADH₂ + 2 ATP

Question 9

Oxidative phosphorylation, rate limiting step

Answer 9

chain of reactions located in inner mitochondrial membrane:
ADP + Pi = ATP

• Rate limiting step: availability of ADP

Question 10

Concept of uncoupling

Answer 10

• 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’

Question 11

how much energy do you lose in the form of heat?

Answer 11

~80%
(~60% due to biochemical inefficiency of converting duel energy into ATP + ~24% heat loss due to biochemical inefficiency of coupling ATP to work)

Question 12

energy yields of glucose/palmitic acid/alanine

Answer 12

• glucose = 3.8kcal / g
• palmitic acid = 9.3kcal / g
• alanine = 3.5kcal / g

Question 13

what are the major functions of the GI tract (3)

Answer 13

1. digest complex molecules
2. absorb nutrients
3. barrier to entry of bacteria

Question 14

what are the anti bacterial and digestive components of saliva? (4)

Answer 14

anti-bacterial: thiocyanate, lactoferrin, lysozyme

digestive: amylase

Question 15

glands in stomach secrete gastric juice containing… why is it so acidic?

Answer 15

• water, electrolytes, enzymes
• activates zymogens, denatures proteins (exposes areas on macronutrients), kills bacteria

Question 16

role of small intestine

Answer 16

• bulk absorption; movement of solutes, water, nutrients
  maximized surface area for greater absorption