PHSL-P 215
13-1 Course notes – Fall 2023
Nutrition and Metabolism
OBJECTIVES
• Identify the major macronutrients used by the body, and for what purposes each are used.
• Understand the role of micronutrients in metabolism.
• Define metabolism and distinguish catabolic from anabolic reactions.
• Describe what happens in the following types of reactions: hydrolysis, dehydrations synthesis/condensation,
phosphorylations, dephosphorylatsion, oxidation, reduction
• Describe the role of ATP in energy metabolism.
WATCH
https://www.youtube.com/watch?v=fR3NxCR9z2U
READ
•
I.
Principles of Human Physiology- Stanfield
o Chapter 3 Cell Metabolism Sections 3.7; Review 3.1, 3.4
o Chapter 21 Regulation of Energy Metabolism & Growth Sections 21.2, 21.3, 21.4
Nutrition
a. Food intake
i. Calorie (kcal) - amount of heat required to raise one liter of water by one degree centigrade.
Measures the capacity to do work.
ii. Calories vary by composition of food, which provides the energy to do work
1. Carbohydrates and Protein: 4 kcal/g
2. Fats: 9 kcal/g
iii. Macronutrients: carbohydrates, proteins, fats (lipids)
iv. Micronutrients: ___________________________
v. Essential Nutrients: can not be synthesized by the body; ________________________
b. Macronutrients: Carbohydrates have chemical formula CnH2nOn
i. Stored in muscle, liver, and blood
ii. Starch is the healthiest carbohydrate because starchy foods also contain other nutrients.
iii. Sucrose and corn syrup provide energy but no other nutrients
(empty calories) - excess sugars will be stored as fat.
iv. Dietary fiber
1. Water soluble: oats, beans, peas, carrots, brown rice, fruits
reduces blood cholesterol and LDL’s.
2. Water insoluble fiber: ________________, hemicellulose, lignin
stimulates peristalsis in the intestines.
c. Macronutrients: Lipids - contain mostly C-H (non-polar)
i. 15-25% body fat by weight is considered healthy
ii. Most of the body’s stored energy
iii. 80-90% of resting energy needs
iv. Glucose-sparing and protein-sparing effect:
v. Helps absorb & transports fat soluble vitamins
vi. Cell membranes
vii. Cholesterol → forms steroid hormones
viii. Protection of internal organs and insulation
ix. Should be no more than 30% of daily intake of calories
x. Forms of lipids transported in blood: chylomicron, VLDL, LDL, HDL
1. High levels of _____________ in blood contribute to atherosclerosis.
PHSL-P 215
13-1 Course notes – Fall 2023
Nutrition and Metabolism
d. Macronutrients: Proteins
i. 12-15% of body mass
ii. Muscle, cilia, flagella, membranes, enzymes
iii. Can be fibrous or globular
iv. Buffers in the blood
v. Osmotic balance in the blood
vi. Complete protein vs. Incomplete protein (essential amino acids)
vii. Sources: meat, eggs, mixed vegetables (and grains)
e. Micronutrients: Vitamins
i. Generally _________________ (only a few can be made by the body)
ii. Required in small (mg to gram) quantities per day.
iii. Mostly involved with enzyme-catalyzed reactions (co-enzymes). They assist in transfer of
electrons from one molecule to another. For example, Vitamin C is essential for the
production of collagen, and Vitamin B12 is essential for DNA replication.
iv. Vitamins A,D,E, and K are fat-soluble
f. Micronutrients: Minerals
i. Bones (Ca), teeth (Ca), action potentials (Na and K), hemoglobin (Fe), muscle function (Ca),
phosphate for nucleotides
ii. Required in small (mg to gram) quantities per day.
iii. Most Americans consume four times the Recommended Daily Allowance of sodium. Can
Contribute to hypertension (high blood pressure)
g. Micronutrients serve as ___________________ for many Enzyme-catalyzed reactions
i. Without the cofactor, the reaction can’t take place at a sustainable rate
h. Our body requires energy to fuel everyday processes, like keeping our organs functioning.
i. Metabolic Rate describes our body’s energy needs
i. Metabolic rate - The amount of energy used by the body per hour (or per day).
ii. _________metabolic rate – minimum amount of energy needed to sustain life (organ function)
1. Factors Influencing Basal Metabolic Rate
a. Age
b. Sex
c. Body Surface Area (dependent on height and weight)
d. Hormones
e. Genetics
f. Drugs
PHSL-P 215
13-1 Course notes – Fall 2023
j.
II.
Nutrition and Metabolism
iii. Total metabolic rate - amount of energy needed to sustain organs + complete daily activities
iv. With regular cardiovascular exercise you can increase your resting metabolic rate because you
build more lean muscle tissue - Can be 10* BMR
Calorimetry is used to measure Metabolic Rate
Metabolism = the sum of all _________________________ in body
a. Anabolism – Synthesis
i. Generally, dehydration synthesis (condensation) reactions
ii. Ex. Gluconeogenesis – Formation of New Glucose from non-carbohydrates
iii. Ex. Glycogenesis – synthesis of glycogen from glucose
iv. Ex. Protein Biosynthesis, Fatty Acid Synthesis (lipogenesis)
b. Catabolism – Breakdown
i. Generally, hydrolysis reactions
ii. Ex. ______________ – splitting of glucose into 2 pyruvates
iii. Ex. Glycogenolysis – hydrolysis of glycogen to glucose
iv. Ex. Lipolysis, Proteolysis, Glycolysis
Fig. 2.1
III.
Energy Storage and Utilization: Metabolism of Carbohydrates, Fats, and
Proteins
A. ATP
a. Energy release from food serves to phosphorylate ADP to ATP
b. ATP available in cells is the immediate energy source.
c. ATP produced by Anaerobic metabolism----Short term source.
d. ATP produced by Aerobic Metabolism-----Long term source.
B. Catabolic pathways – transfer high energy electrons
a. Energy in complex molecules is carried by the electrons. Some
reactions in catabolic pathways function to strip the electrons from complex molecules
and transfer the electrons to carrier molecules such as NAD+ and FAD+.
b. The NADH now carries the high energy electrons that used to be on pyruvate.
c. We say that NAD+ is __________________ to NADH when it gains electrons.
C. Phosphorylation and dephosphorylation
a. A + Pi → A—P
D. Oxidation—reduction reactions
a. C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy
E. During aerobic exercise, the reactions involved in energy metabolism in the working skeletal
muscles would be classified, in general, as what kinds of reactions?
F. What are some signs that energy is being released from the chemical reactions involved in
exercise?