ATP: a highly compound composed of purine (adenosine), a sugar (ribose), and three phosphate groups
with high energy bonds
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Released during the breakdown of glucose, fatty acids, and amino acids
Phosphate group’s negative charge allows for hydrolysis
Is a coupled reaction aka anabolic + catabolic
o 50% efficiency, rest lost as heat
Energy is released when high-energy phosphate bond is broken
With loss of phosphate group high-energy ATP becomes low-energy ADP
Energy is required when a phosphate group is attached to ADP making ATP
ADP needs energy from breakdown of carbs, fat, and protein to make ATP
Metabolism: sum of the total of all the chemical reactions that go on in living cells (how the body uses
food to meet its needs)
Energy Metabolism: includes all the reactions by which the body obtains and expends the energy (how
body obtains and uses energy from food)
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Liver cells most metabolically active
Plant cells use photosynthesis
Anabolism: reaction in which small molecules are put together to build larger ones
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Building body compounds (requires energy) aka condensation
Catabolism: reactions in which large molecules are broken down to smaller ones
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Breaking down body compounds (releases energy) aka hydrolysis
Anaerobic: not requiring oxygen, quick energy needs (ex. pyruvate to lactate) (ex. weightlifting)
Aerobic: requires energy, slower energy needs (ex. pyruvate to acetyl CoA) (ex. running marathon)
Glycolysis: the metabolic breakdown of glucose to pyruvate (does not require oxygen aka anabolic)
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2 pyruvate molecules yielded
Hydrogen atoms released by electron transport chain by coenzymes made by B vitamin Niacin
*Pyruvate can be converted back to glucose (ex. liver cells, some kidney cells)
Lactate: a 3-carbon compound produced from pyruvate during anabolic metabolism
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When pyruvate accepts hydrogens it converts to lactate when mitochondrial lack or oxygen
absence (anaerobic)
Occurs limited at rest and Produces ATP quickly
Lactate accumulates in muscles (burning feeling then fatigued)
Cori cycle: pathway in which glucose is metabolized to lactate (anaerobic glycolysis) in the muscles
lactate is converted back to glucose in the liver and glucose is returned to muscle
Gluconeogenesis: making of glucose from noncarbohydrate source such as amino acids or glycerol
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Liver major site but kidneys become involved during starvation
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To obtain amino acids protein tissue must be broken down, muscle and liver tissue break down
during fasting
Any amino acids not used become energy source for body cells
Deamination: before entering the metabolic pathway amino acids lose their nitrogen containing amino
group and are cleared from body via urea synthesis in liver and excretion kidneys
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Amino acids then entered into energy pathways in several ways (pyruvate, acetyl CoA, or eneter
TCA cycle directly)
If entered to make pyruvate generates glucose (gluconeogenesis)
If entered to make acetyl CoA generates additional energy or body fat
If entered directly can continue in cycle and generate energy or alt. glucose (gluconeogenesis)
*protein is a good source of glucose when carb not available
(gluconeogenesis) amino acid to glucose
Oxaloacetate: a carbohydrate intermediate of the TCA cycle
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Used in the final steps of energy metabolism, made from pyruvate not made from fat
When insufficient it slows TCA cycle and cells face energy crisis
Must be available for acetyl CoA to enter TCA cycle, from carbohydrates in diet (because glucose
produces pyruvate during glycolysis)
(each turn of TCA cycle releases 8 electrons)
Mitochondria: cellular organelles responsible for producing ATP aerobically, made of membranes with
enzymes mounted on them
Satiety: feeling of fullness and satisfaction that occurs after a meal and inhibits eating until the next
meal (determines how much time passes between meals) signal to not start eating again
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High-fiber foods, high-fat foods are strong satiety signals
Satiation: the feeling of satisfaction and fullness that occurs during a meal and habits eating (determines
how much food is consumed during a meal) signal to stop eating
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Protein is most satiating
BMI: measure of a person’s weight relative to height; determined by dividing the weight (in kg) by the
square of the height (in meters)
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Underweight is less than 18.5
Overweight is greater than healthy range of 25-29.9
Obese is 30 or more
*1 POUND OF FAT = 3500 CALORIES
Central obesity: excess fat around the trunk of the body also called abdominal fat or upper-body fat
(apple shape, visceral fat)
Waist circumference: anthropometric measurement used to assess a person’s abdominal fat
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Indicator of fat distribution and central obesity
Other body composition measurements:
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Waist to hip ratio
Total body water
Radioactive potassium count
Near-infrared spectrophotometry
Ultrasound
Computed tomography
Magnetic resonance imaging
*If excess fat in diet then glycerol and fatty acids (if sedentary) store in adipose tissue