Biology Chapter: Metabolism and Nutrition

Micronutrients

• Vitamins and minerals
• Obtained only from diet

Macronutrients

• Carbohydrates (monosaccharides)
• Lipids (glycerol/fatty acids)
• Proteins (amino acids)

Glycolysis

• Glucose broken down into 2 pyruvate

Citric Acid Cycle

• Each pyruvate converted into 1 Acetyl CoA

Cellular Respiration Waste Products

• Carbon dioxide (CO2)
• Water (H2O)

Beta-oxidation of Fatty Acids

• Fatty acids broken down in mitochondria
• Acetyl-CoA enters citric acid cycle for energy production

Metabolic Acidosis

• Too much acid or too little bicarbonate in the blood
• Body secretes H+, reabsorbs bicarbonate

Metabolic Alkalosis

• Too little acid or too much bicarbonate in the blood
• Body secretes bicarbonate, and reabsorbs H+ ions

Low Blood Sugar

• Glucagon signals the liver to release stored glucose (glycogenolysis) and produce new glucose (gluconeogenesis)

High Blood Sugar

• Insulin helps cells absorb glucose for energy storage, lowering blood sugar levels

Byproducts of Glucose Metabolism

• Lactic acid

Byproducts of Amino Acid Metabolism

• Urea
• Filtered through kidneys

Cholesterol

• Fatty substance in the body
• Aids in cell building and hormone production
• High levels can cause health problems like heart disease
• Produced in the liver
• Cholesterol component of steroid hormones, bile salts, and vitamin D

Absorptive/Fed State

• 4 hours
• Insulin is the dominant hormone
• Hyperglycemic state
• Stores excess glucose for later use

Post Absorptive State

• 6-12 hours
• Glucagon is the dominant hormone
• Hypoglycemic state

Insulin

• Produced by beta cells of the pancreas
• Lowers blood sugar levels

Glucagon

• Produced by alpha cells of the pancreas
• Raises blood sugar levels

Thyroxine

• Produced by the thyroid
• T3 and T4 regulate metabolism, energy, production, and growth

Catabolism

• Breaking down complex molecules into smaller units

Metabolism

• Sum of all chemical reactions in a cell (catabolism + anabolism)

Basal Metabolic Rate

• Amount of energy body uses for basic functions at rest

Metabolic Rate

• Amount of energy used in a given period (often a day)

Spermatogenesis

• Process of sperm production
• 4 sperm cells produced from each primary spermatocyte

Spermiogenesis

• Final stage of spermatogenesis
• Changes in immature sperm cells to form mature, motile sperm
• 4 sperm produced from each primary spermatocyte

Oogenesis

• Process of egg (ova) production in females
• 1 egg produced from each primary oocyte

Progesterone

• Prepares body for pregnancy
• Regulates menstrual cycle

Estrogen

• Regulates menstrual cycle
• Promotes female sexual characteristics
• Crucial for pregnancy and bone health

Testosterone

• Influences male sexual characteristics, libido, and sperm production
• High initial levels signify puberty
• Promotes muscle, growth, strength, and recovery

FSH

• Helps ovaries prepare eggs for ovulation
• Stimulates follicle development to produce estrogen

LH

• Triggers ovulation in ovaries
• Stimulates testosterone production in testes

Ovarian Cycle

• Follicular phase, ovulation, luteal phase

Menstrual Cycle

• Proliferative phase, secretory phase (if pregnancy), and ischemic phase (if no pregnancy)

EXTRA CREDIT

• Tachycardia: abnormally fast heart rate
• Bradycardia: abnormally slow heart rate
• Ventricular fibrillation: disorganized rapid electrical activity in ventricles
• Heart sounds (Lub-dub): closing of heart valves (S1 and S2)
• P wave: atrial depolarization

Test your knowledge on key concepts related to metabolism, including the roles of macronutrients and micronutrients, glycolysis, and cellular respiration. This quiz also covers the physiological responses to low and high blood sugar levels and the mechanisms of metabolic acidosis and alkalosis.