Vitamins and Minerals in Human Body

Glycolysis

• Glycolysis is a catabolic reaction that converts glucose into two molecules of pyruvic acid.
• It is an anaerobic process that occurs in the cytoplasm.
• Final products of glycolysis are 2 pyruvic acid, 2 NADH + H+, and a net gain of 2 ATP.
• If O2 is not readily available, pyruvic acid is converted to lactic acid.
• If O2 is available, pyruvic acid enters the aerobic pathways.

Krebs Cycle

• The Krebs cycle occurs in the mitochondrial matrix and does not directly use O2.
• It utilizes the 2 pyruvic acids from glycolysis.
• Products from each pyruvic acid are 3 NADH + H+, 1 FADH2, 2 CO2, and 1 ATP.

Electron Transport Chain and Oxidative Phosphorylation

• This process occurs on the inner mitochondrial membrane and directly uses oxygen.
• It utilizes the hydrogen atoms from NADH + H+ and FADH2 from glycolysis and Krebs cycle.
• Products of oxidative phosphorylation are about 28 ATP.

Cellular Respiration

• Cellular respiration is the process of generating energy from the food we eat.
• It involves the breakdown of glucose and other nutrients to produce ATP.

Glycogenesis and Glycogenolysis

• Glycogenesis is the formation of glycogen when glucose supplies exceed the need for ATP synthesis.
• Glycogenolysis is the breakdown of glycogen to release glucose in response to low blood glucose.

Lipid Metabolism

• Lipogenesis is the formation of triglycerides (fat) when ATP and glucose levels are high.
• Lipolysis is the breakdown of triglycerides into glycerol and fatty acids.
• Triglycerides are routinely oxidized for energy (ATP).
• Beta oxidation is the breakdown of fatty acids to produce ATP in the mitochondria.

Protein Metabolism

• When dietary protein is in excess, amino acids are oxidized for energy or converted into fat for storage.
• There are three interconvertible pools of nutrients: amino acids, carbohydrates, and fats.

Lipoproteins

• There are four types of lipoproteins: HDLs, LDLs, VLDLs, and chylomicrons.
• HDLs have the highest protein content and are thought to protect against heart attack.
• LDLs are cholesterol-rich and high levels increase the risk of heart attack.

Plasma Cholesterol Levels

• Saturated fatty acids are solid fats that stimulate liver synthesis of cholesterol and inhibit cholesterol excretion.
• Unsaturated fatty acids are liquid fats that enhance cholesterol excretion.
• Trans fats are found in processed foods and are more harmful to the heart and blood vessels than saturated fats.

Energy Balance

• Heat energy is produced by the body and cannot be used to do work.
• Heat energy warms the tissues and blood, helps maintain homeostatic body temperature, and allows metabolic reactions to occur efficiently.

Obesity

• Obesity is a condition where the body has an excess amount of fat.
• Body mass index (BMI) is used to determine whether a person is overweight or obese.
• Obesity is associated with a higher incidence of atherosclerosis, diabetes mellitus, hypertension, heart disease, and osteoarthritis.

Metabolic Rate

• Basal metabolic rate (BMR) is the energy required by the body to perform its most essential activities.
• Thyroxine is the most important hormone affecting BMR.
• Factors that influence BMR include the ratio of body surface area to volume, age, temperature, and stress.

Regulation of Body Temperature

• Body temperature is regulated by the balance between heat production and heat loss.
• At rest, the liver, heart, brain, kidneys, and endocrine organs generate most heat.
• During exercise, heat production from skeletal muscles increases dramatically.

Homeostatic Imbalance

• Hyperthermia is a condition where the body temperature is elevated, depressing the hypothalamus.

• Hypothermia is a condition where the body temperature is low, and vital signs decrease.

• Fever is a controlled hyperthermia caused by infection, cancer, allergies, or CNS injuries.### Vitamins and Minerals

• Fat-soluble vitamins A, D, E, and K are absorbed with lipid digestion products and stored in the body, except for vitamin K

• Vitamins A, C, and E act as antioxidants

• Minerals are required in moderate amounts, including calcium, phosphorus, potassium, sulfur, sodium, chloride, and magnesium

• Minerals work with nutrients to ensure proper body functioning

• Uptake and excretion of minerals must be balanced to prevent toxic overload

• Examples of minerals and their functions:

  • Calcium, phosphorus, and magnesium salts harden bone
  • Iron is essential for oxygen binding to hemoglobin
  • Iodine is necessary for thyroid hormone synthesis
  • Sodium and chloride are major electrolytes in the blood

Metabolism

• Metabolism involves biochemical reactions inside cells involving nutrients
• There are two types of metabolic reactions:
  • Anabolism: synthesis of large molecules from small ones
  • Catabolism: hydrolysis of complex structures to simpler ones
• Cellular respiration: catabolism of food fuels and capture of energy to form ATP in cells
• Stages of metabolism:
  1. Digestion, absorption, and transport to tissues
  2. Cellular processing (in cytoplasm): synthesis of lipids, proteins, and glycogen, or catabolism (glycolysis) into intermediates
  3. Oxidative (mitochondrial) breakdown of intermediates into CO2, water, and ATP

Cellular Respiration

• Oxidation of glucose: C6H12O6 + 6O2 → 6H2O + 6CO2 + 36 ATP + heat
• Glucose is catabolized in three pathways:
  1. Glycolysis: catabolic reaction based on the conversion of glucose into two molecules of pyruvic acid
  2. Krebs cycle: occurs in the mitochondrial matrix, uses the 2 pyruvic acids from glycolysis
  3. Electron transport chain and oxidative phosphorylation: occurs on the inner mitochondrial membrane, utilizes hydrogen atoms from NADH + H+ and FADH2 from glycolysis and Krebs cycle

Glycolysis

• Glycolysis is a catabolic reaction that converts glucose into two molecules of pyruvic acid
• Anaerobic process that occurs in the cytoplasm
• Final products of glycolysis:
  • 2 pyruvic acid
  • 2 NADH + H+
  • Net gain of 2 ATP
• If O2 is not readily available, pyruvic acid is converted to lactic acid
• If O2 is readily available, pyruvic acid enters aerobic pathways

Krebs Cycle

• The Krebs cycle occurs in the mitochondrial matrix
• Does not directly use O2
• Utilizes the 2 pyruvic acids from glycolysis
• Products of the Krebs cycle:
  • 3 NADH + H+
  • 1 FADH2
  • 2 CO2
  • 1 ATP

Electron Transport Chain and Oxidative Phosphorylation

• Occurs on the inner mitochondrial membrane
• Utilizes the hydrogen atoms from NADH + H+ and FADH2 from glycolysis and Krebs cycle
• Products of oxidative phosphorylation:
  • About 28 ATP