Energy, Lipids and Omega-3 Fatty Acids

• Chapter 2 focuses on the chemical level of organization in the body.

Chemical Reactions

• Chemical reactions involve forming new bonds or breaking existing ones.
• Reactants are the initial substances in a chemical reaction.
• Products are the substances that result from the chemical reaction.
• Metabolism encompasses all chemical reactions occurring in the body.

Forms of Energy and Chemical Reactions

• Energy is defined as the capacity to perform work.
• Potential energy: Stored energy.
• Kinetic energy: Energy of motion.
• Chemical energy: Energy stored in chemical bonds.
• The law of conservation of energy states that energy is neither created nor destroyed, but can be converted.
• The total amount of energy at the beginning and end of a reaction remains constant.

Energy Transfer

• Activation energy is the energy needed to initiate a reaction.
• Activation energy is affected by temperature and concentration.

Catalysts

• Catalysts accelerate chemical reactions.
• Catalysts achieve this by lowering the activation energy required.

Enzyme-Substrate Complex

• Enzymes bind to specific substrates.
• When the reaction is complete, the enzyme is unchanged and is able to catalyze the same reaction again.
• Normal body temperature, 37° C, affect enzyme activity.
• A body temperature during exercise of 40° C also affect enzyme activity.

Energy Transfer Reactions

• Exergonic reactions release energy.
• Endergonic reactions require energy input.
• Coupled reactions involve an exergonic reaction providing energy to drive an endergonic reaction.

The Breakdown of Glucose

• The breakdown of glucose goes from C6H12O6 + 6 02 to 6 CO2 + 6 H2O.

Main Types of Chemical Reactions

• Synthesis reactions involve combining two or more ions, atoms, or molecules to create larger molecules, aka anabolism.
• Decomposition reactions involve breaking larger molecules into smaller atoms, ions, or molecules, aka catabolism.

Inorganic vs. Organic Compounds

• Inorganic compounds typically lack carbon and are simple molecules.
  • Water is the most important and abundant inorganic compound in all living things.
• Organic compounds always include carbon, usually include hydrogen, and commonly have covalent bonds.

Carbohydrates

• Carbohydrates are composed of carbon, hydrogen, and oxygen.
• Carbohydrates include sugars, glycogen, starches, and cellulose
• Carbohydrates are a primary source of chemical energy.
• Carbohydrates constitute 2-3% of total body mass.

Major Carbohydrate Groups

• Carbohydrates are a main energy source.
• Monosaccharides are simple sugars containing 3 to 7 carbon atoms.
  • Glucose is main blood sugar, and fructose is found in fruits, while Galactose is is in milk sugar.
  • Deoxyribose occurs in DNA, and Ribose appears in RNA.
• Disaccharides are simple sugars made from two monosaccharides through dehydration synthesis.
  • Sucrose (table sugar) = glucose + fructose
  • Lactose (milk sugar) = glucose + galactose
  • Maltose = glucose + glucose
• Polysaccharides consist from tens to hundreds of monosaccharides
• Glycogen is a stored form of carbohydrates in animals.
• Starch is a stored form of carbohydrates in plants. It is also a main carbohydate in foods.
• Cellulose, aka fiber, is found in plant cell walls, indigestible by humans, but aids food movement.

Types of Lipids in the Body

• Fatty acids are used to synthesize triglycerides and phopholipids, or catabolized to generate adenosine triphosphate (ATP).
• Triglycerides, as fats and oils, are provide protection, insulation, and energy.
• Phospholipids are the major lipid component of cell membranes.
• Steriods: cholesterol is a minor component of all animal cell membranes, the precursor of bile salts, vitamin D, and steroid hormones.
• Steriods: Bile salts are critical to the absorption of dietary lipids.
• Steriods: Vitamin D helps reguate calcium level in body, and is critical for bone growth.
• The adrenocortical hormones regulate metabolism, resistance to stress, and satl and water balance.
• The sex hormones stimulate reproductive functions and sexual characteristics.
• Eicosanoids have modifiying responses to hormones, blood clotting, inflammation, immunity, stomach acid secretion, airway diameter, lipid breakdown, and smooth muscle contraction.
• Carotenes make visual pigments in the eye, and function as antioxidants.
• Vitamin E promotes tissue wound healing, aids normal structure and function of nervous system, and acts as an antioxidant.
• Vitamin K is required for synthesis of blood clotting proteins.
• Lipoprotiens are required to transport lipids in flood, carry triglycerides and cholesterol to tissues, and remove excess cholesterol from the blood.

Fatty Acids

• Fatty acids can be saturated or unsaturated.
• Omega-3 fatty acids are Polyunsaturated (flax, canola & olive oils, seafood)
• EPA (eicosapentaenoic acid)
• DHA (docosahexaenoic acid)
• ALA (α- linolenic acid)
• Omega-3 fatty acids have a number of health benefits -They decrease inflimmation -They increase muscle protein synthesis pathways -Increase oxygen delivery to heart during exercise -Increase nerve conduction velocity -Fish is associated with a reduced risk of death from heart disease

Triglycerides

• Triglycerides are the major form of lipid in food and in the body.
• Triglycerides consist of three fatty acids attached to a glycerol molecule.

Phospholipids

• Phospholipids are an important component of cell membranes.

Amino Acids

• Amino acids are the building blocks of proteins.
• Essential (indispensable) amino acids cannot be made by humans in sufficent amounts, thus they must be included in the diet.
• Nonessential (dispensable) amino acids can be made by the human body in sufficent amounts.
• Each amino acid contains a central carbon atom bound to a hydrogen atom, an amino group, an acid group, and a side chain.
• Amino acid pool includes all amino acids in body tissues and fluids that are available for use by the body.
• Protein turnover is the continous synthesis and breakdown of body proteins.
• Proteins give structure to the body, regulate processes, provide protection, assist in muscle contraction, transport substances, and serve as enzymes.

Protein Structure

• Peptide bonds are chemical bonds that link to amino acids together.
• Peptide Bonds are formed between the acid group of one amino acid and the nitrogen group of the next amino acid.
• Dipeptide bonds are formed between two amino acids.
• Polypeptides are formed between many amino acids (10+).
• A rotein is made of one or more pplypeptide chains folded into a three-dimentional shape.
• Proteins can be structural, regulatory, or contractile.
• Protiens aslo can be immunological, transport, and catalytic

Nitrogen Balance

• Nitrogen balance =Nitrogen intake = nitrogen output
• Nitrogen balance= Total body protein does not change
• Negative nitrogen balance=Nitrogen intake < nitrogen output
• Negative nitrogen balance= Total body protein decreases
• Postive netrogen banace= Nitrogen intake> nitrogen output
• Postive netrogen banace= Total body protein increases

Nucleic Acids

• DNA forms the genetic code in the nuclei of body cells and it regulates most of cells activities
• RNA guides protein formation

DNA

• DNA is made out of two strands twisted in a spiral staircase-like structure called a doube hellix
• Each strand consists of nucleotides blund together Each nucleotide cinsists of a deoxyribose sugar bound to a phosphate group and one of 4 nitrogenous bases [(adenine (A), thymine (T), guanine (G), cytosine (C) The nitrogenous bases pair together through hydrogen bounding to form the "steps" of the double helix.
• Adnenine pairs with thymine and guanine pears with cytosine

DNA vs RNA

• Differ in nitrogenous bases, DNA has thymine whereas RNA has uracil.
• Difference in sugar: DNA is deocyribose while RNA is ribose.
• DNA has 2 stranded (double helix) while RNA has 1 strand.
• DNA is self replicating whereas RAN needs DNA has a blueprint.
• DNA encodes for protiens whereas RNA carries the genetic code and assists proteins.

Adenosine Triphosphate (ATP)

• ATP is the principal energy-storing molecule in the body.
• Cellular respiration is when carbohydrates, lipids and proteins are catabolized.
• Cellular repiration releases energy to attach phosphate to ADP to reproduce ATP. There are two phase, anaerobic(without oxygen) which glucose partially broken down into pyruvic acid witj a yield of 2 ATP.
• Alternatiy there is aerobic which needs oxygen, the Glucose lipids and protein are broken into CO₂ and H₂O), and the yield is 32 ATP.

Test your knowledge of energy conservation, catalysts, and reaction types. Explore the roles of lipids like triglycerides in the body and the cardiovascular benefits of Omega-3 fatty acids, especially for athletes looking to enhance muscle protein synthesis.