BIOCHEM SEMIFINALS

• Steroids


  a nucleus which has 4 carbon rings, with attached groups that make the different types of compounds, and no fatty acids
• Cholesterol


  Is the most abundant steroid in the body, insoluble in water (need a water soluble carrier), has methyl CH3- groups, alkyl chain, and -OH attached to the steroid nucleus
• cholesterol

  • Obtained from meats, milk, and eggs
  • Synthesized in the liver from fats, carbohydrates and proteins
• Cholesterol


  • Needed for cell membranes, brain and nerve tissue, steroid hormones, and Vitamin D
  • Clogs arteries when high levels form plaque (because it is insoluble in blood)
  • No cholesterol in vegetable and plants
• Steroids hormones are molecules that are synthesized in one part of an organism, which then elicit a response at a different site
• Types of steroid hormones

  • Sex hormones
  • Adrenal cortical steroids
• Sex hormones


  Estrogens & progestins in females, Androgens in males
• Androgens


  Testosterone and Androsterone are androgens made in the testes, they control the development of secondary sex characteristics in males
• Anabolic steroids


  Synthetic androgen analogues that promote muscle growth, have the same effect as testosterone but are more stable, used by athletes and body builders but not permitted in competitive sports, prolonged use can cause physical and psychological problems
• Estrogens


  Estradiol and estrone control development of secondary sex characteristics, regulate the menstrual cycle, and are made in the ovaries
• Progestins


  Progesterone is the "pregnancy hormone", responsible for the preparation of the uterus for implantation of a fertilized egg
• Aldosterone


  Regulates blood pressure and volume by controlling the concentration of Na+ and K+ in body fluids
• Cortisone and cortisol


  Serve as anti-inflammatory agents, also regulate carbohydrate metabolism
• Prolonged use of adrenal cortical steroids can have undesired side effects, including bone loss and high blood pressure
• Prednisone


  A synthetic alternative to cortisone, has similar anti-inflammatory properties but can be taken orally
• Cortisone are used to suppress organ rejection after transplant surgery and to treat many allergic and autoimmune disorders
• Waxes


  Because of their long nonpolar C chains, they are very hydrophobic and form protective coatings in plants to prevent loss of water and damage from pests, and in humans and animals to provide waterproof coating on skin and fur
• Triacylglycerols


  Lipids transported through the bloodstream to tissues where they are stored, used for energy, or to make hormones
• Lipoproteins


  Spherical particles with polar surface and nonpolar inner, water-soluble form of lipids (soluble in blood)
• Types of lipoproteins


  • VLDL: very-low-density lipoprotein
  • LDL: low-density lipoprotein (bad Cholesterol)
  • HDL: high-density lipoprotein (good Cholesterol)
• Recommended levels are: HDL > 40 mg/dL, LDL < 100 mg/dL, total serum cholesterol < 200 mg/dL
• Negative risk factors in atherosclerosis

  • Elevated HDL cholesterol
  • Low LDL cholesterol
  • Good genes
  • Female gender (estrogen)
  • Exercise
• Lipids


  Fat-soluble organic compounds required in small quantities for normal metabolism
• Fat-soluble vitamins


  • Vitamin A
  • Vitamin D
  • Vitamin E
  • Vitamin K
• Vitamins are either water soluble or fat soluble
• Fat-soluble vitamins


  Lipids and nonpolar, excess stored in adipose cells to be used when needed
• Vitamins must be obtained from the diet as our cells cannot synthesize them
• Vitamins are found in fruits, vegetables, fish, liver, and dairy products
• Vitamin A


  Found in liver, fish, and dairy products, made from β-carotene, needed for vision and healthy mucous membranes
• Vitamin A deficiency


  Causes night blindness and dry eyes and skin
• Vitamin D


  Can be synthesized from cholesterol, obtained from diet especially milk, helps regulate Ca and P metabolism
• Vitamin D deficiency


  Causes rickets (bone malformation)
• Vitamin E


  An antioxidant, protects unsaturated side chains in fatty acids from unwanted oxidation
• Vitamin E deficiency


  Causes numerous neurological problems, although it is rare
• Vitamin K


  Regulates the synthesis of clotting proteins (prothrombin), deficiency leads to excessive or fatal bleeding
• Protein Basics

  • Protein function
  • Protein structure
  • Primary
  • Amino acids
  • Linkage
  • Sequence similarity and variation
• Protein Functions

  • Structural role
  • Cell wall
  • Cell membrane
  • Cytoplasm
• Structural proteins


  • Function: Support
  • Examples: Keratin is the protein of hair, horns, feathers, and other skin appendages. Insects and spiders use silk fibers to make their cocoons and webs, respectively. Collagen and elastin proteins provide a fibrous framework in animal connective tissues.
• Enzymes


  • Catalyze biological reactions
• Movement


  • Muscle expansion and contraction