SNAB Topic 7: Run for your life

• Muscle Definition

  Effector organs that respond to nervous stimulation and create movement through contractions.
• The muscle that contracts is the agonist.
• The muscle that relaxes is the antagonist.
• Muscles exist as antagonistic pairs because the muscles are only able to pull (can’t push).
• A joint is where two or more bones meet. Three main type:

  • Fibrous (immoveable).
  • Cartilaginous (partially moveable) where connections are made of cartilage. (E.g. between vertebrae and spine)
  • Synovial (freely moveable) most common and allow wide range of movement. 6 types of synovial joints: Pivot, hinge, saddle, plane, condylold, ball-and-socket
• Tendons join muscle to bone.
• Ligaments join bone to bone.
• The synovial membrane secretes synovial fluid. This acts as a lubricant that is a non-Newtonian fluid and reduces friction.
• Osteoarthritis is caused by the cartilage between joints wearing away.

  Inflammatory/rheumatoid arthritis causes inflammation and tenderness around the joints.

  Risk factors: smoking, obesity, inactive lifestyle.
• Skeletal muscles are attached to bones.
• In antagonistic muscle pairs, extensors act to straighten the joint, whilst flexors act to bend the joint.
• Sliding Filament Theory

  1. Calcium ions released from sarcoplasmic reticulum following an action potential via T tubules.
  2. Calcium ions bind to troponin, displacing tropomyosin and exposing myosin binding sites on actin.
  3. Bulbous heads of the myosin attach to the binding sites on the actin filaments.
  4. Myosin heads change position to achieve a lower energy state and slide the actin filaments past the stationary myosin.
  5. ATP binds to heads, detaching them.
  6. ATP hydrolysis provided energy to reset the heads.
  7. Calcium ions reabsorbed.
  8. Troponin reverts to original shape,binding sites blocked.
• What are the four stages of aerobic respiration?

  1. Glycolysis
  2. Link reaction
  3. Kreb‘s Cycle
  4. Oxidative Phosphorylation (ETC)
• Where does glycolysis occur?

  In the cytoplasm.
• In glycolysis, glucose is phosphorylated to produce 2 molecules of pyruvate, 2 ATP and 2 NADH.
• What is anaerobic respiration in animals called?

  Lactate fermentation.
• What is anaerobic respiration in plants called?

  Ethanol fermentation.
• ATP is a phosphorylated nucleotide that can be hydrolysed to form ADP and Pi (inorganic phosphate).
• The link reaction occurs in the mitochondrial matrix.
• What reaction builds large molecules?

  Anabolic.
• What reaction breaks down large molecules into smaller ones?

  Catabolic.
• What are the 3 stages of Glycolysis?

  1. Phosphorylation
  2. Splitting of hexose sugars.
  3. Oxidation
• Glycolysis:

  1. Glucose phosphorylated to hexose biphosphate.(6C)
  2. Hexose biphosphate (6C) split into 2 triose phosphate (3C).
  3. Triose phosphate oxidised to pyruvate (3C).
  4. NAD used as coenzyme to oxidise the reaction.
• What is phosphorylation?

  The addition of one or more phosphate groups to a molecule.
• What are the products of the link reaction?

  1 Acetyl coA, 1 carbon dioxide, 1 NADH