molecules transport and health

• Molecules, transport and health exam.
• Water as a solvent:

  • Hydrogen atoms in water are more positive than the oxygen atom, causing one end of the molecule to be more positive than the other
  • Water has a permanent dipole, making it a polar molecule
  • Substances can dissolve in water due to positive and negative charges within the molecule, allowing chemical reactions to occur
• Carbohydrates:

  • Consist of carbon, hydrogen, and oxygen
  • Long chains of sugar units called saccharides
  • Three types of saccharides: monosaccharides, disaccharides, and polysaccharides
  • Monosaccharides are soluble in water and small, simple molecules
  • Glucose is a key example of a monosaccharide
• Disaccharides:

  • Formed by condensation of two monosaccharides
  • Examples include maltose, sucrose, and lactose
• Polysaccharides:

  • Formed from many monosaccharides of glucose joined together
  • Used as energy stores
  • Glycogen is the main energy storage molecule in animals
  • Starch is the primary energy store in plants, consisting of amylose and amylopectin
• Joining monosaccharides:

  • Monosaccharides can join through condensation reactions to form disaccharides and polysaccharides
  • Glycosidic bonds are formed between monosaccharides
  • Hydrolysis reactions break apart polysaccharides by adding a water molecule
• Lipids:

  • Biological molecules with functions such as energy storage, organ protection, thermal insulation, and making cell membranes
  • Non-polar and insoluble in water, but soluble in organic solvents
  • Saturated lipids do not contain carbon-carbon double bonds, while unsaturated lipids do
• Triglycerides:

  • Made of one glycerol molecule and three fatty acids joined by ester bonds
  • Used as long-term energy reserves in plant and animal cells
• Mass transport:

  • Larger organisms have mass transport systems to supply all cells with vital substances
  • Circulatory system consists of the heart, arteries, veins, and capillaries
• Structure of the heart:

  • Comprised of left and right atria, and left and right ventricles
  • Atrioventricular valves prevent backflow from ventricles to atria
  • Semilunar valves prevent backflow from arteries to ventricles
  • Mammals have a double circulatory system
• Cardiac cycle:

  • Controlled by contracting and relaxing of heart muscles
  • Three stages: atrial systole, ventricular systole, and cardiac diastole
• Transport of gases in the blood:

  • Haemoglobin is a globular protein found in red blood cells
  • Haemoglobin can carry 4 oxygen molecules
  • Oxygen binds to haemoglobin to form oxyhaemoglobin
  • Affinity of oxygen for haemoglobin varies with partial pressure
  • Dissociation curves illustrate the change in haemoglobin saturation as partial pressure changes
• Dissociation curves illustrate the change in haemoglobin saturation as partial pressure changes
• The saturation of haemoglobin is affected by its affinity for oxygen
• In high partial pressure, haemoglobin has high affinity for oxygen and is highly saturated
• Saturation can also have an effect on affinity, as after binding to the first oxygen molecule, the affinity of haemoglobin for oxygen increases due to a change in shape
• Fetal haemoglobin has a higher affinity for oxygen compared to adult haemoglobin
• The Bohr effect: The affinity of haemoglobin for oxygen is affected by the partial pressure of carbon dioxide
• Atherosclerosis is the hardening of arteries caused by the build-up of fibrous plaque called an atheroma
• Atheroma formation is the cause of many cardiovascular diseases
• The endothelium which lines the arteries is damaged, leading to blood clotting and an inflammatory response causing plaque formation
• Blood clots are formed to minimise blood loss from damaged vessels and prevent pathogens entering the bloodstream
• Risk factors for cardiovascular disease:
• Genetics and family history increase the risk
• Diets high in cholesterol and certain fats increase plaque build-up on arteries
• Age and high blood pressure increase the risk of CVD
• Smoking damages the lining of arteries and can cause atheromas
• Inactivity has been linked with an increase in blood pressure
• Oxidative stress is an imbalance of antioxidants and free radicals of oxygen in the body
• Antioxidants can donate electrons to make the oxygen radical stable
• Intake of additional antioxidants in the diet should help prevent some cases of cardiovascular disease
• Cholesterol is transported in the body in high-density lipoproteins (HDLs) or low-density lipoproteins (LDLs)
• High-density lipoproteins reduce cholesterol levels and transport cholesterol to the liver to be expelled
• Low-density lipoproteins increase cholesterol levels and transport cholesterol to the arteries where it can build up and form plaque
• Treatment of cardiovascular diseases:
• Antihypertensives are used to lower blood pressure
• Statins are used to lower cholesterol levels and reduce plaque build-up on artery walls
• Anticoagulants help prevent blood clots
• Platelet inhibitors interrupt the cascade through which blood clots are formed
• Obesity indicators: