TOPIC 1

• water is an important solvent in transport and has a dipole nature.

  it has two slightly positively charged H+ and one slightly negatively charged O-
• a protein is made up of amino acids joined together by peptide bonds. it can fold into different shapes depending on its function. proteins have many functions including enzymes, hormones, antibodies, structural support and movement.
• hydrogen bonding is where a hydrogen atom covalently bonds with another electronegative element such as oxygen or nitrogen. The other end of this bond will be attracted to the negative side of another electronegative element creating a weak attraction between them called a hydrogen bond.
• the hydrophobic effect occurs when non polar molecules are surrounded by water, they repel the water molecules due to their similar charge.
• what is a monosaccharide and state its properties along with its use

  a simple sugar monomer, reducing sugar

  sweet soluble crystalline

  source for energy in respiration
• disaccharides are sugars formed by 2 monosaccharides with glycosidic bond. they are sweet, soluble, and crystallin. eg maltose sucrose and lactose
• polysaccharides are made by many monosaccharides joined together by glycosidic bond between 1,4 carbon in glucose. it is crystalline. eg: starch, glycogen and cellulose
• starch is made from amylose and amylopectin.

  amylose is not branched and has helix coiled shape. it has only 1,4 bond and found in plants.

  amylopectin is branched at every 20 monomer. it has 1,4 and 1,6 glycosidic bonds
• what is the name of reaction used to break down glycosidic bonds

  hydrolysis, addition of water
• what is the name of reaction used to make glycosidic bonds

  condensation, removal of water
• what is the role of each in providing and storing energy?

  starch: is a polymer so has high energy content, is a large molecule so its insoluble and osmotic effect prevented. it is branched / helical so its compact and takes up less space. large number of glucose can be stored in small space. Amylopectin is branched so ends can easily undergo hydrolysis by enzymes into glucose for respiration.

  glycogen: same thing but with no helical structure
• lipids are organic compounds that do not contain carbohydrates or proteins. they are insoluble in water. they have low density (low specific gravity) and are non polar. they store energy and act as structural components. they include fats, waxes, steroids and phospholipids
• cellulose is long chain polymers of beta-glucose. it forms microfibrils which form cell walls of plant cells. it provides support and protection against pathogens. it is indigestible because humans lack enzyme that breaks down beta-glucose
• glycogen is similar to amylopectin but more highly branched. it is stored in liver and muscle cells as an emergency source of energy when blood sugar levels fall. it is broken down into glucose during exercise or fasting. it is also used to maintain normal blood sugar level
• fatty acids are long chain carboxylic acid. they consist of a hydrocarbon tail and a carboxyl group (-COOH). they are non-polar because there is no dipole moment due to equal numbers of electrons and protons.
• triglyceride is synthesized by the formation of ester bonds during condensation reactions between glycerol and three fatty acids
• what is the difference between saturated and unsaturated lipids?

  Saturated lipids have no double bonds in their fatty acid chains which are straight chains, while unsaturated lipids have one or more double bonds with bent chain and lower C-H ratio
• why do many animals have a heart and circulation

  because mass transport is needed to overcome the limitations of diffusion is meeting the requirements of organisms
• how do the structures of blood vessels relate to their function

  1. Arteries: wide walls to withstand high blood pressure. has elastic fibers which stretch and recoil to maintain pressure. has smooth endothelium lining to reduce friction.
  2. Veins: thin walls with collagen and less elastic because blood pressure is low. has a large lumen for more blood to flow with many valves to prevent back flow. carry deoxygenated blood to heart
  3. Capillaries: one cell layer thick to reduce diffusion distance with pores for exchange of materials
• does atria contract or relax in atrial systole?

  contract
• does ventricle contract or relax in atrial systoles?

  relax
• does ventricle contract in ventricular systole?

  yes
• in which systole is atrioventricular open?

  atrial systole
• in which systole is semilunar valve open?

  ventricular systole
• in diastole what happens to atria and ventricle

  relax
• in diastole is AV valve open


  it is slightly open
• in diastole is SL valve closed

  yes
• Haemoglobin acts as a buffer by combining with hydrogen ions (H+) released from carbonic acid, forming haemoglobinic acid
• Carbon dioxide released from respiring cells diffuses into the cytoplasm of red blood cells
• Inside red blood cells, carbon dioxide combines with water to form H2CO3 catalysed by carbonic anhydrase
• Carbonic acid dissociates into hydrogen ions (H+) and hydrogen carbonate ions (HCO3-)
• Negatively charged hydrogen carbonate ions (HCO3-) are transported out of red blood cells via a transport protein in the membrane
• To prevent an electrical imbalance, negatively charged chloride ions are transported into the red blood cells via the same transport protein (chloride shift)
• If the chloride shift did not occur, red blood cells would become positively charged due to a buildup of hydrogen ions from the dissociation of carbonic acid
• what is oxygen dissociation curve?

  relationship between partial pressure of oxygen and binding of hemoglobin to oxygen
• as partial pressure of oxygen increases number of oxygen bound by haemoglobin increases and so does saturation of haemoglobin
• sigmoid curve is to cooperative binding which is the ease of oxygen binding.
• in BOHR effect when carbon dioxide increases hemoglobin affinity for oxygen decreases so they dissociate easily and the curve shifts to the right
• oxygen affinity in fetal haemoglobin is higher than adult haemoglobin
• what is the course of events that lead to atherosclerosis

  1. endothelium lining damaged
  2. inflammatory response triggered
  3. large white blood cells enters walls and engulfs lipoprotein
  4. cholesterol accumulate
  5. atheroma forms
  6. calcium salts and fibrous tissues accumulate
  7. hard plague formed and wall elasticity reduced
  8. lumen narrows raising blood pressure