Topic 1

• features of a mass transport system

  vessels

  transport medium

  maintained speed
• mass transport required for some organisms

  larger animals have a smaller surface area to volume ratio and a higher metabolic rate. diffusion alone is insufficient to supply all cells with the substances they need.

  need to produce mass flow
• definition of double circulatory system

  blood is pumped into the lungs by the right side of the heart. blood is pumped to the body by the other side of the heart
• why a double circulatory system is useful

  helps mammals carry out efficient gas exchange

  one side of the heart transports blood to heart, other side to the body

  this separates oxygenated and deoxygenated blood

  maintains concentration gradient, and maximises supply of blood

  blood pressure is lower for lungs and higher for body

  maximises good supply of oxygen, as mammas are very active
• structure of capillaries related to function

  walls only one cell thick which allows short diffusion distance

  very narrow so can permeate tissues

  red blood cells can high flat against wall

  effectively delivers oxygen

  numerus and highly branched

  provides high surface area
• comparison between aorta and pulmonary artery

  aorta has thicker layer of collagen, elastic tissue and muscle tissue

  collagen in walls to withstand high pressure

  muscular tissue to maintain high pressure

  elastic tissue for elastic recoil
• why is water a dipolar molecule

  oxygen more electronegative than hydrogen

  attracts the electron density in the covalent bond more strongly

  forms O8- and H8+
• important properties of water

  polar molecule so acts as universal solvent

  solvent so metabolic reactions occur faster in solution. transportation also

  example condensation, hydrolysis, photosynthesis and respiration.

  high specific heat capacity so buffers change in temperature

  large latent heat of vaporisation so provides a cooling effect by evaporation

  cohesion between molecules so supports columns of water in plants and produces surface tension, supporting small organisms

  can move in mass flow systems due to H bonds. Distributes thermal energy around body
• water as an ideal transport medium

  solvent because water molecules surround polar molecules

  liquid so has the ability to flow

  allows molecules to dissolve
• how water from tissue fluid is returned to the circulatory system

  plasma proteins remain which creates a water potential gradient

  water moves to blood by osmosis

  returns to blood by lymphatic system
• how salt affects tissue fluid

  due to high absorption of salt

  results in higher than normal concentration of salt in blood plasma entering capillaries

  higher salt results in lower water potential of tissue fluid

  less water returns to capillary by osmosis at veil end

  leads to build up of tissue fluid
• how proteins affect tissue fluid

  low concentration causes accumulation of tissue fluid

  water potential in capillary not as low

  more tissue fluid formed at article end

  less water absorbed back into blood capillary by osmosis
• how blood pressure affects tissue fluid

  high blood pressure=high hydrostatic pressue

  increased outward pressure from arterial end of the capillary

  more tissue fluid formed

  leads to accumulation
• structure of atria related to function

  thin walled and elastic

  can stretch when filled with blood
• structure of ventricles related to function

  thick muscular walls pump blood under high pressure

  left ventricle is thicker than the right because it has to pump blood all around the body
• atrial systole


  the atria contract simultaneously

  ventricles are relaxed

  the atrioventricular valves are open

  pressure increases

  semi lunar valves closed
• ventricular systole


  semi lunar valves open as oxygenated blood is formed out of the heart

  through the aorta to the body and through the pulmonary artery to the lungs

  pressure increases further

  atrioventricular valves closed
• cardiac diastole


  the ventricles begin to relax the drop in blood pressure forces the semi lunar valves closed

  heart relaxes

  atria filled with blood, pressure increases

  atrioventricular valves opened

  blood pushed into relaxing ventricles
• monosaccharides and functions


  glucose-main carbon atom for respiration

  ribose-component of DNA and RNA
• disaccharides components and functions

  maltose - a glucose and a glucose

  in germinating seeds, barley, malt, sugar

  sucrose-a glucose and fructose

  stored in sugar beet or cane

  lactose-a glucose and galactose

  in milk and sugar
• alpha vs beta glucose

  isomers

  alpha means hydroxyl group attached to c1 and ch2oh on c5 lie on the bottom of the ring

  bets means this group on top
• starch components


  amylose- made of alpha glucose

  linear structure

  (1,4) glycosidic bonds

  amylopectin-made of alpha glucose

  branched structure

  (1,4) and (1,6) glycosidic bonds

  easily hydrolysed to release energy

  insoluble
• glycogen components


  made of alpha glucose

  much like amylopectin

  more compact and branched

  (1,4) and (1,6) glycosidic bonds

  easily hydrolysed to release energy
• cellulose

  made of beta glucose

  unbranched

  long chain cannot coil

  OH groups stick out to make a microfibril structure with H bonds

  resistant to hydrolysis

  (1,4) glycosidic

  insoluble
• lipid components


  big molecules made of smaller subunits

  vital part of cell membrane as impermeable, so cell can be compartmentalised

  low density so allow aquatic animals to float

  H on glycerol and OH on fatty acid forms ester bond
• Explain the role of the heart in the formation of tissue fluid

  contraction of ventricle produces high blood pressure and high hydrostatic pressure

  this forces water and some dissolved substances out the capillaries
• why does blood pressure change as blood travels through different blood vessels?

  contact between blood and walls of the blood vessel causes friction

  impedes the flow of blood

  large surface area of arterioles and capillaries resist the blood flow even more

  slows it down and causes the pressure to fall

  increases due to atrial systole

  increases further due to ventricular systole

  decreases due to diastole
• assess the relative importance of carbohydrates to plants and animals

  glucose- for respiration in both. used as transport sugar in animals.

  starch- energy storage in plants. composed of amylose and amylopectin.

  glycogen- energy storage in animals.

  cellulose- cell walls in plants. higher proportion of carbohydrate in plants as a structural molecule.

  pentose sugars- ribose and deoxyribose within DNA, RNA and ATP for both

  glycolipid and protein- in both. protein as antibodies and on cell surface membrane. lipids in cell membranes

  lipids- more energy storage use in animals. more carbohydrate in plants
• unsaturated triglycerides


  -made of unsaturated fatty acids

  -has less hydrogen

  -usually soft or liquid at room temp

  -primarily found in plant seeds where they serve as an energy and carbon source for germinating plants

  -have one or more double bonds between carbons

  -plant oils

  -kink in fatty acid chain
• glycogen


  An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch.

  to provide glucose for respiration

  rapidly hydrolysed

  compact
• explain the effect that a lipoprotein would have on blood cholesterol levels

  increased

  triglyceride used is saturated

  lipoprotein is an LDL

  LDLs transport cholesterol

  LDL binds to receptors on cell surface membrane

  cholesterol brought back to liver

  reverse cholesterol transport process
• explain why high sugar intake can lead to obesity

  energy intake higher than energy output

  excess energy converted to fat

  leads to weight gain

  obesity indicted by BMI over 30
• HDL vs LDL


  HDL smaller

  more proteins

  less cholesterol
• Anticoagulant drugs


  reduce the likelihood of blood clotting

  internal bleeding likely
• statins


  lower cholesterol in the blood and reduce its production in the liver by blocking the enzyme that produces it

  can lead to inflammation, nausea etc.
• Diuretics


  medications administered to increase urine secretion in order to rid the body of excess water and salt

  lower blood volume and pressure

  leads to muscle cramps and dizziness
• ACE inhibitors


  reduce blood pressure

  stop arterial constriction

  (beta blockers do the opposite. reduce frequency of heart contractions)
• why high blood pressure can increase CVD risk

  high bp can be causes by high salt intake

  causes damage to endothelium

  inflammatory response/ build up of cholesterol leads to atheroma formation

  white blood cells accumulate

  calcium salts and fibrous tissue build up

  plaque develops and narrows lumen of the artery
• role of LDLs in atherosclerosis

  carries cholesterol in the blood

  cholesterol is deposited to form atheroma

  in the endothelium of the artery
• explain how a blood clot can form

  collagen exposed when wall of blood vessel damaged

  leads to release of thromboplastin

  thromboplastin catalyses conversion of prothombin into thombin

  thombin is an enzyme

  catalyses the conversion of fibrinogen into fibrin

  mesh of polymerised fibrin traps platelets/red blood cells to form a clot