Biology topic 1 question

• Define monosaccharide and give the structural isomers for glucose

  Carbohyrate monomer which cannot be broken down further

  - fructose

  -galactose
• Alpha Glucose structure --

  
• Monosaccharide general properties


  small - can diffuse through cell membranes

  soluble - in water so can dissolve in blood for transport

  sweet
• How are disaccharides and polysaccharides formed? Bonding?

  Condensation reactions (reversible, passive)

  Glycosidic 1-4 bonds

  Water produced
• Where are Maltose, sucrose and lactose found, and what monosaccharides and bonding do they each have?

  maltose: 2 glucose, found in barley seeds, alpha 1-4 glycosidic bonds

  sucrose: plants, glucose and fructose, alpha 1-2 glycosidic bonds

  lactose: milk sugar, galactose and B glucose, beta 1-4 glycosidic bonds
• Describe the structure of starch

  - mixture of amylose and amylopectin

  - amylose is linear, non-branched, 1-4 bonds only

  - amylopectin is branched, with 1-6 bonds for branches - it is less compact than amylose and is broken down more quickly
• Function of starch


  - short term storage of energy in plants, which does not disrupt osmotic gradient

  - found in plasmids, stored as starch grains, insoluble

  
• Glycogen structure


  Branches have alpha(1,6) bonds; Linkages have alpha(1,4) bonds

  Highly branched - more than amylopectin - animals have higherbasal metabolic rate so needs energy faster and more

  - less dense than starch

  - broken down by glycogen phosphoyrlase

  
• fatty acid structure


  COOH carboxyl group head, hydrocarbon tail (R group that varies in length)

  saturated or unsaturated

  
• Difference between saturated and unsaturated fatty acids?

  Saturated = full

  - they have no double bonds and no kinks - one straight chain - this means they can pack more tightly and require more energy to split apart - solid at RTP

  Unsaturated = not full

  - they have at least one double bond (mono or polyunsat) creating kinks

  - they don't pack as tightly and require less energy to break apart so liquid at RTP
• What elements are lipids made of?


  carbon, hydrogen, oxygen
• What elements are carbohydrates made of?

  carbon, hydrogen, oxygen
• What elements are proteins made of?

  carbon, hydrogen, oxygen, nitrogen
• What is the structure of a triglyceride?

  one glycerol and three fatty acids

  ester bonds

  condensation reaction

  CH2O-OC.R x3

  
• Properties of triglycerides


  -insoluble - storage of energy

  -hydrophobic

  -less dense than water -- buoyancy

  
  

  - used in insulation and protection too

  -poor heat conductor - insulating layer of subcutaneous fat

  - does not disrupt osmotic gradients
• Phospholipids structure


  phosphate group head, 2 fatty acids, glycerol backbone

  ester bonds

  condensation

  amphipathic - hydrophobic tails and hydrophilic heads

  
• Functions of phospholipids relating to structure

  cell membrane!

  phospholipids form a bilayer in water because of hydrophobic tails and hydrophilic heads

  self-sealing if punctured or opened

  fluid so individual molecules can move laterally
• emulsion test for lipids

  - Shake test substance with ethanol for about a minute, then pour the solution into water.

  
  

  - Any lipid will show up as a milky emulsion.

  
  

  - The more lipid there is, the more noticeable the milky colour will be.
• Homeotherm definition


  Organism that can regulate its core temp
• Roles of lipids and why their structure allows this

  - long term energy store: insoluble, non-polar, higher proportion of H atoms to O atoms compared to carbs and proteins so release a larger amount of energy

  
  

  - thermal insulation: poor heat conductors

  - electrical insulation: poor electrical conductors e.g. myelin sheath

  
  

  - buoyancy - less dense than water so float on surface

  
  

  - protection from knocks - organs not protected by skeletal system

  - cell membranes - phospholipids form a bilayer because amphipathic
• Describe how hydrogen bonding determines many properties of water

  polar - because of both +ve and -ve charge

  cohesion - H bonds between molecules form a strong lattice and allows water molecules to stick together

  adhesion - attracts other charged molecules and polar molecules

  habitat - constant temp of sea and ice freezes top down because of air spaces making it less dense - forms an insulating layer and keeps sea water liquid

  evaporation - allows heat loss during homeostasis

  solvent - other polar molecules can dissolve in, allowing water to be a transport medium

  thermal insulator - high latent heat capacity gives a relatively stable temperature, (same as habitat point)

  surface tension
• Why do multicellular organisms need transport systems?

  smaller SA:Vol ratio than single-celled organisms so diffusion would take much longer, also there are layers of cells where there would need to be a lower concentration in the next layer
• Where does diffusion take place in multicellular organisms?

  - alveoli (lungs)

  - villi (small intestines)

  - Ca2+ ions sarcoplasmic reticulum during respiration
• What is the difference between an open and closed circulatory system? Describe them both.

  open - basic, molluscs have this, haemolymph fluid pumped by heart through vessels into a haemocoel (cavity) and back into the heart. It is quite slow as steep concentration gradients are not maintained

  
  

  closed - more complex, blood is fully enclosed, preventing the mixing of oxygenated and deoxygenated blood, gradients are maintained and regulation is quicker and more efficient
• Difference between single and double circulatory systems?

  single - one way, two chambered heart, e.g. in fish, relies on a single pump to direct deoxygenated blood towards the gills for instance, where once oxygenated it continues to travel to the body

  
  

  double - two separate loops: pulmonary and body, 4 chambered heart to avoid mixing oxygenated and deoxygenated blood, delivery is faster due to steeper concentration gradients, and pressure is higher.
• Describe the heart structure

  - left and right atria

  - left and right ventricles

  - atrioventricular valves

  - semilunar valves

  - septum

  - tendinous cords

  - aorta

  - vena cava

  - pulmonary veins and arteries

  
• What do semilunar valves prevent?


  Backflow of blood from the aorta (high BP) back into left ventricle during diastole
• What do atrioventricular valves prevent?

  Backflow of blood into the left and right atria from the ventricles during ventricular systole
• Why does the LHS of the heart have a more muscular wall?

  It has to make a stronger contraction to push the blood at a higher pressure further around the body than the right side, which only has to push it to the lungs
• What would be the result of a hole in the septum of the heart?

  Oxy and deoxy blood would be able to mix -> blood would have a lower % saturation of oxygen so the heart and breathing rates would have to increase to supply the cells with enough O2 for respiration
• What would be the result of atrioventricular valve failure?

  - backflow of blood into atria

  - O2 delivered less efficiently and slower

  - fatigue and shortness of breath
• What would be the result of a blocked coronary vein?

  - no oxygenated blood would reach cardiac tissue

  - cells revert to anaerobic respiration, producing lactic acid which builds up and causes tissue damage, heart attacks and angina
• Describe atrial systole


  atria (full of blood) contract and force blood through the atrioventricular valves and into the ventricles

  - 70% of the blood flows passively
• Describe ventricular systole


  atria relax, thick muscular ventricle walls contract and force blood into the aorta and pulmonary artery

  the pressure of blood causes the atrioventricular valves to shut, preventing backflow of blood into the atria

  - first part of heartbeat
• Describe diastole

  - ventricles relax

  - BP drops below the BP in the arteries, causing semilunar valves to shut

  - heart muscle relaxes and blood from vena cava and pulmonary vein trickles into atria
• Describe how the cardiac cycle appears on a graph

  - ventricular systole is more forceful and high pressure than atrial systole

  - when the atria/ventricles relax, the pressure decreases

  
• What is the rate of depolarisation of the SAN(sinoatrial node) affected by?

  adrenaline -> excitatory effect, faster and stronger contractions due to adrenaline binding to SAN receptors

  noradrenaline -> excitatory effect

  acetylcholine -> inhibitory effect, slowing HR
• Describe what an elevated ST segment shows on an ECG


  enlarged left ventricle or impending heart attack, possibly due to CVD
• Describe what ventricular fibrillation shows in an EEG

  absence of a coordinated ventricular contraction, caused by chaotic electrical activity
• CPAC: effect of caffeine on daphnia

  - cotton wool on cavity slide to restrict movement

  - distilled water added to maintain sufficient O2 supply

  - view under low power light so temperature doesn't get too high and damage the daphnia

  - count heartbeats per min

  - repeat with different concentrations of caffeine solution

  - CVs: temp, vol of caffeine solution, same age/gender/size of daphnia