Describe the role of ester bonds within lipids and the mode of ester bonds formation and breakage. (3)
- to link fatty acids and glycerol
- formed by esterification
- resulting in a water molecule as a by-product
Compare and contrast the structures of saturated and unsaturated fatty acids. (3)
Similarities:
- both have hydrocarbon tails
- both have -COOH group at one end
Differences:
- unsaturated has double C=C bonds
- saturated has straight chains
Describe how the misuse of alcohol can increase the risk of CVD. (2)
- alcohol can increase heart rate
- this can strain artery walls, increasing risk of atheroma forming
Explain why increased blood pressure causes an increase in the risk of cardiovascular disease. (3)
- high blood pressure damages artery walls
- so arteries lose elasticity
- atheroma formation
Explain how a diuretic may reduce blood pressure and relieve the symptoms. (2)
-reduces blood volume
- which reduces blood pressure in blood vessels.
Compare and contrast the structures of alpha and beta glucose. (3)
Similarities:
- both contain 6 carbon atoms
- both have ring structure
Differences:
- location of -H & -OH group on carbon 1
State why the properties of glucose make it a good molecule for its role. (4)
- Small mass
- Ability to polymerise
- Solubility
- High energy content
- Small mass: easily transportable
- Ability to polymerise: good candidate for storage compounds e.g. glycogen
- Solubility: ideal for easy transport in aqueous systems
- High energy content: high energy yield
State two features of a glucosidic bond. (2)
- strong covalent bond
- glycosidic bond formed from 2 OH- groups on seperate monosaccharides.
State two features of starch and how they allow it to act as a storage substance. (4)
- Insoluble
^ doesn’t affect water potential - Large molecule
^ contains many glucose molecules
Around 25% of BMR is used to release energy into nervous system. What is this energy released for? (2)
- keeping neurones polarised
- by active transport
State and explain one feature of capillaries. (2)
- Narrow diameter
^ slows down passage of red blood cells
Explain why multicellular organisms require a circulatory system and single-celled ones do not. (2)
- Multi-cellular organisms are made up of many layers of cells
- the diffusion distance to cells deep in the body would be too great
Define: mass transport system. (1)
- the bulk movement of gases or liquids in one direction usually via a system of vessels & tubes.
Describe how lungs and circulatory system work together to allow efficient mass transport. (3)
- faster transport of oxygen from lungs to cells.
- faster removal of CO2 from cells to lungs.
- maintains concentration gradient at alveoli and respiring cells.
Describe and explain one structure of a vein and an artery. (4)
- Artery:
^ thick muscle layer for withstanding high blood pressure - Vein:
^ valves to prevent back flow of blood
Explain one property of water that makes it an ideal transport medium. (2)
- water acts as a solvent
- can transport dissolves substances in blood e.g. glucose
Explain role of hydrogen bonding in transporting water. (2)
- allows water molecules to stick together
- Hydrogen bonds form b/w water & other molecules
Explain the dipolar nature of water molecules. (3)
- Electrons shared unequally between O and H atom.
- O has greater electronegative charge than H
- Therefore water is a polar molecule
Explain why pressure increase in aorta is important for organism. (4)
- ensures blood leaving heart is under high pressure
- so oxygenated blood reaches all of body
- and oxygen is delivered to all cells
- for aerobic respiration
Discuss ethical issues when using Daphnia. (2)
- organism cannot give consent to be apart of experimental procedures
- cannot express when they feel pain
Name two precautions that should be used when handling live organisms. (2)
- handle organisms with care
- wash hands after handling
