1.2 Diet & Health

Question 1

Explain how diet can increase risk of CVD

Answer 1

• high saturated fat intake increases risk, as it increases blood cholesterol levels and therefore atheroma formation
• high salt intake increases risk, as it increases blood pressure due to water being retained in the blood by the kidneys

Question 2

Explain how high blood pressure can increase risk of CVD

Answer 2

increases risk of damage to artery walls (caused by high alcohol consumption, stress and diet)

Question 3

Explain how smoking can increase risk of CVD

Answer 3

• carbon monoxide from incomplete combustion binds permanently with haemoglobin, disabling the molecule as well as increases deposition of cholesterol
• nicotine makes platelets stickier, increase chance of blood clots
• free radicals in smoke can damage endothelium
• reduces HDL levels

Question 4

Explain how lack of exercise can increase risk of CVD

Answer 4

• decreases HDL levels and elasticity of arteries
• make heart weaker

Question 5

State and explain uncontrollable risk factors of CVD

Answer 5

• genetics: alleles inherited that cause high blood pressure/cholesterol levels
• age: elasticity of arteries decreases and plaque build up increases with time
• gender: men are more likely to suffer from CVD due to different hormone levels (less oestrogen which increases HDL levels)

Question 6

State pros and cons of antihypertensives and what they do

Answer 6

reduce blood pressure (vasodilators widen blood vessels, beta-blockers increase heartbeat strength, diuretics reduce sodium reabsorbed by kidneys therefore reducing blood volume)

pros:
- many varying types of antihypertensives can be used at once (as they do differing things)
- blood pressure can be monitored at home, instant feedback
- lower blood pressure, lower risk of damage to endothelium so lower risk of atheromas and CVD
cons:
- palpitations, arrhythmia, fainting, headaches and drowsiness are side effects caused by too low blood pressure
- doesn’t undo damage already formed in arteries

Question 7

State pros and cons of statins and what they do

Answer 7

reduce blood cholesterol by reducing LDLs produced in liver

pros:
- reduce risk of CVD development, minimal side effects
cons:
- muscle/joint pain, digestive problems, increased diabetes risk are side effects

Question 8

State pros and cons of anticoagulants and what they do

Answer 8

reduce blood clotting (platelet inhibitory drugs, e.g. aspirin, also reduce blood clots)

pros:
- can be used to treat those already with CVD to prevent further damage
cons:
- cannot get rid of existing clots
- injuries may cause the person to excessively bleed, causing fainting and possibly death (may damage foetus if person is pregnant)

Question 9

Explain what causes oedema

Answer 9

• at arterial end of capillaries, hydrostatic pressure is greater forcing plasma into nearby tissue
• at venule end of capillaries, hydrostatic pressure is lower, so some tissue fluid moves back into the venules, and some are drained lymphatically
• when someone has oedema, the pressure is too high or low, leading to a build up of fluid in blood/tissue

Question 10

State what LRNI, EAR and HRNI stand for

Answer 10

Lower Reference Nutrient Intake
Estimated Average Requirement
Higher Reference Nutrient Intake

Question 11

State the meaning of BMI and how to calculate it

Answer 11

Body Mass Index
Mass (kg) / (Height (m) ^2)

Question 12

State how to calculate waist to hip ratio

Answer 12

waist circumference / hip circumference

Question 13

What are the components of a triglyceride and what is it useful for

Answer 13

3 fatty (carboxylic) acid tails connected to glycerol via ester bonds (via condensation reactions)
used as an insulator and storage of water and energy (insoluble so doesn’t effect water potential)

Question 14

Explain the difference between saturated and unsaturated lipids

Answer 14

Saturated - no double bonds “saturated with hydrogen” - liquid at room temp (olive oil)
Unsaturated - carbon double bonds - solid at room temp (animal fats)

Question 15

Explain the differences between HDLs and LDLs, and what they are

Answer 15

• cholesterol needs to attach to a protein to move, so lipoproteins are formed for its transport (protein + lipid)
• High Density Lipoproteins are mainly proteins, transporting cholesterol to liver GOOD STUFF
• Low Density Lipoproteins are mainly lipids, binds to cell receptors, reducing receptor activity, leading to high blood cholesterol levels NOT SO GOOD STUFF

Question 16

Name three disaccharides and the monomers that form them

Answer 16

maltose = α-glucose + α-glucose
sucrose = fructose + glucose
lactose = galactose + glucose

Question 17

Compare and contrast starch and glycogen

Answer 17

Similarities:
- amylopectin and glycogen very similar, with 1-4 and 1-6 glycosidic bonds and branches
- both formed only from α-glucose
- both used as energy storage
- both insoluble so dont effect water potential
Differences:
- starch in plants, glycogen in humans
- starch is made of two types of monomer, amylose and amylopectin whereas glycogen is just one
- amylose has only 1-4 glycosidic bonds (with coiled structure and no branches)

Question 18

PRACTICAL
Explain how you would investigate the Vitamin C content in difference fruit juices

Answer 18

IV: type of fruit juice
DV: volume needed to decolourise 1cm3 of DCPIP
CVs: volume and conc of DCPIP, temp (use thermometer)
Method: titrate the fruit juice drop by drop while swirling against the 1cm3 DCPIP until X on test tube can be seen (can use burette) and repeat
Analysis: results can be average and compared to calibration curve to get vit c content data
Conclusion: negative correlation between vitamin C content and volume to decolourise

Question 19

Give features of a good scientific study

Answer 19

• Clear aim/hypothesis
• Representative sample (including large enough sample size)
• Valid and reliable results