Application- Chapter 2

Question 1

Comparison of the thermal properties of water and methane

Answer 1

Both small molecules with atoms linked by single covalent bond
However water molecules are polar and can form hydrogen bonds

As a result physical properties are very different

Question 2

Use of water as a coolant in sweat:

Answer 2

Sweat is carried along narrow ducts to the surface of the skin- heat needed for evaporation of water in sweat is taken from tissues of the skin, reducing temp- blood flowing through skin is therefore cooled

Question 3

Use of water as a coolant in sweat:

What is sweat controlled by?

Answer 3

Hypothalamus of the brain- if body is heat is over stimulates the sweat glands to secrete up to two litres of sweat per hour

Question 4

What are lipids more suitable for

Answer 4

Long term energy storage than carbohydrates

Question 5

Scientific evidence for health risks of trans fat and saturated fatty acid

Explain

Answer 5

Positive correlation has been found between saturated fatty acid intake and rates of CHD

Populations that do not fit correlation- Maasai of Kenya have diet rich in meat, fat, blood and milk- high consumption of saturated fat yet there is no CHD

Mediterranean- rich in olive oil - low rates of CHD - however intake of tomatoes could explain this?

Question 6

Evaluation of evidence and the methods used to obtain the evidence for health claims made about lipids

Answer 6

Evaluation is defined as an assessment of implications and limitations

Implication- do the results of the research support the health claim strongly, moderately or not?

Limitations - were the research methods used rigorous or are there uncertainties about the conclusions because of weaknesses in methodology?

Question 7

Evaluation of evidence and the methods used to obtain the evidence for health claims made about lipids

Answering implication/ limitation

Answer 7

1)Analysis the results of the research- easiest in graph
Look at correlation
Mean
Standard deviation

2) how large was sample size?
How even was size in age, gender etc?

Question 8

Crick and watsons discovery of the structure of DNA using model making:

Answer 8

-1st model consisted of a triple helix with bases on the outside of the molecule and magnesium holding the two strands together - fitted the X Ray pattern obtain by rosalind Franklin
- didn’t fit- Franklin pointed out there wasn’t enough magnesium
- DNA pieces of cardboard were cut out - put completary base pairs together with hydrogen
- figured out double helix run in opposite direction - must be anti Parrel!
They did it!

Question 9

Production of human insulin in bacteria as an example of be universality or to genetic code allowing gene transfer between species

Answer 9

1) Porcine and bovine insulin has been used- from pigs and cattle- 1 diff, 3 diff- despite differences they all bind to human insulin receptor causing lowering of blood glucose levels
2) human insulin is preferred due to allergies
3) human insulin became more available by the genetically modified E. Coli bacteria

Question 10

Urea as an example of a compute that is produced by living organisms but can also be artificially synthesized :

Formulae and used

Answer 10

Ammonia + carbon dioxide –> ammonium carbamate –> urea + water

Used as a nitrogen fertiliser on crops