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AS Human Biology Unit 12
Text questions
| P204/Q1 | a) |
Partial blockage of a coronary artery → limited
blood supply to the cardiac muscle → cardiac muscle
respires anaerobically → lactic acid produced →
cramp (→chest pain/angina); |
| b) |
Partial blockage of coronary artery (angina) → … (as
above) … → accumulation of lactic acid in the cardiac
muscle → death of a certain area of the cardiac
muscle (→myocardial infarction / heart attack). |
|
| P205/Q2 |
Lipids are non-polar molecules (hydrophobic)
→ they will not
mix with the blood plasma. Lipoproteins mix with
blood better, because proteins (polar molecules) are
hydrophilic; |
|
| P207/Q3 |
Protein component of the LDL are compatible with the
membrane receptors →
LDL-receptor complex formed → leakage of LDL across the endothelium → LDL accumulates in the cells of tunica media of arteries (= atheroma). |
|
| P208/Q4 | a) |
Animal fats = high proportion of saturated
triglycerides (ST); ST found commonly in LDL, hence reducing animal fats → drop in LDL; |
| b) |
High intake of NaCl →
lower WP of blood →
diffusion/osmosis of water
→ hypertension. Hence, low NaCl → hypertension less likely to occur. |
|
| P209/Q5 | a) |
Lung cancer |
| b) |
Passive/active smoking |
|
| c) |
(i) Cancer of the cervix (ii) Cancer of the prostate gland; |
|
| P209/Q6 |
If the regulatory processes that control cell
division break down, a cell continues to divide
→ a
mass of cells/tumour; |
|
| P211/Q7 | a) |
This means, that after 6 minutes half of the p53
protein molecules will no longer be present within
the cell in the same form as before (they pair up to
form active dimers); |
| b) |
p53 protein helps to inhibit cell divisions. If p53
accumulates (because its half life is longer than
normally) this would suggest, that the protein does
not perform its function properly (probably as a
result of its changed structure following mutation
of the p53 gene). Consequently, the cells will
divide more frequently than normally. |
|
| P212/Q8 |
p53 gene damaged →
active p53 proteins not synthesised
→ only inactive
p53 dimers present in the cell → cell divisions not inhibited → tumours more likely. |
|
| P213/Q9 |
Smoking targets are derived from percentages of
smokers in those countries. The percentages are
different, and so are the targets for reducing them. |
|
| P215/Q10 |
Average duration of bright sunshine is higher in
Australia than in England. |
Assignment
| P216/Q1 | a) | Cells without DNA will not divide. Destroying
DNA in cancerous cells
→ the cells cannot divide → cancerous cells die. |
| b) | Cells, which produce keratin, divide rapidly.
Therefore these cells are killed as well as
cancerous cells. As a result hair falls out. |
|
| P216/Q2 | a) | Mitochondria (respiration)
→ ATP (for cell
division). Hence, no mitochondria
→ no ATP
→ no cell
division. |
| b) | CT2548 stimulates an enzyme involved in the
production of phosphatidic acid (in cancerous
cells), which (in high concentration) destroys
mitochondria. It is assumed that this enzyme is
active in cancer cells but not in normal cells. |
|
| P216/Q3 | a) | All molecules of the particular sort of protein
will have identical 1° structure. 1° structure
determines 2° and 3° structures. Hence, 2° and 3°
structures will be the same in all molecules of the
protein. |
| b) | (i) The antibodies (immunoglobulins) are
proteins and as such they have a specific 3°
structure, which binds onto specific protein
molecules in the cancer cells` plasma membrane.
(ii) The enzyme attached to the antibody molecule
converts the inactive pro-drug into its poisonous
form. |
|
| P218/Q4 | a) | Isolate integrin →
work out a/a sequence →
use genetic code to work out base sequence coding
for the protein →
synthesise DNA probe →
after extracting DNA from human cells use the DNA
probe to indicate the position of the target (integrin
coding) gene →
use restriction enzyme to cut out the target gene
→ use the same
restriction enzyme to cut open DNA of the vector
→ splice the
target gene into the vector's DNA
→ use the vector
to introduce recombinant DNA (coding for integrin)
into isolated cancer cells. |
| b) | GM cancer cells, which produce integrin, should
damage most of the 2° tumours. However, drugs are
needed to destroy the 1° tumours and undamaged 2°
tumours. |
|
| c) | To compare how effective the GM cancer cells
have been in damaging the 2° tumours. |
|
| P218/Q5 | a) | No VEGF →
new blood vessels not developed
→ tumour
under-supplied with blood (: oxygen, nutrients,
etc.) → atrophy
of the tumor cells →
death of cancer cells. |
| b) | All other cells in the body are well served by
the blood vessels →
no new blood vessels needed to maintain their vital
functions. Therefore, the cells of the body will not
be affected by drugs, which stop VEGF to stimulate
the development of new blood vessels. |
Examinations
| P218/Q1 | a) |
(i) There is a continuous decrease in the percentage
of smokers; (ii) Generally, more smokers amongst males than
females; |
| b) |
|
|
| c) |
|
