Bio

Question 1

Describe monclonal antibodies

Answer 1

An antigen is injected into a mouse
2. The mouse naturally produces lymphocytes, which produce
antibodies specific to the antigen
3. Spleen cells which produce the lymphocytes are removed
during a small operation
4. The spleen cells are fused with human cancerous white blood
cells called myeloma cells to form hybridoma cells which
divide indefinitely
5. These hybridoma cells divide and produce millions of
monoclonal antibodies specific to the original antigen

Question 2

What are moncloanl antibodies

Answer 2

• Monoclonal antibodies (mAb) are a single type of antibody that are identical and are directed against a specific epitope (antigen, antigenic determinant) and are produced by B-cell clones of a single parent or a single hybridoma cell line.

Question 3

Describe how preganacy test works

Answer 3

4. Control window:
   Immbobilised antibodies that are specfic to the mobile antibodies from the reaction zone are found here.
5. Result window:
   Immbobilised antibodies that are specfic to hCG around found here.
6. Reaction zone:
   There are mobile antibodies specific to hCG here. These antibodies can move and have a blue dye attached to them.
7. Urine applied here

Question 4

Advanatges and disadvantages of embroyonjc stem cells

Answer 4

Can treat a wide variety of diseases
Can become any cell type
Possible harm/death of the embryo.
Human rights/ethical issues (the embryo cannot give consent).
Unreliable as this is not a well-tested method.

Question 5

Adult stem cell advantage and disadvantage

Answer 5

No ethical issues as adult can give consent for the stem cells to be collected.
Safer, as this is a well-tested method.
Possibility of infection during extraction of stem cells.
Adult stem cells can only become one type of cell (same as the tissue it came from).
Can be very painful to extract.

Question 6

Embroyonic stem cells

Answer 6

Stem cells extracted from human embroyes they are highly affective and cna be specialsed to almost any tyoe of cell

Question 7

Adult stem cells

Answer 7

Undiffernated cells found living with differnt tissues

Question 8

Explain why potatoaes in 0.4 soulution decreased in mass

Answer 8

Water molecules left the pototatoe
Solution contained a low conc of water than potatie
Water moves out by osmosis

Question 9

A fungal celldivides every 90 min how many times would this fungal celll divide in 24 hours

Answer 9

16

Question 10

Where is protein digested in human digestive systme

Answer 10

Stomach

Question 11

Which chemical could be used to tets if the burgers contiwn protien

Answer 11

Biuret ragent

Question 12

Evualte teh use of burgers made from meat comaperd to meat free

Answer 12

protein is higher, in meat burgers.
this is needed for growth and repair
- fibre is higher in meet free buzers hich helps in digestion.
fibre con lead
A lack of
to constipation
- fat is higher in meat burgers which
can lead to obesity. Obesity is
a
üish factor. of
Ere 2 diabetes
- cartotydrate amounts are similar which is needed for energy
Overall, , meat free burgers are
Better at providing a healtheri diet
diet amount of all nutrients and are less likely tu cause such as obesity, diabeles and coronary heert disease.

Question 13

Iodine solutuin is an irratant plan to minimise risk

Answer 13

Wear gloves

Question 14

Explain why a thin layer of onion epidermis is used

Answer 14

So light can pass through so you can see an indivula cell

Question 15

Cover slip is lowerd on to the onion

Answer 15

Prevents air bubles

Question 16

Caculate the length of cell z

Answer 16

M=1/a
400=4.8/a
4.8/400=0.012x10000=120

Question 17

Two way improve drawing of onion cell

Answer 17

Connect all lines
No shading

Question 18

Decsirbe how mitosis produces two gentically identical cells

Answer 18

chronosomes /ONA duplicate
- chromosomes pulled to spposile parts of the call
- gloplosm and cell membene divide into
twO
- chromosomes in both cells -are mad up indientick dna

Question 19

Describe two differnces between the transpirtaion and translocation

Answer 19

tonspiration stream occurs in the xylem traslocation ocars in the phloems
2
tenspiration stream tensports water, trenslocation transports sugars

Question 20

Starch

Answer 20

Place a small amount of the food on a spotting tile.
Add 2.3 drops of iodine to the food sample
If colour changes from yellow/red to blue/black, starch is
present

Question 21

Sugar

Answer 21

How to test a food samole for the presence of sugar
2.
Place a sample of the food solution) is a test tube
Add 2-3 drops of benedict’s solution to the food sample.
Heat the test-tube in a warm water bath at 80 ).
It colour changes from blue to brick red, sugars are present.

Question 22

Protein

Answer 22

Place a sample of the food solution) is a test tube.
Add 2-3 drops of biuret solution to the food sample. Heat
The reset de warn warer earn
If colour changes from pale blue to violet, protein is pre

Question 23

Nitrate ions need a different method of transport into the root hair cell.
Explain how the nitrate ions in Figure 4 are transported into the root hair cell.
Use information from Figure 4 in your answer.
Name of process
Explanation

Answer 23

Name of Process: active transport
er the root
Explanation: because energy is required to move the nitrate ions from a lower concentration in the soil to a higher concentration in the root.

Question 24

Describe how the mAbs and a fluorescent dye could be used to see any
Candida albicans pathogens on the slide.

Answer 24

bind fluorescent dye to mAbs
put (bound) fluorescent mAbs on the slide
Pathigens then will show up

Question 25

It has been shown that this mAbs treatment is effective in the laboratory using both:
• infected tissue culture cells
• infected live animals.
The mAbs treatment for Candida albicans is now ready for clinical trials on people.
Describe how the clinical trials should be carried out.

Answer 25

• given first to healthy volunteers
• at (very) low dose
• to test it is safe or to test for toxicity or to check for any side effects
• then to some patients (with the disease or people with the disease
• to test for the correct / optimum dose
• to check for any side effects
• to test for efficacy or to test if it works
• in a double blind trial
• where neither patients nor doctors know who has the mAbs and who has a placebo (or alternative treatment)

Question 26

A scientist noticed that in one area the gorse plants had yellow leaves and had
stunted growth.
One reason for yellow leaves and stunted growth is a deficiency of nitrate ions in the soil.
+
Explain two other possible reasons for the yellow leaves and stunted growth.
Do not refer to nitrate ions in your answer.
[5 marks]
Reason 1
Explanation
[Answer?
Reason 2
Explanation

Answer 26

(so) not enough chlorophyll for (efficient) photosynthesis
(1)
(so) not enough glucose to make proteins for growth or not enough glucose to release energy for growth (1)
• infection by pathogen / bacteria / virus / fungus (1)
(so) leaves become
discoloured / yellow so less photosynthesis (1)
(so) not enough glucose to make proteins for growth or not enough glucose to release energy for growth (1)
• infected by aphids (1)
(which) remove sugars from phloem (1)
(so) not enough glucose to make proteins for growth or not enough glucose to release energy for growth (1)
• lack of (available) light (1)
(so) chlorophyll breaks down