Page 130 - Knowledge Organiser Yr9 24-25

Knowledge Base/Builder: Science B1: Cell Biology Year 9
13. Stem Cells
13.1
What is a stem cell?
An undifferentiated cell, capable of giving rise to many more cells of the same type which can differentiate into specialised cells.
13.2
What is the function of embryonic stem cells?
To differentiate into all types of body cell.
13.3
Why are embryonic stem cells important in medical research?
They can be cloned and made to differentiate into most different types of human cell.
13.4
Where can stem cells be found in adults?
Bone marrow.
13.5
What can adult stem cells differentiate to form?
Blood cells and some other cells.
13.6
What plant tissue can differentiate into any type of plant cell?
Meristem tissue.
13.7
Name two medical conditions that could be treated with stem cells.
Diabetes and paralysis.
13.8
What is therapeutic cloning?
When an embryo is produced with the same genes as the patient.
13.9
What is the benefit of therapeutic cloning?
Stem cells from the embryo are not rejected by the patients body.
13.10
Name two potential problems with the use of stem cells in therapeutic cloning.
Transfer of viral infection, ethical/ religious objections.
13.11
What can stem cells from meristems in plants be used to produce?
Clones of plants (quickly and economically).
13.12
What is the benefit of using meristems to produce clones of plants?
Rare species can be cloned to protect from extinction, cloning disease resistant plants.
Knowledge Builder – Osmosis required practical:
14.1
Describe a method that to carry out
the experiment shown in Figure 1.
1. Cut three pieces of potato to the same length. 2. Dry each piece on a paper towel.
3. Weigh each piece using a top-pan balance.
4. Place each piece in a different concentration
of sugar solution.
5. Leave all three pieces for 2 hours.
6. Remove the three pieces of potato from the solutions.
7. Dry each piece on a paper towel.
8. Measure the length and mass of each piece of potato.
9. Calculate the percentage (%) change in mass of each piece. 10. Repeat steps 1-8 multiple times and calculate a mean.
11. Record results in a table & represent in a line graph.
14.2
What is the independent variable?
The factor you change is the concentration of sugar solution.
14.3
What is the dependent variable?
The factor you measure is the percentage change in mass.
14.4
What are 3 control variables?
The factors that you keep the same are volume of plant tissue, time left in solution, temperature of the solution, type of plant tissues and surface area of the plant tissue.
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