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B1 - Final Exams - Coggle Diagram
B1 - Final Exams
L5 - Specialised Cells
Sperm cells contain acrosome (containing enzymes) in their heads, contain mitochondria and have a flagellum for movement.
Muscle cells contain filaments of protein that can slide over each other to cause muscle contraction. They also contain many mitochondria.
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The phloem makes use of companion cells that contain many mitochondria, they release energy for the phloem.
L9 - Stem Cells
Embryonic stem cells can differentiate into any type of cell but there are ethical concerns surrounding their use. They are required in an embryo's development.
In plants, stem cells are located in the meristem (at the roots or shoot).
Therapeutic cloning is a process in which embryonic stems cells are created containing the genetic material of the patient.
The cloning of plants has the potential to save species from extinction as well as producing plants that are genetically engineered to be economically beneficial.
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L3 - Microscopy
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Light microscopes are cheap, portable and require little assembly or preparation. They cannot see ribosomes.
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L6 - Differentiation
Most animal cells differentiate at a very early stage. Most plant cells can retain the ability to differentiate throughout life.
When a cell differentiates, it gains different sub-cellular structures that enable it to carry out a function.
L10 - Diffusion
A good diffusion surface has:
- Large SA.
- Good blood supply.
- Short diffusion distance.
- Moist (gasses dissolve).
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L4 - Microscopy Method
- Place the specimen on a slide using forceps.
- Add a drop of dye (iodine) using a pipette.
- Lower the coverslip onto the specimen using forceps.
- Rid of excess stain with filter paper.
- Start with the lower objective lens and focus using the focusing wheels.
- Increase the magnification.
L7 - Chromosomes
There are 23 pairs of chromosomes in each cell; the nucleus of a cell contains chromosomes. These chromosomes contain a large number of genes.
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