B2.1 Supplying The Cell Flashcards
Define diffusion
The net movement of molecules from an area of high concentration to an area of low concentration down their concentration gradient
How does temperature affect diffusion?
As the temperature increases, the rate of diffusion increases as the particles have more kinetic energy and move faster
How does the concentration gradient affect diffusion?
The greater the concentration gradient (the difference between the two areas), the faster the rate of diffusion
How does the surface area of the membrane affect diffusion?
If the surface area increases so does the rate of diffusion as there is more space for the particles to move through
Define osmosis
The net movement of water molecules from a high water potential to a low water potential down their concentration gradient across a partially permeable membrane
Define active transport
The movement of molecules from a low concentration to a high concentration against their concentration gradient using energy
Describe mitosis (including the cell cycle)
1) The chromosomes are replicated
2) The chromosomes line up in the middle
3) The chromosomes are pulled apart
4) Membranes form around the chromosomes and the
cytoplasm divides
5) The two cells then continue growing
Define cell differentiation
Differentiation is where cells become specialised for a particular function
How are sperm cells specialised to their function?
- Large tail for movement
- Acrosome (containing enzymes) to digest the egg membrane
- Lots of mitochondria for energy
- Haploid nucleus
How are nerve cells specialised to carry impulses?
- They have a long axon to transport the impulse long distances
- Contain extensions to connect to other nerve cells and contain neurotransmitters to transmit the impulse
How are root hair cells specialised to take up water and minerals?
- They have lots of mitochondria to generate energy
- They have a large surface area for faster diffusion
What are stem cells?
Stem cells are undifferentiated cells and can develop into lots of different types of cells
Where are animal stem cells found?
Animal stem cells are found in embryos and in the bone marrow
What is the difference between adult and embryonic stem cells?
Embryonic stem cells can differentiate into any type of cell whereas adult stem cells can only differentiate into cell types from the tissue the stem cells are in
Where are plant stem cells found?
Plant stem cells are found in meristematic tissue
