Paper 2 Flashcards
What is the function of red and white blood cells?
RED = carrying oxygen WHITE = defending from disease
What is cell differentiation?
The process by which a cell changes to become specialised for a job.
What is an undifferentiated cell?
A stem cell - it can multiply and differentiate (turn in to) different cells depending on the instructions given.
Why are doctors excited by stem cells? (further)
They have potential to turn into any type of cell which brings great possibilities for research and development.
Where can undifferentiated cells be found?
In feutus’
Where can adult stem cells be found?
Bone marrow
What is the difference between embryonic stem cells and adult stem cells?
Embryonic stem cells can be differentiated into any cell, adult stem cells can only turn into certain cells, such as red blood cells.
Why are some people against stem cell research? and what is the counter argument for this point?
They feel human embryo’s should not be used for research as every one is a potential human life.
Counter Argument - People who are suffering great deals of pain need these stem cells
How are adult stem cells used in medicine today?
Stem cells are transferred from the bone marrow of a healthy person to a patient who cannot produce their own blood cells.
What is a potential use for embryonic cells in medicine?
Nerve cells for those paralysed by spinal injuries
What risks are there for using stem cells in medicine?
Cells grown in a lab may become contaminated with a virus and passed on to the human.
What is a root hair cell?
The cells on the plant root grow into long ‘hairs’ which stick out in the soil. Each branch of ‘hair’ is covered in millions of root hair cells.
What process’ does a root hair cell use to absorb water?
Osmosis - higher concentration of water in the soil than in the cell.
Active Transport - Dissolve mineral ions from the soil.
What are the main 4 factors affecting transpiration rates?
- Light Intensity
- Temperature
- Wind Speed
- Humidity
What is transpiration?
The loss of water from a plant through the stomatal pores.
What processes cause transpiration?
evaporation and diffusion
What can be used to measure transpiration rates?
Potometer
When does photosynthesis occur?
In the day or in synthetic lightning.
What gases are taken in and given out hen a plant respires?
Oxygen is taken in and Carbon Dioxide comes out, just like humans
How are leaves adapted for diffusion?
- Broad, so there’s a large surface area for diffusion.
- Thin, this provides a short distance for diffusion.
- Air spaces, gases can move between cells easily.
- Stomata, allow gases in and out (and water out).
- Stomatal opening and closing caused by guard cells
How do guard cells change the stomatal opening?
By changing their own shape and volume - as guard cells increase in volume they open stomata. When guard cells decrease in volume they close stomata.
What are platelets?
Small fragments in the blood (that help blood to clot).
What is the function of platelets?
Platelets prevent blood loss by forming clots at the damaged area.
What holds platelets together at a blood clot?
A mesh of a protein called fibrin.