Past paper 4 Flashcards
Describe three benefits of producing cloned plants from stem cells.
Genetically identical plants – Cloning means can keep desirable characteristics, such as disease resistance or high yield.
Quick production of large numbers – Stem cells can rapidly produce many plants, which is useful for farming and restoring endangered species.
Grow plants all year round - Cloned plants can be grown in controlled conditions, so they’re not limited by seasons or weather.
Why can’t all body cells be used to grow different types of cell?
Because they have become specialised and once that’s happened it can’t be changed.
Apart from bone marrow where can you find stem cells? TWO
embryos
skin
Medical conditions that can use stem cells for treatment? THREE
Type 1 Diabetes
Heart disease
spinal cord injuries
Risks of using stem cells in treatment? TWO
- Rejection by the body
- Infection when implanted
What is therapeutic cloning?
A form of stem cell harvesting by creating an embryo by fusing the nuclei of a body cell and an egg cell.
Ethical issues of therapeutic cloning
They are considered potential human life and it is wrong to experiment on them.
However, some argue that these are unwanted embryos that would be thrown out anyway.
Why can plants not just rely on diffusion for absorbing mineral iions?
The soil often has low concentration of these - so they need to use active transport.
TWO ways active transport differs from diffusion?
- It’s from low concentration to high concentration.
- It requires energy - diffusion is passive.
FOUR ways in which root hair cells are adapted for their function?
Long, thin extensions (root hairs) – Increase the surface area.
Thin cell walls – Makes it easier for water to move into the cell by osmosis.
Lots of mitochondria – Provide energy for active transport of mineral ions from the soil into the cell.
Large vacuole – Helps maintain a low water concentration in the cytoplasm, encouraging water to enter by osmosis
