Stem Cells

Question 1

What are stem cells?

Answer 1

• Stem cells are able to divide by mitosis to form more cells.
• Stem cells are able to differentiate into special cells e.g. skin cells, nerve cells.

Question 2

How are embryonic stem cells formed? (Human life)

Answer 2

• When a sperm cell fertilises an egg cell, it forms a single cell called a zygote.
• The zygote is now its organism and during the following few days, divides due to mitosis repeatedly to form a group of cells called an embryo.
• These cells are called embryonic stem cells.

Question 3

Can embryonic stem cells differentiate into any type of cell?

Answer 3

Yes, e.g: skin cells, nerve cells, blood cells.

Question 4

Overtime, what happens to the group of embryonic stem cells?

Answer 4

• They continue to divide and differentiate into all the other important cells we need, and after 9 months, forms into a baby.

Question 5

What happens to stem cells once you become an adult?

Answer 5

• Stem cells can no longer differentiate into absolutely anything, like the embryonic stem cells can.
• Instead, there are other types of stem cells which have already specialised a bit meaning that they can only differentiate into a smaller range of cells
• e.g: In the middle of some large bones there is a jelly-like substance called bone marrow, containing adult stem cells.

Question 6

What can adult stem cells do?

Answer 6

• Divide through mitosis as much as they like
• They can only differentiate into different types of blood cells. e.g: Red blood cells, White blood cells, Platelets.
• They can replace damaged to keep up alive, but they don’t form any new tissues, like embryonic stem cells do.

Question 7

Where are plant stem cells found?

Answer 7

• Found in plant tissues called ‘Meristems’
• Meristems are found in areas of the plan that are continuously growing e.g. the tips of roots and shoots.

Question 8

What happens to the plant stem cells as the plant grows?

Answer 8

• The unspecialised plant cells differentiate into all the cells and tissues that the plant needs e.g. Palisade cells (for photosynthesis)

Question 9

What is a difference between plant stem cells and embryonic stem cells?

Answer 9

• Plant stem cells persist for the plant’s entire life, where as embryonic stem cells which disappear by the time we have fully developed.