topic 1 - cell biology: cell division

Question 1

where are chromosomes located in a cell and what are they made up of?

Answer 1

located in the nucleus and made up of DNA molecules

Question 2

are chromosomes found alone or in pairs?

Answer 2

in pairs

Question 3

describe the three stages of the cell cycle.

Answer 3

1. cell growth and DNA replicated to form two copies of each chromosome
2. mitosis - one set of chromosomes are pulled to each end of the cell and the nucleus divides
3. the cytoplasms and cell membranes divide to form two identical cells.

Question 4

why is cell division by mitosis important? hint: which organisms?

Answer 4

important in the growth and development of multicellular organisms.

Question 5

what is a stem cell?

Answer 5

an undifferentiated cell of an organism which is capable of giving rise to many more cells of the same type, and from which certain other cells can arise from differentiation.

Question 6

what is the function of stem cells in embryos?

Answer 6

can be cloned and made to differentiate into most different types of human cells.

Question 7

what is the function of stem cells in adult animals?

Answer 7

stem cells from adult bone marrow can form many types of cells including blood cells.

Question 8

what is the function of stem cells in meristems?

Answer 8

can differentiate into any type of plant cell thoughout the lifetime of the plant.

Question 9

which two conditions can be treated with stem cells?

Answer 9

diabetes and paralysis

Question 10

what are some of the risks involved in using stem cells?

Answer 10

transfer of viral infection, and some people have ethical or religious objections.

Question 11

what are some of the benefits of using stem cells in plants?

Answer 11

1. rare species can be cloned to protect from extinction
2. crop plants with special features such as disease resistance can be cloned to produce large numbers of identical plants for farmers.