cell cycle and mitosis

Question 1

how can chemicals stop the growth of roots? (3)

Answer 1

-stops mitosis
-stops spindle fibres forming
- prevents sister chromatids being pulled apart

Question 2

describe the appearance and behaviour of chromosomes during mitosis (7)

Answer 2

PROPHASE
-chromosomes condense and become visisble
- appear as two sister chormatids joined at centromere

METAPHASE
-chromosomes line up along equator of cell
-attach to spindle fibres
-by centromere

ANAPHASE
-centromere splits
-chromosomes pulled to opposite poles

TELOPHASE
-chromosomes uncoil

Question 3

Describe how you would determine a reliable mitotic index from tissue observed with an optical microscope. (3)

Answer 3

-count cells in mitosis in field of view
-divide by total cells in field of view
-repeat at least 10 times