RP2

Question 1

Explain purpose of incubating the root tip with HCl

Answer 1

Stop mitosis, and hydrolyses middle lamella and be separated easily.

Question 2

Why press the coverslip down firmly rather than smearing

Answer 2

No bubbles, form a single layer, chromosomes may be damaged.

Question 3

How much time a cell spends in a phase of a cell cycle.

Answer 3

Number cell / Total number cells x number of minutes in metaphase.

Question 4

Number of minutes cells spends in a phase of a cell cycle

Answer 4

Mitotic Index x Number of minutes spend in metaphase.

Question 5

Explain the behavior of pro

Answer 5

PROPHASE
Chromosomes are becoming visible because they are condensing; Chromosomes are arranged at random because they are not attached to spindle fibres yet;
Chromosomes appear as two sister chromatids joined at the centromere because DNA has replicated.
METAPHASE
Chromosomes are lined up on the equator (metaphase plate); the chromosomes attach to spindle fibres by their centromeres. ANAPHASE
Centromeres divide & chromatids from each pair are pulled to opposite poles of the cell as the spindle fibres shorten; V-shape shows that chromatids have been pulled apart at their centromeres.
TELOPHASE
Chromosomes become longer/thinner because they decondense.