Sabtu, 30 Jun 2012

Biology Form 4

 Plant & Growth

1. Name the phase in which the:

a) centromeres of chromosomes are lined up at an imaginary plane across the middle of the cell

Metaphase

b) nucleolus re-forms and the spindle fibres disappear

Telophase

c) chromosomes are visible as duplicated, thick and short thread-like structures

Prophase

d) cell is about ready to divide by cytokinesis

Telophase

e) cell is gathering its energy to begin active mitosis

Interphase

f) two sister chromatids of each chromosome separate at the centromere

Anaphase





Based on the diagram, answer the following questions:

a) Name the tissue found at the tip of a plant root.

Apical meristem

b) Where else in a plant is this tissue usually found?

Shoot tip

c) State the characteristics of the cells found in the tissue named in (a).

Very small in size / isodiametric in shape /contain a dense cytoplasm / have a large nucleus
 
For secondary growth in a plant, mitosis occurs in the vascularcambium, a tissue found between the xylem and phloem tissue in dicotyledons.

 Mitosis is important for growth because it increases the number of cells in the organism.