Practise CAIE AS Biology 5.2 by identifying mitotic stages in images and explaining how chromosomes, the spindle, nuclear envelope and cell surface membrane behave.
The graphs show various distance measurements taken from the start of metaphase of mitosis. The graphs are to scale when compared to one another.
Which row correctly identifies the distance measurement for each graph?
X
Y
distance between poles of spindle
distance of centromeres from poles of spindle
distance between poles of spindle
distance between sister chromatids
distance of centromeres from poles of spindle
distance between sister chromatids
distance of centromeres from poles of spindle
distance between poles of spindle
Which row correctly shows the behaviour of the nuclear envelope, the centrioles and the spindle during a stage of mitosis?
nuclear envelope
centrioles
spindle
disappears
replicate
spindle microtubules begin to form
not present
begin to move to poles of cell
spindle microtubules fully formed
begins to reform
at opposite poles of the cell
some spindle microtubules shorten
reforms
one beside each nucleus
spindle microtubules break down
Eukaryotic organisms grow and increase in size as a result of cell division. The diagram shows some stages of mitosis with one stage missing, labelled X .
What happens in stage X ?
Spindle fibres attach to the centromeres and the chromosomes line up along the equator.
The chromatin coils and condenses and the nuclear membrane disintegrates.
The chromosomes line up in pairs along the equator of the cell.
Microtubules shorten so that spindle fibres contract and the centromeres divide.