Question

points Cells from advanced malignant tumors often have very bromal chromosomes and an abnormal number of chromosomes What might explain the association between malignant tumors and chromosomal abnormalities? A Cancer cells are arrested in the stage of the cell cycle B. Cancer cells use enzymes to break their chromosomes into smaller pieces, increasing the surface area of genes. C. Cancer cells do not have cell cycle checkpoints in place to prevent cells with damaged chromosomes from dividing D. Cancer cells lack a sufficient number of Cdk proteins.

Answer 1

Why advanced malignant tumors have very abnormal chromosomes or an abnormal number of chromosomes?

Cancer cells do not have cell cycle checkpoints in place to prevent cells with damaged chromosomes from dividing.

This is a hallmark of malignancy. Cancer cells lack basic cell cycle checkpoints (mutation in cell cycle regulating proteins). This leads failure of proofreading during cell cycle. Damaged chromosomes are passed on to the next stage of cell cycle without being repaired.

Other options are wrong.

Cancer cells are not arrested in the G1 stage of the cell cycle (In fact, they are not arrested at any stage of cell cycle, they just keep dividing – uncontrolled cell division).

Cancer cells do not break their chromosomes. If it happens, they will die of apoptosis or induced inflammation.

Cancer cells do not lack sufficient number of Cdk proteins. They have enough Cdk proteins. They just lack regulatory mechanism.