Final answer:
If DNA wasn't organized into chromosomes, errors in segregation during cell division could lead to genome instability or disease.
Step-by-step explanation:
During cell division, if DNA was not properly wrapped into chromosomes, several issues could arise. Structurally, DNA wraps around histone proteins to form nucleosomes, which then coil into chromatin and further condense into chromosomes.
This packaging is crucial for the organized segregation of genetic material during cell division. If DNA did not condense into chromosomes, it would result in a 'mass of strings', which would be difficult to accurately segregate, leading to genome instability and possibly cell death or diseased states.
A failure in separating sister chromatids during mitosis would result in cells with an improper number of chromosomes, a condition known as aneuploidy, which can lead to genetic disorders or cell death. A mutation that prevents the production of DNA binding proteins could impede DNA replication, as these proteins stabilize single-stranded DNA and guide enzyme activity. Without them, the replication could be faulty or halted.
During anaphase, if sister chromatids are not properly attached to their respective microtubules and aligned at the metaphase plate, it could prevent correct chromosome separation, leading to aneuploidy. DNA replication before cell division ensures each daughter cell receives a complete set of genetic instructions. Incomplete or absent replication prior to division would result in cells with incomplete sets of DNA, which could lead to malfunctioning cells or cell death.
Finally, occurrences such as errors during the S phase or during prophase I of meiosis could lead to mutations if not repaired, influencing genetic variability. Duplications can contribute to genetic variation, while translocations usually have more severe consequences. It is the organized and accurate replication and segregation of DNA during cell division that maintains the integrity and function of an organism.