[Campbell Biology P.287] A newt lung cell has 22 chromosomes. Based on the information and i... | Practice Question
A newt lung cell has 22 chromosomes. Based on the information and illustrations provided, how many DNA molecules double helices would be present in a single newt lung cell during prometaphase?
Explanation
The text states that in prometaphase, chromosomes have duplicated during S phase, prior to G2 and each duplicated chromosome appears as two identical sister chromatids. Each chromatid is a single DNA molecule double helix . Therefore, if a newt lung cell has 22 chromosomes, then in prometaphase when they are duplicated , it would have 22 chromosomes x 2 DNA molecules/chromosome = 44 DNA molecules.