Question

question 1
1 pts
which statement about sister chromatids is true?
○ only homologous chromosomes can contain sister chromatids. non-homologous chromosomes do not ever contain sister chromatids.
○ they arise by replication during s phase.
○ they are the same as homologous chromosomes
○ they usually contain different versions of a gene (maternal and paternal) because the chromatids join at the centromere during fertilization.

Explanation:

• Sister chromatids are identical copies of a single chromosome created during the S phase of the cell cycle via DNA replication.
• All chromosomes (homologous and non-homologous) form sister chromatids during replication, so the first option is false.
• Homologous chromosomes are pairs of chromosomes (one maternal, one paternal) with similar genes, while sister chromatids are identical copies of one chromosome, so they are not the same, making the third option false.
• Sister chromatids are identical, so they have the same gene versions, and they join at the centromere during replication, not fertilization, making the fourth option false.

Answer:

They arise by replication during S phase.