Understanding Chromatids and Chromosomes

This video from Moomoomath and Science explains the differences between sister chromatids and homologous chromosomes. Sister chromatids are identical copies of a chromosome connected by a centromere, formed during DNA replication in the S phase of interphase. They are separated during mitosis or the second division of meiosis. Homologous chromosomes consist of one paternal and one maternal chromosome, pairing during meiosis. They are similar in size and gene location but may have different alleles. The video concludes with a call to subscribe for daily math and science content.

Why is DNA replication necessary before a cell divides?

• To ensure each new cell has a complete set of DNA

• To create more space in the cell

• To remove old DNA

• To change the cell's function

What holds sister chromatids together?

• A mitochondrion

• A ribosome

• A spindle fiber

• A centromere

During which phase are sister chromatids separated?

• Interphase

• Prophase

• Mitosis or the second division of meiosis

• Cytokinesis

What is a characteristic of homologous chromosomes?

• They are held together by a centromere

• They are identical copies

• They consist of one paternal and one maternal chromosome

• They are only found in prokaryotic cells

How do homologous chromosomes differ from sister chromatids?

• They can have different alleles

• They are only present during mitosis

• They are identical in every way

• They are held together by a centromere

What is true about the size and gene location of sister chromatids?

• They are the same size and have genes at the same location

• They vary in size and gene location

• They have genes located randomly

• They are larger than homologous chromosomes

Which of the following is true about alleles in homologous chromosomes?

• They are only present in sister chromatids

• They are not involved in genetic variation

• They are always identical

• They can differ because one is from the mother and one is from the father

What is the main difference between sister chromatids and homologous chromosomes?

• Sister chromatids are identical, while homologous chromosomes can have different alleles

• Sister chromatids are different sizes, while homologous chromosomes are identical

• Sister chromatids are not involved in cell division

• Sister chromatids are found in meiosis, while homologous chromosomes are found in mitosis