Question

if a eukaryotic cell is in the g₁ phase of the cell cycle, which statement about the cell’s chromosomes must be correct?

the chromosomes are preparing for dna synthesis.

each chromosome is made of a complex of dna and associated proteins.

each chromosome consists of two identical chromatids.

Explanation:

1. Analyze Option 1: In the \( G_1 \) phase, the cell is preparing for DNA synthesis (which occurs in the S phase), but the statement "The chromosomes are preparing for DNA synthesis" is not about the structure of chromosomes in \( G_1 \) and is less a "must - be - correct" structural statement. Also, the main event of \( G_1 \) is cell growth and preparation for S phase, not the chromosomes themselves being described as "preparing" in a direct structural sense.
2. Analyze Option 2: Chromosomes in eukaryotic cells, at any stage of the cell cycle (including \( G_1 \)), are composed of a complex of DNA and associated proteins (like histones). This is a fundamental structural characteristic of eukaryotic chromosomes.
3. Analyze Option 3: Chromosomes consist of two identical chromatids (sister chromatids) only after DNA replication, which occurs in the S phase. In the \( G_1 \) phase, DNA replication has not yet taken place, so chromosomes do not have two identical chromatids.

Answer:

B. Each chromosome is made of a complex of DNA and associated proteins.