Question

value: 8
the subphase of interphase in which dna replicates.
a. g1
b. s
c. g2
d. r
e. m
value: 8
the structure that holds the two sister chromatids together.
a. kinetochore
b. centrosome
c. chromosome
d. centromere
e. centriole
value: 8
the two main stage of the cell cycle.
a. g1 and s
b. interphase and prophase
c. interphase and mitosis
d. metaphase and telophase
e. telophase and interphase
f. mitosis and anaphase

Explanation:

1. In the cell - cycle, DNA replication occurs during the S (synthesis) phase of interphase. G1 is the first gap phase for cell growth, G2 is the second gap phase for preparation for mitosis, R is not a standard phase in the cell - cycle, and M is the mitosis phase.
2. The centromere is the structure that holds two sister chromatids together. A kinetochore is a protein structure for spindle - fiber attachment, a centrosome is involved in organizing microtubules, a chromosome is a DNA - protein complex, and a centriole is part of the centrosome in animal cells.
3. The two main stages of the cell cycle are interphase (where the cell grows, replicates DNA, and prepares for division) and mitosis (where the cell divides its nucleus and then cytoplasm).

Answer:

1. b. S
2. d. Centromere
3. c. Interphase and Mitosis