Question

• What is the functional value of the regular checkpoints that are a feature of the cell cycle? Use complete sentences in your response. • Can anaphase takes place before metaphase during mitosis? Why or why not? Use complete sentences in your response. For questions 8-11, match each stage of the cell cycle to its current description: • G; stage S stage At the end of this stage, each chromosome consists of 2 attached chromatids. G2 stage . During this stage, daughter chromosomes are distributed to 2 daughter nuclei M stage The cell doubles its organelles and accumulates the materials needed for DNA synthesis The cells synthesis the proteins needed for cell division

Answer 1

1.Functional value of regular checkpoints that are feature of cell cycle.

Ans: In eukaryotic cell cycle, cell examines external and internal cues and decides to move forward or not with cell division. This point of examination are called checkpoints.There are three checkpoints in cell cycle.

i. G1 check point at G1/S transition: This point checks for cell size, nutrients, growth factors and DNA damage before proceeding to next cell cycle.

ii. G2 checkpoint at G2/M transition: This point checks for DNA damage, DNA replication completeness.

iii. Spindle checkpoint at transition from methaphase to anaphase: Checks for chromosome attachement to spindle at methaphase plate.

2. Can anaphase takes place before metaphase during mitosis.

Ans: Phases of cell division are Prophase-methaphase-Anaphase-Telophase.

Anaphase cannot take place before methaphase because, there is a checkpoint called Spindle checkpoint for cell division to move to anaphase from metaphase.Spindle checkpoint ensures that all the chromosomes are at the metaphase plate with their kinetochore correctly attached to microtubles, then cell division moves to the next phase called anaphase.

3. Match the following.

G1 stage----The cell doubles its organelles and accumulates the materials needed for DNA synhesis.

S stage ----At the end of this stage each chromosomes consists of 2 attached chromatids.

G2 stage----The cells synthesis the proteins needed for cell division.

M stage ----During this stage, daughter chromosomes are distributd to 2 daughters nuclei.