Why do some species employ both mitosis and meiosis, whereas other species use only mitosis?

• They need meiosis if the cells are producing organs such as ovaries.
• They need only meiosis if they produce egg cells.
• They need both if they are producing plant gametes.
• They need only mitosis to make large numbers of cells such as sperm.

They need both if they are producing plant gametes.

Ex.

The production of gametes in plants is a function of both mitosis and meiosis. The form of cell division that produces animal gametes is meiosis, not mitosis.

A human bone marrow cell, in prophase of mitosis, contains 46 chromosomes.

• True
• False

True

Which of the following is true of kinetochores?

• They are sites at which microtubules attach to chromosomes.
• They are located at the center of the centrosome; their function is to organize tubulin into elongated bundles called spindle fibers.
• They attach to the ring of actin along the cytoplasmic surface of the plasma membrane, causing the actin to contract to form the cleavage furrow.
• They are the primary centromere structures that maintain the attachment of the sister chromatids prior to mitosis.

They are sites at which microtubules attach to chromosomes.

G1 follows cell division.

• True
• False

True

In some organisms, such as certain fungi and algae, cells undergo the cell cycle repeatedly without subsequently undergoing cytokinesis. What would result from this?

• a decrease in chromosome number
• division of the organism into many cells, most lacking nuclei
• a rapid rate of gamete production
• large cells containing many nuclei

large cells containing many nuclei