Chapter 11

Plant cell cytokinesis

*a cell wall forms between daughter cells *vesicles fuse to form a cell plate

Animal cell cytokinesis

*a contractile ring pinches the cell in two *cleavage produces a furrow around the cell

What are the functions of mitotic cell division?

*growth of multicellular organisms *asexual reproduction *cell regeneration

What functions do centrosomes have during mitosis?

*help produce the mitotic spindle *act as the microtubule organizing center

The cell cycle is a repeating sequence of events that leads to the duplication and division of a cell. Place the stages of the cell cycle in the order of their occurrence, from the earliest stage of cell growth through the latest stage of cell division.

*interphase *prophase *prometaphase *metaphase *anaphase *telophase *cytokinesis

Cyclins

*only expressed at specific times during the cell cycle *do not have enzymatic function *activate cyclin-dependent kinase

Cyclin-dependent kinases

*phosphorylate specific amino acids on other proteins *require cyclin binding to function *directly activate proteins important at specific phases of the cell

Place the steps of the prokaryotic cell cycle in order

*prokaryotic chromosome attaches to the plasma membrane *prokaryotic chromosome replicates *cell elongates, pulling each chromosome to a different end of the cell *plasma membrane and cell wall grow inward and divide the cell *two genetically identical daughter cells are produced

M checkpoint

all chromatids are checked for proper attachment to spindle fibers

During which phase of mitosis do spindle fibers shorten, pulling sister chromatids apart from one another and toward opposite ends of the cell?

anaphase

During the cell cycle, the cell must pass through several checkpoints that confirm that the cell is ready to progress to the next phase of the cycle. If the requirements of one phase have not been met, the cell cannot proceed to the next phase. These checkpoints help control the rate of cell division. If a mutation disables one of these checkpoints, what is most likely to happen?

cells begin dividing faster, leading to cancer

Benign tumors are non-cancerous tumors. How are malignant tumors different from benign tumors?

cells in malignant tumor exhibit uncontrolled growth, the ability to invade other tissues, and may be able to metastasize

As genetic material replicates, sister chromatids are linked in an X-shaped structure. What is the term used to describe the area where the two chromatids are linked?

centromere

In general, what causes normal cells to become cancer cells?

loss of cell cycle control

G2 checkpoint

proper replication of all chromosomes is verified

What is the function of the mitotic spindle?

separating sister chromatids

How does mitosis and cytokinesis in eukaryotes differ from binary fission in prokaryotes?

sister chromatids attach to spindle fibers during mitosis, whereas binary fission does not use spindle fibers to separate the replicated chromosome

During which phase of mitosis do nuclear membranes reform around the separated copies of DNA?

telophase

G1 checkpoint

the cell determines whether resources are sufficient to proceed with the cell cycle

Which phrase describes a sister chromatid?

the exact copy of a single chromosome

Cell division by mitosis is a mechanism of asexual cell replication. Some single-cell organisms reproduce by cell division, and cell division enables multicellular organisms to grow and to repair damaged cells. Which of the following are products of cell division by mitosis?

two cells genetically identical to the original cell