Chapter 12- The Cell Cycle

Rb protein

Rb protein

The ________ serves as a gatekeeper that enforces the G1 checkpoint.

spindle apparatus

The ________ is a structure that produces mechanical forces that:

Eukaryotic chromosomes

________ consist of DNA wrapped around globular histone proteins.

Cancer

________ is a general term for disease caused by cells that divide in an uncontrolled fashion, invade nearby tissues, and spread to other sites in the body.

Regulatory proteins

________ such as p53 are called tumor suppressors.

Serum

________ is the liquid portion of blood that remains after blood cells and cell fragments have been removed.

Growth factors

________ are polypeptides or small proteins that stimulate cell division.

Howard

________ and Pelc coined the term cell cycle to describe the orderly sequence of events that leads a eukaryotic cell through the duplication of its chromosomes to the time it divides.

Negative feedback

________ occurs when a process is slowed or shut down by one of its products.

genetic material

The process of copying the ________ is separated, in time, from the partitioning of replicated chromosomes during M Phase.

telophase

During ________, the nuclear envelope re- forms around each set of chromosomes, and the chromosomes begin to decondense.

multicellular organisms

In ________, cells that keep dividing in this way may die or form a mass of cells called a tumor.

Centrosome

________ is a structure that contains a pair of centrioles.

sister chromatids

At the start of anaphase, the cohesins that hold ________ together at 1e centromeres are cleaved by an enzyme.

MPF

The substance that initiates M- phase in oocytes is now called the M- phase- promoting factor, or ________.

Mitosis

________ begins with the events of prophase which is when chromosomes condense into compact structures.

MPF deactivation

________ illustrates two key concepts about regulatory systems in cells:

DNA copies

Each of the double- stranded ________ in a replicated chromosome is called a chromatid.

Removal of the envelope

________ allows the cytoplasmic microtubules to attach to chromosomes at specialized structures called kinetochores.

Chromatid copies

________ that remain attached at their centromere are referred to as sister chromatids.

MPF

________ is a dimer consisting of a cyclin and a cyclin- dependent kinase.

The four cell-cycle checkpoints have the same purpose

They prevent the division of cells that are damaged or that have other problems

Chromosome

refers to these threadlike structures

Gene

is a region of DNA in a chromosome that codes for a particular protein or ribonucleic acid (RNA).

Chromatid

Each of the double-stranded DNA copies in a replicated chromosome is called a