The Cell Cycle

Front 1

Interphase

Back 1

Phase in which a cell spends most of it life, where the following stages happen: G1, S Phase, G2

Front 2

G1 Phase

Back 2

The first "gap", or growth phase of the cell in which the cell grows large enough to divide into two cells that will be normal size and function

Front 3

S Phase

Back 3

Part of Interphase where the replication of genetic material

Front 4

M Phase

Back 4

The dividing phase of the cell, the only phase in which stained chromosomes can be observed after they have condensed into compact structures

Front 5

Cytokinesis

Back 5

The division of the cytoplasm into two distinct cells, resulting in two daughter cells

Front 6

Histones

Back 6

The protein in which the DNA double helix of chromosomes wraps itself around

Front 7

Chromatid

Back 7

Each of the DNA copies in a replicated chromosome

Front 8

G2 Phase

Back 8

The second growth stage of the cell after the S phase in which the cell contains replicated chromosomes consisting of their sister chromatids

Front 9

M Phase

Back 9

The dividing phase of the cell consisting got th amitotic sub phases Prophase, Prometaphase, Metaphase, Anaphase, Telophase

Front 10

Centromere

Back 10

The place of attachment of the two sister chromatids of chromosomes within the cell

Front 11

Kinetochore

Back 11

Specialized structures where the microtubule (spindle) attaches to the chromosome during Prometaphase. Complex of many proteins that build a base on the centromere region of the chromosome

Front 12

Centrosome

Back 12

NOT THE SAME AS CENTROMERE

Structure that acts as an organizing center for microtubulescontains a pair centrioles- comprise microtubules, and aid in moving the chromosomes to opposite sides of the nucleus

Front 13

Anaphase

Back 13

Anaphase operates by pulling the sister chromatids toward separate poles via microtubules. It is the depolymerizing of these microtubules that “frays” them into becoming shorter

Front 14

How do Microtubules Move Chromosomes During Anaphase?

Back 14

Microtubule are disassembled at the kinetochore during anaphase. Kinetochore microtubules remain stationary, but shorten because tubular units are lost from their plus ends.

Front 15

Mitotic Spindle Fibers

Back 15

The spindle apparatus is composed of microtubules, which are composed of a and b tubular dimers, microtubules also have a plus and minus end.

Front 16

Chromatin

Back 16

The material that makes up eukaryotic chromosomes; consist of a DNA molecule complexed with histone proteins.

Front 17

Prophase

Back 17

First Stage of Mitosis

-Chromosomes Condense into Compact structures

-Nuclear Envelope is still present

-Spindle Apparatus begins to form

Front 18

Order of The Cell Cycle

Back 18

Interphase

Prophase

Prometaphase

Metaphase

Anaphase

Telophase

Front 19

Prometaphase

Back 19

Second Stage of Mitosis:

-Nuclear Envelope Breaks down

-Microtubules contact chromosomes at kinectochores

-

Front 20

Metaphase

Back 20

The Third Stage of Mitosis:

-Chromosomes are lined up in the center of the cell

Front 21

Anaphase

Back 21

The fourth stage of Mitosis:

-sister chromatids are pulled apart toward the opposite ends of the cell by the shrinking microtubules

Front 22

Telophase

Back 22

The Fifth and Final Stage of Mitosis:

-Two nuclear envelopes form around the two sets of chromosomes

Front 23

Cytokinesis

Back 23

The division of the cytoplasm during telophase:

-Actin-myosin ring causes the plasma membrane to begin pinching in, and two new daughter cells form.

Front 24

What are the four major checkpoints in the cell?

Back 24

G1 Checkpoint

G2 Checkpoint

M Phase Checkpoint- there are two within the m phase

Front 25

MPF

Back 25

M phase-promoting factor

-Induces M phase in all eukaryotic cells

Front 26

How does MPF work?

Back 26

MPF contains protien and a cyclin

-The protein is a cyclin dependent kinase or Cdk

-MPF is turned on by two phosphorylation events

-In the G2 phase, an enzyme removes an inhibitory phosphate, this dephospho rylation coupled with activation of the phosphate, changes the Cdk's shape in a way that turns on kinase

-Once MPF is activates, it triggers the onset of the M-phase

Front 27

How is MPF turned off?

Back 27

During anaphase, an enzyme complex begins degrading the MPF's cyclin subunit. The enzy,e attaches small proteins called ubiquitous to MPF's cyclin sub unit marks the unit for self destruction

Front 28

The G1 Checkpoint

Back 28

Determines whether the cell will continue through the cycle and divide, or exit the cycle and enter G0.

The passing of the check point is determined by:

-Size- must be large enough

-Availability of Nutrients

-Social Signals- signaling molecules from other cells

-Damage to DNA-If DNA is physically damaged, the protein p53 activates genes that either stop the cell cycle until the damage can be repaired.

-Rb protein is one of the key tumor suppressor molecules

Front 29

G2 Checkpoint

Back 29

The second checkpoint that occurs after the s phase

Passing is determined by:

-Undamaged DNA- if they were not replicated correctly, then the MPF is not turned on

Front 30

M-Phase Checkpoints

Back 30

The first Checkpoints regulates the onset of anaphase- cells in M-phase will not split the chromatids until all spindle is attached properly

The second checkpoint regulates the progression through M-phase into G1- the enzymes responsible for cyclin destruction are only activated when all chromosomes have been properly separated

Front 31

Cancer Cells have which two defects?

Back 31

Defects that make the proteins required for cell growth active when they shouldn't be, and defects that prevent tumor suppressors ( like p53) from shutting down the cell cycle.

Front 32

Ras

Back 32

A protein that is a key component in signal transductions systems including phosphorylation cascades that trigger cell growth. Many cancers have defective forms of Ras that constantly send signals that trigger mitosis and cell division

Front 33

What is a Malignant tumor?

A Benign tumor?

Metastasis?

Back 33

A Malignant tumor is a mass of invasive cells that are cancerous. Non invasive masses are called benign tumors. When cells Metastasize, this means that they spread from the primary tumor site to the secondary tumors elsewhere in the body.

Front 34

Social Control

Back 34

Cells often divide in response to signals from other cells. This control is based on growth factors

Front 35

What does cyclin overproduction result from?

Back 35

Excessive amounts of growth factors or cyclin overproduction in the absence of growing signals