Cell Cycle and p53 Protein Functions

<p>Embryo cells have very short cell cycles of less than 20 minutes, and liver cells have a cycle of a year or two. (C)</p> Signup and view all the answers

<p>Unrestricted cell division (A)</p> Signup and view all the answers

<p>The cell containing damaged DNA will continue to divide unchecked. (B)</p> Signup and view all the answers

<p>Mature nerve and muscle cells, which do not divide after maturity. (D)</p> Signup and view all the answers

<p>That different cell types can have different division frequencies based on the organism’s needs. (B)</p> Signup and view all the answers

<p>Inhibition of p53 gene activity is a common requirement for all cancers. (D)</p> Signup and view all the answers

<p>About 12-24 hours, meaning they have a relatively short cycle. (B)</p> Signup and view all the answers

<p>G0 phase, or a similar resting phase, as they are not actively dividing. (C)</p> Signup and view all the answers

<p>To permit cells to duplicate their genetic material and divide, which is vital for growth and replacement. (B)</p> Signup and view all the answers

<p>They enter a non-dividing state called G0, which is effectively permanent. (C)</p> Signup and view all the answers

<p>Six (B)</p> Signup and view all the answers

<p>Activation of ‘suicide’ genes (C)</p> Signup and view all the answers

<p>Overcoming anchor and density dependence (A)</p> Signup and view all the answers

<p>Exposure to high altitude (D)</p> Signup and view all the answers

<p>It halts cell division at the original site (B)</p> Signup and view all the answers

<p>The spread of cancer cells to new tissues. (C)</p> Signup and view all the answers

<p>Rapidly dividing cells (C)</p> Signup and view all the answers

<p>Activation of touch-sensor genes (B)</p> Signup and view all the answers

<p>They represent points where the cell commits to DNA replication and sister chromatid separation respectively. (A)</p> Signup and view all the answers

<p>To halt the cell cycle if critical processes are incomplete or errors are detected. (D)</p> Signup and view all the answers

<p>Transition into the G0 phase, a non-dividing state. (C)</p> Signup and view all the answers

<p>The successful completion of DNA synthesis. (D)</p> Signup and view all the answers

<p>It represents a non-dividing state where most human cells reside. (D)</p> Signup and view all the answers

<p>Liver cells can re-enter the cell cycle from G0, while nerve and muscle cells cannot. (A)</p> Signup and view all the answers

<p>Incorrect separation of sister chromatids, leading to aneuploidy. (A)</p> Signup and view all the answers

<p>Whether the cell has achieved adequate size and has sufficient nutrition. (B)</p> Signup and view all the answers

<p>They catalyze phosphorylation reactions that can either activate or inactivate cell signals. (C)</p> Signup and view all the answers

<p>To trigger the passage through different stages of the cell cycle by phosphorylating cellular proteins. (D)</p> Signup and view all the answers

<p>It causes cell division to cease when cells become too crowded. (C)</p> Signup and view all the answers

<p>Cells must be attached to a substrate to undergo cell division. (D)</p> Signup and view all the answers

<p>The interaction of different cyclins with Cdks triggers the cell to proceed through different phases. (A)</p> Signup and view all the answers

<p>It implies that these regulatory mechanisms are fundamental requirements for cellular life and have remained largely constant across evolution. (D)</p> Signup and view all the answers

<p>By converting into oncogenes that promote uncontrolled cell growth and division. (B)</p> Signup and view all the answers

<p>Oncogenes promote cell growth, while tumor suppressor genes inhibit cell division. (D)</p> Signup and view all the answers

<p>By stimulating the division of fibroblasts, assisting in tissue repair. (D)</p> Signup and view all the answers

<p>Ensuring DNA replication has been completed before mitosis initiates. (C)</p> Signup and view all the answers

<p>All chromosomes must be properly attached at the metaphase plate. (A)</p> Signup and view all the answers

<p>To bind to cell surface receptors and send signals that stimulate cell division. (B)</p> Signup and view all the answers

<p>Cdks phosphorylate proteins to activate or inactivate them, and cyclins regulate Cdk activity. (D)</p> Signup and view all the answers

<p>Chemical signals such as proteins, either activators or inhibitors. (D)</p> Signup and view all the answers

<p>Internal signals include 'promoting factors', while external signals include growth factors. (B)</p> Signup and view all the answers

The process of timing and regulating cell division among various tissues and organs in a multicellular organism.

The rate at which different types of cells divide varies significantly.

Cells in an embryo divide very rapidly, with a cycle of less than 20 minutes.

Skin cells regularly divide throughout life, typically every 12-24 hours.

Liver cells can divide but do so infrequently, approximately once every year or two.

Once mature, nerve and muscle cells do not divide at all and remain in the G0 phase.

The cell cycle consists of interphase (G1, S, G2) followed by mitosis (M) and cytokinesis (C).

The resting phase in the cell cycle where mature nerve and muscle cells remain permanently.

A protein that regulates the cell cycle and prevents division with damaged DNA.

The point in the cell cycle where p53 checks for DNA damage before division.

Normal p53 triggers DNA repair and allows cell division only if DNA is intact.

Abnormal p53 fails to stop division of damaged DNA, leading to cancer development.

All cancers require the shutdown of p53 activity to progress.

Cancer develops after about 6 critical mutations, known as 'hits'.

Cancer cells turn on growth promoter genes for unrestrained growth.

Cancer cells can ignore cell cycle checkpoints by turning off tumor suppressor genes.

Cancer cells deactivate suicide genes to avoid programmed cell death.

Abnormal cells that remain localized and can often be surgically removed.

Cancerous tumors that invade nearby tissues and spread through the body.

Methods like high-energy radiation and chemotherapy target rapidly dividing cells.

Mutations can originate from UV radiation, chemical exposure, and genetics among others.

The mechanism regulating the progression of the cell cycle.

Stages in the cell cycle that cannot be reversed, such as DNA replication.

Critical points in the cell cycle that assess and possibly halt progression.

The primary decision point of the cell cycle determining if DNA synthesis can begin.

Factors from the environment that can prompt cell division.

Check that all chromosomes are properly attached to the spindle before separation.

The process by which cells receive signals to start the division.

Chemical signals that instruct cells on actions, often involving proteins.

Protein signals that promote cell growth and division.

A mechanism where kinases add phosphate groups to activate or inactivate cell signals.

Regulatory proteins whose levels cycle during the cell cycle to control progression.

Enzymes that phosphorylate proteins to control the cell cycle stages.

The combination that triggers progression through the cell cycle stages.

A triggering factor that initiates the mitosis phase of the cell cycle.

External proteins that stimulate cell division and coordinate growth between cells.

The phenomenon where crowded cells stop dividing due to limited growth factors.

Requirement for cells to be attached to a substrate to divide.

Normal genes that can become cancer-causing if mutated, stimulating excessive growth.

Genes that inhibit cell division; if inactivated, can lead to cancer.

Cancer results from uncontrolled cell division due to lost regulatory control.