Biology Prophase I and Cell Cycle

<p>To hold sister chromatids together (D)</p> Signup and view all the answers

<p>By facilitating the exchange of DNA between homologous chromosomes (C)</p> Signup and view all the answers

<p>Two homologous chromosomes paired together (B)</p> Signup and view all the answers

<p>It increases the likelihood of multiple recombination events between homologous chromosomes. (B)</p> Signup and view all the answers

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

<p>At the end of the G1 phase (A)</p> Signup and view all the answers

<p>To trigger the pre-replication complex, allowing only one cycle of DNA replication. (C)</p> Signup and view all the answers

<p>It remains inactive during this phase. (A)</p> Signup and view all the answers

<p>Disintegration of the nuclear envelope. (D)</p> Signup and view all the answers

<p>By the removal of phosphate groups by Cdc25 phosphatase. (B)</p> Signup and view all the answers

<p>To accurately duplicate DNA and segregate it into genetically identical daughter cells. (D)</p> Signup and view all the answers

<p>It makes up about 95% of the cell cycle and involves cell growth and DNA replication. (D)</p> Signup and view all the answers

<p>S phase (A)</p> Signup and view all the answers

<p>The cell is in a resting phase due to unsuitable division conditions, and may or may not re-enter the cycle. (B)</p> Signup and view all the answers

<p>To link sister chromatids together after DNA replication. (A)</p> Signup and view all the answers

<p>The cell would not have enough time to double its mass before division, becoming successively smaller. (A)</p> Signup and view all the answers

<p>G2 phase (B)</p> Signup and view all the answers

<p>Division of the nucleus and cytoplasm. (B)</p> Signup and view all the answers

<p>23 (C)</p> Signup and view all the answers

<p>Anaphase (D)</p> Signup and view all the answers

<p>Anaphase I (A)</p> Signup and view all the answers

<p>Disappearance of the nuclear membrane (D)</p> Signup and view all the answers

<p>Meiosis II results in haploid cells, while mitosis results in diploid cells (A)</p> Signup and view all the answers

<p>Checkpoint (C)</p> Signup and view all the answers

<p>DNA damage (D)</p> Signup and view all the answers

<p>20 (C)</p> Signup and view all the answers

<p>Transcription (A)</p> Signup and view all the answers

<p>Division of centromeres (D)</p> Signup and view all the answers

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

<p>The number of chromosomes in the daughter nuclei is half that of the parent cell - reduction (1n) (D)</p> Signup and view all the answers

<p>INK4 proteins, such as p15 and p16. (A)</p> Signup and view all the answers

<p>To bind to and inactivate E-Cdk2 and A-Cdk2 complexes, influencing the cell's decision to enter the G0 phase or start a new cell cycle. (D)</p> Signup and view all the answers

<p>P53 regulates p27 at the transcription stage, influencing its production. (D)</p> Signup and view all the answers

<p>An active process requiring ATP and involving the activation of specific genes. (C)</p> Signup and view all the answers

<p>Necrosis is a random, passive process that does not require energy, whereas apoptosis is an active process requiring energy. (B)</p> Signup and view all the answers

<p>To induce or increase the rate of cell division via signal transduction. (C)</p> Signup and view all the answers

<p>Their expression levels fluctuate significantly throughout the cell cycle. (B)</p> Signup and view all the answers

<p>By ubiquitination and subsequent degradation in the proteasome. (D)</p> Signup and view all the answers

<p>It removes inhibitory phosphate residues from the Cdk, activating the complex. (A)</p> Signup and view all the answers

<p>To phosphorylate Rb protein (pRb), leading to the activation of transcription of genes required for cell cycle progression. (B)</p> Signup and view all the answers

<p>Cyclin A-Cdk2 (S-Cdk) (A)</p> Signup and view all the answers

<p>To inhibit the activity of cyclin-kinase complexes, halting cell cycle progression. (A)</p> Signup and view all the answers

<p>Increased concentrations of the respective cyclin allow the formation of an active cyclin-Cdk complex, which plays a decisive role in a given phase of the cell cycle. (D)</p> Signup and view all the answers

<p>Mitogen-activated protein kinase (MAPK) and phosphatidyl-inositol 3-kinase (PI-3K). (A)</p> Signup and view all the answers

<p>Triggers degradation of M-phase cyclins and securin, leading to sister chromatid separation during anaphase. (C)</p> Signup and view all the answers

Stage in Prophase I where chromatin condenses into chromosomes.

Cells with two sets of chromosomes (2n), e.g., somatic cells.

Cells with one set of chromosomes (1n), e.g., gametes.

Stage where homologous chromosomes pair to form bivalents.

Structure that holds homologous chromosomes together during synapsis.

Cell division producing two identical daughter cells with the same number of chromosomes.

Cell division reducing chromosome number by half, producing four genetically diverse gametes.

Stage where chromosomes further condense and crossing-over occurs.

The phase of the cell cycle where the cell grows and DNA is replicated; makes up 95% of the cycle.

Exchange of genetic material between non-sister chromatids.

The first gap phase where the cell grows and synthesizes proteins and organelles.

Point where homologous chromosomes exchange segments during crossing-over.

The synthesis phase where DNA replication and centrosome duplication occur.

Stage where crossing-over ends and chromosomes start to separate.

The second gap phase for further growth and preparation for mitosis.

Final stage of Prophase I before metaphase, chromosomes are fully condensed.

Resting phase where cells temporarily or permanently stop dividing.

The mitotic phase where karyokinesis and cytokinesis occur, leading to cell division.

Stage in meiosis where bivalents align at the cell's equatorial plane, and spindle fibers attach to homologous chromosomes.

Stage in meiosis where homologous chromosomes are pulled apart to opposite poles of the cell.

Stage where two daughter cells are formed with half the number of chromosomes (1n) due to cytokinesis.

Follows meiosis I without DNA replication, separating sister chromatids into four haploid gametes.

Second meiotic phase where chromosomes condense again and the nuclear envelope disappears.

Stage where sister chromatids line up along the equator and are attached to spindle fibers.

Stage where sister chromatids are pulled apart at the centromere to opposite poles.

Control mechanisms that ensure proper cell progression through the cell cycle, checking for internal/external conditions.

Check during the S phase for DNA damage and replication accuracy before proceeding.

A complex essential for DNA replication initiation at the G1 to S phase transition.

A structure activated by Cyclin A that ensures only one DNA replication cycle occurs during S phase.

A complex of Cyclin B and Cdk1 that pushes cells into mitosis (M phase) but is initially inactive in G2 phase.

An enzyme that activates MPF by removing phosphate groups, enabling the cell to enter M phase.

A phenomenon where activated MPF complexes stimulate further activation of more MPF complexes during M phase.

Proteins that inhibit cyclin-dependent kinases (Cdk), regulating the cell cycle.

A category of Cdk inhibitors that bind to Cdk1, Cdk2, Cdk4, and Cdk6.

Another category of Cdk inhibitors that specifically target Cdk4 and Cdk6.

A KIP inhibitor that decides if a cell starts a new cycle or rests in G0.

Programmed cell death, an active, energy-requiring process for cellular regulation.

A protein that triggers cell division by signaling pathways.

Proteins that regulate the cell cycle by activating CDKs.

Proteins that are activated by cyclins to drive cell cycle progress.

A type of cyclin associated with the G1 phase, activating CDK4 and CDK6.

A complex that helps transition from G1 phase to S phase by phosphorylating proteins.

A cyclin that partners with CDK2 during the S phase for DNA replication.

The process where CDK is activated by cyclins and dephosphorylation.