Cell Cycle and Meiosis Quiz
50 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of a cell during interphase?

  • To undergo the final stages of cell division.
  • To initiate the process of DNA condensation.
  • To replicate its chromosomes and prepare for division. (correct)
  • To divide into two daughter cells.

Which of the following best describes the sequence of phases in the cell cycle?

  • G1, S, G2, Mitosis (correct)
  • Mitosis, G1, S, G2
  • S, G1, Mitosis, G2
  • Mitosis, G2, S, G1

During which phase of the cell cycle does DNA replication occur?

  • G1 phase
  • S phase (correct)
  • Mitosis
  • G2 phase

What characterizes the G1 phase of the cell cycle?

<p>Cell growth and synthesis of proteins needed for DNA replication. (B)</p> Signup and view all the answers

If a cell is not actively dividing, in which phase of the cell cycle would it most likely be found?

<p>G0 Phase (B)</p> Signup and view all the answers

Approximately how long does the S phase, where chromosome replication occurs, typically lasts?

<p>7.5-10 hours (C)</p> Signup and view all the answers

What is the consequence of un-replicated areas of DNA during the S phase?

<p>Formation of anaphase bridges. (C)</p> Signup and view all the answers

Which of the following statements is true about observable changes during interphase?

<p>DNA replication cannot be seen under the microscope. (D)</p> Signup and view all the answers

What is the primary function of meiosis I?

<p>Separating homologous chromosomes (B)</p> Signup and view all the answers

During which stage of meiosis I does synapsis occur?

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

What is the consequence of non-disjunction during Anaphase II?

<p>Incorrect separation of sister chromatids (D)</p> Signup and view all the answers

Which event occurs during the pachytene stage of prophase I?

<p>Exchange of DNA between non-sister chromatids (D)</p> Signup and view all the answers

How many cells result from one round of meiosis?

<p>Four haploid cells (C)</p> Signup and view all the answers

Which cyclin is primarily responsible for promoting entry into the cell cycle?

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

What is the name of the complex that forms during synapsis?

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

What is the ploidy of the cells at the end of meiosis I?

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

At which stage of the cell cycle are S-phase cyclins synthesized?

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

What process primarily regulates cyclin levels during the cell cycle?

<p>Ubiquitin-mediated protein degradation (A)</p> Signup and view all the answers

What is the status of the nuclear membrane during diakinesis?

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

Which cyclin is responsible for promoting entry into and progression through mitosis?

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

Which CDK is associated with S-phase cyclins and is directly involved with DNA synthesis?

<p>CDK2 (D)</p> Signup and view all the answers

When do the levels of S-phase cyclins decline?

<p>In early mitosis (C)</p> Signup and view all the answers

Mitotic cyclin-CDK complexes are synthesized during S-phase and G2 phase, but their activity is held in check until what event?

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

Which of the following is NOT a class of cyclins defined by their presence and activity during the cell cycle?

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

What is the main purpose of the M/G1 checkpoint?

<p>To check for proper mitotic spindle assembly and chromosome segregation before cytokinesis. (C)</p> Signup and view all the answers

What are the two main classes of regulatory molecules that control cell cycle progression?

<p>Cyclins and cyclin-dependent kinases (CDKs). (C)</p> Signup and view all the answers

Which cyclin is primarily responsible for coordinating the cell cycle with extracellular signals such as growth factors?

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

What is the role of the Cyclin E-CDK2 complex in the cell cycle?

<p>It triggers the G1-S phase transition, committing the cell to division. (B)</p> Signup and view all the answers

If a cell does not pass a cell cycle checkpoint, what is the most likely outcome?

<p>The cell cycle will be halted to allow for repair or programmed cell death. (B)</p> Signup and view all the answers

What is the significance of the START point in the cell cycle?

<p>It's the point at which cells are irreversibly committed to cell division. (C)</p> Signup and view all the answers

Based on information in the text, which of the following is NOT directly regulated at the M/G1 checkpoint?

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

Which cyclin is known to accumulate during the late G1 phase of the cell cycle?

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

What is the primary role of cyclins in cell cycle regulation?

<p>To bind to and activate cyclin-dependent kinases (CDKs). (A)</p> Signup and view all the answers

How can the activity of the cyclin-CDK complex be modulated?

<p>By phosphorylation and other binding proteins, such as p27. (A)</p> Signup and view all the answers

What is a key function of the retinoblastoma protein (pRb) in the cell cycle?

<p>To prevent excessive cell growth by inhibiting cell cycle progression. (A)</p> Signup and view all the answers

During which phase of the cell cycle would you expect to find cells with twice the DNA content of cells in G1?

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

What is the function of the E2F transcription factor family regulated by Rb?

<p>To play a pivotal role in cell division control. (A)</p> Signup and view all the answers

Which cellular structure is responsible for organizing the microtubules of the mitotic spindle?

<p>The centrosome. (D)</p> Signup and view all the answers

What is the process by which the cyclin controlling a specific cell cycle phase is removed?

<p>Ubiquitination and degradation by proteasomes. (C)</p> Signup and view all the answers

What is the main purpose of mitosis?

<p>To partition replicated chromosomes equally into two daughter cells. (A)</p> Signup and view all the answers

During which phase of mitosis do the nuclear lamina and nuclear pore complexes disassemble?

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

What is a common feature of cells deficient in RB function?

<p>Uncontrolled cell proliferation. (C)</p> Signup and view all the answers

What is the direct product of a primary spermatocyte in spermatogenesis?

<p>Four haploid sperm cells (C)</p> Signup and view all the answers

During oogenesis, at what stage are fetal oocytes arrested until ovulation?

<p>Diplotene of Prophase I (A)</p> Signup and view all the answers

Which cell type is considered a 'static cell' and is known for not undergoing division?

<p>Skeletal muscle cells (A)</p> Signup and view all the answers

Which of the following cell types is classified as a ‘stable cell population’?

<p>Endothelial cells in blood vessels (A)</p> Signup and view all the answers

Which cells are known for their rapid renewal rate?

<p>Epithelial stem cells of the skin (D)</p> Signup and view all the answers

Which of the following is NOT a characteristic of renewing cell populations?

<p>Do not divide after differentiation (D)</p> Signup and view all the answers

What is a key difference between spermatogenesis and oogenesis?

<p>Spermatogenesis occurs continuously, oogenesis arrests at prophase I (D)</p> Signup and view all the answers

Where are the majority of human female future egg cells in the human body at birth?

<p>Held in prophase I of meiosis (B)</p> Signup and view all the answers

Flashcards

Interphase

The period of time during which a cell grows, performs its normal functions, replicates its chromosomes, and prepares for cell division.

Mitosis

The process by which a cell divides into two daughter cells, each containing a complete set of chromosomes.

G1 Phase

The first phase of interphase, during which the cell grows and synthesizes proteins and RNA necessary for DNA replication.

S Phase

The phase of interphase during which DNA replication occurs, resulting in two identical copies of each chromosome.

Signup and view all the flashcards

G2 Phase

The second gap phase of interphase, during which the cell continues to grow and synthesize proteins needed for mitosis.

Signup and view all the flashcards

G0 Phase

A state of temporary or permanent inactivity in which cells are not actively dividing.

Signup and view all the flashcards

Sister Chromatid

A structure that results from the replication of a chromosome, consisting of two identical chromatids joined at the centromere.

Signup and view all the flashcards

Centromere

The constricted region of a chromosome that holds sister chromatids together, and where microtubules attach during mitosis.

Signup and view all the flashcards

M/G1 Checkpoint

A cell cycle checkpoint that takes place in the G1 phase. It ensures the proper assembly of mitotic spindles, prevents premature entry into anaphase, and verifies correct chromosome segregation before allowing the cell to proceed to the next phase.

Signup and view all the flashcards

Cell Cycle Regulators

The molecules responsible for regulating the cell cycle, ensuring it proceeds in a controlled and orderly manner.

Signup and view all the flashcards

Cyclins

A class of proteins that activate cyclin-dependent kinases (CDKs), essential for the progression of the cell cycle.

Signup and view all the flashcards

G1 Cyclins (Cyclin D)

A type of cyclin that is active during the G1 phase of the cell cycle. They work with CDK4 and CDK6 to coordinate the cell cycle with external signals, like growth factors, and promote entry into the cell cycle.

Signup and view all the flashcards

START

The point in the G1 phase where the cell irreversibly commits to cell division. Once a cell passes this point, it cannot return to the G1 state and will continue through the rest of the cell cycle.

Signup and view all the flashcards

G1/S Cyclin (Cyclin E)

A type of cyclin that accumulates during the late G1 phase. It binds to CDK2, forming a complex that triggers the transition from G1 to the S phase.

Signup and view all the flashcards

Cyclin E-CDK 2 Complex

A complex formed by Cyclin E and CDK2. This complex plays a crucial role in initiating the G1-S phase transition by pushing the cell into the S phase, where DNA synthesis takes place.

Signup and view all the flashcards

S-phase Cyclins (Cyclins E and A)

A type of cyclin that is active primarily during the S phase of the cell cycle. They play a crucial role in controlling DNA replication.

Signup and view all the flashcards

Spermatogenesis

The process of meiosis within a spermatogonium that produces four haploid sperm cells from a single primary spermatocyte.

Signup and view all the flashcards

Oogenesis

The process of meiosis within an oogonium that produces a primary oocyte, which then divides into one haploid egg and three polar bodies.

Signup and view all the flashcards

Static cells

These cells are permanently non-dividing and have reached their final functional state. They are often called post-mitotic cells.

Signup and view all the flashcards

Stable cell populations

These cells are typically in the G0 phase and divide slowly to maintain organ structure and function.

Signup and view all the flashcards

Renewing cell populations

These cells are actively dividing, either rapidly or slowly, producing daughter cells or stem cells.

Signup and view all the flashcards

Rapidly renewing cell populations

These cells are rapidly renewing, replenishing cell populations quickly.

Signup and view all the flashcards

Slow renewing cell populations

These cells are slowly renewing, replenishing cell populations at a gradual pace.

Signup and view all the flashcards

Fetal oocytes' status

These cells are held in the diplotene of prophase I until released.

Signup and view all the flashcards

Meiosis I

The first stage of meiosis, which separates homologous chromosomes into two daughter cells.

Signup and view all the flashcards

Meiosis II

The second stage of meiosis, which separates sister chromatids into four daughter cells.

Signup and view all the flashcards

Synapsis

The pairing of homologous chromosomes during prophase I of meiosis, where they align side-by-side.

Signup and view all the flashcards

Crossing Over

The exchange of genetic material between non-sister chromatids of homologous chromosomes during prophase I of meiosis.

Signup and view all the flashcards

Synaptonemal Complex

Specialized protein structures that hold homologous chromosomes together during synapsis in prophase I of meiosis. It allows for proper alignment and crossing over.

Signup and view all the flashcards

Disjunction

The process of separating homologous chromosomes during anaphase I of meiosis.

Signup and view all the flashcards

Non-disjunction

The failure of homologous chromosomes or sister chromatids to separate correctly during meiosis, leading to an abnormal number of chromosomes in the daughter cells.

Signup and view all the flashcards

What are CDKs and what do they need to function?

Cyclin-dependent kinases (CDKs) are protein kinases that require a separate subunit, a cyclin, to function.

Signup and view all the flashcards

What is the role of CDKs in the cell cycle?

Cyclin-dependent kinases (CDKs) are essential for cell cycle regulation, controlling cell division and modulating transcription.

Signup and view all the flashcards

How is the CDK family classified?

The CDK family in mammals is divided into three subfamilies: G1, S-phase, and M-phase CDKs, each associated with a specific cell cycle phase.

Signup and view all the flashcards

When are Cyclin A and Cyclin E synthesized and when do their levels peak?

Cyclin A and Cyclin E are synthesized at the end of G1 phase and their levels remain high throughout S phase.

Signup and view all the flashcards

What is the role of Cyclin A and Cyclin E in the cell cycle?

Cyclin A and Cyclin E trigger S phase and are responsible for DNA replication.

Signup and view all the flashcards

What is the function of Cyclin B?

Cyclin B is a mitotic cyclin that is responsible for promoting entry into and progression through mitosis.

Signup and view all the flashcards

How is the activity of mitotic cyclin-CDK complexes controlled?

The activity of mitotic cyclin-CDK complexes is tightly regulated and held in check until DNA synthesis is complete.

Signup and view all the flashcards

What is the most important regulatory control mechanism for cyclins?

Ubiquitin-mediated protein degradation is the key regulatory mechanism that restricts cyclins to the appropriate cell cycle stage.

Signup and view all the flashcards

Cyclin-dependent kinase (CDK)

A protein kinase that binds to cyclin, forming an active complex essential for controlling the cell cycle.

Signup and view all the flashcards

E2F factors

A protein family that plays a crucial role in cell division control by activating genes required for DNA replication and other cell cycle events.

Signup and view all the flashcards

RB protein

A crucial tumor suppressor protein that prevents uncontrolled cell growth by inhibiting the cell cycle progression.

Signup and view all the flashcards

Prophase

The first phase of mitosis, during which chromatin condenses into chromosomes, the nuclear envelope breaks down, and the mitotic spindle begins to form.

Signup and view all the flashcards

Centrosome

A structure that produces microtubules responsible for forming the spindle fibers that connect to chromosomes during mitosis.

Signup and view all the flashcards

Metaphase

The stage of mitosis where the chromosomes align at the center of the cell, attached to the spindle fibers.

Signup and view all the flashcards

Anaphase

The stage of mitosis where the sister chromatids of each chromosome separate and move to opposite poles of the cell.

Signup and view all the flashcards

Telophase

The final stage of mitosis where the chromosomes uncoil, the nuclear envelope reforms around each set of chromosomes, and the cytoplasm divides.

Signup and view all the flashcards

Study Notes

Cell Cycle and Cell Division

  • The cell cycle is a series of events that take place in a cell as it grows and divides.
  • It's generally divided into two phases: interphase and mitosis.
  • During interphase, the cell spends most of its time performing its unique functions.
  • Mitosis is the phase of the cell cycle during which the cell divides into two daughter cells.
  • Interphase consists of three distinctive phases: G1 (presynthesis), S (DNA replication), and G2 (post-DNA duplication).
  • G0 is a resting state for some cells.
  • There are three main checkpoints in the cell cycle: G₁/S, G₂/M, and M/G₁.
  • Checkpoints ensure that the cell proceeds to the next phase only when the proper requirements of that phase are met.
  • The cell cycle checkpoints are used by the cell to monitor and regulate the progress of the cell cycle.
  • Cell cycle checkpoints are used by the cell to monitor and regulate the progress of the cell cycle.

Overview of Cell Cycle

  • The cell cycle includes the process through which cells replicate and make two new cells.

Stages of Cell Cycle

  • Cells spend most of their time in interphase during which they grow, replicate their chromosomes, and prepare for cell division.
  • The cell then undergoes mitosis, and completes its division.
  • The resulting cells are called daughter cells, and each enters their own interphase.

Cell Cycle Phases

  • G₁ phase: The cell gathers nutrients and synthesizes RNA and proteins required for DNA synthesis and chromosome replication.
  • S phase: DNA synthesis occurs, forming new chromatids. This phase takes about 7.5 to 10 hours. Replication starts at many sites along the chromosome called "replicons".
  • G₂ Phase: The cell examines replicated DNA in preparation for cell division. Cell growth and cytoplasmic organelle reorganization can occur during this phase.

Cell Cycle Control

  • The preparations of the cell are checked by regulatory molecules (proteins).
  • Detection and repair of genetic damage are critical parts of cell cycle regulation.
  • The cell cycle regulation involves two classes of proteins: Cyclins and Cyclin-dependent kinases (CDKs).

Cell Cycle Checkpoints: G1/S, G2/M, and M/G1

  • G₁/S checkpoint: Checks for cell size, nutrients, DNA damage, and proper preparations for DNA replication.
  • G₂/M checkpoint: Checks for proper DNA replication, all preparations required for the M phase, including tubulin synthesis. P53 regulates the progression through the G1 phase to ensure DNA damage can be repaired.
  • M/G₁ checkpoint: Checks the assembly of mitotic spindles, prevents premature entry into anaphase, and checks the chromosome segregation. Checks whether the M phase cyclins and Cdk complex are activated to initiate mitosis.

Cyclins

  • Cyclins are regulatory proteins that determine the activity of CDKs.
  • There are four classes of cyclins: G₁ Cyclins (Cyclin D), G₁/S Cyclin (Cyclin E), the S-phase cyclins (Cyclins E and A), and M-phase cyclins (Cyclin B).
  • The most important regulatory control is ubiquitination-mediated protein degradation.

CDKs

  • CDKs (Cyclin-dependent kinases) are protein kinases.
  • They play important roles, controlling cell division and mediating transcription responses to extra- and intracellular cues.
  • A CDK binds a regulatory protein (cyclin) to become active.
  • CDK activity is also modulated by phosphorylation and other binding proteins.
  • CDKs are divided into sub-families linked to specific cell cycle stages.

Major Cyclin and Cyclin-dependent Kinase Complex Proteins

  • There are examples of target proteins for cyclin complexes, including Phosphorylates Rb protein, which releases E2F. E2F is a transcription factor. E2F activation is critical for several G₁ activities. This complex also regulates many other proteins in the cell cycle.

Mitotic Catastrophe

  • The improper distribution of chromosomes during mitosis can compromise cellular functions, reduce fitness or contribute to malignant transformation.
  • Mitotic catastrophe is an onco-suppressive mechanism of cell death, it precedes apoptosis, necrosis or senescence, and plays an important role in cancer formation and progression.
  • Some drugs (e.g., vinca alkaloids) can induce mitotic catastrophe by affecting microtubule functions.

Cell Division

  • A crucial process for increasing cell numbers, tissue renewal, and wound repair.

Mitosis

  • Mitosis is a form of cell division where replicated chromosomes and their genes are equally partitioned into two identical groups.
  • Mitosis occurs in all somatic cells.
  • Includes: Karyokinesis (division of the nucleus) and Cytokinesis (division of cytoplasm and organelles).
  • Mitosis has 4 phases: Prophase, Metaphase, Anaphase, and Telophase.

Prophase

  • The nucleolus disappears.
  • Replicated chromatin condenses.
  • Centrosomes and duplicated centrioles separate and organize the mitotic spindle.
  • Lamins and inner nuclear membrane are phosphorylated.

Metaphase

  • Chromosomes are condensed further.
  • Chromosome alignment occurs at the metaphase plate.
  • Microtubules move chromosomes into alignment.

Anaphase

  • Sister chromatids separate.
  • Moves towards opposite spindle poles.
  • Microtubule motor proteins cause shortening of the microtubules.

Telophase

  • The two sets of chromatids are at the spindle poles.
  • Microtubules depolymerize.
  • The nuclear envelope reassembles around the chromosomes.
  • A cleavage furrow forms as actin filaments pull the membrane inward.
  • The constriction leads to the final division.

Meiosis

  • Meiosis is a specialized cell division that only occurs in germ cells to produce gametes (sperm and eggs).
  • Meiosis results in four haploid cells that contain half the number of chromosomes as the parent cell.
  • It involves two consecutive cell divisions (Meiosis I and Meiosis II), producing 4 genetically unique cells.
  • Meiosis includes crossing over events that lead to unique combinations of genes.

Spermatogenesis

  • The process of meiosis that produces four haploid sperm cells from one primary spermatocyte.

Oogenesis

  • The process of meiosis that produces one haploid egg (Ovum) and three polar bodies.
  • All primary oocytes (future eggs) are present at birth, arrested at prophase I.

Cell Renewal

  • Static/Non-dividing cells: Do not divide (e.g., central nervous system cells).
  • Stable cell populations (facultative mitotic cells): Divide regularly and slowly (e.g., cells in bone and cartilage).
  • Renewing cell populations (labile cells): Divide frequently (e.g., blood cells).

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Cell Cycle and Cell Division PDF

Description

Test your knowledge on the cell cycle and meiosis with this comprehensive quiz. Explore topics such as interphase, DNA replication, and the phases of meiosis. Challenge yourself to see how well you understand the key concepts involved in cell division.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser