MBIO flashcards

All 30 cards

1. Card 1

   What is the primary event that occurs during the S phase of the cell cycle?

   During the S phase, DNA replication takes place, resulting in the duplication of the cell's chromosomes. Each chromosome then consists of two identical sister chromatids.

2. Card 2

   Which stage of mitosis is characterized by chromosomes lining up at the cell's equator?

   Metaphase is the stage of mitosis where chromosomes align themselves along the metaphase plate, which is the imaginary equator of the cell.

3. Card 3

   Define a 'replicated chromosome'.

   A replicated chromosome consists of two identical chromatids joined together at a centromere. This structure forms after DNA replication during the S phase of the cell cycle.

4. Card 4

   What is the 'centromere' in the context of chromosomal structure?

   The centromere is the constricted region on a replicated chromosome where the two identical sister chromatids are attached. It plays a crucial role in chromosome segregation during cell division.

5. Card 5

   Which of the following describes the 'Anaphase' stage of mitosis? A. Chromosomes condense and the nuclear membrane breaks down. B. Chromosomes line up in the center. C. Sister chromatids are pulled apart. D. Nuclear membranes reform around chromosomes.

   C. Sister chromatids are pulled apart. In Anaphase, the sister chromatids separate and move to opposite poles of the cell.

6. Card 6

   What is the main event that occurs during 'Telophase' in mitosis?

   During Telophase, nuclear membranes reform around the separated chromosomes at each pole of the cell. This leads to the formation of two distinct nuclei.

7. Card 7

   How does 'Cytokinesis' differ in plant and animal eukaryotic cells?

   Cytokinesis does not occur the same way in all eukaryotic cells. While animal cells form a cleavage furrow to divide the cytoplasm, plant cells form a cell plate that grows outwards to create a new cell wall.

8. Card 8

   What are 'oncogenes' and what is their role in cell growth?

   Oncogenes are genes that stimulate cell growth. When mutated, they can contribute to uncontrolled cell division and the development of cancer.

9. Card 9

   Distinguish between 'oncogenes' and 'tumor suppressor genes'.

   Oncogenes stimulate cell growth, and their overactivity can lead to cancer. In contrast, tumor suppressor genes stop cell division and initiate programmed cell death, acting as brakes on cell growth.

10. Card 10

    What is 'apoptosis' and how do cancer cells avoid it?

    Apoptosis is programmed cell death, a normal process for eliminating damaged or unnecessary cells. Cancer cells avoid apoptosis despite having mutations, allowing them to proliferate unchecked.

11. Card 11

    True or False: The process of mitosis creates two daughter cells from one parent cell.

    True. Mitosis is a form of cell division that results in two daughter cells, each having the same number and kind of chromosomes as the parent nucleus.

12. Card 12

    True or False: DNA replication occurs during prophase of mitosis.

    False. DNA replication occurs during the S phase of Interphase, which precedes mitosis, not during prophase of mitosis.

13. Card 13

    What is the primary difference between Meiosis I and Meiosis II in terms of chromosome separation?

    Meiosis I separates homologous chromosomes, resulting in two haploid cells with duplicated chromosomes. Meiosis II, similar to mitosis, separates sister chromatids, leading to four haploid cells with unduplicated chromosomes.

14. Card 14

    During which specific stage of meiosis does 'crossing over' occur?

    Crossing over occurs during Prophase I of meiosis. This process involves the exchange of genetic material between homologous chromosomes.

15. Card 15

    What is the final result of meiosis in terms of cell number and genetic makeup?

    The final result of meiosis is four genetically different haploid cells. These cells each contain half the number of chromosomes as the original parent cell.

16. Card 16

    True or False: Meiosis always produces four, genetically identical daughter cells.

    False. Meiosis produces four genetically *different* daughter cells due to processes like crossing over and independent assortment of homologous chromosomes.

17. Card 17

    Which of the following correctly describes the separation of sister chromatids in meiosis? A. They separate during Anaphase I. B. They separate during Prophase II. C. They separate during Anaphase II. D. They separate during Telophase I.

    C. They separate during Anaphase II. Sister chromatids are pulled apart and move to opposite poles during Anaphase II of meiosis.

18. Card 18

    What is the term for a local mass of cancer cells?

    A local mass of cancer cells is called a tumor. This is an abnormal growth of tissue resulting from uncontrolled cell division.

19. Card 19

    What is 'metastasis' in the context of cancer?

    Metastasis is the process by which cancer cells spread from their original source to other parts of the body. This allows cancer to invade new tissues and organs.

20. Card 20

    Why is interphase considered the largest portion of the cell cycle?

    Interphase is the largest portion because it includes the G1, S, and G2 phases, during which the cell grows, replicates its DNA, and prepares for division. These preparatory stages take significantly longer than mitosis itself.

21. Card 21

    What is an 'unreplicated chromosome'?

    An unreplicated chromosome consists of a single chromatid. This is the state of a chromosome before DNA replication occurs during the S phase of the cell cycle.

22. Card 22

    True or False: The daughter cells from mitosis have fewer chromosomes than the parent cell.

    False. The daughter cells from mitosis have the *same number* of chromosomes as the parent cell, ensuring genetic continuity.

23. Card 23

    What are 'carcinogens'?

    Carcinogens are substances that cause cancer by inducing mutations that change the DNA sequence of genes related to cell growth.

24. Card 24

    True or False: Somatic cells of humans are haploid, while gametic cells are diploid.

    False. Somatic cells of humans are diploid (containing two sets of chromosomes), while gametic cells (sperm and egg) are haploid (containing one set of chromosomes).

25. Card 25

    What is the memory tactic associated with 'Prophase' in mitosis, and what happens during this stage?

    The memory tactic for Prophase is 'Prepare'. During this stage, chromosomes condense and become visible, the nuclear membrane breaks down, and the spindle apparatus begins to form.

26. Card 26

    Define the primary purpose of meiosis.

    The primary purpose of meiosis is the production of gametes (sperm and egg cells). It ensures that these reproductive cells are haploid and genetically diverse, which is essential for sexual reproduction.

27. Card 27

    During which phase of meiosis does crossing over occur?

    Crossing over occurs during Prophase I of meiosis. This process involves the exchange of DNA between homologous chromosomes, leading to new gene combinations.

28. Card 28

    Which of the following is a key difference between the daughter cells produced by mitosis and meiosis? A. Mitosis produces haploid cells, while meiosis produces diploid cells. B. Mitosis produces genetically identical cells, while meiosis produces genetically different cells. C. Mitosis results in 4 daughter cells, while meiosis results in 2 daughter cells. D. Mitosis is for gamete production, while meiosis is for growth and repair.

    B. Mitosis produces genetically identical cells, while meiosis produces genetically different cells. Mitosis creates two identical diploid daughter cells, whereas meiosis creates four genetically different haploid daughter cells.

29. Card 29

    How many cell divisions occur during meiosis?

    Meiosis involves two successive cell divisions: Meiosis I and Meiosis II. Meiosis I separates homologous chromosomes, and Meiosis II separates sister chromatids.

30. Card 30

    Explain why genetic variability is important for populations.

    Genetic variability is crucial for populations because it helps them adapt and survive environmental changes, resist diseases, and evolve over time. This diversity increases the chances that some individuals will possess traits beneficial for survival in changing conditions.

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